Babesia

Question 1

What type of parasite are babesia spp?

Answer 1

Apicomplexan protozoan parasite

Question 2

Where are babesia found in the body?

What transmits them?

Answer 2

Intra-erythrocytic

Transmitted by ticks

Host specific

Question 3

What two babesia spp are found in the UK and what transmits (or should I say trans-mites) them?

Answer 3

Babesia divergens- transmitted by Ioxdes ricinus

Babesia major- transmitted by haemophysalis punctata, uncommon SE England only

Question 4

What babesia spp are found in tropics and subtropics and what transmits them?

Answer 4

Babesia bovis and B bigemina

Transmitted by Boophilus spp

Highly pathogenic

Question 5

What are the names of these three morphology stages of babesia?

Answer 5

Question 6

Describe the structure of a merozoite

Answer 6

Question 7

How can species be differentiated at the merozoite stage?

Answer 7

The distance between the two nuclei between the apical complex

Small species- B.divergins, B.bovis

Large species- B.bigemina, B.major

Question 8

Describe the lifecycle of babesia

Answer 8

Merozoite transmitted by vector of tick
Sporozoite enter RBC and become merozoites or pre-gametocytes

Tick feeds and gametocytes enter tick and fuse in the tick midgut lumen and become zygote

Zygote invades midgut cells and multiplication occurs and becomes Kinete
Kinetes enter either ovary (transovarial transmission) and are passed to other ticks in eggs
when the infected larvae start feeding sporogony in salivary glands occurs and produces a sporozoite

Sporozoites enter RBCs

Merogony occurs- sporozoite to trophozoite to merozoite

Question 9

What are the clinical signs of babesiosis?

Answer 9

Increased temperature

Haemoglobinuria

Haemolytic anaemia

Diarrhoea which ceseases around 36 hours then becomes constipation

Begins 2 weeks after infection

High levels of mortality

Question 11

When does babesiosis usually occur?

Answer 11

Usually seen from May to November

Question 12

Why does babesiosis occur from May to November?

Answer 12

Tick host is active

Herds are out at pasture

Question 13

Where is babesiosis endemic in Britain and what does it usually affect?

Answer 13

Endemic in western areas of britain

Particulaly affects yearlings

Question 14

What is unusual about immunity to babesiosis?

Answer 14

Calves up to 9 months old are resistant to disease but susceptible to infection

Premunity- asymptompatic carriers that are immune to disease

Inverse age resistance

Question 15

What is endemic stability?

Answer 15

A climax relation between hotst, disease agent, vector and environment in which all coexist with the virtual absence of clinical disease

Question 16

What occurs if endemic stability is disrupted and how can it be disrupted for babesiosis?

Answer 16

Disruption might resuly in an increase in clinical disease incidence

Expose young stock infection
Cycling of infection between cattle and ticks
Endemic stability can break down resulting in outbreak: buying naive animals, introducing partial tick control, reseeded pasture removing the ticks

Question 17

How can babesiosis be diagnosed?

Answer 17

Clinical signs

History of exposure

Season

Stained blood smears- Giemsa- ID of merozoites

PCR

Question 18

What can babesiosis be treated with?

Answer 18

Imidocarb
provides protection from clinical disease for upto 4 weeks
allows suffucuent level of infection for immunity to develop
withdrawl- milk 21 days, meat 213 days