Babesiosis in ruminants and horses.

Question 1

Babesia species in cattle:

Answer 1

Large:

• Babesia bigemina
• Babesia major
• Babesia ovata

Small:

• Babesia bovis
• Babesia divergens
• Babesia occultans
• Babesia beliceri

Small: 1-2um, at the periphery of RBCs, obtuse angle
Large: 2-5um, in centre of RBCs, acute angle

Question 2

Babesia species in horse:

Answer 2

• Babesia equi - reclassified to Theileria equi
• Babesia caballi

Question 3

final host & vector of babesiosis in ru, eq

Answer 3

• Ticks - sexual reproduction, transovarial & transstadial
• B. bigemina: Rhipicephalus microplus, Boophilus annulatus - texas cattle cattle fever

Question 4

IH of babesiosis in bo, eq

Answer 4

Bovine & equine

(asexual reproduction)

Question 5

location of babesiosis in bo, eq

Answer 5

Intraerythrocytic
.
Pyriform, round or oval parasites of the:
* Erythrocytes
* Lymphocytes
* Histiocytes
* Erythroblasts
.
* T. equi - in lymphocytes

Question 6

life cycle of babesiosis in bo, eq

Answer 6

1) In intermediate host, there is Schizogony/Merogony: Sporozoites are passed into the blood of the intermediate host by the tick taking a blood meal. The sporozoites enter red blood cells, do binary fission and becomes merozoites. The red blood cell ruptures and the merozoites infect new red blood cells, and some will change into gametocytes.
2) In tick, there is Gametogony: a new tick will recieve gametes via blood meal, and the gametes will fertilize inside the gut of the tick. A motile zygote migrates to the salivary glands of the tick.
3) Sporogony: Inside salivary glands it will undergo sporogony. A zygote is produced, turns into a ookinete (motile zygote) - sporozoites will be ready to be injected into a new intermediate host.

TRANSOVARIAL TRANSMISSION: From adult tick to eggs - sporozoites can move to the ovaries and into the eggs of the tick. All eggs will have babesia - only in large babesia.

TRANS-STADIAL TRANSMISSION: Infection is transmitted through moulting stages of the ticks (larva - nymph - adult).

Question 7

Pathogenesis of babesiosis in bo, eq

Answer 7

Anaemia due to lysis of erythrocytes. Lack of oxygen will cause necrosis. There will be accumulation of toxic materials which affects CNS.
Most severe in adult, calves less than 1 year are seldom affected.
Mortality is 50-90%.
IP: 8-15 days, acute disease animal will die in 4-8 days. Cattle that recover are usually immune for life.

Question 8

CS of babesiosis in bo, eq

Answer 8

Fever, anaemia, icterus, pigmenturia, coca-cola urine, anorexia, large lymph nodes.

Question 9

Dx of babesiosis in bo, eq

Answer 9

• Blood sampling by vena jugularis
• Blood smear
• Capillary blood from ear & tail tip

Question 10

Tx of babesiosis in bo, eq

Answer 10

Bovine:

• Diminazine

Equine:

• Imidocarb dipropionate:
• Diminazene aceturate - not approved everywhere, toxicity risk

Question 11

Control of babesiosis in bo, eq

Answer 11

Prevention:

• Tick control
• Regular dipping of cattle

Question 12

Zoonotic babesia

Answer 12

• B. divergens
• B. bigemina
• B. equi
• B. microti

Question 13

vectors of specific babesia species

Answer 13

• Babesia bigemina - Rhipicephalus microplus & Boophilus annulatus
• Babesia major - Heamophysialis puncata
• Babesia bovis - Rhipicephalus microplus
• Babesia divergens - Ixodes ricinus