As with most wild-living mammals, red squirrels carry a variety of ticks and fleas. However, although some fleas are common, a species of flea found on red squirrels on the Continent has also been recorded at Pitlochry, Perthshire. It is possible that it arrived in Scotland on red squirrels introduced from Europe in the 19th century.
Red squirrels also carry a species of flea introduced with the grey squirrel. Heavy infestation of fleas and lice can cause problems for red squirrels and can lead to hair loss and balding.
Red squirrels are also known to suffer from a viral infection (parapox virus) which causes symptoms similar to those of myxomatosis in rabbits. The disease is invariably fatal and can lead to local extinctions. Although there have been no confirmed records of the disease in Scotland, the detection of a parapox-like virus in grey squirrels in Hampshire suggests that they may act as carriers of the disease. Consequently there is always a possibility of this disease occurring in Scotland.
Red squirrels are also susceptible to other diseases, most notably coccidiosis, an intestinal parasite which can also be fatal. Such diseases can become especially evident when animals are stressed or under nourished.
