Parasitology Exam 2

abundance of density

Average number of parasites of one species per sample of host individuals of the same species, equal to the arithmetic mean (addition of # of parasites in one sample)/(# of individuals in sample)

anergy

B cells enter a state of permanent unresponsiveness and fail to respond to their specific antigen

schistosoma japonicum

more concentrated in the veins of the small intestine - least host specific - reservoir hosts include: rodents, cats, dogs, pigs, cattle, horses, and deer

Digenea body form

most are dorsoventrally flattened and oval in shape; others as thick as they are wide -length ranges from 1.0mm to 6.0cm

oral sucker

muscular sucker that surrounds the mouth

both T helper cell groups are able to inhibit the activation of the other group using

their own cytokines

lymphocytes produced in red bone marrow, migrate to _____ (primary lymphoid organ) where they mature (VDJ recombination of T cell receptor) and undergo selection

thymus - to get educated

Schistosomes: Pathology: Migratory phase

time from penetration until schistosome is reproductively mature - often no symptoms or dermatitis reaction

female reproductive system: mehlis' gland

unicellular mucous and serous glands surrounding the ootype

T cells

can regulate the immune responses of other cells (CD4) or indirectly kill cells (CD8) that carry specific antigens

cytons

cell bodies containing nuclei; lie beneath superficial muscle layer

myocyton

cell body of a muscle cell where nuclei occur; connect to fiber bundles

digenea nervous system

cerebral ganglia with orthogonal nervous system

bothria

usually 2 in number (dorsal and ventral), and take the form of shallow pits

bothridia

usually in groups of 4; can have highly mobile, leaflike margins with adaptations for adhesion (looks like a plant)

acetabulum

ventral sucker of a fluke

female reproductive system: Laurer's canal

vestigial vagina

what cells produce the bulk of the shell material and yolk of the egg?

vitelline cells

polyzoic

a strobila consisting of more than one proglottid

acetabula

a sucker on the scolex of a tapeworm; normally 4 acetabula on a scolex

IgD

monomer, present only on surfaces of B cells; serves as antigen receptor

female reproductive system: oogenotop

"egg forming apparatus"

scolex

"head" or holdfast organ of a tapeworm - may have suckers, grooves, hooks, spines, glands, or tentacles - contains the neural ganglia of the worm

intensity

# of parasites of one species in an infected host

clonorchis sinensis: epidemiology

- Can live 8 years in humans - clonorchiasis is common in countries that eat raw fish - Reservoir hosts include dogs, cats, pigs, and rats that contaminate streams - Widely distributed in Japan, Korea, China, Taiwan, and Vietnam - Eating frozen, dried, or pickled fish imported from endemic areas has caused infection - Metacercariae will withstand freezing, drying, pickling, salting, and smoking fish - may be futile to get millions of people to break century old habit - educating people to cook fish not one for many because fuel is luxury - fish farms contaminated with human feces ("night soil") used as fertilizer throughout much of Asia

Dicrocoelium dendriticum: epidemiology

- Common throughout most of Europe, Asia, Africa, North and South America - Acquired by accidental ingestion of ants on fresh herbs or vegetables

Leucochloridium variae

- Def. host: warblers - embryonated eggs are ingested by the terrestrial snail (Succinea ovalis) - sporocyst divided into 3 parts: 1. central body in snail's hepatopancreas 2. tube connecting the central body to the broodsac 3. broodsac in the head-foot of the snail and enters its tentacles - brightly colored broodsac pulses in enlarged snail tentacles - tailless cercariae develop in branched sporocysts; metacercaria encyst in broodsac *pathogenic*

Diphyllobothrium latum epidemiology

- Eating undercooked freshwater fish - Accidental ingestion of copepod from unfiltered water - Insufficiently cooked frog, snake, or pig - Poulticing inflamed area or wound with split frog

MHC class II proteins

- Found only on antigen presenting cells (macrophages, B cells, and dendritic cells) - TH cells (CD4) respond to exogenous antigen bound to MHC class II proteins *flag pole analogy

echinococcus granulosus epidemiology

- Humans become infected when they accidentally ingest egg when playing with dog - some tribes in Kenya relish dog intestine roasted on a stick - some tanners in Lebanon use dog scats as ingredient of a solution for tanning leather - echinococcosis disease can be eliminated in infected areas by the following: 1) general education program 2) denying access of dogs to offal 3) destroying stray dogs

TH2 cells mainly secrete

- IL-4: growth factor for B cells; suppresses TH1 cell production - IL-5: stimulates B cells for growth, differentiation, and production of antibodies; activates eosinophils - IL-10: inhibits TH1 cells and cytotoxic T cells; leads to marked immune-suppression

Taenia saginata epidemiology

- Infection is highest where beef is a major food and sanitation is deficient - One person who defacates in pasture can infect entire herd - Use of human feces as fertilizer - Cattle are coprophagous

hymenolepis nana pathology

- Light infections are asymptomatic - Heavy infections can occur because of autoinfection - Symptoms are similar to those previously mentioned for Taenia saginata

hymenolepis nana epidemiology

- More than 20 million people infected world wide - Prevalence of infection is highest for small children; ingestion of eggs - Ingestion of grain products contaminated with infected insects (flour beetles) - rodent control measures and protection from their droppings

hymenolepis diminuta pathology

- Most infections are asymptomatic - Some symptoms may include nausea, abdominal pains, diarrhea, and anorexia

dipylidium caninum epidemiology

- Most likely to occur in small children who kiss or are licked by infected pet - Periodic deworming of infected dogs and cats and control of fleas is essential

