Arthropod Vectors of Human Diseases

Sheep Tick

Ixodes ricinus

Ixodes ricinus is a hard tick that transmits Lyme disease and tick-borne meningoencephalitis.

Lyme disease is caused by bacteria of the genus Borrelia and is transmitted in the saliva of the ticks during blood-feeding, although the tick does usually have to be attached for at least a day before transmission will occur.

Initial symptoms of Lyme disease include a diagnostic, outwardly-expanding, "bullseye" rash around the site of the bite as well as flu-like symptoms (fever, headache, joint pains, etc.).

If left untreated, debilitating symptoms may develop after several months. These can affect many parts of the body including joints, central nervous system, eyes and heart. In the most severe cases permanent, non-reversible paraplegia may occur.

The fully bloodfed sheep tick in the photos above was found in, and removed from, the ear of a pet cat. When removing ticks, the best, and safest, method is to gently pull the tick straight out using fine tweezers. Do not twist when pulling, as this may cause the mouthparts to break and be left behind in the bite, increasing the risk of infection.