Parasitic Diseases- Helminths Flashcards
what are the 3 classifications of helminths?
- trematodes: plathelminths, flatworms
- cestodes: plathelminths, tapeworms
- nematodes: nemathelminths, roundworms
give one example of trematodes that we are studying
fasciola hepatica- flukes
what kind of life cycle do flukes have?
indirect
what is special about flukes’ sexual bits?
they are hermaphrodites, do not asexually reproduce, just do both parts on their own
what kind of animal is the final host for flukes?
ruminants, like cattle, sheep, alpacas, and llamas
what is the intermediary host of flukes?
freshwater snails
what is the one health concern about flukes?
zoonotic; humans can be accidental final host and not close the cycle via ingestion of unwashed/contaminated veggies
what is the severity of a fasciola hepatica infection in sheep, alpacas, and llamas?
devastating, acute, often fatal
what is the severity of a fasciola hepatica infection in cattle?
asymptomatic infection, chronic, rarely fatal
where is fasciola hepatica most often found? why?
south US; more rainfall and ponds means more freshwater snail intermediary hosts
how do you diagnose a fasciola hepatica infection and why?
use sedimentation because the eggs don’t float due to the operculated nature of their eggs (an opening in the top)
what kind of infection does fasciola hepatica cause in cattle?
chronic, rarely fatal
what is black disease?
occurs when fasciola hepatica infection concurrent Clostridium novyi infection, common in sheep and usually fatal becuase it fucks the liver
what are the signs of a fasciola hepatica infection (mostly in small ruminants)
- anemia
- unthriftiness
- submandibular edema
- reduced milk production
what are the signs of fasciola hepatica in heavily infected cattle?
may show now clinical signs!! (HAHA trick question, keep up the studying gal)
what are the 3 aspects of control of fasciola hepatica?
- removal of flukes in affected animals with antihelminthics
- reduction of the intermediate host snail population
- prevention of livestock access to snail-infected pasture
describe the indirect life cycle of fasciola hepatica (kinda messy, Suarez didn’t describe so probs not as important as others)
unembryonated eggs are passed in feces, and they become embryonated in water, where they evolve into miracidia and hatch in the water to invade a snail host, where they change into cercariae inside the snail, which are released and encyst on freshwater plants and migrate up to the top of grass and are ingested, as flukes, by ruminants, where they undergo sexual reproduction to make eggs that enter the bile system, then the intestine, and are secreted in the liver
what 3 cestodes are we studying?
- Taenia solium
- Taenia saginata
- Taenia multiceps
describe the body of cestodes
long, segmented, and tapelike
how long are most cestodes?
a few mm to up to 20 meters
describe the sexual bits of most cestodes
hermaphroditic
what are the 3 main sections of cestodes’ bodies?
- head (scolex): has hooks (rostellium) and suckers
- neck
- strobila (proglottids)
what do the hooks on the cestode head do?
anchor to the intestinal mucosa
what do the suckers on the cestode head do?
attach to the intestinal mucosa
do cestodes have a digestive tract? what absorbs nutrients if not?
no digestive tract, head absorbs nutrients
describe the strobila of cestode bodies
segments, each is a full hermaphroditic repro unit,are excreted in feces and look like rice
describe the life cycles of cestodes
most indirect, have 2 hosts: intermediate and final
describe the severity of the diseases caused by most cestodes
usually subclinical or mild, and serious complications are usually rare
what is the name of the disease caused by both/either Taenia solium and taenia saginata?
cysticercosis
what is the life cycle of Taenia solium and Taenia saginata?
indirect
who is the final host for Taenia solium and Taenia saginata?
humans
who is the intermediate host for Taenia SOLIUM?
pigs
who is the intermediate host for Taenia SAGINATA?
cattle
describe the indirect life cycle of Taenia solium and Taenia saginata
humans shed eggs in feces (that they got by ingesting infected/undercooked meat), pigs and cattle eat contaminated soil/pastures, then the Taenia eggs hatch in their intestines and migrate to striated muscle and develop into cysticerci
describe the larval stage of Taenia, or cysticerci
a large, fluid filled cavity or vesicle or bladder found in the musculature of pigs and cattle with ONLY ONE LARVA INSIDE
is infection due to Taenia solium and Taenia saginata common in developed countries? why or why not?
not common in developed places due to the presence of plumbing preventing human feces from ingestion by pigs and cattle
what are the symptoms of Taenia solium and Taenia saginata in the final host (humans)
unthrifitiness, malaise, decreased appetite, mild diarhhea or colic, possible weight loss
what are the symptoms of Taenia solium and Taenia saginata in the intermediary hosts? (pigs and cattle)
inflammation associated with cysticerci, though large numbers of migrating immature larvae can occasionally cause illness
what is the most important factor in control of Taenia solium and Taenia saginata infections in animals?
human sanitation
how do you diagnosis Taenia solium and Taenia saginata in the final host?
proglottids in feces, and eggs in feces by fecal float, sedimentation, or other techniques
what is the disease caused by Taenia multiceps?
coenurosis
what if the life cycle of Taenia multiceps?
indirect
who is the final host of Taenia multiceps?
dogs, IMPORTANT for hunting dogs
who is the intermediate host of Taenia multiceps?
small ruminants and wild life (like deer and rabbits, which is why dog final host is bad news bears)
how do the final hosts (dogs) of Taenia multiceps get it?
via ingestion of scraps from cleaning meat after hunting
what is the one health concern of Taenia multiceps?
zoonotic, humans accidental intermediate hosts
describe the larval stage of Taenia multiceps?
