Parasitology 5 Flashcards

Terms Definitions
Eimeria oocysts
gliding parasite
Do Filaroide migrate?
Caused by ectoparasite
Infective stage of Hookworms?
Hookworms for cat
Ancylostoma tubaeforme
Cryptosporidium Parvum
Coccidian parasite
Worldwide distribution
Recognized as a veterinary pathogen 1907, 1st human case 1976
Intracellular pathogen; microvilli
in small intestine
Oocysts move into intestine where excyst to sporozoites; Oocysts resistant to disinfection; ID50 is 130 cysts or so
Pathogenesis of diarrhea unclear; microvilli atrophied and blunted. Sporozoites seen along apical surfaces of intestinal epithelial cells
Transmission water>>fecal-oral>person-person
quartan fever
2 days free
What are helminths?
multicellular/ extracellular parasites. Transmitted by oral ingestion (ascaris), Direct penetration of unbroken skin (hookworm), Arthropod vectors bites (filariasis). Cuticle for protection. Complex life-cycles with environmental and animal reserviors
Who see Toxascaris in mostly?
Infective stage of Oxyuris?
larvated egg
Most common strygulus sp.
Strongylus edentatus
attachment exchange of genetic material between sister cells
Dirofilaria immitis
dog heartworm; causes "coin lesion"
What age start heartworm prophylaxis?
8 weeks
Where do Ancylostoma caninum live?
Small intestines
Fileriasis (wuchereria bancrofti ex.) causes what disease symptoms?
Lymphnode inflamation
Milky urine (lymph in urine)
possible elephantiasis only in small percentage of pts, ususally unilateral
Permanent Stained smear
Trichrome or Iron-hemotoxylin stains
malarial dormant stage, persist in liver
antimalarial drugs
no resistance - oral chloroquine
Resistance – malarone atovaquone-proguanil
Proliferation of this organism within the lung causes a 'fungus ball' that must be removed surgically
Aspergillus fumigatus
most common tapeworm in North america
Hymenolepsis nana
Heartworm test of choice for dog?
Antigen test
carry parasite from host to host; could be an intermediate host; 2 types: biological and mechanical
Ostertagia and cyathostomes are both a result of large numbers of larvae resuming development and emerging? T or F.
An assoc. between 2 organisms of diff. species in which one lives on or w/in the other member and may cause harm. Parasite is dependent on the host.
Cestode is what type of worms?
Tape worms...
Strongiloides Pathogenesis
Adult worms embedded in small intestinal mucosa lead to local inflammation
Larvaetissue inflammation during migration
Penetrating larvae may carry enteric bacteria
direct wet mount
detects motile organisms (Giardia) usually in duodenal drainage , with saline or iodine
direct lifecycle
parasite is transmitted directly form one host to another
rabies virus
Neurological, bite of rabid animal delivers virus to tissue, spreads to CNS, humans are a dead end host. Furious and paralytic forms
What's the infection to worry about with contact lense wearers who go swimming?
Acanthamoeba (protazoa).
Dissemination to the liver can result in abscess formation with a characteristic anchovy paste aspirate.
Entamoeba histolytica
dx of Onchocerca volvulus
microfilariae in skin or nodules
How Strongyloides transmitted?
Ingest L3, penetrate skin, and lactogenic transfer
Which worm has large football shaped eggs?
Nematodirus sp.
Eggs of Trichinelloidea/whip worms?
eggs w/ polar plugs; symmetrical
Ascarids are zoonotic?
Yes, can cause visceral larval migrans
Parasite lives on the body of the host. EX: Fleas on dogs. Will produce and infestation on the host.
Strongyloides stercoralis infect by what path?
can penetrate skin,
enter circulation,
goes through heart to lungs,
coughed up and ingested
Acsaris Life cycle
Ingested eggs hatch in small intestine. Larva pass through intestinal wall into venous system to liver; then through heart to lungs. In lungs larvae mature and pass into airways where they are then coughed up and swallowed. Then complete develop into adult worms in small intestine.
During there passage through tissues (intestinal wall and lungs can cause inflammation with eosinophilia
One month to complete

can cause pneumonia and disease in the SI
A 2-year old indoor/outdoor cat presented with vomiting of several weeks duration. The animal originally came from a cattery. What parasite will NOT be included on your differential diagnostic list.

