Parasitology - Exam 1

What is Chilomastix mesnili and Retortamonas intestinalis? Where do they live? What do they cause?

Chilomastix mesnili is a non-parasitic[1] member of primate gastrointestinal microflora, commonly associated with but not causing parasitic infections. Live in the cecum and colon; similar to giardia with no effect. Retortamonas intestinalis is a species of retortamonads which is found in the gastrointestinal tract. Similar to giardia. Commensalism

How are ecology and epidemiology similar and different?

Ecology is the relations of organisms to one another and to their physical surroundings. Epidemiology is concerned with all ecological aspects of a disease to explain its transmission, distribution, prevalence, and incidence.

Compare and differentiate the classes Rhombozoa and Orthonectida. What are Rhombozoans? Where would you look for one?

Rhombozoans also known as dicyemida are a type of mesozoan that parasitize the renal organs of cephalopods such as squid. Orthonectida are mesozoans that parasitize brittle stars and other marine invertebrates.

What are Hypnozoites and why are they important? Which two species possess these?

Exoerythrocytic schizozoite of Plasmodium vivax or P. ovale in the human liver, characterized by delayed primary development; thought to be responsible for malarial relapse.

Describe an example how deliberate government programs can exacerbate transmission of malaria. How can they help?

"Blanket" spraying programs especially in areas with year-round mosquitoes can become costly and ineffective and even detrimental as it can produce mosquitoes that are resistant to insecticides. Insecticide bed net programs can select in favor of exophilic mosquitoes and actually increase transmissions outside the homes. Government detection and treatment programs have helped reduce cases of malaria, however. In areas where malaria is recognized quickly and treated, transmission of malaria remains rare or non-existent.

Dollo's law of irreversibility

"an organism never returns exactly to a former state, even if it finds itself placed in conditions of existence identical to those in which it has previously lived ... it always keeps some trace of the intermediate stages through which it has passed."

Manter's rules

(1) Parasites evolve more slowly than their hosts; (2) the longer the association with a host-group, the more pronounced the specificity exhibited by the parasite group; (3) a host species harbors the largest number of parasite species in the area where it has resided longest, so if the same or two closely-related species of host exhibit a disjunct distribution and possess similar parasite faunas, the areas in which the hosts occur must have been contiguous at a past time.

Define and differentiate the following sets of terms. coelozoic and histozoic

Coelozoic - inhabiting a cavity of an animal's body. Histozoic - living in the tissues of a host.

Discuss the action of antibodies.

A basic antibody molecule consists of four polypeptide strands: two identical light chains and two identical heavy chains held together in a Y-shape. The variation in the fork of the Y-shape determine which antigen will bind to the antibody. Antibodies can function in several ways: Opsonization - foreign particles become coated with IgG antibodies and are engulfed by a macrophage. Neutralization - IgG and IgM bind to the toxins to prevent them from binding to their target cells. Activation of complement - can activate a series of innate enzyme release sequences where they can be phagocytized. Antibody-dependent, cell-mediated cytotoxicity - binds to the surface of an invader and trigger a contact kill by the host cells.

Naegleria fowleri: Write a short (1 paragraph) public service announcement. You will want to include who needs to be prepared for this parasite, and what they should do to prevent infection. Make sure to include enough detail so the reader will clearly know if they or their pets need to worry about the parasite, and if they need to worry what should they do to prevent infection?

Naegleria is an ameba (single-celled living organism) commonly found in warm freshwater (for example, lakes, rivers, and hot springs) and soil. Only one species (type) of Naegleria infects people: Naegleria fowleri. Rarely found in the US. The early symptoms of Naegleria fowleri infection are similar to those caused by other more common illnesses, such as bacterial meningitis . People should seek medical care immediately whenever they develop a sudden onset of fever, headache, stiff neck, and vomiting, particularly if they have been in warm freshwater recently. Personal actions to reduce the risk of Naegleria fowleri infection should focus on limiting the amount of water going up the nose and lowering the chances that Naegleria fowleri may be in the water.

Define chronic trypanosomiasis. What causes it?

Trypanosoma brucei gambiense is found in 24 countries in west and central Africa. This form currently accounts for 97% of reported cases of sleeping sickness and causes a chronic infection. A person can be infected for months or even years without major signs or symptoms of the disease.

What is Hexamita meleagridis? What is it similar to? What is the host?

a protozoan parasite of turkeys, pheasants, pigeons, and some game birds. Similar to giardia because flagellated with teardrop shape.

A parasite that is not normally found in that host is called a/an ______________ parasite. Parasites that come and go from a host like a tick are called _______________ parasites.

accidental/incidental; temporary/intermittent

The host where the parasite reaches sexual maturity is the ____________ host. Any animal that can transmit a parasite to humans is a/an _______________ host.

definitive; reservoir

The study of factors responsible for the transmission and distribution of a disease is ______________________.

epidemiology

Defense mechanisms that do not depend on prior exposure to a parasite are called _______________ immunity.

innate immunity

Draw the lifecycle of Entamoeba histolytica. What does it cause? Describe treatment and prevention of this disease. Describe mortality rates due to this disease.

1. Cysts and trophozoites excreted in feces. 2. mature cycts ingested. Causes amoebic dysentery or amoebiasis. For prevention you can also make tap water safe for drinking by filtering it through an "absolute 1 micron or less" filter and dissolving chlorine, chlorine dioxide, or iodine tablets in the filtered water; treatment stay hydrated and take Flagyl (metronidazole). If it reaches fulminant amoebic colitis mortality is 55-87.5%.

Draw the lifecycle of Plasmodium spp. What does it cause? What are the four species that humans can host? Which is the most virulent?

1. Mosquito takes a blood meal and injects sporozoites that travel to the liver where schizonts are formed. 2. The schizont ruptures and immature trophozoites infect RBC (ring stage). 3. The trophozoite matures and produces a schizont that ruptures OR creates gametocytes that are ingested by a feeding mosquito. 4. Within the mosquito, the gametocytes mature into oocysts that rupture and releasae sporozoites. Causes malaria. Vivax, malariae, ovale, and falciparum. Falciparum is most virulent.

Draw the lifecycle of Naegleria fowleri. What does it cause?

1. cyst in the water transforms into a trophozoite 2. person in the water has amoeba penetrate the nasal mucosa. 3. amoeba migrates to the brain via the olfactory nerve and cause primary amoebic meningocencephalitis.

Describe accidental and natural transmission factors for malaria.

Accidental - mother to fetus, blood transfusions, shared needles Natural - mosquito bite, reservoir hosts

What are opportunistic parasites? Give three specific examples.

An opportunistic infection is an infection caused by pathogens (bacteria, viruses, fungi, or protozoa) that take advantage of an opportunity not normally available, such as a host with a weakened immune system, an altered microbiota (such as a disrupted gut flora), or breached integumentary barriers. Ex. Staph, salmonella, toxoplasma

What is Babesia bigmina? What does it cause? What is the vector? Differentiate between Babesia bigmina, B. microti, and Theileria parva?

Babesia bigemina is a species of alveolates belonging to the phylum Apicomplexa and the family Babesiidae. In cattle, it causes babesiosis, also called "Texas red-water fever". Red colored urine. Tick vector Boophilus annulatus. All have a tick vector with variation in genus and species. B.b and T.p have little significance to human health, while B. microti infects humans. Red urine in B.b. Flu like symptoms in T.p and B. m.

Differentiate between the following sets of taxa. Balantidium coli, Babesia bigemina, Ichthyophthirius spp. and Myxobolus cerebralis.

