Chapter 5- Eukaryotes- Parasites and Protozoa

________ - an association of two or more different species of organisms -_____________ - Any organism that lives on the surface of another -_____________ - Any organism that lives within another organism

symbiosis ectosymbiont endosymbiont

•Flagellate •Injected into the lymphatic system and bloodstream •Multiply asexually in the plasma and interstitial fluid of host

Trypanosoma brucei

-flagellate •Endemic throughout much of Mexico, Central America, and South America where an estimated 8 million people are infected •Broad range of vertebrate hosts including mammals, birds, and reptiles •Can infect and multiple in many different cell types within a host

Trypanosoma cruzi

Trypanon, Greek for auger ~ Twice as long as a red blood cell Silvery under the microscope

Trypanosoma spp.

Trypanosoma brucei •Flagellate •Develop in the ___________ and are transmitted via saliva to the blood of vertebrate hosts •Injected into the lymphatic system and bloodstream •Multiply asexually in the plasma and interstitial fluid of host •Genetic exchange may occur in the ___ ___ •Hosts: Humans and domestic animals; wild animals may be ___ ___

Tsetse fly Tsetse fly asymptomatic carriers

What is VSG? Found in trypanosoma spp. and reason for why so hard to kill

Variant surface glycoprotein

Are protozoa generally bigger than bacteria?

Yes

Does changing climates result in spreading of parasites to different locations?

Yes

What is another name for the two stages of Trypanosoma brucei?

1. hemolymphatic 2. neurological

Trypanosoma brucei: Pathogenesis •Disease: Trypanosomiasis or "______________ _____________"

"African Sleeping Sickness"

Giardia intestinalis (G. lamblia) •Flagellate •Disease - Giardiasis (____________________; ___________________) •Most commonly identified waterborne illness in the U.S.; ______________________________ •Reservoirs - humans, dogs, cats, cattle, beavers and deer •Two Stage Life Cycle: -Trophozoite •Feeding form •Four flagella •Binary fission -Cysts •Thick chitin wall •Can survive over 2 months in cold water

(Backpacker's disease... Beaver fever) worldwide distribution

•Parasitic protozoans vary in size •Defined by three characteristics: -________________ -________________ -________________ •They can be classified on the basis of their methods of _____________ and _____________

- eukaryotic - unicellular - lack a cell wall - reproduction and movement

2. Indirect effects of the parasite on the host: -____________________ : Tissue damage may be caused by immunological response of the host • e.g. nephritic syndrome following Plasmodium infections -Excessive _____________ of certain tissues due to invasion by some parasites can also cause tissue damage in humans •e.g. fibrosis of liver after deposition of the ova of Schistosoma

- immunological reaction - proliferation

•Route of transmission of a disease, when pathogens in _____________ pass from one host and introduced into the _____________ of another host

fecal particles... oral cavity

Pathogenesis of Malaria •The incubation period is about ___ ___ •Clinical manifestations depend on the species of Plasmodium •Malaria is associated with a cycling of symptoms called __________________ -___ begins with a cold stage (20-60 minutes) -Continuous shaking and chills -Then a __ __ - body temperature increase for 3-8 hours -Profuse sweating

-2 weeks -malarial paroxysm (alternating between hot and cold) -Paroxysm -hot stage

Life Cycle of Plasmodium •___ ____ ___ are responsible for the clinical manifestations of the disease. •Within 72 hours, infected red blood cells begin to __________ -Merozoites are released -Some infect other RBCs -Some transform into the gametocyte form -Gametocytes are then taken up by the next mosquito

-Blood stage parasites -rupture

Pathogenesis of Malaria •Symptoms of malaria include: - - -

-Fever -Anemia -Circulatory changes

•We will discuss three arthropod vectors:

-Tsetse Fly -Triatomine Bug -Anopheles Mosquito

Plasmodium spp. •_____________ •Human ____ is caused by one of four species of Plasmodium: -P. falciparum •Also cause of cerebral malaria •The most lethal -P. vivax, P. malariae, P. ovale •Transmitted by the female ________________ (definitive host)

-apicomplexan -malaria -mosquito

PATHOGENESIS OF MALARIA •The recurrent hot and cold stages cause ___. •By the third week, the sequence becomes synchronized •The most deadly form of malaria involves the ___ ___ ___ •___ ___ -Results in delusions, paralysis, coma, and death

-exhaustion -central nervous system -Cerebral malaria

We will group and discuss parasitic protozoa based on methods of transmission: -_____________ •Entamoeba histolytica - rhizopod •Giardia intestinalis (Giardia lamblia) - flagellate •Toxoplasma gondii - apicomplexa •Balantidium coli - ciliate -_____________ •Trypanosoma brucei - flagellate •Trypanosoma cruzi - flagellate •Plasmodium spp. - apicomplexa -_____________ •Trichomonas vaginalis - flagellate