Pathology of Fasciola hepatica

- Much necrosis results from migration of flukes through liver parenchyma - Anemia sometimes results from heavy infections - Worms in bile ducts cause inflammation, edema, and stimulates fibrosis - Migrating juveniles cause ulcers in ectopic locations: eyes, brain, skin, & lungs

Digenean: Fasciola hepatica

- Parasite of ruminants (cattle, goats, sheep, deer, etc.), and humans - Adult parasite feeds on lining of bile ducts

Diphyllobothrium latum pathology

- Pernicious anemia; large amount of B12 absorbed by tapeworm - Sparganosis: infectious disease caused by migrating plerocercoids in host tissues -> can reach 35 cm in length; can live for at least 30 years 1) swallowing procercoid-infected copepods in drinking water 2) eating amphibians, reptiles, and mammals containing plerocercoids 3) applying plerocercoid-infected flesh to wounds as a poultice

cyclophyllidea: echinococcus multilocularis

- adult E. multilocularis mainly found in foxes - dogs, cats, and coyotes can also serve as definitive hosts - several species of rodent serve as intermediate host: mice, rats, voles, lemmings - E. multilocularis metacestode is alveolar or multilocular hydatid

echinococcus granulosus

- adults are in small intestine of carnivores, particularly dogs and other canines - herbivores (int host) are infected by eating eggs on contaminated herbage - within liver or lungs oncosphere metamorphoses into unilocular hydatid - slyvatic cycle: life cycles that involve wild animals (ex: wolf-moose, lion-warthog, etc) - urban or domestic cycle: life cycles that involve rats and domesticated animals (ex: dog-sheep, dog-goat, dog-pig, etc) -metacestode: hydatid

Cyclophyllidea: taenia saginata

- beef tapeworm - occurs in humans in countries where beef is eaten - 3-5 m length; > 2,000 proglottids - adult beef tapeworm lives in small intestine - gravid segments detach and pass out with feces or migrate out of anus - proglottid begins to dry and ruptures, thus releasing eggs - larvae (hexacanth) remain viable for weeks - looks like corn beef (has cysticerci)

Pseudophyllidea: Diphyllobothrium latum

- broad fish tapeworm - occurs in humans, bears, cats, dogs, and other fish-eating carnivores - adults live in small intestine - 10 meters length; > 4,000 proglottids; sheds 1 million eggs per day - eggs released through uterine pore - can get sparginum from this (sparginosis)

Epidemiology of Fasciola hepatica

- can live as long as 11 years - infection begins when metacercarial cyst is ingested from water or vegetation - human often infected by eating watercress - sheep, cattle, goats and rabbits are most frequent reservoirs of infection in US - few human cases in US; most common in the South and West - human infections occur Europe, Northern Africa, Cuba, South America, and other locales - WHO estimate 2.4 million persons were affected with fascioliasis worldwide in 2018

digenea muscular system

- circular muscles lies beneath the basal membrane of tegument - longitudinal and diagonal layers underlying the circular muscles envelop body - muscle fibers are smooth, often in syncytial clusters

Digenean: Dicrocoelium dendriticum

- common in the bile ducts of sheep, cattle, goats, deer, and pigs - no need for aquatic environment for any life cycle stages

cyclophyllidea: dipylidium caninum

- common parasite of dogs and cats all over the world; often occurs in children - adult worms found in the small intestine - gravid proglottids detach and either wander out of anus or is passed with feces - when detached segment desiccates, egg capsules are released

Dicrocoelium dendriticum pathology

- conditions of dicrocoeliasis is similar to fascioliasis, but less severe - no trauma to gut wall or liver parenchyma (no migrating juveniles) - chronic constipation, bile duct inflammation, fibrosis, and hepatocyte degeneration

taenia solium pathology

- cysticerci can be found in any organ and tissue including 1) subcutaneous connective tissues 2) eye 3) brain (epilepsy, blindness, paralysis, disequilibrium, disorientation, etc) 4) muscles 5) heart 6) liver 7) lungs 8) coelom

albendazole (Albenza)

- developed by Smithkline in 1972 - broad-spectrum anhelmintic - on the World Health Organization's List of Essential Medicines - alternative drug of choice by CDC effective against: Clonorchiasis - binds to colchicine-sensitive site of tubulin eliminating its polymerization into microtubules leading to impaired uptake of glucose - available in the United States as Albenza by GlaxoSmithkline (1 dose pack - 2 tablets - $215.00)

praziquantel (biltricide)

