Africa's genetic solution to intestinal worms

The Red Maasai, a type of sheep bred in Africa's Great Rift Valley for over five hundred years, has been found to be genetically resistant to intestinal worms. Geneticists working in the International Livestock Research Institute (ILRI) in Nairobi believe that this resistance derives from a small number of genes. If these can be identified and isolated they could then be used to transfer immunity to other breeds of sheep throughout the world, or to develop anti-worm vaccines. (See also Undramatic loss and Ethnoveterinary medicine for other developments in this area).

credit: D. Elsworth, ILRI

ILRI has been crossbreeding the Red Maasai over several generations with South African Dorper sheep, a breed particularly susceptible to worms. The next stage will be to compare the genetic make-up of those offspring that show resistance with those that do not, and thereby pinpoint the genes responsible. ILRI is committed to this knowledge benefiting not only farmers in wealthy nations, but also those in countries with scarce resources. Demand for livestock products is forecast to double over the next ten years and much of that extra production will be in the developing world.

Further examples of research at ILRI that could benefit tropical farmers include study of the West African N'Dama cattle which are resistant to trypanosomosis, and of other animal species that have resistance to malaria.

The story of the Red Maasai illustrates the importance of the FAO's recently published Worldwatch List on threatened domestic animal breeds. The report estimates that unless adequate action is taken, over half the domestic animal breeds in the world will be extinct within 20 years. With them would die the genetic resources they have developed to prosper in the face of extreme environments and disease, resources that may be vital for feeding and clothing future generations in both developed and developing worlds.

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