Protozoa Flashcards

PROTOZOA WIKIBUGS FLASHCARDS

Toxoplasma gondii - Ke Hu and John Murray

Protozoa

Question	Answer	Article
What are the four different ways protozoa can move?	Cilia Flagellum Pseduopodia Gliding	Link to Answer Article
How do protozoa reproduce?	By binary fission By schizogony By sporogony By gametogeny	Link to Answer Article
Briefly summarise the life cycle of protozoa	The infectious sporozoite are released from the oocyst invading epithelial tissue The nucleus of the sporozoites divides forming a schizont which contains merozoites (schizogony) Schizont ruptures releasing merozoites which form micro and macrogamonts in the epithelial tissue (gametogeny) Microgamonts penetrate the macrogamont forming the zygote The zygote forms the oocyst which is passed in the faeces Sporulation occurs which makes the oocyst infectious	Link to Answer Article

Coccidia

Question	Answer	Article
What is the transmission and life cycle of Eimeria species?	Direct transmission Faecal-oral route	Link to Answer Article
What is the transmission and life cycle of Isospora species?	Usually direct transmission by the faecal-oral route Some species use facultative intermediate hosts forming tissue cysts Transmission is then by the faecal-oral or route or via ingestion of the intermediate host	Link to Answer Article
How long is the prepatent period of poultry Eimeria species?	1 week Sporulation takes 2-3 days	Link to Answer Article
Name the malabsorptive Eimeria species	E. maxima E. acervulina E. mitis E. praecox	Link to Answer Article
Name the haemorrhagic Eimeria species	E. necatrix E. brunetti E. tenella	Link to Answer Article
Which area of the gastrointestinal tract does E. acervulina, E. maxima, E. tenella and E. necatrix affect and what kind of lesions are produced?	E. acervulina affects the proximal gut forming white ladder lesions E. maxima affects the mid-gut producing a pink exudate E. tenella affects the ceaca forming a core of dark, haemorrhagic blood E. necatrix affects the mid-gut forming salt and pepper leions	Link to Answer Article
What are the two main Eimeria species which affect cattle and what is the prepatent period?	E. zuernii E. bovis 2-3 week prepatent period	Link to Answer Article
What are the two significant Eimeria species which affect sheep and what is the prepatent period?	E. ovinoidalis E. crandalis 2 week prepatent period	Link to Answer Article
What is the most significant species of Isospora which affects pigs and what the prepatent period?	I. suis 1 week prepatent period	Link to Answer Article
Which parts of the gastrointestinal tract do the Eimeria species which affects rabbits inhabit?	2 inhabit the caecum 1 inhabits the bile duct epithelium (E. steidae)	Link to Answer Article

Cryptosporidia

Question	Answer	Article
What is the main species of Cryptosporidium which infects humans and domestic animals?	C. parvum	Link to Answer Article
True or False: In Cryptosporidium infections unsporulated oocysts are passed in the faeces	False Sporulated oocysts are passed in the faeces	Link to Answer Article
How are Cryptosporidium infections passed between hosts?	Direct faecal-oral transmission Water-bourne infections Autoinfection can also occur	Link to Answer Article
How are Cryptosporidium infections prevented?	Isolate and quarantine brought in calves Good hygiene and adequate disinfection of calf pens Goog hygiene of humans working and visiting farms Halofuginone and other drug treatments	Link to Answer Article

Giardia

Question	Answer	Article
What is the key points of the life cycle and prepatent period of Giardia?	Simple life cycle Direct life cycle Reproduce by binary fission 5-6 day prepatent period	Link to Answer Article
How do both people and animals become infected by Giardia?	Water bourne transmission Direct faecal-oral transmission	Link to Answer Article
How would you diagnose a Giardia infection?	The cysts are heavy and do not float well in saturated sodium chloride solution Cysts excretion is intermittent so faeces need to be collected and sampled over 3 days Cyst antigen can be detected in faeces by an immunoassay	Link to Answer Article