- developed by bayer and Merck in the mid 1970s - on the world health organization's list of essential medicines - drug of choice by CDC effective against: Alariasis, clonorchiasis, paragonimiasis, dicrocoeliasis, schistosomiasis, dipylidiasis, hymenolepiasis, taeniasis - increases calcium ion permeability of membranes; induces contraction and paralysis - available in the United States as biltricide by bayer (1 dose pack - 6 tablets - $105.00)

cyclophyllidea: hymenolepis nana

- dwarf tapeworm (4cm) - one of the most common custodies of humans - int host is optional (can develop normally in larval and adult beetles) - human or rodent ingests egg, oncosphere hatches out of egg in duodenum - oncosphere penetrates mucosa and develops into cysticercoid (metacestode) - within 6 days cysticercoid return to lumen of small intestine to attach and mature

Fasciola hepatica: ruminants

- enormous losses in livestock because of mortality - reduction of milk and meat products; and especially spoiled livers - secondary bacterial infections - expensive anthelmintic treatment

Digenean: clonorchis sinuses pathology

- erosion of epithelium in larger bile ducts and main branches - inflammation becomes prominent, fibrosis, necrosis, and atrophy of surrounding liver tissue - trapped eggs become surrounded by granulomas, interfering with liver function - eggs and sometimes entire worms become nuclei of gallstones - cancer of the bile duct is often associated with clonorchiasis

epidemiology of Alaria Americana

- found in various species of Canidae in northern North America - Mesocercariae are pathogenic to human - Acquired by eating undercooked frog legs - Transmammary transmission of mesocercariae to offspring via milk

echinococcus multilocularis alveolar cyst

- has thin wall and germinal epithelium - may bud externally and spread in any direction or even metastasize

Schistosomes: Epidemiology

- human waste water containing intermediate host is #1 empidemiological factor S. mansoni: broad distribution: Africa, Middle East, South America, and carribean S. japonicum: limited to Japan, China, Taiwan, the Philippines, and Southeast Asia S. haematobium: limited to Africa and adjacent regions - schistosomes may live 20 to 30 years - schistosomiasis transmission has been reported from 78 countries - more than 75.3 million people were treated for schistosomiasis in 2021 - 200,000+ deaths per year

echinococcus granulosus hydatid

- hydatid has thick outer noncellular layer and thin inner nucleated germinal layer - brood capsules on inner layer of hydatid, each capsule has 10-30 protoscolices - brood capsules within hydatid break down and release "hydatid sand"

protogyny

- in a few species the ovary matures first - female develops first

taenia solium epidemiology

- infection highest where pork is major food source - eggs transmitted through blowfly - infected (domestic help) person can contaminate households or food -> ex: 1.3% orthodox jewish community in New York infected by T. solium - cysticercosis is highly endemic in Mexico, central and much of south America, sub-Saharan Africa, India, china, and other parts of eastern asia

dipylidium caninum pathology

- light infections are often asymptomatic - some individuals experience abdominal pain, diarrhea, and anal itching

protandry (androgyny)

- maturation first of male gonads and then of females -in a few species the ovary matures first known as protogyny -may be an adaptation that prevents self fertilization of the same proglottid -usually reproductive pores of both sexes open into a genital atrium

pathology of Alaria americana

- mature Alaria spp. very pathogenic causing severe enteritis - often kills host in severe infections - can be fatal in humans when accumulated in large numbers

digenea: reproductive system

- most trematodes are hermaphrodites, and some can self-fertilize - always cross-fertilize if 2 or more digeneans are in the same host - exception are schistosomes that are dioecious (separate M and F) - ectolecithal system: yolk is contributed by vitelline cells, yolk not stored in female gamete

hymenolepis diminuta

- much larger than H. nana (90 cm) - common in rats; human infections not common - completion of lifecycle requires an arthropod intermediate host ( >90 insect species) - other life cycle characteristics similar to H. nana

Digenean: Ribeiroia ondatrae

- national attention in 2007 regarding widespread reports of deformed amphibians - 1st intermediate host are various freshwater snails - 2nd intermediate hosts are fish and larval amphibians (frogs and salamanders) - large numbers of metacercariae encyst where hind limb buds form in tadpoles - encysted metacercariae cause deformation of hind limbs - definitive hosts include herons, hawks, and badgers

Third line of defense: four important aspects of immune response include

- nonself recognition - antigen-specific - systemic response - "memory"

niclosamide

- on the world health organization's list of essential medicines - used specifically to treat cestode infections - alternative drug of choice by CDC effective against: Dipylidiasis, and Taeniasis - uncouples oxidative phosphorylation severely limiting ATP production - not available in the United States

triclabendazole (eaten)

- on the world health organization's list of essential medicines - drug of choice by CDC effective against: fascioliasis - binds to beta-tubulin preventing the poymerization of microtubules leading to impaired uptake of glucose and depletion of glycogen - not available in the United States, but is available through CDC

paragonimus westernmani pathology

- once in lung or ectopic site, worm stimulates an inflammatory response - parasite becomes enshrouded in a granuloma - eggs in surrounding tissues result in pseudotubercles - worms in spinal cord can cause paralysis - fatal cases are seen when Paragonimus spp. locate in heart or brain - pulmonary cases are rarely fatal; chronic cough, breathing difficulty, sputum containing blood