Balantidium coli - Balantidium coli, though rare in the US, is an intestinal protozoan parasite that can infect humans. These parasites can be transmitted through the fecal-oral route by contaminated food and water. Balantidium coli infection is mostly asymptomatic, but people with other serious illnesses can experience persistent diarrhea, abdominal pain, and sometimes a perforated colon. Babesia bigemina - Members of the genus Babesia are Apicomplexan parasites commonly referred to as the 'piroplasms'. They have a two-host life-cycle involving a tick and a mammal. In the mammalian host the organisms reproduces asexually. Out of at least six Babesia species that have a considerable impact on livestock health and productivity, two species, Babesia bovis and Babesia bigemini have the greatest affect. Both are transmitted by Boophilus species as tick vectors Ichthyophthirius - endoparasite of freshwater fish which causes a disease commonly known as white spot disease, or ich.[1] Ich is one of the most common and persistent diseases in fish. It appears on the body, fins and gills of fish as white nodules of up to 1 mm, that look like white grains of salt. Each white spot is an encysted parasite. Myxobolus cerebralis - myxosporean parasite of salmonids (salmon, trout, and their allies) that causes whirling disease in farmed salmon and trout and also in wild fish populations. Whirling disease afflicts juvenile fish (fingerlings and fry) and causes skeletal deformation and neurological damage.

Define and differentiate the following sets of terms. Ciliophora, Paramecium, dimorphic nuclei, cytostome, kinetodesma, trichocysts, and toxicysts

Ciliophora - a phylum or subphylum of protozoans that possess cilia during some phase of the life cycle and usually have nuclei of two kinds Paramecium - a single-celled freshwater animal that has a characteristic slipperlike shape and is covered with cilia. Dimorphic nuclei - special characteristic of having two different kinds of nuclei in a cell Cytostome - cell mouth is a part of a cell specialized for phagocytosis, usually in the form of a microtubule-supported funnel or groove. Kinetodesma - Longitudinally oriented cytoplasmic fibrils associated with and always on the right of, the kinetosomes of ciliates. Trichocysts - any of numerous minute, rodlike structures, each containing a protrusible filament, found near the surface of ciliates and dinoflagellates. Toxicysts - an organelle which resembles a trichocyst but in which the filament carries a poison that can kill other protozoa

Differentiate between the following sets of taxa. Cryptosporidium parvum and Pneumocystis carinii.

Cryptosporidium parvum - one of several species that cause cryptosporidiosis, a parasitic disease of the mammalian intestinal tract. Primary symptoms of C. parvum infection are acute, watery, and nonbloody diarrhea. C. parvum infection is of particular concern in immunocompromised patients, where diarrhea can reach 10-15 l per day. Other symptoms may include anorexia, nausea/vomiting, and abdominal pain. caused by ingestion of sporulated oocysts transmitted by the faecal-oral route. Pneumocystis carinii - causes respiratory manifestations, cough, fever; uses cysts and trophozoites

A student returns from a trip to India and develops the following sore. What parasite do you suspect? ___________________________ How would you diagnose and then treat the parasitic infection? _______________________

Cutaneous leishmania. Diagnosis with a skin biopsy, stain, and view. Treat using supportive care and wound treatment because often times heals on own. Can use ketoconizole.

Draw the microstructure of a cilium and compare the microtubules and dynein arms. Compare the structure and function of flagella and compare them with cilia. Explain how they are used in several kingdoms and phyla.

Dynein is a family of cytoskeletal motor proteins that move along microtubules in cells. They convert the chemical energy stored in ATP to mechanical work. Dynein transports various cellular cargos, provides forces and displacements important in mitosis, and drives the beat of eukaryotic cilia and flagella. Cilia are short and there are usually many (hundreds) cilia per cell. On the other hand, flagella are longer and there are fewer flagella per cell (usually one to eight). Though eukaryotic flagella and motile cilia are structurally identical, the beating pattern of the two organelles can be different.

Differentiate epidemic, pandemic, endemic, and incidence.

Epidemic - a widespread occurrence of an infectious disease in a community at a particular time. Pandemic - (of a disease) prevalent over a whole country or the world. Endemic - (of a disease or condition) regularly found among particular people or in a certain area. Incidence - the occurrence, rate, or frequency of a disease, crime, or something else undesirable.

What are Gregarines? What did early biologists call them?

Gregarines are a diverse group of apicomplexan parasites that inhabit the intestines, coeloms and reproductive vesicles of marine, freshwater and terrestrial invertebrates. Were originally called parasitic worms.

Differentiate between the following sets of taxa. Haemoproteus and Leucocytozoon.

Haemoproteus - a genus of alveolates that are parasitic in birds, reptiles and amphibians. The protozoa are intracellular parasites that infect the erythrocytes. They are transmitted by blood sucking insects including mosquitoes, biting midges (Culicoides), louse flies (Hippoboscidae) and tabanid flies (Tabanidae). Leucocytozoon - a genus of parasitic alveolates belonging to the phylum Apicomplexa. use blackflies (Simulium species) as their definitive host and birds as their intermediate host.

Differentiate between the following sets of taxa. Hepatozoon catesbianae, Eimeria tenella, and Cyclospora cayetanensis.

Hepatozoon catesbianae - Hepatozoon is a genus of Apicomplexa alveolates which incorporates over 300 species obligate intraerythrocytic parasites. Hepatozoonosis, therefore, results when an animal eats an infected tick - the disease is not spread by tick bites. Eimeria tenella - a species of Eimeria that causes hemorrhagic cecal coccidiosis in young poultry. Cyclospora cayetanensis - a protozoan that causes disease in humans, and perhaps primates. It has been linked in the United States to fecally contaminated imported produce. he health risk associated with the disease is usually confined to adult foreigners visiting regions where the species is endemic and acquiring the infection; consequently, C. cayetanensis is a cause of "traveler's diarrhea".

What is Histomonas meleagridis? What is the host? What does it cause? Describe the annual loss due to this parasite.

Histomonas meleagridis is species of parasitic protozoan that infects the ceca and liver of a wide range of birds including chickens, turkeys, peafowl, quail and pheasants, causing infectious enterohepatitis, or histomoniasis (blackhead dieases). Turkey mortality estimated at $2 million

Describe Malaria relapse. How does it compare to recrudescence? Which species are capable of each?

Relapse can occur in vivax and ovale because of hypnozoites that hang around in the liver dormant. Recrudescence is simply when you don't get rid of all the organisms and it takes some time before they build back up in number and symptoms begin to show again. This can occur in any of the species, but malariae is known to be in the blood the longest with some recorded at 50+ years.

What are microsporidians? Are they intracellular or extracellular parasites? What is the function of their polar filaments? Do they prefer invertebrates or vertebrate hosts? Describe how they can be opportunistic parasites of humans and which populations are most at risk.

The Microsporidia constitute a group of spore-forming unicellular parasites. They are intracellular. In the spore, the polar tube is connected at the anterior end, and then coils around the sporoplasm. Upon appropriate environmental stimulation the polar tube rapidly discharges out of the spore pierces a cell membrane and serves as a conduit for sporoplasm passage into the new host cell. Tend to parasitize parasitic flatworms. Microsporidia have emerged as causes of infectious diseases in AIDS patients, organ transplant recipients, children, travelers, contact lens wearers, and the elderly.

Discuss the work of Flegr on Toxoplasma on human behavior and traffic accidents.

The subjects with latent toxoplasmosis have significantly increased risk of traffic accidents than the noninfected subjects. Relative risk of traffic accidents decreases with the duration of infection. These results suggest that 'asymptomatic' acquired toxoplasmosis might in fact represent a serious and highly underestimated public health problem, as well as an economic problem. Decreased motor performance, impaired learning capacity, slower reaction times.

Differentiate between the following sets of taxa. Toxoplasma gondii, Leishmania, Cryptosporidium, and Giardia lamblia

Toxoplasma gondii -obligate intracellular, parasitic alveolate that causes the disease toxoplasmosis. most go unnoticed with some showing flu like symptoms. Leishmania - genus of trypanosomes that are responsible for the disease leishmaniasis. spread by sandflies Cryptosporidium - apicomplexan parasite that causes the diarrheal disease cryptosporidiosis. can live in the intestine of humans and animals and is passed in the stool of an infected person or animal Giardia lamblia - a flagellated parasite that colonizes and reproduces in the small intestine, causing giardiasis

What parasite causes African Sleeping Sickness? ___________________ a. What is the vector of this disease? ________________________ b. If you suspected Sleeping Sickness in a patient how would you attempt to diagnose it? ________________________________

Trypanosoma brucei Tsetse fly Diagnose via a blood smear and look for the organisms in the extracellular space. Look for a sore caused by the bite wound.