-fecal-oral - vector-borne -sexual

Trichomonas vaginalis •____________ •Anaerobic, protozoa with multiple flagella, and an undulating membrane •Possesses a barb-like _________ for host attachment •No _______ form - _________ only •Disease: Trichomoniasis •Transmission: Sexual contact, moist objects like towels or bathtubs; newborn infants from infected mothers during birth (rare)

-flagellate -axostyle -cyst... trophozoite

LIFE CYCLE OF PLASMODIUM Inside a Mosquito 1.Sexual life cycle begins when a mosquito ingests infected blood from a ___ 2.Male fertilizes female _____________ 3.Resulting zygote forms an oocyst filled with ______________ 4.Oocyst ___ releasing sporozoite into body 5.Sporozoites penetrate ___ ___

-human -gametocytes -sporozoites -ruptures -salivary glands

Trypanosoma brucei: Pathogenesis •First Stage: -In some patients, a ___ ___ (a chancre) will develop at the site of the tsetse bite -Multiply in ___ and ___ -The repeated cycles of host antibody production and parasite destruction leads to cyclic fevers, headaches, joint pain and itching •Second Stage: -Invasion of the ___ ___ ___ (few weeks to years) causes personality changes, daytime sleepiness with nighttime sleep disturbance, and progressive ___

-large sore -blood and lymph -central nervous system -confusion

1. Direct effects of the parasite on the host: -________________ - may be inflicted by a parasite by means of pressure as it grows larger - Hydatid cyst causes blockage of ducts such as blood vessels producing infarction -Deleterious effect of ______ substances - in Plasmodium falciparum production of toxic substances may rupture of infected RBCs -Deprivation of __________, fluids and metabolites - parasite may produce disease by competing with the host for _____________

-mechanical injury -toxic -nutrients -nutrients

LIFE CYCLE OF PLASMODIUM Inside a Liver Cell 1.Asexual life cycle begins when a mosquito bites ___ ___ 2.Sporozoites infect liver cells and mature into schizonts , which rupture and release ____________

-new host -merozoites

Parasites are traditionally divided into two groups: -_____________ - microscopic, single-celled eukaryotes. -____________ - macroscopic, multicellular worms.

-protozoans -helminths

LIFE CYCLE OF PLASMODIUM Inside a Red Blood Cell 1.Merozoites infect ___ ___ ___ 2.The ___ ___ trophozoites mature into schizonts, which rupture releasing merozoites 3.Some parasites differentiate into _______________

-red blood cells -ring stage -gametocytes

PARASITIC FACTORS •Presence of a __ __ •__of the host •__ from the host •__ __ outside of host •__ AND __ conditions

-suitable host -Habits -Escape -Favorable conditions -Economic and social

Trypanosoma cruzi: Transmission •Undergo hindgut development in the _____________________ •Acquired through contact with the ______ of an infected triatomine bug (or "kissing bug"), a blood-sucking insect that feeds on humans and animals •These bugs are found in ___ made from materials such as mud, adobe, straw, and palm thatch

-triatomine bug -feces -houses

REQUIREMENTS FOR A SUCCESSFUL INFECTION 1. 2. 3. 4. 5.

1. Entry-getting in 2. Establishment-staying in 3. Defeat the host defenses 4. Damage the host 5. Exit the host and be transmitted to another host

What are the 3 different kinds of hosts?

1. definitive (primary) host 2. intermediate (secondary) host 3. reservoir host

The damage which pathogenic parasites produce in the host may be described in the following two ways: 1.____________ 2.____________

1. direct effects 2. indirect effects

The protozoa that are infectious to humans can be classified into four groups based on their mode of movement: 1._____________ - move using pseudopods •Entamoeba histolytica 2._____________ - move with flagella •Giardia intestinalis, Trypanosoma spp., Trichomonas vaginalis 3._____________ - move using cilia •Balantidium coli 4._____________ - organisms whose adult stage is not motile •Toxoplasma gondii, Plasmodium spp.

1. rhizopods 2. flagellates 3. ciliates 4. apicomplexans

Entamoeba histolytica: Pathogenesis •Infection can last from months to years •Only about ____________ of people who are infected with E. histolytica become sick from the infection

10% to 20%

Giardia intestinalis: Pathogenesis •Symptoms (present in ___of infected people) -___ - indigestion, gas, nausea -___ - vomiting, explosive, greasy diarrhea, abdominal cramps •Duration - ___ weeks without treatment •Colonization - upper portion of the ___ ___ •Infectious Dose - ___ ___

2/3 ... Mild... Severe... 1-4... small intestine... 10 cysts

______________________ •Unicellular and cyst •Mostly ____________ parasites •They alternate between _______ and _______ reproduction •Complete part of their life cycle inside of cells of a host organism

APICOMPLEXANS intracellular sexual and asexual

RHIZOPODS •_____________ •The most primitive form of protozoans that: •Multiply by simple binary fission •Move by using __________ •Produce a chitinous cyst for protection

Amoebas pseudopods

What type of parasite is Toxoplasma gondii?