Taenia solium

- pork tapeworm - most dangerous adult tapeworm to humans - humans can serve as definitive & int host - life cycle same as beef tapeworm except the normal intermediate host is pig - humans become an int host when the eggs are accidentally ingested or a gravid proglottid ruptures releasing eggs before it leaves the body - humans become a definitive host when ingesting cysticerci in undercooked pork

hymenolepis diminuta epidemiology

- primarily a zoonosis: a disease of animals transferable to humans - rodent control measures to prevent insect consumption of their droppings - protection from insects of cereals, grains or other non-cooked foods

panagonimus westernmani epidemiology

- reservoir hosts often include felids, canids, rodents and pigs - worms can live 10 to 20 years - human become infected by eating raw or insufficiently cooked crustaceans - marination in brine, vinegar, or wine have no affect on metacercariae - exposure can also come from contaminated fingers and cooking utensils - some ethnic groups use of juices strained from crushed crab or crayfish for medicinal purposes (poultice) - variety of mammals and some birds can serve as paratenic hosts ex. guinea pigs: considered a delicacy in Ecuador and peru

Cestoidea: tegument

- tegument of cestodes is a syncytium - no digestive tract - all required substances are absorbed through their tegument - distal cytoplasm is connected to futons by channels or internuncial processes

echinococcus granulosus pathology

-Hydatid cyst can occur in any organ: liver, lungs, brain, etc. -Type and extent of pathology depends on cyst size and location -As cyst size increases it crowds adjacent tissues and organs interfering with function -Cyst can become enormous: > 3 gallons of fluid, millions of protoscolices -Release of hydatid fluid may cause anaphylactic shock

Taenia saginata pathology

-May be asymptomatic -Symptoms of dizziness, abdominal pain, diarrhea, headache, and nausea -Intestinal obstruction with need for surgical intervention sometimes occurs -loss of appetite is not frequent -delirium is rare

ice cream analogy

-giradelli dark chocolate brownies -haagen daggz vanilla ice cream - whipped cream

cestoidea: excretion and osmoregulation

-main excretory canals run from the scolex to the posterior end of strobila -canal empties at the end of the strobila when terminal proglottids detach -excretory ducts are lined with microvilli -flame cell protonephridia provide motive force to the fluid in the system - end products of cestode energy metabolism are excreted through the tegument -osmoregulation is also function of tegument

cestoidea: reproductive system

-monoecious; few exceptions -in mature proglottid, sperm is transferred and oocytes are fertilized -usually male organs mature first, sperm is stored until maturation of the ovary -Protoandry - male develops faster

cestoidea: muscular system

-muscle cells consist of 2 portions: contractile myofirbil and noncontractile myocyton -contractile portion contains actin and myosin fibrils, and it is nonstriated -myocytons comprise most of the cestodes parenchyma -bundles of longitudinal and circular muscle fibers lie below the distal cytoplasm -more powerful musculature lies below the superficial muscles

cestoidea: nervous system

-nervous system of cestodes displays the orthogon plan typical of Platyhelminthes -main nerve center is located in the scolex -innervation of ganglia, commissures, and motor and sensory occurs at the main nerve center; complexity often depends on complexity of scolex -sensory function most likely includes tactoreception and chemoreception

type 2 flag pole analogy

-not every cell gets it; only professional antigen presenting cells get it; they have type 1 and will get type 2 -ex: macrophages/B cells -exogenous antigenic material- smth that was built outside of the cell & then cell did phagocytosis and engulfed it, chopped it into little pieces, then put it on flag pole -CD4 (helper T cell) checks out type 2 flag pole

cestoidea: male

-one to many testes, each has vas efferens, unite into common vas deferens -sperm channeled toward the genital pore -cirrus pouch: a muscular sheath containing cirrus -the male copulatory organ is the muscular cirrus, which may have spines

cestoidea: female

-ovary and associated structures -the entire complex is known as the oogenotop -vitelline cells contribute yolk and shell material to the embryo -as oocytes leave ovary through the oviduct, which has a sphincter, or oocapt

MHC class 1 proteins

-present on every nucleated cell of the body (few exceptions) -cytotoxic T cells (CD8) respond to endogenous antigen bound to MHC class 1 proteins *endogenous antigenic material- on flag pole

Second line of defense: complement

1. Consists of approx. 30 different proteins 2. Circulate freely in blood plasma, generally in inactive form (zymogen) 3. Complement can be activated by classical pathway (antigen-antibody complex) or alternative pathway (spontaneously) or lectin pathway (cell wall polysaccharides of certain bacteria and fungi) 4. Complement proteins (C3b) coat pathogen surface (opsonization), thus promoting phagocytosis and destruction of pathogen by macrophages and neutrophils, which have receptors for C3b 5. C5a is an important chemotsctic protein, helping recruit infllammatory cells 6. Complement C5b initiates pathway for membrane attack complex (MAC) that form pores in pathogens that have lipid membrane to induce lysis

cestoidea: development

1) embryogenesis within the egg gives rise to larva (oncosphere) 2) oncosphere hatches and penetrates extraintestinal site 3) metamorphossi of the larva into a juvenile (metacestode) in extraintestinal site 4) metacestode develops into adult in the intestine

second line of defense: interferons (IFN-A, IFN-B, IFN-Y)