Describe the life cycle of Encephalitozoon cuniculi. What does it cause?

a eukaryotic organism belonging to the phylum Microsporidia, in the kingdom Fungi.[2] An obligate intracellular parasite, E. cuniculi occurs in laboratory mice and rabbits, monkeys, dogs, rats, birds, guinea pigs, and other mammals including humans. The infective form of microsporidia (E. cuniculi) is a resistant spore which can survive for a long time in the environment. The spore extrudes its polar tubule and infects the host cell. The spore injects the infective sporoplasm into the eukaryotic host cell through the polar tubule. Inside the cell, the sporoplasm undergoes extensive multiplication. This multiplication occurs either by merogony (binary fission) or schizogony (multiple fission). Microsporidia develop by sporogony to mature spores in the cytoplasm or inside parasitophorous vacule. During sporogony, a thick wall is formed around the spore. The thick wall formed provides resistance to adverse environmental conditions. Once the spores increase in number and completely fill the cytoplasm of the host's cell, the cell membrane is disrupted and releases the spores to the surroundings. These free mature spores can infect new cells thus continuing the cycle.

What is Nosema apis? What is the host? Describe the annual loss due to this parasite.

a microsporidian, a small, unicellular parasite recently reclassified as a fungus that mainly affects honey bees. It causes nosemosis, also called nosema, which is the most common and widespread of adult honey bee diseases.

Compare and contrast epidemiology and epizootiology.

epidemiology - the branch of medicine that deals with the incidence, distribution, and possible control of diseases and other factors relating to health. epizootiology - a science that deals with the character, ecology, and causes of outbreaks of animal diseases.

Differentiate between the following sets of taxa. formaniferans, heliozoans, and radiolarians

formaniferans - members of a phylum or class of amoeboid protists characterized by: streaming granular ectoplasm for catching food and other uses; and commonly an external shell (called a "test") of diverse forms and materials. Heliozoans - microbial eukaryotes (protists) with stiff arms (axopodia) radiating from their spherical bodies, which are responsible for their common name. radiolarians - protozoa of diameter 0.1-0.2 mm that produce intricate mineral skeletons, typically with a central capsule dividing the cell into the inner and outer portions of endoplasm and ectoplasm.The elaborate mineral skeleton is usually made of silica.

Differentiate between microsporidians and myxozoans.

microsporidians - a group of spore-forming unicellular parasites. myxozoans - a group of aquatic, obligately parasitic cnidarian animals.

Define and differentiate the following sets of terms. pseudopodia, endoplasmic stream, lobopodia, filopodia, and ectoplasmic tube

pseudopodia - a temporary protrusion of the surface of an amoeboid cell for movement and feeding. endoplasmic stream - lobopodia - a blunt limb, or an organ resembling a limb, in particular. filopodia - a long, slender, tapering pseudopodium, as found in some protozoans and in embryonic cells. ectoplasmic tube - mation of pseudopods. Another function of ectoplasm in certain amoebae is for food ingestion. When the food comes in contact of an amoeba cell, the ectoplasm forms a tube called ectoplasmic tube, takes the food into it

Draw life cycles for the following parasites; Dirofilaria immitis.

1. A mosquito takes a blood meal from a dog and L3 larvae enter the bite wound. *infective stage* 2. Adults mature in the pulmonary arteries and produce microfillariae that can be found in peripheral blood. 3. Another mosquito takes a blood meal and the microfillariae penetrate the mosquito's midgut and migrate to the Malpighian tubules. 4. In the tubules, they mature through L1 larvae into L3 larvae. At which point they migrate to the head and proboscis of the mosquito. *L3 larvae can be injected into humans; rare, but doesn't cause many issues.

Draw life cycles for the following parasites; Toxoplasma gondii

1. A rat or bird containing tissue cysts is consumed by a cat. The cat then excretes a fecal oocyst. 2. This can then infect swine and sheep in the form of a tissue cyst, which infects people who consume undercooked meat. 3. From the fecal oocyst phase it could also travel to a human via contaminated food, water, or from cleaning the litter box. 4. Both 2 and 3 could then result in tissue cycts and congenital infections. *Blood transfusions from infected organisms could also spread the parasite*

Draw the lifecycle of Toxoplasma gondii. What does it cause? What is the main concern for humans? How is it treated? How can it be prevented?

1. A rat or bird containing tissue cysts is consumed by a cat. The cat then excretes a fecal oocyst. 2. This can then infect swine and sheep in the form of a tissue cyst, which infects people who consume undercooked meat. 3. From the fecal oocyst phase it could also travel to a human via contaminated food, water, or from cleaning the litter box. 4. Both 2 and 3 could then result in tissue cycts and congenital infections. *Blood transfusions from infected organisms could also spread the parasite* A single-celled parasite called Toxoplasma gondii causes a disease known as toxoplasmosis. Most people who become infected with Toxoplasma gondii are not aware of it. Some people who have toxoplasmosis may feel as if they have the "flu" with swollen lymph glands or muscle aches and pains that last for a month or more. Concern in pregnant women. Cook meat thoroughly. Peel and wash fruits and veg. Freeze meat to sub zero. Wash hands, cutting boards, and utensils.

Discuss six types of innate immunity.

1. Cell signaling - molecules from the external environment bind to receptors on the cells' surface, resulting in initiation of intracellular signal cascades; can trigger transcription factors, gene regulation, phagocytosis, or secretions. 2. Cytokines are protein hormones that play important roles in immune response and are a major form of cell communication. Trigger transcription factors. 3. Antimicrobial Molecules - important on the surface where organism meets the environment; not highly specific, effective against type of microbe (gram + or -); are peptides; immediate with no prior exposure required. 4. GPIs - glycolipids that are only found in eukaryotic cell membranes; serve as anchors for proteins on membranes; interact with host immune systems and have pathogenic effects. 5. Other - low pH, antimicrobial enzymes, parasiticidal substances in mucous (IgA), and lysozyme (attacks bacteria cell walls). 6. Phagocytes - engulfment of an invading particle within an invagination of the phagocyte's cell membrane.

Draw life cycles for the following parasites; Naegleria fowleri

1. Cyst in the water 2. Infective trophozoite in the water 3. Flagellated form in the water 4. Person comes in contact when engaging in water-related activities and the amebae penetrate the nasal mucosa. 5. Amebae migrates to the brain via the olfactory nerves causing primary amebic meningoencephalitis.

Draw life cycles for the following parasites; Spirocerca lupi

1. Eggs are eaten by coprophagic beetles, where they hatch to produce larvae. 2. Dogs eat the beetles or eat other animals that have ingested the beetles. 3. In the dog, the larvae migrate through the stomach wall via the blood vessels to the aortic arch where they mature into adult worms. 4. Adult worms migrate to the esophagus where the produce nodules and lay their eggs. 5. Eggs are then passed in the dog's feces.

Outline the general life cycle of malarial organisms with names of several stages. Name the genus of the organism that causes malaria. Where in the world should you be concerned about malaria? How can it be prevented? What explains the resurgence of malaria in recent years?

1. Mosquito takes a blood meal and injects sporozoites that travel to the liver where schizonts are formed. 2. The schizont ruptures and immature trophozoites infect RBC (ring stage). 3. The trophozoite matures and produces a schizont that ruptures OR creates gametocytes that are ingested by a feeding mosquito. 4. Within the mosquito, the gametocytes mature into oocysts that rupture and releasae sporozoites. Plasmodim are the genus that cause malaria. Malaria occurs in more than 100 countries with about 1/2 the world's population being at risk. Mainly African, Eurasia, and South America. To prevent malaria, avoid getting bitten by mosquitos when at all possible. Also check with your health care provider about malaria prevention tablets if travelling to an area where risk is high. Resurgence could be attributed to a variety of things including less widespread use of pesticides with an increase in mosquito numbers (DDT).

Draw the lifecycle of Trypanosoma brucei brucei. What does it cause in humans? What is the vector? Where specifically can you find these vectors?

