Babesia spp Flashcards
What kind of parasite is Babesia?
Apicomplexan protoxoa
How is Babesia transmitted?
By ticks
Name the two species of bovine Babesia found in the UK
Babesia divergens
Babesia major
Babesia divergens is transmitted by which tick?
Ixodes ricinus
Give two examples of bovine Babesia spp found in the tropics and subtropics
Babesia bovis
Babesia bigemina
Inside of which cells do Babesia replicate?
Host red blood cells
Describe the 3 intra-erythrocyte stages
- The host is infected when the sporozoite invades the RBCs
- Once in the RBC the sporozoite nucleus divides by binary fission, resulting in the ring stage – trophozoite = nuclear division
- The entire cell then divides again resulting in two cells called merozoites = cellular division
How do ticks become infected with Babesia?
- Merozoites divide by asexual binary fission in red blood cells
- Tick ingests the infected red blood cells
Describe the life cycle of Babesia within the tick host
- Multiplication and sexual reproduction in the tick
- Dissemination of Babesia throughout the tissues into the ovaries
- Trans-ovarian transmission
- Infection passes onto new host by the next generation of ticks
- As the tick attaches and starts to feed, sporogony occurs in salivary glands
- Sporozoites (phase that is infective to the cow) injected into host with the tick saliva
Name the disease caused by Babesia infection
Redwater
What are the clinical signs of Babesiosis?
- Begin 2 weeks after infection
- Fever
- Haemoglobinuria
- Haemolytic anaemia
- Diarrhoea ==> constipation
- High levels of mortality
At what time of the year is Babesia most commonly seen?
May -> Novemebr
What is inverse age-resistance to Babesia?
- Calves up to about 9 months old are resistant to disease but susceptible to infection
- Don’t develop clinical signs but can be infected
- Disease is typically only observed in animals more than 9 months old
Define the term premunity
asymptomatic carriers that are immune to disease
Define endemic stability
“A climax relation between host, disease agent, vector and environment, in which all coexist with the virtual absence of clinical disease.”