1. A class of proteins synthesized upon parasitic infection of a cell 2. Act as messengers to protect normal cells in vicinity from becoming infected 3. IFN-a and IFN-b induce the degradation of RNA and block protein production 4. IFN-y is produced by TH cells and natural killer cells to stimulate cells in the cellular response

Cell signaling

1. Ligand binds to a specific cell receptor protein, initiating intracellular signal cascades 2. Ligands may be located on cell surface of neighboring cells, dissolved in blood (cytokines) or on the surface of or secreted by pathogens 3. Cascades may activate transcription factors or proteins that control gene induction, phagocytosis, apoptosis, or secretion

flame cell formula steps

1. draw a vertical line down the center from anterior to poster end 2 [ ( ) + ( ) ] 2. Draw a horizontal line where the main collecting ducts bifurcate 3. starting anteriorly from the upper quadrant count the number of flame cells in a common cluster. add this number to other number of flame cells in the remaining cluster 2 [ (3+3+3) + () ] 4. repeat with the lower quadrant working from anterior to posterior 2 [ (3+3+3) + (3+3+3) ]

Cytokines

1. protein hormones utilized by immune cells to communicate 2. Can affect some cells that produce them, cells nearby, or cells distant in body Ex: interferon, interleukin, growth factors, etc.

B cells recognize their cognate antigen in its native form with its B-cell receptors (antibodies); each lg can bind

2 identical epitopes

Cell signaling ex: JAK-STAT pathway

3 main components: - Receptor - Janus Kinase (JAK) - Signal Transducer and Activator of Transcription (STAT) 1. transmembrane receptor, activated by cytokine 2. Activated the JAK protein, which adds phosphate groups (P) to the receptor :Kinases: are proteins that add phosphate groups to other proteins :Phosphate groups: act as "on" and "off" switches on proteins 3. STAT is recruited and itself becomes phosphorylated, forms diner, and moves into the cell nucleus, where it binds to DNA promoter region

acquisition of nutrients: -> feeding and digestion

: varies with nutrient type and habitat within the host - ex: flukes of lungs, intestine, urinary bladder rectum, and bile ducts draw a plug of tissue into their oral sucker and use pharynx as a pump to erode tissue - ex: flukes living in blood vessels are immersed in its semifluid blood food, so has no necessary to breach host tissue

chemoreceptors

A sensory receptor that responds to a chemical stimulus (some strikingly similar to olfactory receptors of vertebrate nasal epithelium)

Scavenger Receptors

Bind lipoproteins and lipopolysaccharides from bacterial cells including Gram-positive bacteria (lipoteichoic acid) and Gram-negative bacteria (lipopolysaccharide)

helper T cells have __________ protein

CD4 coreceptor

cytotoxic T cells have _____ protein

CD8 coreceptor

Basis of self and nonself recognition: Major histocompatibility complex (MHC):

Cell surface glycoproteins, highly polymorphic

B cell: each "arm" is called _____ and the "stem" is called ______

Fab (fragment antigen-binding) region; Fc (fragment crystallizable) region

Digenean: Schistosoma spp.

Family: Schistosomatidae: have no 2nd intermediate host in their life cycles - mature in the blood vascular system of their definitive host - most species are dioecious Genus: Schistosoma: refers to the "split body" of the male considerable sexual dimorphism exists which include: - males have tegumental tubercles - males are shorter and stouter than females - males have a ventral longitudinal groove (gynecophoral canal)

IgE

Fc binds to mast cells, basophils, etc; often secreted In response to helminth worms; low concentration in plasma

TH1 cells mainly secrete

IL-2: growth factor for T and B cells; natural killer cells become lymphokine-activated killer (LAK) cells IFN-y: inhibition of TH2 cells, strong macrophage-activating factor TNF: major mediator of inflammation; high concentrations increase synthesis of prostaglandins, resulting in fever GM-CSF: Granulocyte-Macrophage Colony Stimulating Factor

which class of immunoglobulin is the major antibody secreted during the secondary response

IgG

Complement receptors

Integral membrane proteins that recognize fragments of complement and mediate various defense functions, including phagocytosis

HLA I Is another way of saying

MHC class 1

Digenean: Alaria americana

Parasite of wolves, foxes, coyotes, and the domestic dog (def host) (humans are accidental hosts) - miracidia hatch out of egg and penetrate snail - sporocysts shed cercariae - cercaria penetrate tadpole - mesocercaria. develop in tadpole (infective to next host, either paratenic or definitive host) - water snake (paratenic host) eats infected tadpole of frog - canid eats infected snake and mesocercariae are freed by digestion - mesocercariae penetrate gut, move to diaphragm & then lungs (metacercaria) - (after 5 weeks) they migrate up the trachea and then to the small intestine

"Memory"

Recognizes and mounts stronger attack on previously encountered pathogens

Schistosomes: Pathology: Chronic phase

S. mansoni: hepatic and pulmonary cirrhosis, hepatosplenomegaly S. haematobium: bladder wall becomes ulcerated, bloody urine (hematuria) S. japonicum: hepatic and pulmonary cirrhosis, hepatosplenomehaly; cerebral schistosomiasis

Toll-like receptors (TLRs)

Single, membrane-spanning, receptors that recognize structurally conserved molecules of carbohydrates, nucleotides, and proteins derived from viruses, bacteria, protozoa, and helminthes parasites.