1. Tsetse fly takes a blood meal and injects metacyclic trypomastigotes which transform in the bloodstream and multiply via binary fission. 2. The tsetse fly then takes another blood meal and ingests trypmastigotes from the blood. These transform into procyclic trypomastigotes in the midgut. 3. The procyclic transform into epimastigotes and head to the salivary glands where they multiply and become metacyclic trypomastigotes. This sub species does not effect humans. The vector is the tsetse fly. Found in rural areas of sub-Saharan Africa

Draw the lifecycle of Giardia. What does it cause? How is it treated? How can it be prevented? Why is it interesting phylogenetically and metabolically? What common organelle do they lack?

1. trophozoites are passed in stool where they form a cyst 2. food or water is contaminated with cyst 3. cyst ingested by human Causes giardiasis usually characterized by abdominal cramps, bloating, nausea, and diarrhea. Can be diagnosed via stool tests. Flagyl (metronidazole) can be used to treat. Avoid eating or drinking items that could be contaminated. Follow proper sanitation guidelines (washing hands). Filter or boil water. They lack mitochondria, peroxisomes, and components for oxidative phosphorylation.

How does homoplasy obscure monophyletic relationships?

A homoplasy is a character shared by a set of species but not present in their common ancestor. This could lead to taxa being grouped together that actually are not closely related. This would then result in a polyphyletic group which has little validity. Monophyletic groups are discovered by assessing patterns of synapomorphy, which is the evidence that allows us to recognize them. Homoplasy, in this regard, is simply patterns of character distribution that add extra steps to the most parsimonious tree because the features appear to arise more than once, or to be gained and then lost, in various taxa.

Do parasites evolve into more or less virulent forms? Why?

A long-established paradigm states that parasites should evolve into less virulent forms, mainly because death of a host should have a negative effect on parasite survival. However, they could evolve to a point of optimal virulence where maximum parasite numbers are achieved. Theoretically vertical transmission selects for less virulent while horizontal transmission selects for more virulent strains.

What are Protozoans? Are they animals? Then why are we studying them?

A single-celled microscopic animal of a group of phyla of the kingdom Protista, such as an amoeba, flagellate, ciliate, or sporozoan. They exhibit animal characteristics such as mobility and heterotrophy. We study them because many of them take on parasitic life styles such as plasmodiums or giardias.

Toxoplasma gondii: Write a short (1 paragraph) public service announcement. You will want to include who needs to be prepared for this parasite, and what they should do to prevent infection. Make sure to include enough detail so the reader will clearly know if they or their pets need to worry about the parasite, and if they need to worry what should they do to prevent infection?

A single-celled parasite called Toxoplasma gondii causes a disease known as toxoplasmosis. While the parasite is found throughout the world, more than 60 million people in the United States may be infected with the Toxoplasma parasite. Of those who are infected, very few have symptoms because a healthy person's immune system usually keeps the parasite from causing illness. However, pregnant women and individuals who have compromised immune systems should be cautious; for them, a Toxoplasma infection could cause serious health problems. Most people who become infected with Toxoplasma gondii are not aware of it. Some people who have toxoplasmosis may feel as if they have the "flu" with swollen lymph glands or muscle aches and pains that last for a month or more. Severe toxoplasmosis, causing damage to the brain, eyes, or other organs, can develop from an acute Toxoplasma infection or one that had occurred earlier in life and is now reactivated. Severe cases are more likely in individuals who have weak immune systems, though occasionally, even persons with healthy immune systems may experience eye damage from toxoplasmosis. Individuals most at risk areInfants born to mothers who are newly infected with Toxoplasma gondii during or just before pregnancy. Persons with severely weakened immune systems, such as individuals with AIDS, those taking certain types of chemotherapy, and those who have recently received an organ transplant.If you suspect that you may have toxoplasmosis, talk to your health care provider. There are several general sanitation and food safety steps you can take to reduce your chances of becoming infected with Toxoplasma gondii. Cook food to safe temperatures. A food thermometer should be used to measure the internal temperature of cooked meat. Freeze meat for several days at sub-zero (0° F) temperatures before cooking to greatly reduce chance of infection. Peel or wash fruits and vegetables thoroughly before eating. Wash cutting boards, dishes, counters, utensils, and hands with hot soapy water after contact with raw meat, poultry, seafood, or unwashed fruits or vegetables. Wear gloves when gardening and during any contact with soil or sand because it might be contaminated with cat feces that contain Toxoplasma. Wash hands with soap and water after gardening or contact with soil or sand. Teach children the importance of washing hands to prevent infection.

What is epidemiology?

A study concerned with all ecological aspects of a disease to explain its transmission, distribution, prevalence, and incidence.

What is sickle-cell anemia? How does it relate to the topics covered in this course? Make sure to include a discussion of the disease, how it is passed, and the selection mechanisms that drive this pattern in human populations. Include statistics in your discussion so it is clear who might be more likely to have this. Discuss the symptoms, detection, and treatment for each form.

A switch from glutamic acid to valine results in an abnormality in the oxygen-carrying protein haemoglobin (haemoglobin S) found in red blood cells.[2] This leads to a rigid, sickle-like shape under certain circumstances. Due to the shape of the misformed RBC parasites such as malaria either cannot inhabit the cell or take a much longer time to reach full infection. Sickle cell is genetic and passed down from parents. Those that are homozygous for the disease will have mostly sickle shaped cells and usually die before they are 30. Those that are heterozygous for the disease will have a mixture of regular and misformed RBCs and have an 85-95% resistance to malaria. Due to the resistance to malaria, this trait has been naturally selected for in Africa because those are the individuals that survive and are able to reproduce. About 80% of sickle cell disease cases occur in sub-Saharan Africa and is fairly frequent in India, Arabian peninsula, and those of African origin. Symptoms of sickle cell include vaso-occlusion, chest pain, anemia, and respiratory issues. These usually begin in childhood and worsen as the individual ages. Blood tests can be done to detect haemoglobin levels and smears can be performed to look at RBC shape. Various treatments are available with varying results. L-glutamine is the current drug of choice starting at the age of 5 which can help decrease complications.

Outline four common protozoan parasites that might cause diarrhea. Make sure to discuss the biogeography, symptoms, epidemiology, diagnosis, and treatment for each. Then design a traveler's medical kit that includes diagnostic tools, treatments and instructions for each of the four common parasites. Make sure the instructions are clear and simple so a buyer that contracts diarrhea, can diagnosis and treat themselves and return to the U.S. parasite free.

Ameobic dysentery - caused by Entamoeba histolytica; common in people in tropical areas with poor sanitation conditions; can be ingested with an item that has touched feces of someone infected or drinking water that contains the organism; only 15% infected become sick; incubation 2-4wks; symptoms: diarrhea, stomach pain and cramping; diagnosis can be difficult but would be performed using a stool sample; You can also make tap water safe for drinking by filtering it through an "absolute 1 micron or less" filter and dissolving chlorine, chlorine dioxide, or iodine tablets in the filtered water; treatment stay hydrated and take Flagyl (metronidazole). Sleeping sickness - caused by microscopic parasites of the species Trypanosoma brucei. It is transmitted by the tsetse fly (Glossina species), which is found only in rural Africa; the fly bite is often painful and can make a sore; symptoms include headaches, extreme fatigue, swollen lymph nodes, and aching muscles; neurological problems may also develop; incubation 1-3wks; skin biopsy, blood tests, and spinal tap can be forms of diagnosis; wear protective clothing, take insect repellent, wear neutral colored clothing, avoid bushes and shrubs; treatment is difficult and depends on type of infection (gambiense or rhodesiense) and stage of the disease, can use pentamidine for early infections. Malaria - Malaria is a serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of mosquito which feeds on humans. People who get malaria are typically very sick with high fevers, shaking chills, and flu-like illness. Although malaria can be a deadly disease, illness and death from malaria can usually be prevented. Malaria is a serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of mosquito which feeds on humans. People who get malaria are typically very sick with high fevers, shaking chills, and flu-like illness. Although malaria can be a deadly disease, illness and death from malaria can usually be prevented. The World Health Organization estimates that in 2016 malaria caused 216 million clinical episodes, and 445,000 deaths. Among the malaria species that infect humans, P. vivax and P. ovale can develop dormant liver stages that can reactivate after symptomless intervals. The first symptoms of malaria (most often fever, chills, sweats, headaches, muscle pains, nausea and vomiting) are often not specific and are also found in other diseases (such as the "flu" and common viral infections). Likewise, the physical findings are often not specific (elevated temperature, perspiration, tiredness). In severe malaria (caused by Plasmodium falciparum), clinical findings (confusion, coma, neurologic focal signs, severe anemia, respiratory difficulties) are more striking and may increase the index of suspicion for malaria. If possible, clinical findings should always be confirmed by a laboratory test for malaria. Various forms of quinine partnered with doxycycline or clindamycin can be used to treat, can also treat with chloroquine. Primaquine works against the hypnozoites and prevents relapse. Giardia- Giardiasis can be spread by: Swallowing Giardia picked up from surfaces (such as bathroom handles, changing tables, diaper pails, or toys) that contain feces (poop) from an infected person or animal Drinking water or using ice made from water sources where Giardia may live (for example, untreated or improperly treated water from lakes, streams, or wells) Swallowing water while swimming or playing in water where Giardia may live, especially in lakes, rivers, springs, ponds, and streams Eating uncooked food that contains Giardia organisms Having contact with someone who is ill with giardiasis Traveling to countries where giardiasis is common Anything that comes into contact with feces (poop) from infected humans or animals can become contaminated with the Giardia parasite. People become infected when they swallow the parasite. It is not possible to become infected through contact with blood. Giardia infection can cause a variety of intestinal symptoms, which include: Diarrhea, Gas or flatulence, Greasy stool that can float, Stomach or abdominal cramps, Upset stomach or nausea, Dehydration, strong smell of sulfur; To prevent and control infection with the Giardia parasite, it is important to: Practice good hygiene, Avoid water (drinking or recreational) that may be contaminated, Avoid eating food that may be contaminated, Prevent contact and contamination with feces (poop) during sex; Flagyl (metronidazole) can be used as a treatment.

