FA Protozoa

Question 1

Name two species of Babesia which cause equine babesiosis

Answer 1

Theileria equi

Babesia caballi

Question 2

Which tick transmits Babesia divergens in the UK?

Answer 2

Ixodes ricinus

Question 3

Which species of tick transmits Tropical bovine babesiosis?

Answer 3

Boophilus

Question 4

Describe/ draw the morphology of Babesia divergens in an erythrocyte

Answer 4

Merozoites

Apical complex

Nucleus

Question 5

Name two species of “large “ and “small” Babesia.

Answer 5

Small - divergens, bovis

Large - bigemina, major

Question 6

Outline the lifecycle of Babesia species.

Answer 6

• 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)

Question 7

What are the clinical signs of Babesiosis?

Answer 7

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

Question 8

Which stain is used to identify Babesia?

Answer 8

Giemsa

Question 9

How can Babesiosis be treated?

Answer 9

Imidocarb

Question 10

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

Answer 10

9 months

Question 11

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

Answer 11

Dermacentor reticulatus

Rhipicephalus sanguineus

Question 12

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

Answer 12

The apical complex aids protozoal penetration into host cells

Question 13

Describe the clinical signs associated with Canine/ bovine neosporosis.

Answer 13

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

Question 14

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

Answer 14

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

Question 15

Describe exogenous transplacental transmission of N. caninum.

Answer 15

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.

Question 16

Describe endogenous transplacental transmission of N. caninum.

Answer 16

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).

Question 17

True or false.

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

Answer 17

True - NC ~ 500,000, TG millions

Question 18

Describe an “abortion storm”

Answer 18

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

Question 19

How can N. caninum be diagnosed?

Answer 19

• 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

Question 20

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

(x4 strategies)

Answer 20

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

Question 21

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

Answer 21

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

Question 22

Describe the characteristics of Cryptosporidium infection.

Answer 22

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

Question 23

How is Crypto transmitted?

Answer 23

Faecal-oral route

Question 24

What clinical signs and pathological features are associated with Crypto?

Answer 24

Associated with calf diarrhoea

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

Question 25

How can crypto infection be diagnosed?

Answer 25

Clinical signs and signalment * Oocysts * 4-5um * ZN staining

Question 26

How can farmers control crypto infection in their calves?

Answer 26

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