Apicomplexan

Only member of the ciliate group that is pathogenic for humans

Balantidium coli

Rhizopod, Cause of amebiasis or amoebic dysentery.

Entamoeba histolytica

3._________________ - a host that makes the parasite available for the transmission to another host and is usually not affected by the infection

reservoir host

Flagellate. Disease - Giardiasis. •Reservoirs - humans, dogs, cats, cattle, beavers and deer

Giardia intestinalis (G. lamblia)

What is the most common vector?

Insects

What is an apicomplast or apical complex?

Makes apicomplexes intracellular parasites. Complexes allow them to bore within and between cells.

What is the difference between male and female mosquitos?

Males feed on nectar, females need blood to nurture eggs

TRUE OR FALSE- Toxoplasma gondii makes rats less afraid of cats so they will be eaten?

TRUE!

What does infectious dose mean? (ID50)

The amount needed of parasite for 50% of the population to become infected

Why are RBC's a good place for parasites to hide?

They have no nucleus

___ is common in malaria.

Thrombocytopenia (blood clotting complications)

_____________________________ •Obligate intracellular parasite •The definitive host is the CAT •Humans and other mammals are __________ _________

Toxiplasma gondii... intermediate hosts

Toxoplasma gondii •Transmission: -Ingestion or -___ ___ from an infected mother to the fetus can occur •___ is considered to be a leading cause of death attributed to foodborne illness in the United States •More than 60 million men, women, and children in the U.S. carry the Toxoplasma parasite, but very few have symptoms because the ___ ___ usually keeps the parasite from causing illness

Transplacental transmission... Toxoplasmosis... immune system

Trypanosoma cruzi •Flagellate •Transmission: _________________ vectors •________________

Triatomine (or "Kissing Bug") Chagas disease

•Anaerobic, protozoa with multiple flagella, and an undulating membrane contracted through sexual transmission

Trichomonas vaginalis

TREATMENT OF MALARIA •Two factors are involved: -Species of Plasmodium -Immunocompetency of the infected individual •Successful treatment requires destruction of __________________. •There are several treatments for malaria

all the parasites

"zoa" means...

animal-like heterotrophic

Trypanosoma spp. evade immune cells by modifying their surface membranes, multiplying with every surface change in a process known as _____________ _____________

antigenic variation

PROTOZOAN LIFE CYCLE AND REPRODUCTION •Reproduction -_________ - Binary or Multiple Fission -_________ - involving meiosis and the fusion of gametes resulting in a diploid zygote

asexual sexual

Toxiplasma gondii: Pathogenesis •Disease -Healthy people are usually _____________ (immune system keeps parasite from causing illness) -When illness occurs, it is usually mild with "flu-like" symptoms (e.g., tender lymph nodes, muscle aches, etc.) that last for several weeks and then go away •Parasite remains in their body in an inactive state -It can become reactivated if the person becomes __________________.

asymptomatic immunosuppressed

•Parasitic infections affect __ of people in the world. -More than __ __ people are infected with malaria -More than __ __ (mostly children) die each year from malaria

billions... 500 million... 2 million

•Indirect transmission of an infectious agent that occurs when a vector ____ or ________ a person

bites or touches

What is dysentery?

bloody diarrhea

Toxoplasma gondii: Pathogenesis •If a woman is pregnant and becomes newly infected with Toxoplasma during or just before pregnancy, she can pass the infection to her unborn baby (_______________). •The damage to the unborn child is often more severe the earlier in pregnancy the transmission occurs. •Potential results can be - - -___ (e.g., abnormal enlargement or smallness of the head) •Infants infected before birth often show no symptoms at birth but may develop them later in life with ___ , ___ , and ___

congenital transmission -a miscarriage -a stillborn child -a child born with signs of toxoplasmosis potential vision loss, mental disability, and seizures.