Define the parasite. Use appropriate vocabulary from lecture to describe the parasite.

An organism that lives in or on another organism (its host) in a symbiotic relationship. The organism benefits by either harming or in some sense living at the expense of the host.

Define and differentiate the following sets of terms. antigens, antibodies, somatic antigens, and metabolic antigens

Antigens - a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies. Antibodies - a blood protein produced in response to and counteracting a specific antigen. Antibodies combine chemically with substances that the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood. Somatic antigens - A somatic antigen is an antigen located in the cell wall of a gram-positive or gram-negative bacterium. Metabolic antigens - secretory antigens

Support the statement, "The gregarine Ophryocystis elektroscirrha parasite influences Danaus plexippus (host) migratory behavior. Hint: Research Altizer, Bartel, and Han 2011 in Science 331:296-302.

Because parasite prevalence reaches a peak during the monarch's reproductive period, they migrate to get away from the parasites and increase reproductive success. (migratory escape). Those infected with the parasite flew shorter distances with reduced flight speeds meaning that the infected ones would get left behind and not spread the parasite to the new location (migratory culling). Longer migration distances cull monarchs carrying virulent parasite genotypes.

Define several types of asexual reproduction.

Binary fission - most frequent; one individual divides into two. Multiple fission (merogony, schizogony) - in amoebas and Apicomplexa; nucleus and essential organelle divide repeatedly before cytokinesis; produce lots of daughter cells simultaneously; Schizont is mother cell, Merozoites are daughter cells all at same developmental phase. Multiple fission (sporogony) - meiosis immediately following the union of gametes; completely different life cycle stages. Budding (plasmotomy) - division of multinucleate cells into two or more multinucleate cells. Budding (external) - uneven division Budding (internal/endopolyogeny) - same as schizogony except have their own membranes inside mother cell.

Compare T. b. rhodesiense and T. b. gambiense with T. b. brucei? How can they be diagnosed? How are they treated? What are the side effects of the commonly used drugs? Discuss the epidemiology and pathogenesis of each of the three subspecies.

Brucei doesn't effect people while the others do; Usually effects ruminants. Gambiense and Rhodesiense cause African sleeping sickness. All are extracellular and live in the blood, lymph, and spleen. Rhodesiense rarely invades nervous system; slower death Gambiense invades nervous system and causes true sleeping sickness. Can diagnose using a blood smear. Treatment - drugs can cause eye damage, resistant strains, not good prognosis if gambiense, can use melarsoprol in late stages but could kill patient. Control the vectors; graze herds at night; use pesticides such as DDT to kill the flies. T.b.b - in cattle (can be resistant), swine are reservoir hosts, causes death 15 days to 4mo. T.b.r - quick death, swollen lymph, fever, pain T.b.g - invades nervous system, apathy, mental dullness, paralysis, sleepiness.

What is Chagas' disease? What causes it? Where is it a concern? How is it treated?

Caused by the parasite Trypanosoma cruzi from kissing bug vector, which is transmitted to animals and people by insect vectors that are found only in the Americas (mainly, in rural areas of Latin America where poverty is widespread). Chagas disease (T. cruzi infection) is also referred to as American trypanosomiasis. Benznidazole can be used for treatment in early stages, but later stages can only be slowed. Other treatments depend on a lot of variations.

Define and differentiate the following sets of terms. cyclodevelopmental transmission, propagative transmission, and cyclopropagative transmission

Cyclodevelopmental transmission - Insect borne filarial parasites are the only examples of this type of transmission. Microfilarial parasites ingested by the vector with the blood meal undergo development to 3 rd stage larvae (L3) before being transferred back to another vertebrate host. Propagative transmission - the agent multiplies in the transmission vehicle. Cyclopropagative transmission - the agent undergoes both development and multiplication in the transmitting vehicle.

What is the parasitologist's dilemma?

Decreasing the numbers of parasites will lead to increases in human population. This can in turn overburden resources if a lower birth rate is not also implemented. If you start saving people, something else has to be done to limit populations and their growth. Animals don't have this problem because they disperse and act territorially and often don't compete for the exact same resources.

Define and differentiate the following sets of terms. definitive host, intermediate host, paratenic host, vector, reservoir host, and hyperparasitism

Definitive host - an organism that supports the adult or sexually reproductive form of a parasite. Intermediate host - an organism that supports the immature or nonreproductive forms of a parasite. Paratenic host - An intermediate host whose presence may be required for the completion of a parasite's life cycle but in which no development of the parasite occurs. Vector - an organism, typically a biting insect or tick, that transmits a disease or parasite from one animal or plant to another. Reservoir host - A host that serves as a source of infection and potential reinfection of humans and as a means of sustaining a parasite when it is not infecting humans. Hyperparasitism - a parasite whose host is itself also a parasite.

You sample 10 mice and find 10 worms in the gut of one mouse and no worms in the other 9. What is the density of this worm? _________ What is the prevalence of this worm? __________

Density = 1 worm/mouse; Prevalence = 1/10 or 10%

You sample 100 mice and find 20 worms in the gut of one mouse, 80 worms in the gut of another mouse and no worms in the other 98. What is the density of this worm? _________ What is the prevalence of this worm? __________

Density = 1 worm/mouse; Prevalence = 2/100 or 2%

Discuss the difference between parasite density and parasite prevalence.

Density is the average number of parasites per host. Prevalence is what percent of the hosts are infected. For instance, ten animals could be in a population with three that have two parasites each. The density for that population would be 6/10 or 60%. The prevalence would be 3/10 or 30%.

Describe several mechanisms protozoans use to transport materials in and out of the cell through the cell membrane.

Diffusion - the net passive movement of particles (atoms, ions or molecules) from a region in which they are in higher concentration to regions of lower concentration. Osmosis - a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane. Active transport - the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy. Passive transport - movement of ions and other atomic or molecular substances across cell membranes without need of energy input. Carrier-assisted transport - A membrane transport protein (or simply transporter) is a membrane protein involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane. ... The proteins may assist in the movement of substances by facilitated diffusion or active transport. Vesicle-mediated transport - A cellular transport process in which transported substances are moved in membrane-bounded vesicles; transported substances are enclosed in the vesicle lumen or located in the vesicle membrane.

How do we distinguish the terms for Germ layers; ectoderm, mesoderm, and endoderm? How are these terms relevant to parasitology?

