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Flashcards in FA Protozoa Deck (26):

Name two species of Babesia which cause equine babesiosis

Theileria equi

Babesia caballi


Which tick transmits Babesia divergens in the UK?

Ixodes ricinus


Which species of tick transmits Tropical bovine babesiosis?



Describe/ draw the morphology of Babesia divergens in an erythrocyte


Apical complex



Name two species of "large " and "small" Babesia.

Small - divergens, bovis

Large - bigemina, major


Outline the lifecycle of Babesia species.

  • Merozoites divide by asexual binary fission
  • Tick ingests infected red blood cells, multiplication and sexual reproduction in tick
  • Dissemination of Babesia throughout tissues of the tick, move to ovaries - trans-ovarian transmission
  • Infection passes onto new host by the next generation of ticks
  • Tick attaches and feeds, sporogony occurs in salivary glands
  • Sporozoites injected into host with saliva of tick
  • Sporozoites invade red blood cells, start to divide (merogony)


What are the clinical signs of Babesiosis?

  • Disease – red water fever
  • Fever
  • Haemoglobinuria (haemoglobin in the urine)
  • Haemolytic anaemia
  • Diarrhoea
  • Acute onset
  • High levels of mortality


Which stain is used to identify Babesia?



How can Babesiosis be treated?



Calves up to what age are resistant to disease but susceptible to infection?

9 months


B. canis is transmitted by which tick species in the UK?

Dermacentor reticulatus

Rhipicephalus sanguineus


Label the apical complex of this Neospora protozoa and state its function.

The apical complex aids protozoal penetration into host cells


Describe the clinical signs associated with Canine/ bovine neosporosis.

  • Neurological disease
  • Ascending hindlimb paresis
  • Young puppies
  • Abortion in cattle


Describe the lifecycle of N. caninum when protozoa are ingested by the dog.

Dogs scavenge infected bovine tissue, protozoa go through an enteric sexual cycle, dogs excrete oocysts in dog faeces which contaminate bovine food/water supplies.


Describe exogenous transplacental transmission of N. caninum.

Pregnant cows ingest oocysts.

Tachyzoites emerge and pass through gut wall infecting cows tissues

Crosses placenta and infects foetus - either leads to abortion or persistently infected calves.


Describe endogenous transplacental transmission of N. caninum.

Cows neural tissue contains slow growing bradyzoites.

During pregnancy bradyzoites differentiate into rapidly dividing tachyzoites (recrudescence)

TPT then occurs leading to abortion (recrudescence early preg) or persistently infected calves (recrudescence later preg).



True or false.

Shedding of Neospora caninum in dog faeces is significantly lower than that in Toxoplasma gondii.

True - NC ~ 500,000, TG millions


Describe an "abortion storm"

  • >10% abortion over 12 weeks
  • Associated with exogenous TPT
  • Ingestion of oocysts during pregnancy
  • Epidemic abortion


How can N. caninum be diagnosed?

  • Maternal serology - ELISA
    • Monitor antibody fluctuation during pregnancy - more likely to see rise in second half of pregnancy
  • Foetus
    • Ab detection in foetal fluids
    • Histology - brain/ heart - non-suppurative encephalitis
    • Immunohistology 


Outline a management strategy for controlling endogenous N. caninum transmission.

(x4 strategies)

  1. Identify +ve cows
    1. Serology (not totally effective throughout preg)
    2. Test calves at birth
  2. Cull infected cows
    1. Can be expensive
  3. Selective beef breeding
    1. x cow-cow transmission
    2. No zoonotic risk
  4. Embryo transfer
    1. Ensure recips are negative


Outline a management strategy for control of exogenous N. caninum transmission.

  1. Reduce dog infection 
    1. Biosecurity
  2. Minimise cattle feed/ water contamination
  3. Bioseurity
  4. Role of pets/ wildlife


Describe the characteristics of Cryptosporidium infection.

  • Intracellular, extracytoplasmic - enterocyte microvilli border
  • Sporulates within host
  • Non-host specific


How is Crypto transmitted?

Faecal-oral route


What clinical signs and pathological features are associated with Crypto?

Associated with calf diarrhoea

  • Pathology
    • Enteritis
    • Villous atrophy
    • Crypt hyperplasia
    • Loss of mature epithelial cells 


How can crypto infection be diagnosed?

Clinical signs and signalment

  • Oocysts
    • 4-5um
    • ZN staining


How can farmers control crypto infection in their calves?

  • Halofuginone in calves
  • Control of environmental transmission - oocysts are highly resistant
  • Boil water
  • General hygiene