Letters

Blood donated after vaccination with rabies vaccine derived from sheep brain cells might transmit CJD

In many countries in Asia and Africa limited supplies of imported rabies vaccines derived from culture of human cells have been available. Many people continue to be offered indigenously produced sheep brain vaccine after exposure to a rabid animal. Scrapie is known to exist in sheep around many centres where the vaccine is produced. In the mountain sheep of the Kumaon foothills in the Himalayas, for example, scrapie was established more than four decades ago and 1-10% of the flock was reported to have the disease in 1961.² In the Himalayan foothills the Central Research Institute continues to produce four to five million doses of sheep brain vaccine annually. Transmission of abnormal prion protein, PrP^sc, in sheep brain vaccine might have occurred in some of the 30 documented cases of Creutzfeldt-Jakob disease in different regions in India.³ Because Creutzfeldt-Jakob disease has a latency of about 20 years, many recipients of sheep brain rabies vaccine could emigrate to Britain before becoming ill.

Before accepting blood donations from immigrants it would be desirable to ask the potential donors whether they were exposed to a rabid animal and immunised with sheep brain rabies vaccine in their country of origin. Furthermore, indirect assessment should be possible through, for example, assay looking for antibodies specific to rabies.

Clinical microbiologist Centre for Logistical Research and Innovation, M-122 (of part 2), Greater Kailash-II, New Delhi-110048, India

Subhash C Arya 

1. Morgan J. Blood to be screened for CJD. BMJ 1996;313:441. (24 August.) [Free Full Text]
2. Zlotnik I, Katiyar RD. The occurrence of scrapie disease in sheep of the remote Himalayan foothills. Vet Rec 1961;73:543-4.
3. Satishchandra P, Shankar SK. Creutzfeldt-Jakob disease in India (1971-1990). Neuroepidemiology 1991;10:27-32. [Medline]