Pathogen-associated molecular patterns (PAMPS)

Small molecular motifs conserved within a class of pathogens

Memory B cells

Specific to antigen encountered during primary immune response -Can respond quickly following second exposure of same antigen -Long-lived cells

propagatory cell

Stem cells ->they are germinal cells in asexually reproducing forms Ex. additional embryo in miracidium, sporocyst, or redia ->give rise to germ cells in sexual adults Ex. sperm and egg

TH0 cells differentiate into TH1 or TH2 cells depending cytokine environment Cellular response- IL-12 and IFN-y induces ____________; IFN-y inhibits TH2 cells Humoral response: IL-4 drives __________; and inhibits TH1 cell production

TH1 differentiation; TH2 differentiation

B cells: Ig is encoded by different segments of DNA

a V (variable) segment, a D (diversity) segment, a J (joining_ segment, and a constant region; variable regions are shuffled by RAGs

cestoidea

a class within the phylum Platyhelminthes - Monoecious parasites, hermaphrodites - Acoelomate; no digestive system - Adults live in the digestive tract of vertebrates

digenetic trematodes (flukes)

a subclass within the class Trematoda - Digeneans parasitize all classes of vertebrates - Develops in at least two hosts - First host is a mollusk (most often a gastropod/snail) or very, rarely an annelid

female reproductive system: vitellaria

a group of vitelline glands that produce vitelline cells -> vitelline cells produce the bulk of the shell material and yolk of the egg

gravid

a proglottid containing fully developed eggs or shelled embryos

Human immunodeficiency virus (HIV)

a retrovirus that attacks the body's immune system; causes AIDs - HIV mounts direct attack on TH cells by binding to CD4 proteins on cell surface; monocytes are infected because they also express CD4 - HIV kills TH cells, via apoptosis, faster than they can proliferate over time - HIV-encoded proteins also cause a decrease in the expression of MHC class I on infected cells, so these cells are less likely to be recognized and are killed by NK cells - when CD4+ T cell numbers decline below a critical level of 200 cells per uL, cell mediated immunity is lost

proglottid

a segment in a strobila that includes male and female reproductive organs - proglottid can copulate with itself, with others in its strobila; or with those in other worms, depending on the species

aggregated or overdispersed

a situation in which most of the parasites occur in a relative minority of hosts and most host individuals are either uninfected or lightly infected

female reproductive system: ootype

a slightly expanded area of the oviduct that is surrounded by Mehlis' gland

Nonself recognition

ability to distinguish self-antigens from nonself

T cell receptors must recognize self MHC proteins needed for _______, but not the self antigens (self tolerance) that the MHC presents (T-cell eliminated in thymus if criteria not met)

activation

eyespots

allows organism to distinguish light direction

an adult digest with a ventral sucker located at its posterior end would best be described as ______? A. monostome B. distome C. reverstome D. amphistome E. none of the above

amphistome

neck

an undifferentiated zone located between the scolex and the strobila - contains stem cells responsible for giving rise to new proglottid

binding of antigen to lg on surface of appropriate B cell is usually not sufficient to activate the B cell to multiply; so, B cell (APC) internalizes ____________ and incorporates portions of antigen (epitope) on MHC II

antigen-antibody complex

distal cytoplasm

anucleate layer of cytoplasm above a "sunken epidermis"

pathogen

any organism or substance that produces a disease state

landscape epidemiology

approach of epidemiology that employs all ecological aspects of a nidus - by recognizing certain physical conditions, the epidemiologist can anticipate whether a disease can be expected to exist.

Plasma B cells

are large B cells that have been exposed to antigen -produce and secrete large amounts of antibodies -short lived cells and undergo apoptosis when the inciting agent that induced immune response is eliminated

microtriches

are numerous minute finger-shaped tubes that extend out of the tegument - increases the absorptive area of the tegument - completely cover the worm's surface - glycocalyx is found on the surface membrane of microtriches - below microtriches is a layer of distal cytoplasm

humoral immunity

based on antibodies on cell surfaces and in body fluids (blood, lymph, etc)

B cells recirculate only between

blood and lymphoid organs, activated in secondary lymphoid organ (ex: lymph nodes, MALT, which includes tonsils and appendix)

cytotoxic T cells

kill cells that are infected with viruses (or other pathogens)

internuncial processes

channels that connect cytons to distal cytoplasm

spines

consistent of crystalline actin; often present in certain areas of the tegument - spines lie above the basement membrane of distal cytoplasm - most flukes can absorb small molecules including amino acids and hexoses

somatic cell

contributes to body tissue of the embryo

other transmembrane proteins closely linked to T-cell receptors serve as ________, such as CD4 and CD8

coreceptors

virulence

deals with the consequences of the presence of the foreign species on the transmission of the hosts genes -> a parasite is virulent if it reduces host reproductive success

antigen-presenting cell (APC) often include ______ cells (professional APC)

dendritic

syncytial

describes the continuous distal cytoplasm with no intervening cell membranes

orthogon

describes the ladderlike arrangement of nervous system in flatworms - 3 main pairs of longitudinal trunks (dorsal, ventral, and lateral) - cross-sectioned by a series transverse commisures - sensory endings extended from tegument; many types in cercaria and miracidium

hyperapolysis

detachment of a proglottid while still immature, before eggs are formed - may lead an independent existence in the gut while maturing

analysis (pseudoapolysis)

detachment of senile proglottid after it has shed its eggs

polyembryony

development of a single zygote into more than one offspring

digenea: digestion

digestion in most flukes is predominantly extracellular in the ceca - waste is expelled through: -> excretory system or tegument -> stored in worm tightly bound to protein -> periodically regurgitated