a coernus or oncosphere, large fluid-filled cavity with MULTIPLE LARVAE INSIDE
where do the larvae of Taenia multiceps develop? (5)
in skeletal muscle, myocardium, subcutaneous tissues, CNS, and viscera
what are the symptoms in the final host of Taenia multiceps?
unthriftiness, malaise, decreased appetite, mild diarrhea, weight loss (same as other Taenia final host symptoms)
what are the symptoms of Taenia multiceps in the intermediary host, specifically sheep? (7)
- behavioral abnormalities
- circling
- head pressing
- ataxia
- blindness
- convulsions
- hyperexcitability
describe control of Taenia multiceps?
keep dogs from hunting or eating intermediate hosts and keep intermediate hosts away from dog feces (see the cycle here? eggs in feces of direct, ingested by intermed. host, larvae in muscle, eaten, repeat)
describe diagnosis of Taenia multiceps?
proglottids in feces of fianl host, and eggs in the feces by fecal flotation, sedimentation, or other techniques
describe the bodies of nematodes (roundworms)
elongated and cylindrical with a protective coating or cuticle
describe the sexual bits of nematodes
two differentiated sexes, male has copulation sack, grabs female and gives her a big hug
what are the 3 life stages of nematodes?
- egg
- larva: has 3 stages itself
- adult: develops inside final host
what is cool about nematodes and nutrients?
the have a complete digestive system
what kind of life cycle do Haemonchus contortus nematodes have?
direct
what is the only host for Haemonchus contortus?
small ruminants
what is Haemonchus contortus also called and why?
stomach worms; most often found in the absomasum in gastric glands
what is the coloquial name for Haemonchus contortus and why?
barber shop pole worms, because they have a digestive system that digests the blood from stomach mucosa in a spiral shape around body
where is Haemonchus contortus found?
tropical or subtropical areas or areas with summer rainfall
describe the life cycle of Haemonchus contortus
males can attach to the stomach and the female at the same time (fuck and grab a snack), the females then hatch eggs that exit through host feces. Larva develop through all three stages in the feces, then climb to the top of the grass for small ruminants to eat them and start the cycle again
what impacts the amount of eggs created and passed of Haemonchus contortus? give an example
the physiological state of the host animal; during late pregnancy and early lactation there will be an increase in egg production bc stressed and immunity low
what are the 3 presentations of disease caused by Haemonchus contortus?
- hyperacute disease
- acute disease
- chronic disease
describe hyperacute disease as caused by Haemonchus contortus
death may occur within one week of heavy infection without significant signs or symptoms
describe acute disease as caused by Haemonchus contortus
heavy load causes severe anemia accompanied by generalized edema, becuse worms take proteins from blood
describe chronic disease as caused by Haemonchus contortus
anemia and progressive weight loss
is diarrhea a sign of pure Haemonchus contortus infection?
NO, Haemonchus contortus is commonly combined with other infections
describe how mature sheep are affected by Haemonchus contortus
may develop heavy, even fatal infections, especially during lactation
describe how goats are affected by Haemonchus contortus
goats can kinda “handle” infection by this nematode, not super affected
list the 3 nematodes we are studying
- Haemonchus contortus
- Parascaris equorum - Ascarids
- Dirofilaria Immitis- heartworm
what animal is primary affected by Parascaris equorum? and why?
foals; are under high stress during weaning which decreases their immunity
what is Parascaris equorum coloquially known as?
lungworms in horses
what is the main source of infection of Parascaris equorum for foals?
pastures, paddocks, or stalls contaminated with eggs from foals of the previous year
describe the direct cycle of Parascaris equorum
eggs are excreted in feces, where they mature from larva stage one to larva stage 2, which is ingested and goes to the gut and through the wall of the intestine to the liver and lungs, where it matures to larva stage 3 and stage 4 (ninja warriors) that can crawl up in the trachea and get reingested by the horse where they travel to the small intestine and mature or larva 5 or the adult form that make more eggs to be secreted in feces
why do parasites do a lot of their parasitic things?
because they need a lot of nutrition to mature through life
what is it called when Parascaris equorum larva go through the lungs and what does this cause?
consolidation, causes loss of function and difficulty breathing
what are the symptoms of a heavy Parascaris equorum infection?
poor condition, lack of energy, colic
what kind of life cycle does Parascaris equorum have?
direct, one host is horses
how do you diagnose Parascaris equorum?
by finding eggs in feces
what animals are primarily affected by Dirofilaria Immitus, or heart worm?
primary dogs, but also cats and ferrets
what is the host range type of Dirofilaria Immitus?
narrow, they really like dogs, but cats and ferrets will do
where do adult Dirofilaria Immitus worms usually live?
in pulmonary arteries but heavy infections will spill over into heart chambers and arteries
describe the symptoms caused due to the location of Dirofilaria Immitus?
first produces inflammation, then friction, meaning the heart no longer pumps the same, resulting in vascular dysfunction and exercise intolerance along with hypertension
do most dogs infected with Dirofilaria Immitus show symptoms?
no, most are asymptomatic
what are the most commons outward symptoms of dogs infected with Dirofilaria Immitus?
weight loss, exercise intolerance, cough, labored breathing
what is the most important therapy for Dirofilaria Immitus?
prevention!!
what kind of life cycle does Dirofilaria Immitus have?
indirect
describe the indirect life cycle of Dirofilaria Immitus
adults in the pulmonary arteries of dogs produce microfilaria that are typically found in peripheral blood, a mosquito bites a dog takes a blood meal, ingesting profilariae, which penetrate mosquito midgut and migrate to mosquito “circulation” where they produceL1 larvae, which mature to L2 and L3 larvae and then migrate to the mosquito mouth to directly enter next dog host
