Protozoa 2 Flashcards
What type of protozoa is Eimeria?
Coccidia
What is Eimeria called if it is in the caecum?
Eimeria tenella
What type of lifecycle is Eimeria?
Direct
What are the hosts of Eimeria?
Chicken, infected by ingesting sporulated oocysts
Outline the lifecycle of Eimeria?
- Unsporulated egg passed out of intestine.
- Sporulation > sporocysts
- Ingestion
- Sporozoites released
- Enter gut epithelial cells
- Schizogony
- New parasites/merozoites
- Schizogony
- Develop microgametes for males and macrogametes for females
- Fertilisation
- Zygote
What is the PPP of Eimeria?
3-5 days
What does Eimeria tenella cause?
Thickening of the mucosa
Inflammation
Haemorrhage
Necrosis
What type of protozoa is toxoplasma gondii?
Apicomplexa
What type of lifecycle does toxoplasma gondii have?
Usually direct
What are the hosts of toxoplasma gondii?
DH = cat
IH = rodent or bird
Is toxoplasma gondii zoonotic?
Yes
How log does it take for toxoplama gondii oocysts to sporulate?
1-5 days
What are the two forms of toxoplasma gondii found in outside the IH GI tract?
Tachyzoite
Bradyzoite
Distinguish tachyzoites and bradyzoites.
Tachyzoites - rapidly multiply, crescent shaped, move by apical movement
Bradyzoites - slow growing, clusters within tissue cysts in muscle and brain, can reactivate back into tachyzoites in immunocompromised hosts
Why is toxoplasma gondii infection most common in sheep and goats?
Affects non-immune pregnant females with baortion and foetal abnormality:
- Early to mid gestation = barren ewe, abortion and mummification
- Late gestation = still born or weak lambs
Distinguish the sporulated oocysts of Eimeria and Toxoplasma gondii.
Eimeria = 4 sporocysts contain 2 sporozoites
Toxoplasma gondii = 2 sporocysts contain 4 sporozoites
How can humans become infected with toxoplasma gondii?
- Eating raw or undercooked meat
- Ingesting oocysts
- Faeces of cat
What are the consequences of toxoplasmosis in humans?
- Tachyzoites fatal in very young, very old or AIDS/HIV
- Congenital infection with symptoms later in life
- Healthy person = fly like symptoms
Outline the lifecycle of toxoplasma gondii.
- Oocysts passed in cat faeces
- Ingested by IH
- Tachyzoite
- Bradyzoite
- Endogeny
- DH ingests IH
- Gametogony
- Fertilised zygote
- Oocysts passed in cat faeces
- Can pass to sheep and goats, causing abortion and foetal abnormalities.
- Human ingests oocysts in raw/undercooked meat.
What type of protozoa is neospora caninum?
Coccidia
What are the hosts of neospora caninum?
DH = dog, via eating raw meat or placenta of cattle
IH = cattle, via ingesting sporulated oocysts in dog faeces or contaminated food/water
What are the effects of neospora caninum?
Dog = most severe in puppies, causes paralysis
Cattle = abortion, congenitally infected
What are the accidental hosts of neospora caninum?
Horse, sheep, goat
Why can the lifecycle of neospora caninum continue without the definitive host?
Calf born congenitally infected via endo transplacental transmission seem fine and then bradyzoites reactivate during pregnancy.
What type of protozoa is babesia?
Piroplasm (apicomplexa)
What is the host and vector of babesia canis?
DH = dog
Vector = dermacentor reticulatus, rhipicephalus sanguineus
How is babesia diagnosed?
Blood smear, as it is a parasite of rapid division in the red blood cells
What are the clinical signs of babesia canis?
1-2 weeks post tick feeding
Anaemia
Fever
Haemoglobinuria
Outline the lifecycle of babesia canis.
- Tick feeds on dog
- Sporozoites penetrate RBCs
- Binary fission (asexual)
- Merozoites released
- Tick consumes blood
- Multiply in tick gut cells and salivary glands as well
- Sporozoites released in tick saliva
Use babesia as an example to distinguish transstadial and transovarial transmission.
TS - disease can die out without the host effected by disease goes, pasture spelling gets rid
TO - eggs come readily infected, resting pasture will not prevent, survives in vertical transmission within ticks and so are a reservoir of disease
What is the host and vector of babesia divergens?
DH = cattle
Vector = ixodes ricinus
How is babesia divergens diagnosed?
Blood smear - abnormal inclusions within red blood corpuscles
What are the clinical signs of babesia divergens?
Anaemia
Haemogloburinuria
Anorexia
How does babesia divergens have enzootic stability?
A stage of host-tick pathogen interaction with a high infection in calves but absence of disease due t inverse age resistance = high immunity in adult cattle, so low levels of clinical disease.
What is a risk factor of babesia divergens?
Adults without immunity become very sick, fluctuation in tick numbers
Describe how to control bovine babesiosis.
Ensure tick exposure before 6 months
What type of protozoa is leishmania?
Flagellate
What are the hosts and vectors of leishmania?
Hosts = dog, human, wild animals
Vector = bloodsucking phlebotomine sandfly
What does leishmania infect?
Host macrophages
Describe the epidemiology of leishmania.
Mediterranean Europe, Africa, Asia, America. Risk factor is dogs imported to UK, like rescues.
What is the incubation period of leishmania?
Months to years
What are the clinical signs and pathology of leishmania?
Anaemia
Weight loss
Lethargy
Skin lesions
What type of protozoa is trypanosoma brucei?
Flagellate
What are the hosts and vectors of trypanosoma brucei?
Hosts = production animals and humans
Vector = tsetse fly
What disease does trypanosoma brucei cause in humans and animals?
Humans = sleeping sickness/African trypanosomiasis. Extreme fatigue, headache.
Animals = Nagana. Anaemia, fever
Why can trypanosoma brucei evade host immune response?
Antigenic variation - variable surface glycoprotein coat genes
What type of protozoa is giardia?
Flagellate
Is giardia zoonotic?
Yes
Outline the lifecycle of trypanosoma brucei.
Direct:
- Ingest mature cyst
- Excystment in duodenum
- Trophozoites attach with suckers to small intestine
- Cysts mature in colon and faeces
What are the clinical signs of giardia?
Diarrhoea in dog, human and bird. This is because trophozoites block absorption mechanically.