1.________________________ - a host that harbors a parasite in the adult stage or where the parasite undergoes a sexual method of reproduction

definitive (primary) host

________ - a parasitic organism that lives on the outer surface of its host, e.g. lice, ticks, mites etc. (most do not directly cause disease)

ectoparasite

PROTOZOAN LIFE CYCLE AND REPRODUCTION (All produce trophozoites; only some produce cysts) -___________ - Trophozoite à Cyst -___________ - Cyst à Trophozoite

encystation excystation

____________ - parasites that live inside the body of their host, e.g. Entamoeba histolytica.

endoparasite

________________ - an organism that exhibits both parasitic and non-parasitic modes of living and hence does not absolutely depend on the parasitic way of life, but is capable of adapting to it if placed on a host. e.g. Naegleria fowleri

facultative parasite

Sexually transmitted diseases (STDs) are caused by infections that are passed from one person to another during _______________

sexual contact

Balantidium coli •Only member of the ciliate group that is pathogenic for humans •Hosts: Humans and pigs (harmless in pigs) •_____________ transmission (most commonly from contact with infected pigs) •Global distribution, most prevalent in ________and __________ regions and developing countries -Rare in the U.S. •Two Stage Life Cycle: -Trophozoite - Binary Fission (asexual) -Cyst

fecal-oral subtropical and tropical

FLAGELLATES •Flagellates are unicellular microorganisms •Locomotion using a _______________ •Reproduction is by simple binary fission

flagella

Trypanosoma spp. •Bodies are __________ •Swim by spinning like __________

flat, like a strip drill bits

From an ecological standpoint, protozoa may be divided into _____________ forms and _____________ forms.

free-living forms and symbiotic forms

CILIATES •Cilia are numerous short _________________ covering the cell used for movement. •Firm pellicle to support cilia •Ingest food through a funnel-like primitive mouth called a cytostome (gullet) and eliminate wastes through a cytoproct pore •Large (macro) nucleus and a small (micro) nucleus involved in reproduction •The majority of ciliates are __________ and seldom parasitize humans

hair-like filaments free-living

Disease-causing parasites depend on their __ __ for survival.

infected host

Entamoeba histolytica: Life Cycle 1.Cyst is __ 2.Passes through the __unharmed 3.Excystation occurs in terminal ileum 4.__ mature and colonize the large intestine -May reach __ __ and invade other organs 5.Trophozoites form new cysts which are then excreted in the __ -Cysts can survive for weeks in __ conditions

ingested... stomach ...Trophozoites ...blood vessels ...stool ...moist

2.________________________ - harbors the larval stages of the parasite or an asexual cycle of development takes place. -In some cases, larval development is completed in two different intermediate hosts, referred to as first and second intermediate hosts

intermediate (secondary) host

"neph"

kidneys

There are three groups of flagellates: -__________ •Giardia intestinales -__________ •Trypanosoma spp. - __________ •Trichomonas vaginalis

luminal flagellates hemoflagellates genital flagellates

Protozoa are _____________, _____________ _____________ ubiquitous in moist areas, including the human digestive tract.

microscopic, unicellular eukaryotes

Symptoms of Entamoeba histolytica: -Often _____ - loose feces, stomach pain, and cramping -Can cause _____ of the intestinal mucosa -_________________ is a severe form of amebiasis associated with stomach pain, bloody stools and fever

mild... ulceration... amoebic dysentery

_________________ - this parasite is completely dependent on the host during a segment or all of its life cycle, e.g. Plasmodium spp.

obligate parasite

•A __________ is a living organism, which takes its nourishment and other needs from a host •The ________ is an organism which supports the parasite

parasite host

Some are _____________ and may cause disease.

parasitic

•____________ is the study of parasites •This includes: -their ________ -__________ -the relationship with ______ and ____________

parasitology -morphology -life cycle -host and environment

Entamoeba histolytica is most common in people who live in tropical areas with ___________________ •It is the third highest parasitic cause of deaths worldwide -Only malaria and schistosomiasis are higher •Two Stage Life Cycle: -___________ - Binary Fission (asexual) -________

poor sanitary conditions -trophozoite -cyst

Pathogenesis of Malaria •Anemia is caused by the destruction of ___ ___ ___ -It is accompanied by depression of marrow function and an enlarged spleen.

red blood cells

What does spp. mean?

there are multiple species

PROTOZOAN LIFE CYCLE AND REPRODUCTION •Some alternate between two or more life stages: _______________ - vegetative/active feeding stage __________ - dormant stage capable of surviving harsh conditions outside of a host

trophozoites cyst

(All produce __; only some produce __)

trophozoites... cysts

Parasitologists also study animal _______ -A vector is an organism that transmits disease from one host to another

vectors

FECAL TRANSMISSION The process of transmission may be simple or involve multiple steps. Some examples include: -__ that has come in contact with feces and is then inadequately treated before drinking; -__ that has been prepared in the presence of fecal matter -__ __, like houseflies, spreading contamination from inadequate fecal disposal -poor or absent __ after handling feces or anything that has been in contact with it -__ __ that may involve oral contact with feces, such as anilingus or coprophilia

water... food... disease vectors...cleaning... sexual practices