Ectoderm - the outermost layer of an embryo in early development; skin, nerves Mesoderm - the middle layer of an embryo in early development Endoderm - innermost layer of an embryo in early development; gut lining

Define and differentiate the following sets of terms. ectoparasites, endoparasites, obligate parasites, and facultative parasites

Ectoparasites - a parasite, such as a flea, that lives on the outside of its host. Endoparasites - a parasite, such as a tapeworm, that lives inside its host. Obligate parasites - a parasitic organism that cannot complete its life-cycle without exploiting a suitable host. Facultative parasties - an organism that may resort to parasitic activity, but does not absolutely rely on any host for completion of its life cycle.

What is encystment? What triggers it? Give several examples.

Encystment also helps the microbe to disperse easily, from one host to another or to a more favorable environment. When the encysted microbe reaches an environment favorable to its growth and survival, the cyst wall breaks down by a process known as excystation. Unfavorable environmental conditions such as lack of nutrients or oxygen, extreme temperatures, lack of moisture and presence of toxic chemicals, which are not conducive for the growth of the microbe trigger the formation of a cyst.

Then name four additional protozoa that are parasitic on humans and the mechanism of transmission to the human host.

Entamoeba histolytica - fecal/oral Giardia - ingestion of cysts in water or food or fecal/oral Leishmania - bite of infected female sandfly Balantidium coli - fecal/oral

What is prevalence?

Fraction or percentage of a host species infected at a given time.

What is ecological immunity and how does it apply to parasitology?

Immunity derived from interactions with the environment. For instance, a person that does not consume pork would likely not be at risk of contracting a round worm, tapeworm, or Toxoplasma gondii from undercooked pork.

Dirofilaria immitis: Write a short (1 paragraph) public service announcement. You will want to include who needs to be prepared for this parasite, and what they should do to prevent infection. Make sure to include enough detail so the reader will clearly know if they or their pets need to worry about the parasite, and if they need to worry what should they do to prevent infection?

In companion animals, HW infection is diagnosed primarily in dogs and less commonly in cats and ferrets. HW disease has been reported in most countries with temperate, semitropical, or tropical climates, including the USA, Canada, Australia, Latin America, and southern Europe. In companion animals, infection risk is greatest in dogs and cats housed outdoors. Although any dog or cat, indoor or outdoor, is capable of being infected, most infections are diagnosed in medium- to large-sized, 3- to 8-yr-old dogs living outside. Infected mosquitoes are capable of transmitting HW infections to people, but there are no reports of such infections becoming patent. In dogs, infection is ideally identified by serologic testing before onset of clinical signs. Clinical signs of HW infection, such as coughing, exercise intolerance, unthriftiness. Infected cats may be asymptomatic or exhibit intermittent coughing, dyspnea, heart failure, vomiting, lethargy, anorexia, or weight loss. Heartworm infection is generally completely preventable with macrolide prophylaxis. Year-round prevention is advised. Preventive therapy in dogs is recommended beginning at 6-8 wk of age.

Define and differentiate the following sets of terms. incidental parasite, permanent parasite, intermittent parasite, and parasitoids

Incidental parasite - parasites that establish themselves in or on a host in which they do not normally live; example dog flea biting a human. Permanent parasite - one which lives its entire life within or on its host. Intermittent parasite - It is one which only visits its host to feed on it and then leaves. Parasitoids - an insect (e.g., the ichneumon wasp) whose larvae live as parasites that eventually kill their hosts (typically other insects).

Define and differentiate the following sets of terms. indirect or heteroxenous and direct or monoxenous life cycles

Indirect/heteroxenous life cycles - infesting more than one kind of host; especially : requiring at least two kinds of host to complete the life cycle —used of various parasites (as the malaria parasites or the liver flukes). Direct/monoxenous life cycles - requiring only one host to complete the life cycle.

Define and differentiate the following sets of terms. infection, disease, pathogen, virulence

Infection - the process of infecting or the state of being infected Disease - a disorder of structure or function in a human, animal, or plant, especially one that produces specific signs or symptoms or that affects a specific location and is not simply a direct result of physical injury. Pathogen - a bacterium, virus, or other microorganism that can cause disease. Virulence -the severity or harmfulness of a disease or poison.

Spirocerca lup: Write a short (1 paragraph) public service announcement. You will want to include who needs to be prepared for this parasite, and what they should do to prevent infection. Make sure to include enough detail so the reader will clearly know if they or their pets need to worry about the parasite, and if they need to worry what should they do to prevent infection?

Infections are seen in southern areas of the USA as well as in many tropical and subtropical regions worldwide (eg, Greece, India, Israel, Japan, South Africa). Most dogs with S lupi infection show no clinical signs, but when signs are present, they most commonly include weight loss and coughing. In endemic areas, dogs should be prevented from eating dung beetles, frogs, mice, lizards, etc, and not fed raw chicken scraps.

Define and differentiate the following sets of terms. infrapopulation and microenvironments

Infrapopulation - A subpopulation of the parasite bound to a single host organism Microenvironment - the immediate small-scale environment of an organism or a part of an organism, especially as a distinct part of a larger environment.

Describe the two arms of immune response.

Innate - found in all organisms to some degree; a mechanism of defense that does not depend on prior exposure to the invader. Adaptive - also called acquired; specific to the particular nonself material, requires time for development, and occurs more quickly and vigorously on second exposure.

Define and differentiate the following sets of terms. innate immunity and acquired immunity

Innate immunity - non-specific immune system or in-born immunity system Acquired immunity - Immunity obtained either from the development of antibodies in response to exposure to an antigen, as from vaccination or an attack of an infectious disease, or from the transmission of antibodies

Differentiate between isolate, strain, and subspecies. Use the example of Trypanosoma brucei to show why intraspecific diversity matters.

Isolates - innumerated or labeled with greek letter because it is an example that is separate than others but cannot be crossed to prove same species; mainly asexual. Strain - a genetic variant or subtype of a microorganism (e.g., virus or bacterium or fungus). Subspecies - a taxonomic category that ranks below species, usually a fairly permanent geographically isolated race. T.b.b - only effect cattle T.b.g - effects nervous system, chronic, true sleeping sickness T.b.r - quick death, high fever

Harrison's rule

Large-bodied species of hosts often harbor large-bodied parasites.

What is Leishmania? What causes it? What is the vector? Differentiate between Cutaneous and Visceral Leishmaniasis? How is it diagnosed and treated?

Leishmaniasis is a disease caused by parasites of the Leishmania type. It is spread by the bite of certain types of sandflies. The disease can present in three main ways: cutaneous, mucocutaneous, or visceral leishmaniasis. Cutaneous usually causes lesions on the face and groin. Leishmania donovani causes visceral infections, endema, breathing difficulty, and diarrhea. Usually found in Africa and South America. Lab samples can be performed such as skin samples from lesions or from bone marrow. Blood tests can be done for antibodies. Treatment - cutaneous doesn't have to be treated, heals on own but could use general wound care using ketoconazole; visceral requires treatment which varies with numerous factors, includes supportive care, Liposomal amphotericin B

Discuss how malnutrition exacerbates effects of parasitic infections.

Malnutrition is already putting a tax on the body, often times putting it a compromised states. This makes it easier for a lot of parasites to take advantage. Parasitic infections exacerbate malnutrition by the parasite taking something from the host, most of the time some kind of nutrients which are in limited supply in these nutritional deficiency situations. This can be especially detrimental in situations where the only food available is high in carbs such as rice and that is primarily what the parasite is stealing from the host. This means that all of their nutrients go to the parasite rather than nourishing their body.

Define and differentiate the following sets of terms. mechanical and biological vectors

Mechanical vector - a vector that conveys pathogens to a susceptible individual without essential biologic development of the pathogens in the vector, as in the transfer of septic organisms on the feet or mouth parts of the housefly. Biological vector - a carrier, especially the animal (usually an arthropod) that transfers an infective agent from one host to another. Examples are the mosquito that carries the malaria parasite Plasmodium between humans, and the tsetse fly that carries trypanosomes from other animals to humans.

What are metagenomics studies? Give some examples where they are relevant to study parasites in general.

Metagenomics is the study of genetic material recovered directly from environmental samples. Fecal analysis could be used as a metagenomic technique to show presence of intestinal parasites.

