Changes

The epidemiology of the disease is determined by the number of infected ticks seeking a blood meal at that time. Protective immunity can be achieved from dams that have a carrier state. Cattle can become clinically infected though, without showing any clinical signs and this usually occurs at a young age. If calves less than 9 months are affected, no clinical signs will usually be seen and these cattle will then develop and immunity for life. In tick infested regions, most cattle become immune as calves and clinical disease is rarely seen on such farms. In some cattle, immunity may wane when re-infection does not occur for a long period.

The epidemiology of the disease is determined by the number of infected ticks seeking a blood meal at that time. Protective immunity can be achieved from dams that have a carrier state. Cattle can become clinically infected though, without showing any clinical signs and this usually occurs at a young age. If calves less than 9 months are affected, no clinical signs will usually be seen and these cattle will then develop and immunity for life. In tick infested regions, most cattle become immune as calves and clinical disease is rarely seen on such farms. In some cattle, immunity may wane when re-infection does not occur for a long period.

The disease varies in form worldwide due to different species of ''Babesia'' and different climates. In the UK, sporadic disease occurs leading to enzootic instability as immunity may be established in the case of an outbreak but will then wane if no re-infection occurs for a number of years. When the disease does appear, it occurs mostly during the spring and autumn during periods of greatest tick activity and mostly in stressed cattle under 2 years old on rough grazing.<br>'''''B. divergens '''''is the most common species in the UK.'''''Ixodes ricinus '''''is the vector and trans-ovarial transmission to the next generation occurs.<br>''B. major'' occurs in South East England but is not pathogenic. The vector here is [[Haemaphysalis spp.|''Haemaphysalis'']].

The disease varies in form worldwide due to different species of ''Babesia'' and different climates. In the UK, sporadic disease occurs leading to enzootic instability as immunity may be established in the case of an outbreak but will then wane if no re-infection occurs for a number of years. When the disease does appear, it occurs mostly during the spring and autumn during periods of greatest tick activity and mostly in stressed cattle under 2 years old on rough grazing.<br>'''''B. divergens '''''is the most common species in the UK. '''''Ixodes ricinus '''''is the vector and trans-ovarial transmission to the next generation occurs.<br>''B. major'' occurs in South East England but is not pathogenic. The vector here is [[Haemaphysalis spp.|''Haemaphysalis'']].

Overseas, ''B. bovis'' causes considerable losses in cattle in many tropical and sub-tropical areas. The vector here is [[Boophilus spp.|''Boophilus'']]. ''B. bigemina'' causes problems in Africa and South America where the vector is also ''Boophilus''.

Overseas, ''B. bovis'' causes considerable losses in cattle in many tropical and sub-tropical areas. The vector here is [[Boophilus spp.|''Boophilus'']]. ''B. bigemina'' causes problems in Africa and South America where the vector is also ''Boophilus''.