CASE STUDY: BABESIA – Babesia bovis

A PARASITIC protozoan, Babesia is the causative organism of red water fever in cattle and sheep. It attacks the red blood cells, liberating haemoglobin that is excreted by the kidneys thus leading to the reddish coloured urine of infected animals. Babesia is transmitted by the sheep tick, Ixodes ricinus. The life cycle is summarised below:

A spore-like structure called a sporozoite present in blood sucked by a tick, undergoes the sexual reproductive part of the cycle in the tick.

The sporozoites form gametes, which then fuse to form a diploid zygote. After meiosis, multiplication of spores occurs by asexual reproduction and these spores enter the next cow as the tick sucks blood once again.

Within the cow, the spores form sporozoites which then enter the red blood cells. The cells multiply rapidly infecting other red blood cells.

Eventually they burst, releasing the haemoglobin which is then passed in the urine.

Cattle are usually attacked from the age of six months upwards, and after one attack will have some degree of immunity. In addition, cattle bred on very clean farms will have less resistance than those brought up on infected farms. Babesia is more common in spring and autumn months when ticks are at their maximum activity and areas of long grasses, the natural habitat of the tick, may heighten the prevalence of the disease.