African sheep help diagnose disease
Disease diagnosis in developing countries could have an unlikely saviour in the form of the hair sheep — a breed of sheep native to Africa.
Many diagnostic tests for infectious diseases require blood to culture the pathogens in patient samples.
Now scientists in the United States have discovered that the blood of the hair sheep can be used for these tests.
Developed countries use blood from wool sheep or horses in these tests, but horses are too expensive and wool sheep are difficult to rear in developing countries. Importing blood is expensive and unreliable, so scientists in developing countries resort to using human blood — often their own.
But human blood is different from sheep and horse blood, making it hard to compare the results with those from developed countries, according to Ellen Yeh, a pathology resident at Stanford University and a co-author of the research, published this month (3 July) in PLoS ONE.
Yeh and colleagues found that blood from hair sheep performed just as well as wool-sheep blood in standard tests. They also showed that it can be stored in blood donation bags and does not need to be processed before use.
Hair sheep are ideal for rearing in developing countries because they are low maintenance, parasite resistant and tolerant of hot, dry climates, the researchers say. Hair sheep are already being reared for meat in countries such as Botswana.
Yeh's co-researcher Ellen Jo Baron, a pathology professor at Stanford University, is trying to promote the use of hair sheep in developing countries. She is setting up a pilot project in Botswana in which a veterinary department provides the blood to a diagnostic laboratory.
Jim McLaughlin, a microbiology laboratory adviser with the Diagnostic Microbiology Development Program in Cambodia, says: "It is essential that diagnostic microbiology laboratories have a supply of sheep blood."
"The finding that hair-sheep blood supports the growth of human pathogenic bacteria … is a significant finding for diagnostic microbiology laboratories in developing countries," he adds.
"It is now important that donor agencies that focus on strengthening laboratory medicine promote the introduction of hair sheep into developing countries."