a) Acanthocheilonema (Dipetalonema)

b) Dirofilaria imm
a) Acanthocheilonema (Dipetalonema)
Parasite that lives within the body of the host
no blood or haemorrhage, watery d in intestine, localised in duodenum
Name the 3 types of parasites.
Protozoa, helminths, and ectoparasites. 10-2
Causes the most common subcutaneous mycosis, Rose handler's disease
Sporothrix schenckii(Transmitted by the prick of a contaminated thorn, treated with a dilute solution of potassium iodide [KI] in milk).
What are the clinical presentation of malaria?
1. Potentially life-threatening:ssx:non-specific fever, non-specific anemia, non-specific splenomegaly, CNS problems w/ P.falciparum, Nephrotic syndrome w/ P. malariae, malaise.
how check for MF for difilaria immitis?
Knott's test/filter test
Hosts of Toxascaris?
Cats, dogs, and wild cats and dogs
Where does Strongylus vulgaris like to migrate?
Cranial mesenteric artery
A Parasite that wander from its usual site of infection into and organ or another that is does not ordinarily live. EX: hookworm in the liver
Erratic Aberrant
Anisakiasis's main source of infection are what vector?
Marine fish, mainly sushi
Typanosomaisis B. causes what symptoms?
1. swollen lymphs
2. swollen necks(winterbottom's sign)
3. fever
4. meningoencephelitis
5. lethargy/sleepiness
6. paravascular inflamation in brain causes anoxia in brain (sleepiness), organisms also excrete chemicals that cause sleepiness
Plasmodium is transmitted by
the female anopheline mosquito which injects sporozoites present in the saliva of the insect. Malaria can also be transmitted by transfusion and transplacentally.
type 1 ostertagi
Watery d bright green, weight loss, high morbidity, low mortality
Results in rhinocerebral disease, primarily in patients with diabetic ketoacidosis or leukemia.
Mucor and Rhizopus species of fungus.
Causes flatulence and diarrhea with steatorrhea and the production of bulky and greasy foul-smelling stool.
Giardia lamblia(infection more common among day-care children and campers).
What are Cryptosporidiosis clinical presentations?
1. normal host: self-limiting diarrhea for 1-2 wks. No Rx2. Immunocompromised host (AIDS): chronic, intractable debilitating diarrhea. Hard to Rx.3. Community outbreaks possible
dx for Schisosomiasis
detection of eggs in feces or urine (hematobium)
How diagnose heartworm disease?
fecal; x rays for right heart enlargement, coughing, serology, EKG, CBC, arteriogram
Cryptosporidiosis causes what type of symptoms? how is it diagnost?
Severe diarrhea, malagia, weight loss.
Spores in feces or string test
How do you diagnose onchocerca?
skin scraping, simply look for them
E. Histolytica-lifecycle and mode of infection
Recognizes N and O-linked oligosaccharides in colonic mucinadherence
Ingested cysts (environmentally resistant) transform to trophozoites upon exposure to stomach acid that colonize and in some individuals subsequently invade intestinal mucosa. In most the infection is asymptomatic. In some it invades the intestinal mucosa causing colitis and less commonly, through hematogenous or direct spread, distant infection
Trophozoites can divide and transform to infective cysts in asymptomatic carriers or symptomatic patients that are pasted in the stool
Entameba histolytica cysts are
spherical, with a refractile wall; the cytoplasm contains dark staining chromatoidal bodies  and 1 to 4 nuclei with a central karyosome and evenly distributed peripheral chromatin.
How do tissue nematodes cause disease?
larvae of roundworms are transmitted by mosquitoes etc (filariasis)
After bite the larvae go to lymphatics and mature.
Females get fertilized and then discharge microfilariae (new larvae) into blood.
Lymphatics become blocked, causing elephantiasis.
What are the Ssx of chronic schistosomiasis?