Piroplasmida

Question	Answer	Article
True or False: Both trans-stadial and trans-ovarian transmission can occur in Babesia species	True	Link to Answer Article
What are the recognisable features of small Babesia species and give an example	Peripheral nucleus Obtuse angle B. divergens	Link to Answer Article
What are the recognisable features of large Babesia species and give an example	Central nucleus Acute angle B. major	Link to Answer Article
What are the predisposing features to Babesia infection?	Susceptible animals introduced into an infected area Infected ticks introduced into a clean area Infected cattle introduced into an area with clean ticks Temporary reduction in the tick population decreasing the transmission rate (causing enzootic instability) Infected are transported or stressed in other ways, e.g. parturition	Link to Answer Article
What are the different vectors for Babesia species?	Ixodes ricinus for B. divergens Haemaphysalis for B. major Boophilus for B. bovis and B. bigemina Dermacentor and Rhipicephalus for B. canis	Link to Answer Article
What species are the natural vectors for Cytauxzoon?	Ticks	Link to Answer Article
Where do schizonts of Cytauxzoon felis develop?	In macrophages	Link to Answer Article
What is the main condition caused by Theileria parva?	East Coast Fever	Link to Answer Article
What is the main condition caused by Theileria parva and what is the intermediate host?	East Coast Fever Rhipicephalus appendiculatus	Link to Answer Article
What is the pathogenesis of Theileria parva infections?	Proliferation in the lymphoblasts Proliferation in the local lymph node followed by spread throughout the body Lymphocyte depletion	Link to Answer Article
What are the clinical signs of Theileria parva infection?	Pyrexia Enlarged local lymph node Loss of condition	Link to Answer Article

Tissue Cyst Forming Coccidia

Question	Answer	Article
What are the two main species of Neospora of veterinary interest and which animals do they affect?	N. caninum Dogs N. hughesi Horses	Link to Answer Article
How long is the prepatent period of Neospora?	5 days	Link to Answer Article
What are the clinical signs of Neospora infections in dogs?	Ascending paralysis Sudden collapse due to myocarditis Muscle wasting	Link to Answer Article
What are the clinical signs of Neospora infections in cattle?	Abortion Encephalomyelitis Paresis	Link to Answer Article
What are the clinical signs of Neospora infections in horses?	Myeloencephalitis	Link to Answer Article
How many intermediate and final hosts does Sarcocystis have?	One final host One intermediate host	Link to Answer Article
True or False: Sarcocystis infections are mainly asymptomatic	True	Link to Answer Article
What is Equine protozoal myeloencephalitis?	Necrotising encephalomyelitis affecting the grey and white matter of the CNS Caused by S. neurona Causes spinal cord dysfunction leading to ataxia and paralysis	Link to Answer Article
What is the most pathogenic species of Toxoplasma?	T. gondii	Link to Answer Article
True or False: The life cycle of Toxoplasma is direct	False The life cycle is complex Described as facultatively heterozygous	Link to Answer Article
Describe the acute phase of Toxoplasma infections	Asexual reproduction in the cell by endodyogeny (budding) producing 8-16 tachyzoites Tachyzoites are released when host cell bursts Haematogenous spread as more cells are infected Infection continues until the animal develops immunity (around 2 weeks) at which point the infection enters the chronic phase	Link to Answer Article
Describe the chronic phase of Toxoplasma infections	Slow growing intracellular bradyzoites become walled off forming infective cysts Bradyzoites are protected from the host immune response (whereas extracellular tachyzoites are killed) Cysts remain viable for months to years in muscle and nervous tissue If immunity is suppressed the infection can revert to the acute form	Link to Answer Article
How can Toxoplasma infections be prevented?	ELISA to check for seropositive cats Humans can avoid oocyst ingestion Humans can avoid tissue cyst ingestion Sheep can be vaccinated or given medicated feed	Link to Answer Article

Tropical Protozoa

Question	Answer	Article
What species transmits Leishmania?	Sandflies Phlebotomus spp. in the Old World Lutzomyia spp. in the New World	Link to Answer Article
Which cells are Leishmania species intracellular parasites of?	Macrophages	Link to Answer Article
What are the clinical signs of Leishmania infections?	Cutaneous form Ulcers on the lips, eyelids and pinnae of ears Visceral form Eczema Fever Generalised lympadenopathy	Link to Answer Article
How can you treat or prevent Leishmania infections?	Chemotherapy Prevent sandflies biting dogs through collars containing insecticides Destruction of infected and stray dogs	Link to Answer Article