Define and differentiate the following sets of terms. microparasites and macroparasites

Microparasites - parasite that is short-lived, smaller than other parasites, and reproduces within its host Macroparasites - parasites that are large enough to be seen with the naked eye, in contrast to microparasites. They grow in one host but reproduce by infective stages outside this host.

Define and differentiate the following sets of terms. monophyletic, paraphyletic, and polyphyletic

Monophyletic - (of a group of organisms) descended from a common evolutionary ancestor or ancestral group, especially one not shared with any other group. Paraphyletic - (of a group of organisms) descended from a common evolutionary ancestor or ancestral group, but not including all the descendant groups. Polyphyletic - (of a group of organisms) derived from more than one common evolutionary ancestor or ancestral group and therefore not suitable for placing in the same taxon.

Are protozoan cells more or less complex than the cells of multi-cellular organisms? Why?

More complex because all of their life sustaining processes must occur within that one cell. There is no option of specialization where a cell can be focused on one task.

Why have there been many origins of parasitic species from free-living ancestors, but relatively few examples of parasites evolving to become free-living?

Parasites specialized to become completely dependent on their host; this often led to loss of ability to be free living via form and function changes. In most instances there would be no reason for the organism to go back to free-living when it can mooch off the host species still. The more specialized the parasite becomes, the more difficult it is to regain autonomy.

Eichler's rule

Parasites tend to be highly specific to their hosts, thus it seems reasonable to expect a positive co-variation between the taxonomic richness of hosts and that of their parasites. It is one of the first three coevolutionary rules.

Define and differentiate the following sets of terms. plesiomorphic and apomorphic

Plesiomorphic - Ancestry trait that can be found in both ingroups and outgroups. Not species defining. Apomorphic -A novel evolutionary trait that is unique to a particular species and all its descendants and which can be used as a defining character for a species or group in phylogenetic terms.

Define and differentiate the following sets of terms. hard and soft polytomies

Polytomy is a term for an internal node of a cladogram that has more than two immediate descendents Hard polytomies - represent the literal hypothesis that a common ancestral population split through cladogenesis (i.e., speciation) into multiple lineages. Soft polytomies - depicts a polytomy in a cladogram is not really expecting that the same ancestor gave rise to all daughter taxa, but is uncertain which resolved pattern is the best hypothesis.

Describe three drugs that can be used for malaria prophylaxis. Are there any health concerns, resistance concerns or side effects? If so describe them.

Primaquine and chloroquine in vivax and ovale; Chloroquine only in malariae and falciparum. Some resistance to chloroquine and Fansidar (drug to combat chloroquine resistance). Methoquine is good for multi-drug resistant strains of falciparum. Use mefloquine if able, if not use daily doxycycline. Mefloquine can cause neurological issues as well as have psychiatric effects.

What is similar and different between cilia and flagella? What is the fuel or energy for them?

Same: used to move liquid past the cell surface, used for cell movement, made of 9+2 microtubule structure, both cylindrical shaped tubes, only found in animals Cilia: eukaryotic cells, move materials past immobile cells, shorter, many cilia on one organism; hair like Flagella: true flagella in prokaryotic cells, made of proteins, longer, usually only 1 -3 flagella, whip like Prokaryotic flagella use a proton-motive force or ion gradient across the cell membrane as energy. ATP is used by cilia and some eukaryotic flagella.

Discuss the similarities and differences between Giardiasis and Amoebic Dysentery.

Similarities: both cause diarrhea, can be treated using flagyl, must be ingested usually via contaminated water or food due to poor sanitary conditions, both organisms are protozoans Differences: giardiasis is cause by Giardia while amoebic dysentery is caused by Entamoeba histolytica, amoebic dysentery is usually associated with bloody diarrhea while giardia is just watery; giardia will have a strong smell of sulfur; giardia rarely exhibits a fever while dysentery does.

Define and differentiate the following sets of terms. social parasites, brood parasites, protelean parasites and cleptoparasites

Social parasite - taking advantage of interactions between members of a social species; butterfly larvae that mimic to parasitize ants. Brood parasite - organisms that rely on others to raise their young. Ex. cowbird Protelean parasite - organisms are those that begin the growing phase of their lives as parasites, and in particular, typically as internal parasites. As a rule they end that phase of their lives parasitoidally by killing or consuming the host, and then they emerge as free-living adults; flies used to control fire-ants Cleptoparasite - one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food (as in the case of cuckoo bees, which lay their eggs on the pollen masses made by other bees.

Emery's rule

Social parasites among insects (e.g., kleptoparasites) tend to be parasites of species or genera to which they are closely related.

Define and differentiate the following sets of terms. Stramenopila, Alveolata, Rhizaria, Archaeplastida

Stramenopila - large, heterogeneous group of protists that share tubular mastigonemes that branch into three fine filaments. Parasitic forms often found in the intestines of organisms. Alveolata - superphylum of stramenopila that have micropores and membranous pellicular vesicles or alveoli. Rhizaria - super-group of ciliophora that have axopodia or simple, branching, or anastomosing filopodia. Archaeplastida - A taxonomic kingdom of the domain Eukaryota that includes land plants, green algae, red algae, and glaucophytes

Define and differentiate the following sets of terms. symbiosis, phoresis, mutualism, commensalisms, parasitism, and mycorrhizal epiparasitism

Symbiosis - interaction between two different organisms living in close physical association. Phoresis - a form of symbiosis where the symbiont, termed the phoront, is mechanically transported by its host. Mutualism - symbiosis that is beneficial to both organisms involved. Commensalism - an association between two organisms in which one benefits and the other derives neither benefit nor harm. Parasitism - A symbiotic relationship in which one organism (the parasite) benefits and the other (the host) is generally harmed. Mycorrhizal epiparasitism - a symbiotic association between a fungus and the roots of a vascular host plant; one parasitic species is parasitized by another to which it is related.

Define and differentiate the following sets of terms. systematics, taxonomy, cladistics, phylogeny, and cladogram

Systematics - an initiative to study systems from a holistic point of view. Taxonomy - the branch of science concerned with classification, especially of organisms; often synonymous with systematics Cladistics - a method of classification of animals and plants according to the proportion of measurable characteristics that they have in common. Phylogeny - the evolution of a genetically related group of organisms as distinguished from the development of the individual organism Cladogram - a branching diagram showing the cladistic relationship between a number of species.

Describe the life cycle of Trypanosoma brucei complex, T. evansi, and T. cruzi. Compare and contrast the epidemiology of these species.

T.b - 1. Tsetse fly takes a blood meal and injects metacyclic trypomastigotes which transform in the bloodstream and multiply via binary fission. 2. The tsetse fly then takes another blood meal and ingests trypmastigotes from the blood. These transform into procyclic trypomastigotes in the midgut. 3. The procyclic transform into epimastigotes and head to the salivary glands where they multiply and become metacyclic trypomastigotes. T.c - 1. kissing bug takes a blood meal and trypomastigotes enter bite wound or mucosal membrane. 2. metacyclic trypomastigotes penetrate cells and become amastigotes which divide via binary fission in tissues. 3. Intracellular amastigotes transform into trypomastigotes and burst out of cell into blood stream. 4. Kissing bug ingests and it develops in the bug through epimastigotes into metacyclic trypomastigotes.

How do we distinguish the terms Taxonomy, Paraphyletic, Monophyletic, Polyphyletic, and Metazoans? How do Monophyletic, Paraphyletic, and Polyphyletic taxa differ? How do these differences affect the validity of such taxa for both evolutionary and cladistic taxonomies?

Taxonomy -study of the principles of scientific classification; ordering and naming organisms Paraphyletic - a group of taxa that includes a hypothetical ancestor but does not include all that ancestor's descendants Monophyletic - a group of taxa that includes a hypothetical ancestral taxon and all its descendents Polyphyletic - a group of taxa that do not share a common ancestor, hypothetical or otherwise. Metazoans - a group that comprises all animals having the body composed of cells differentiated into tissues and organs and usually a digestive cavity lined with specialized cells. Monophyletic would be the most trustworthy grouping because it contains all of the organisms that are related within the taxa. Next would be paraphyletic because it contains the common ancestor but lacks furthering in terms of descendants. The least valid would be the polyphyletic because it is essentially a random grouping of animals that don't share ancestry of any type.

