Parasitology - VTNE Review Exam Questions and Answers

Protozoa - One celled, microscopic parasites What are examples of protozoa? - Ameba (Entamoeba) Flagellates (Guardia, Leishmania) Ciliates (Balantidium) Sporozoa; coccidians; organisms who's adult stage is not motile. (Plasmodium, Cryptosporidium) What are sample diseases of protozoa? - Malarias, piroplasmoses, coccidioses, trypanosomiases Helminths - Multicelled; usually visible to the naked eye What are examples of helminths? - Flatworms (Platyhelminths) Trematodes (Flukes) Cestodes (Tapeworms) Thorny-headed (acanthocephalins) Roundworms (Nematodes) What are sample diseases of helminths? - Eyeworm, heart worm, onchocerciasis, dipyidiasis, hump sore, etc. Ectoparasites and Arthropods - Live on external surfaces or in the skin. Serve as vectors to transmit infective organisms from one host to another. What are examples of ectoparasites and arthropods? - Diptera: mosquitoes, black flies, horseflies, deer flies Fleas and lice What are sample diseases of ectoparasites and arthropods? - Heartworm (from mosquitoes) Malaria West Nile; equine encephalitis What is the specific gravity of most parasite eggs? - Between 1.100 and 1.200 SG of water is 1.000 What solutions are used for flotation? - Sodium nitrate; SG of 1.200-1.250 Sugar solutions; 1.330 Zinc sulfate solution; 1.180 Saturated sodium chloride solution; 1.200 How much feces is needed for flotation? - 2-4g (0.5-1 teaspoon) When are direct smears used in fecal? - They are used to detect protozoa in feces. Quickly estimate the number of parasites. When is the centrifugal flotation technique used? - Detect Giardia oocysts and Trichuris ova more efficiently than regular flotation technique. What information should fresh specimens have on their package? - Date, location where specimen was obtained, owner's name, animal's species, animal's name or identification number, referring vet, clinic address, and telephone number What parasites are you looking for in skin scrapes? - Sarcoptes (burrowing mite) Demodex (hair follicle mite) Chorioptes (non burrowing mite) Cheyletiella (walking dandruff) What parasites are you looking for when using the cellophane tape method? - Mites and pinworms that are primarily on the skin surface and the hair. Cheyletiella and Oxyuris equi Toxocara canis : dog - Roundworms; found in the small intestines. 3-5 week prepatent period Method of infection: Ingestion, paramedic host, transplacentally, transmammary Clinical signs: poor growth, emaciation, intestinal blockage, vomiting, diarrhea, death Control: remove feces from environment Ancylostoma caninum : dog - Hookworms; found in the small intestines 3-5 week prepatent period Method of infection: Skin penetration, injection, transmammary, paramedic host, transplacentally Clinical signs: anemia, weakness, melena Control: remove feces from environment Uncinaria stenocephalo : dog - Hookworms; found in small intestines 2 week prepatent period Method of infection: ingestion, skin penetration (not likely) Clinical signs: usually no obvious clinical signs. In heavy infection in dogs, hypoproteinemia, dehydration, weakness Control: remove feces from environment Trichuris vulpis : dog - Whipworms; found in large intestines 3 mo prepatent period Method of infection: ingestion Clinical signs: severe watery diarrhea, hematochezia, leading to rapid dehydration and death (in severe cases) Control: remove from environment Eucoleus boehmi : dog - Found in nasal sinuses Uknown prepatent period Method of infection: ingestion Clinical signs: upper respiratory signs, sneezing, and nasal discharge Filaroides spp. : dog - Canine lungworm; found in lungs Prepatent period: 5-10 weeks Method of infection: paratenic host, ingestion Clinical signs: chronic coughing Crenosoma spp. : dog - Found in lungs Prepatent period: 19-21 days Method of infection: ingestion Clinical signs: coughing Spirocerca lupi : dog - Esophageal worm; found in esophagus Prepatent period: 5-6mo Method of infection: ingestion Clinical signs: vomit, dysphagia, weight loss, sudden death Control: dogs should be prevented from eating dung beetles, frogs, mice, and lizards, and they should not be fed raw chicken scraps. Dirofilaria immitis : dog and cats - Heartworm; found in heart Prepatent period: 6-8 months Method of infection: transmission from infective mosquito bites, transplacental infection of microfilariae only Clinical signs: lethargy, exercise intolerance, signs referable to right-sided cardiac enlargement Control: use of preventives, reduce exposure to mosquitoes in endemic areas Acanthocheilonema recondite : dog - Dipetalonema; found in subcutaneous tissue Prepatent period: 9 week Method of infection: transmission for infective flat bites, ingestion Clinical signs: Considered to be nonpathogenic, microfilariae may cause problems in kidney tubules Control: control flea population Dioctophyma renale : dog - Giant kidney worm; found in kidney Prepatent period: 5mo Method of infection: ingestion Clinical signs: may be none; vague abdominal pain after kidney rupture. Adult worms often found in abdominal cavity at surgery. Control: surgical removal; nephrectomy if in the kidney Dracunculus insignis : dog - Guinea worm; found in subcutaneous tissue Prepatent period: 309-410 days Method of infection: ingestion of crustaceans in infected water Clinical signs: pea sized blisters on legs, elbow, and axillary area; break open. Adult worms coiled in subcutaneous tissue Control: surgical removal