Outbreaks of screwworm myiasis in Yemen
Sana'a, Yemen, March 2008. Outbreaks of Old World Screwworm (OWS) have been reported in western Yemen, in February 2008, near the border area with Saudi Arabia and across the relative green upland areas of the country.
The OWS fly causes myiasis, a disease caused by the fly's larvae feeding on the host's necrotic or living tissue, and which may affect both humans and animals. Within Yemen, the affected areas hosts almost 50 percent of the total animal national stock estimated at 15 million sheep, 1.4 million cattle and 250 000 camels.
The recent events in Yemen are of direct relevance to all the countries in the Arabian Peninsula as there is mounting evidence of a progressive spread of OWS, across the Middle East. Incursions of OWS have been reported in Bahrain in 1977, in Oman in 1983, in the United Arab Emirates in 1988, in Iran in 1994 and in Iraq in 1996. This spread is possibly related to a combination of factors including movements of people and livestock, land use and climatic change.
In an effort to contain the spread of the disease, the Yemen General Directorate for Animal Resources launched a swift, rigorous insecticidal campaign in the affected areas. The Ministry of Agriculture and Irrigation requested FAO assistance in order to evaluate the OWS epidemiological situation. FAO, together with the International Atomic Energy Agency (IAEA), and in collaboration with the Arab Organization for Agricultural Development (AOAD), provides technical support, mainly in risk assessment and entomological aspects. FAO initiated the production of OWS risk maps, in collaboration with the Universit Libre de Bruxelles, Belgium. The first generation of these maps has been meanwhile made available to the Ministry of Agriculture and Irrigation of Yemen. Further FAO support aims at training of national staff in OWS risk assessment and modelling, epidemiology, and ecology. Training materials and teaching aids regarding screwworm fly ecology, behaviour and control are made available to assist technical staff.
At some stage in the future, the OWS infestation in the Middle East may perhaps be contained by means of the Sterile Insect Technique (SIT) application. Given the transboundary nature of the problem, it is in the interest of Yemen, the Middle East region as a whole, and the international agencies AOAD, IAEA and FAO to closely follow the events and work together involving all relevant disciplines.