Why is cell membrane important? What composes it? Are membranes flexible or stiff?

The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. The basic function of the cell membrane is to protect the cell from its surroundings. It consists of the phospholipid bilayer with embedded proteins. The plasma membrane is a fluid mosaic. This means that it is flexible and made up of many different types of molecules. Phospholipids form the basic structure of a cell membrane, called the lipid bilayer. Scattered in the lipid bilayer are cholesterol molecules, which help to keep the membrane fluid consistent.

Describe the example of phoresis between Neolithodes grimaldi and Poecilasma kaempferi. Discuss this interaction and propose an evolutionary mechanism strengthening this relationship.

The gooseneck barnacle attaches to the legs and carapace of the crab. The crab then moves around and carries the barnacles along. Could be considered commensalism because the barnacles could accrue some type of benefit. The two species could have coevolved, so that they have traits designed to attach to one another or could have developed specialty mechanisms to help them hold on to the host.

Define the host. Use appropriate vocabulary from lecture to describe the host.

The host is the body or environment in which a parasite resides and participates in a type of symbiosis. Definitive hosts: one in which the parasite reaches sexual maturity. Intermediate hosts: one required for parasite development but the parasite does not reach sexual maturity. Transport (paratenic) hosts: parasite does not develop but remains alive and infective to another host. Reservoir host: animal that harbors an infection that can be transmitted to humans. Hyperparasitism: parasites hosting one another.

Fahrenholtz's rule

The hypothesis that in groups of permanent parasites the classification of the parasites corresponds directly with the natural relationships of their hosts. For example, closely related species of mammals are generally parasitized by closely related species of lice.

Szidat's rule

The more primitive the host, the more primitive the parasites it harbours

Discuss Darwin's concept of the tree of life and a modern alternative that takes into account horizontal gene transfer.

The tree of life or universal tree of life is a metaphor, model and research tool used to explore the evolution of life and describe the relationships between organisms, both living and extinct, as described in a famous passage in Charles Darwin's On the Origin of Species (1859). The term phylogeny for the evolutionary relationships of species through time was coined by Ernst Haeckel, who went further than Darwin in proposing phylogenic histories of life. In contemporary usage, tree of life refers to the compilation of comprehensive phylogenetic databases rooted at the last universal common ancestor of life on Earth. All trees will be subject to error due to the nature of the research, yet HGT throws a wrench in the works. Recent studies have been using several genes or genomic comparison to connect organisms based on their genomic percentage similarities.

How do parasites evade immunological effects?

There are a variety of methods for evading immunological effects of the hosts' immune system. Organisms such as Plasmodium falciparum use polymorphisms and anergy of T cells that allow them to avoid an immune response all together or alter function of memory T cells. Other organisms such as Leishmania evade detection by repressing the MHC 2 gene which prevents antigen presentation or induces production of chemicals that cause immunosupression.

Summarize the depth of suffering caused by tropical parasites. Despite the great suffering caused by these infections, discuss why pharmaceutical research is scarce compared to cancer research.

There are more than enough existing parasites for every living person to have one or more. Some of the common parasites are schistosomes and malaria with 200 mil and 500 mil infections and 20 mil and 40 thousand deaths per year respectively. The majority of the more serious infections occur in tropical regions, particularly in less-developed countries. This can be exacerbated by nutritional deficiencies often seen in these 3rd world countries. While a lot of people are effected, the money simply isn't put into research cures or preventatives because drug companies are reluctant to spend money to develop drugs for treating people who probably don't have the money to pay for it. $543 per cancer case; $0.004 per schistosomiasis case

Describe two types of immunodiagnosis.

There are numerous choices on the market. Indirect hemagglutination (IHA) - RBC are coated with parasite antigen and incubated with the patient's serum. Agglutination of the blood cells indicates the presence of the antibody in the test serum. Enzyme-linked immunosorbent assay (ELISA) - a small quantity of antigen is adsorbed to the bottom of a well in a micropalte. Then the test serum is added to the well. The serum is then removed and the well rinsed several times. If the serum contained antibodies to the antigen, they will have bound to the antigen and will not be removed by rinsing and will usually produce a color.

Discuss how asexual reproduction and hermaphroditism increase reproductive potential and why it is important.

They can eliminate the necessity of finding an individual of the opposite sex for fertilization/reproduction. This increases the chance of a mating and therefore increases the chance of offspring. This could be handy in situations where organisms were extremely isolated or if a population was limited by something such as endangerment or relocation.

Describe experimental studies that prove T. brucei is not just a collection of isolated clones but that these clones are unified by sexual recombination events. Hint: it involves the same colors as street lights.

To visualize the production of hybrids in the fly, parental trypanosome clones were transfected with a gene encoding Green Fluorescent Protein (GFP) or Red Fluorescent Protein (RFP). Co-infection of flies with red and green fluorescent parental trypanosomes produced yellow fluorescent hybrids, which were easily visualized in the fly salivary glands. The strategy of using production of yellow hybrids to indicate mating in trypanosomes provides a robust and unequivocal system for analysis of genetic exchange. Mating occurred with high frequency in these experimental crosses, limited only by the ability of both parental trypanosomes to invade the salivary glands. Yellow hybrids appeared as soon as trypanosomes invaded the salivary glands, implicating the short, unattached epimastigote as the sexual stage.

What is the public-health importance of Toxoplasma, and how do humans become infected with it?

Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii. Infections with toxoplasmosis usually cause no symptoms in adult humans. It is characterized in humans by a few weeks or months of mild flu-like illness such as muscle aches and tender lymph nodes. In some cases, ocular complications may also develop. The mild symptoms may progress to seizures and in coordination in movements in patients with weaker immune response. The condition of congenital toxoplasmosis proves fatal for carrying mothers during pregnancy. Toxoplasmosis can be transmitted to humans by three principal routes. First, humans can eat raw or inadequately cooked infected meat or eat uncooked foods that have come in contact with contaminated meat. Second, humans can inadvertently ingest oocysts that cats have passed in their feces, either in a cat litter box or outdoors in soil (e.g., soil from gardening or unwashed fruits or vegetables). Third, a woman can transmit the infection to her unborn fetus.

Describe the four aspects that need to be studied in order to understand the epidemiology of a parasite.

Transmission = how its passed Distribution = where it is located Prevalence = what is the infection rate Incidence = rate of new infections

Discuss two specific examples of how behavioral attributes can increase a species chances for encountering new hosts.

Trematodes infect land snails as first intermediate hosts and insectivorous birds as definitive hosts. The sporocysts move into the snail's tentacles and create a pulsating band of color that could attract birds. Some thorny headed worms infect freshwater crustaceans. These worms appear as white or orange spots within the clear crustacean and make them stand out from the uninfected ones.

What is Phoresis?

Using the host as a mode of transportation; a form of symbiosis where the phoront is mechanically carried by its host. Could be loosely considered parasitism because the parasite gets a free ride, while the host is slightly harmed by the added weight that expends additional energy and potential drag that the parasites cause.

What are zoonoses?

a disease that can be transmitted to humans from animals

What is "Blackwater fever" and what causes it? What is the mortality rate?

a severe form of malaria in which blood cells are rapidly destroyed, resulting in dark urine. Blackwater fever seldom appears until a person has had at least four attacks of malaria and has been in an endemic area for six months. Treatment for blackwater fever includes antimalarial drugs, whole-blood transfusions, and complete bed rest, but even with these measures the mortality remains about 25 to 50 percent.

Chemicals secreted or excreted by a parasite that a host's immune system responds to are called _______________ ______________.

antigens

Define and differentiate the following sets of terms. hypertrophy, hyperplasiametaplasia, and neoplasia

hypertrophy - the enlargement of an organ or tissue from the increase in size of its cells. hyperplasia - the enlargement of an organ or tissue caused by an increase in the reproduction rate of its cells, often as an initial stage in the development of cancer. metaplasia - abnormal change in the nature of a tissue. neoplasia - the formation or presence of a new, abnormal growth of tissue.