Information On TBF For Farmers And Vets
Tickborne Fever (TBF) is an infectious disease affecting the white blood cells of ruminants. The disease is transmitted by the tick Ixodes ricinus. The causative agent of this diseases is Anaplasma phagocytophilum. Infected ticks transmit the anaplasma organism to sheep and cattle while feeding on them. The infection is carried in the animals blood system, generally in the white blood cells
Signs of infection can vary and are not always noticed and may appear as early as 24 hours after the infected tick bite and last for up to 3 weeks. In sheep, high fever (≥41C) in animals recently moved onto tick infected pastures is often the first indicator of disease. Typically the fever is accompanied by loss of appetite, increased respiratory and pulse rates and, occasionally, coughing. Invasion of white blood cells by the pathogen can cause a severe decrease in number of white blood cells resulting in the impairment of the immune system and can increase susceptibility to a variety of other conditions including tick pyaemia, pasteurellosis, louping ill and listeriosis. In young lambs the main clinical sign is joint ill or spinal paralysis caused by tick pyaemia, while in pregnant ewes abortion storms can occur. Similarly, in infected cattle, clinical signs, which may not always be apparent, include depression, decreased appetite and respiratory signs, while older animals that are newly introduced into endemic areas may be more likely to abort. In dairy cows the most notable sign is a significant sudden drop in milk yield.
PCR testing is particularly useful in identifying infected animals for tickborne fever, individual samples from up to 5 animals can be combined in the laboratory to give one pooled result. Identification of the infectious organism ( Anaplasma phagocytophilum) by PCR is significant for the entire herd
Antimicrobial treatment (oxytetracycline) is generally regarded as the most effective treatment for clinically affected animals Control measures include
- improved pasture management to reduce tick habitats ( Rushes, scrub) and moving electric fences out from hedgerows to reduce risk of grazing cattle coming in contact with ticks.
- Pour-on/ spot-on products for the prevention of tick infestation
- Exposing young calves to tick infested pastures, can boost the development of immunity in later life. It is generally believed animals are immune after 1-2 bouts of diseases. Immunity can wane rapidly however, if animals are removed from tick infested areas.
For more detailed information an, contact FarmLab Diagnostics. Our diagnostic services can help you provide the best care for your sheep and cattle. Contact us to learn more.