IgA

dimer, most abundant form of antibody in body secretions; high density of IgA-secreting plasma cells in MALT

apolysis

disintegration or detachment of a gravid tapeworm segment

rostellum

dome-shaped area on the apex of the scolex, often with hooks

pathogenicity

encompasses the total sum of consequences regarding the presence of a foreign species in the host -> a parasite is pathogenic if it causes changes in the anatomy, physiology or behavior of the host

cytotoxic T cells are activated by __________ antigens bound to MHC class 1 proteins of dendritic cells

endogenous

cell-mediated immunity

entirely associated with cell surfaces, T-cell receptors, that are unable to "see" free antigens

protonephridia

excretory system that is closed at the inner end by a flame cell and opens by a pore at the distal end

TH2 cells communicate attack against

extracellular parasites including helminths

monostome

fluke that lacks a ventral sucker

amphistome

fluke with the ventral sucker located at the posterior end

distome

fluke with two suckers, oral and ventral

strobilation

formation of a chain of proglottids by budding

Schistosoma mansoni

found in the portal veins draining the large intestine - moderate host specificity - reservoir host include: rodents and monkeys

Schistosomes: Epidemiology: concomitant immunity

host is protected against new infections, but the parasite eliciting the immunity remains alive and unaffected

type 1 flag pole analogy

if youre a cell in body and have a nucleus, you get type 1 (most inclusive) -endogenous antigenic material: smth that was generated from within that cell; material has to be chopped up to be put on flag pole -CD8 (cytotoxic T cell)will check out what's on flag pole, can look at it and determine action; they will use their t-cell receptor

Systemic response

immunity is not restricted to the initial infection site

B cell: the heavy chain constant region is translated from 1 of 5 possible DNA sequences named u(mu), (delta,), y (gamma), a (alpha), e (epsilon), which give rise to a particular class of

immunoglobulin

B cells produced in red bone marrow; _________ occurs

immunoglobulin (lg) synthesis occurs - tested for auto reactivity by the immune system before leaving the bone marrow - if highly reactive to self: -> clonal deletion -> receptor editing -> anergy

sparganosis

infectious disease caused by migrating plerocercoids in host tissues -> can reach 35 cm in length; can live for at least 30 years 1) swallowing procercoid-infected copepods in drinking water 2) eating amphibians, reptiles, and mammals containing plerocercoids 3) applying plerocercoid-infected flesh to wounds as a poultice

when 2nd activation signal is complete the originally undetermined T-helped null cell (TH0) releases a potent T cell growth factor called ________, which activates the T cell's proliferation pathways

interleukin 2 (IL-2)

TH1 cells communicate attack against

intracellular bacteria and protozoa

helper T cells

involved in activating and directing other immune cells; their cytokines largely determine whether an immune response is humoral or cell-mediated; no killing ability

intermediate host of Leucochloridium variae

land snails

urban or domestic cycle

life cycles that involve rats and domesticated animals (ex: dog-sheep, dog-goat, dog-pig, etc)

slyvatic cycle

life cycles that involve wild animals Ex. (wolf-moose, lion-warthog, etc.)

B cell: each lg consists of 2 identical short polypeptides called _____ and 2 identical longer polypeptides chains called ________; held together by disulfide bonds to form a Y-shaped molecule

light chains; heavy chains

helper T cells: 1st signal is initiated by exogenous antigens bound to MHC class II proteins of __________

macrophages, dendritic cells (phagocytosis or endocytosis), and B cells (receptor-mediated endocytosis)

hot dog analogy: bun is the _____ & meat is the ______

male; female

immunoglobulins IgM (monomeric form) and IgD are present on ____

mature "naive" B cells

T-cell activation occurs in secondary lymphoid tissue when antigen is displayed with self MHC on _____

mature dendritic cells (DCs)

there will only be an epidemiology is the species is of

medical importance - has to do w all ecological factors associated with distribution or prevalence of a disease causing parasite

cytotoxic T cells activation results in the release of IL-2, TNF, and IFN-y; and they differentiate into ________ (clonal expansion)

memory cells and activated cells

specific TH2 cell recognizes antigen displayed by B cell; cytokines such as IL-4 are released from TH2 cell to activate B cell; produces _____

memory cells and plasma cells that secrete antibodies against the identical antigen

IgG

monomer, major antibody secreted during the secondary response; 75% of plasma antibodies

