Eradication of the screwworm from Libya using the sterile insect technique.

The introduction in 1988 of the New World screwworm into Libya presented a serious threat to the livestock and wildlife sectors o f the African continent and the Mediterranean region. In this article, Moisés Vargas-Terán, Brian S. Hursey and Edward P. Cunningham describe the action taken to determine the extent of the problem, to prevent the spread of the infestation and to eradicate the fly from the region using the sterile insect technique.

[Program fo the eradication of Cochliomyia hominivorax in Northern Africa]. / Le programme d'éradication de la lucilie bouchère d'Afrique du nord.

The New World Screwworm (NWS, Cochliomyia hominivorax) is an obligate parasite of warm-blooded animals. The female lays up to 300 eggs in any break in the skin, and the resulting larvae (screwworms) burrow into surrounding living flesh. Infested animals frequently die, while the annual cost of controlling the pest in domestic animals is about US $10 per head. NWS is endemic in tropical Latin America. In 1988, it was detected in Libya, presumable introduced with imported sheep. By 1990, the infestation had spread to an area of 25,000 km2 containing some 2 million livestock. In early 1991, an internationally funded eradication programme was undertaken by FAO, using sterile insects. Each week, 40 million pupae were flown from a production plant in Mexico, and the emerged adults were distributed by over the infested area. Within a few months, the infestation has been eradicated. Whereas 12,000 infested animals were found in 1990, only 6 were detected in 1991. The programme involved the shipping and distribution of 1.3 billion sterile insects, animal inspections totalling 40 million and laboratory examination of 280,000 trapped flies. While the programme cost close to US $75 million, a benefit/cost ration of 50:1 has been estimated.

Myiasis: the battle continues against screwworm infestation.

The New World screwworm fly (Cochliomyia hominivorax) caused myiasis extensively among livestock in Mexico and the southern third of the USA until eradication was achieved by repeatedly releasing sterile males of the species on a massive scale. The pest appeared in Libya in 1988, the first time it had become established outside the western hemisphere. Because of the threat of myiasis in animals and people, not only in Libya but also elsewhere in Africa and beyond, a concerted campaign of sterile male releases was mounted with strong international support, and the outbreak has been eliminated. Action is continuing against the pest in Central America.