Disease in Squirrels

Squirrels carry a variety of internal and external parasites, including lice, ticks and mites.
Although most cause little discomfort to the animals, two in particular are known for their
severe, often fatal, effects.

Coccidiosis Coccidiosis is caused by a parasitic protoazoan, which lives in the gut. It is thought that this contributed to the dramatic drop in the number of red (and grey) squirrels in Britain between 1900 and 1925. Unfortunately, whilst grey squirrel numbers began to rise again, red squirrel populations never recovered.

Parapox Virus

Parapox virus is a disease that is fatal to red squirrels, the origins of which are unknown. It was
first confirmed in East Anglia in the 1980s, and since then there have been confirmed cases in
red squirrel populations in Lancashire (1995-6) Cumbria (spring 1998), Durham and
Northumberland (1999). It is currently felt that where it is present, parapox virus may be a
significant factor in the decline of red squirrel populations in the UK.

It has been found that the parapox virus is endemic (prevalent) in some grey squirrel
populations, but rarely results in death. It seems likely that grey squirrels act as a reservoir host
(carrier) for the virus, which if it is passed on to red squirrels, results in death. Parapox causes
skin ulcers, lesions and scabs with swelling and discharge around the eyes, mouth, feet and
genitalia; squirrels generally become increasingly lethargic as the disease progresses.