Schistosomes: Pathology: Actute phase (Katayama fever)

occurs when schistosomes begin producing eggs - sufficient time and exposure has elapsed to elicit humoral response - egg production dramatically increases antigen release causing: chills fever, fatigue, headache, malaise, muscle aches, GI discomfort etc

individual B cells only produce _____ antibody

one

receptor editing

opportunity to rearrange their conformation via RAG (recombination activating gene)

IgM

pentamer, 1st antibody secreted during primary immune response; monomer, present on surfaces of B cells

T-cell receptors recognize only a processed ______ that the APC's MHC presents to the T cell receptor, unlike B-cell receptors

peptide fragment

prevalence

percentage in individuals of a single host species infected at a given time ex to find prevalence: # of infected chickens / # of chickens in that sample = a decimal then multiply by 100 to get a % of prevalence (look at slide)

cytotoxic T cells release ________, insert in membrane and make pores, granzymes enter infected cell and activate caspase enzymes that induce apoptosis

perforins

Platyhelminthes (flatworms)

phylum containing simples bilaterally symmetrical animals - Most are parasitic - Acoelomate body plan (no body cavity other than the gut); rarely has anus - Triploblastic (composed of three fundamental cell layers) : ex: mesoderm, ectoderm, & endoderm - Dorsoventrally flattened (greater surface area to respire by diffusion) - Tegument (surficial covering of a multicellular organism, an integument - Parenchyma (loosely arranged mass of fibers and cells of several types) mouth->pharynx->esophagus->cecum *they're flat because diffusion works better*

craspedote

posterior edge of each segment overlaps the anterior edge of next segment (ice cream cone ex)

acraspedote

posterior edge of proglottid does not overlap the anterior edge of the next (sausage ex)

schistosoma haematobium

prefers the veins of the urinary bladder - most host specific (no known reservoir hosts)

tangoreceptors

receptors sensitive to touch

pattern recognition receptors

receptors with broad specificity that bind to molecules on the surface of pathogens; stimulated by PAMPs

Antigen-specific

recognizes and is directed against specific antigens

which primary lymph organ are B cells produced

red bone marrow

primary lymph organs

red bone marrow and thymus

strobila

region of tapeworm behind the scolex and neck; chain of proglottids

excretion

removal of waste takes place across tegument, epithelial lining of gut, exocytosis of vesicles, and via excretory system - removal of waste products of metabolism - removal of unnecessary or harmful substances - regulation of internal osmotic pressure - regulation of internal ionic composition

clonal deletion

removal, usually by apoptosis

flame cell formula

represents number and arrangement of flame cells - used as taxonomic character

helper T cells: 2nd signal is a verification step; naive TH cells express the protein CD28 that must bind to costimulatory B7 protein on professional APCs; a protective measure to ensure TH cells are _______-

responding to a foreign antigen

"naive" T cells recirculate only between the blood and lymphoid organs, do not enter other tissues; activated in ________ (ex: spleen, tonsils, or lymph nodes)

secondary lymphoid organs

population structure

set of quantitative descriptors of a host population, including prevalence of infection, incidence, abundance of density, intensity, variance of a frequency distribution, and curve of best fit * likely to find a # of species with an intermediate snail size *

paragonimus kellicotti

similar to westernmani but this one is found in north america -int host: crayfish -human can get infected if they eat undercooked crayfish

once youre somatic youre always

somatic

flame bulb

specialized hollow excretory or osmoregulatory structure of - one or several small cells containing a tuft of flagella - situated at the end of a minute tubule - connected tubules ultimately open to the outside - rod-like extensions of the flame cell from a filtering apparatus (weir) - ductules of flame cells join collecting ducts that eventually feed into an excretory bladder that opens outside through a single pore

nidus

specific locality of a given disease; result of a unique combination of ecological factors that favors the maintenance and transmission of the disease organism

B cells bind to

specific to free (soluble) antigen or particulate antigen with its membrane bound antibody (B cell receptor); also serves as APC to TH cells

female reproductive system: ovicapt

sphincter muscle that controls the release of oocyte from the ovary

animal in video

stickleback

macroepidemiology

study of the effects of large scale factors, such as climate and culture, on distribution of disease in a population

microepidemiology

study of the effects of small scale factors, such as parasite strains, host genetic variation, and distribution of disease in a population

tegument

surficial covering of a multicellular organism, an integument

monozoic

tapeworm whose "strobila" consists of a single proglottid

Digenea: Male Reproductive System

testes: usually 2, number varies w species -> each testis has a vas efferens that ultimately connects to vas deferens -> internal seminal vesicle; located with cirrus pouch, stores sperm cirrus: male copulatory organ; cirrus pouch encloses the cirrus

mean intensity

the average number of parasites of one species per infected hosts in a sample

parasite community

the number of different parasite species infecting a single host individual

incidence

the number of new infections per unit time divided by the number of uninfected hosts at the beginning of the measured time *always given as a %* *over a time interval*

T-cell receptors are _________ with constant and variable region, like antibodies; composed of 2 chains (alpha and beta)

transmembrane proteins

in cytotoxic T cells, "altered-self" cells expressing the same combination of foreign peptide on MHC class 1 are targeted; may include __________

tumor cells, virally infected cells, or cells with intracellular parasites