1. fatigue, abdominal pain, intermittent diarrhea, hepatomegaly, hematuria, hematemesis2. chronic inflammation with granuloma formation in liver, intestines, bladdera) secondary rxn to eggs:fibrosisb) eggs can get into the liver: fibrosis/cirrhosis, cause portal hypertension. or to colon c, cause polyps, diarrhea3. S maematobium causes lesions in bladder, ureters (hematuria, cystitis)4. Eggs lodged in lungs (pulmonary hypertension), Spinal cord (inflammation, transverse myelitis).5. Cell mediated immunity
What are the clinical presentations of American Trypanosomiasis: Chagas Disease?
Caused by Trypanosoma cruzi1.Acute phase: fever, local swelling, periorbital edema, myocarditis, adenopathy, may last weeks.2.Asymptomatic phase/resolution phase: most patients3. Chronic phase: months-yearsa.Cardiomyopathy with CHF, irregular HRb. Megaesophagous: aspirationc. Megacolon: constipation
What are the clinical presentation of P. carinii in immunocompromised (AIDS) patients?
Pneumonia: shortness of breath, non-productive cough, fever, decreased oxygen levels, bilateral interstitial infiltrates in x-rays
life cycle of schistosomes
eggs excreted by humans and hatch in fresh water forming miracidia. these miracidia penetrate snails and form sporocysts then cercariae (infectious) inside which are released; cercariae penetrate human skin and lose tails to become schistosomulae which enter circulation and mature in liver; they eventually mate and move to venules of bowel,rectum or bladder --> bisexy worm
What causes damage of Oesophagostomum?
When worms emerge from nodules into large intestines; get diarrhea and allergic response
Name the stages of life for taenia-
1. egg
2. oncosphere
3. cysticercus
4. adult
Which worms are associated with water plants?
1. Fasciolopsis buski
2. Fascila hepatica
Which worms are associated with sheep?
1. Fasciola hepatica (sheep liver fluke)
2. Echinococcus granulosus
Four Plasmodium species are responsible for human malaria These are
P. falciparum, P. vivax, P. ovale and P. malariae.
Produces a toxin that results in liver damage upon ingestion of wild mushrooms
Amanita species(ingestion results in life-threatening fulminant hepatitis)
What does an Ascariasis infection look like?
1. light infections: asymptomatic, may pass a worm!2. heavy infection: malnutrition, impaired physical, cognitive functionbiliary obstruction, lower intestinal obstruction: appendicitis, lg. bowel obstruction, pancreatitis., lung symptoms: cough, hemoptysis, transient lung infiltrates (Loeffler's Syndrome), asthma like ssx, worms can be coughed up!
What is the pathophysiology of P. falciparum malaria?
P. falciparum only human malaria parasite: microvascular disease. As it matures, knobs appear on surface of parasitized RBC, that helps cytoadherence to endothelial cells in capillaries and post-capillary venueles of brain, kidner, affected organs. Causes hypoglycemia (parasite glucose consumption), lactic acidosis (glucose depletion, acidosis at tissue level, decrease BP)
What reasons explain a negative serology test when actually positive?
1- immature worms2- males only3- too few worms4- antigen sequestration
What worms have a snail as an intermediate host?
1. Fasciolopsis buski
2. Fasciola hepatica
3. Clonorchis sinensis
4. paragonimus westermani
5. Schistosoma mansoni
How do you make a Babesiosis Dx?
1. Microscopic exam of blood smear: Giemsa or Wright stain, thick/thin blood smears. Look for intracellular forms in "Maltese Cross"2. Antibody: indirect immunofluorescent test3. PCR on blood
What is characteristic sign of Ascaris suum?
Milk spots in liver from migrating larvae! can be lethal
What is the diagnostic stage for strongyloides?
only worm who's diagnostic stage that is larval
Where might you more frequently find a Babesia infection?
What infection is associated with the United States, especially Nantucket Island, Martha's Vineyard, Cape Cod, and sometimes Pennsylvania?
How do you diagnose Taenia solium infections?
1. Exam stool for eggs or non-motile proglotidds.2. MRI to see disseminated cysts.3. Serology done in cysticercosis.
Diagnosis is made by what to ID typanosomes?
Recovery of typanisomes in body fluid in blood (early), CSF(blood)
When get + serology results for heartworm test if positive?
about 5 months (and about 6 months for MF)
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