Protozoa 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 Article
How do protozoa reproduce?	By binary fission By schizogony By sporogony By gametogeny		Link to 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 Article

Coccidia Flashcards

Cryptosporidia Flashcards

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 Article
How do both people and animals become infected by Giardia?	Water bourne transmission Direct faecal-oral transmission		Link to 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 Article

Piroplasmida

Question	Answer		Article
True or False: Both trans-stadial and trans-ovarian transmission can occur in Babesia species	True		Link to Article
What are the recognisable features of small Babesia species and give an example	Peripheral nucleus Obtuse angle B. divergens		Link to Article
What are the recognisable features of large Babesia species and give an example	Central nucleus Acute angle B. major		Link to 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 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 Article
What species are the natural vectors for Cytauxzoon?	Ticks		Link to Article
Where do schizonts of Cytauxzoon felis develop?	In macrophages		Link to Article
What is the main condition caused by Theileria parva?	East Coast Fever		Link to Article
What is the main condition caused by Theileria parva and what is the intermediate host?	East Coast Fever Rhipicephalus appendiculatus		Link to 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 Article
What are the clinical signs of Theileria parva infection?	Pyrexia Enlarged local lymph node Loss of condition		Link to 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 Article
How long is the prepatent period of Neospora?	5 days		Link to Article
What are the clinical signs of Neospora infections in dogs?	Ascending paralysis Sudden collapse due to myocarditis Muscle wasting		Link to Article
What are the clinical signs of Neospora infections in cattle?	Abortion Encephalomyelitis Paresis		Link to Article
What are the clinical signs of Neospora infections in horses?	Myeloencephalitis		Link to Article
How many intermediate and final hosts does Sarcocystis have?	One final host One intermediate host		Link to Article
True or False: Sarcocystis infections are mainly asymptomatic	True		Link to 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 Article
What is the most pathogenic species of Toxoplasma?	T. gondii		Link to Article
True or False: The life cycle of Toxoplasma is direct	False The life cycle is complex Described as facultatively heterozygous		Link to 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 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 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 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 Article
Which cells are Leishmania species intracellular parasites of?	Macrophages		Link to 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 Article
How can you treat and prevent Leishmania infections?	Chemotherapy Prevent sandflies biting dogs through collars containing insecticides Destruction of infected and stray dogs		Link to Article
Which diseases so Trypanosome species cause in cattle and in humans?	Nagana in cattle (wasting disease) Chagas disease in humans, armadillos and possums Sleeping sickness in humans		Link to Article
Fill in the missing words about trypanosoma infections? Salivarian trypanosome species multiply in the ??? and ??? of ???. This is also known as ??? development. Stercorian trypanosome species multiply in the ??? of ??? bugs, keds and ???. This is also known as ??? development.	proboscis foregut Tsetse flies anterior station hindgut Triatomid tabanids posterior station		Link to Article
What are the general clinical signs of trypanosoma infections?	Anaemia Enlarged lymph nodes and spleen Degeneration and inflammation of multiple organs Loss of body condition Oedema of the limbs and genitalia in horses Myocarditis and corneal opacity in dogs and cats		Link to Article
How are trypanosoma infections diagnosed?	Giemsa stained smears Fresh blood films looking for motile trypanosomes Haematocrit tubes looking for motile trypanosomes at the buffy coat/plasma interface		Link to Article

Other Important Protozoa

Question	Answer		Article
What is Balantidium and where is it found?	Ciliate protozoan Commensal organism Found in the lumen of the large intestine of pigs and humans		Link to Article
How would you diagnose Cyclospora infections?	Faecal smear for oocysts Zeihl-Neelson stain positive Oocysts autoflouresce		Link to Article
How can Entamoeba cause abcesses in the liver?	Erosion of the large intestine may allow the parasite to enter the bloodstream Once in the bloodstream the parasite can reach the liver and cause ascesses		Link to Article
What disease does Histomonas meleagridis cause and in which species?	Causes Blackhead Affects turkeys Chickens are asymptomatic carriers		Link to Article
In which caecal nematode worm is H. meleagridis carried?	Heterakis gallinarum		Link to Article
What are the clinical signs of H. meleagridis infections?	Ante-mortem Cyanotic head and wattles Yellow droppings Post Mortem Necrotic mucosa in caecum 1cm diameter circular lesions in the liver		Link to Article
What are the clinical signs of Microsporidia infections?	Head-tilt Incontinence Uveitis Cataracts But mostly asymptomatic		Link to Article
How is Tritrichomonas foetus transmitted?	Venerally		Link to Article
Where is Tritrichomonas foetus found in cattle?	Uterus of cows Preputial cavity of bulls		Link to Article