An investigation into the health and welfare of red squirrels, Sciurus vulgaris, involved in reintroduction studies.

The threats posed by parapoxvirus infection, metabolic bone disease and coccidiosis to the reintroduction of red squirrels into Thetford Chase were investigated by making blood biochemical, radiological and parasitological examinations on the squirrels before they were released and on resident squirrels. Red squirrels found dead in Thetford Chase were examined post mortem by parasitological, electron microscopical and radiological techniques. Parapoxvirus infection was the probable cause of death of two red squirrels. Parapoxvirus infection may be a significant threat to remnant populations of red squirrels in England, and to the success of conservation measures.