Renewed Campaign to Eradicate Screwworm


There is a renewed drive by the Veterinary Services Division of the Ministry of Agriculture and Lands to eliminate the new world screwworm. Veterinary experts at the Ministry say the screwworm fly, if left unchecked, could pose one of the biggest threats to livestock farming. Targets set for this fiscal year include the production, processing and distribution of 20 million sterile flies per week for three months, and re-activation of a public awareness campaign. Director of Veterinary Services in the Ministry, Dr. Headley Edwards, tells JIS News that included in the $300 million budget over the next six months, will be expenditure for the development of radio and television advertisements, including 632 radio spots and 112 television spots; and the design, printing and distribution of 850,000 fliers and pamphlets targeted at specific groups. Obnoxious and destructive, the screwworm is the only insect known to consume the living flesh of warm-blooded animals. It has caused immeasurable suffering and losses in livestock, wildlife, and even human populations the world over.
Dr. Edwards informs that a team of technical advisors from the International Screwworm Eradication Programme were here recently to evaluate the Jamaican situation. “A key finding is that many Jamaicans do not report the cases to the authorities and this poses a challenge, as the insect spreads very easily, especially with dogs that often travel long distances,” Dr. Edwards points out.
The Government, in collaboration with the International Atomic Energy Agency, invested some $125 million in the national screwworm eradication programme in July 1998, with a further extension in July 2003.
Dr. Edwards tells JIS News that there have been challenges in eradicating the insects, due to external circumstances, but this is not uncommon. The Director informs that it took several years for South American countries like Mexico, which is now in a partnership with Jamaica, to eradicate the dreaded insect.
He notes that there have been achievements under the programme, including the purchase and processing of approximately 10.206 billion pre-hatched (pupae) sterile flies, some 7.229 billion of which were dispersed via airplanes across the island. This is called the Sterile Insect Release Technique (SIT). Furthermore, there was the distribution of 1.9 million packets of insecticide and sample collection tubes and the development and airing of radio and television advertisements with accompanying fly trapping and egg collection activities across the island.
Dr. Edwards explains to JIS News that the SIT technique exploits the fact that female flies only mate once in their 21-day lifecycle. SIT involves saturating the environment with artificially reared sterile flies, resulting in the majority of wild females mating with sterile males and producing sterile eggs. He explains that this can dramatically reduce screwworm fly populations, and if maintained over several weeks, can achieve eradication.
The Director says that up to October 2003, the project was progressing smoothly, with plans well advanced to complete eradication within a six-month period. At the six-month cut-off point, due to the external circumstances, eradication was not achieved.
The Director points out that after only three weeks, about 70 per cent of new egg cases found were sterile. After the next three weeks of releases, sterility was 84 per cent, and by the end of the third three-week period, very few egg cases were found and all were sterile.
But the conditions left behind by Hurricane Ivan in September 2004 as well as industrial strikes in Mexico put a fork in the efforts, which were well underway to stamp out the screwworm.
“Whatever happens in Mexico affects us, because the pupae are produced in Mexico, so when they had their strikes, it affected the regularity with which the flies arrived in Jamaica,” Dr. Edwards tells JIS News. He says that due to the nature of the fly’s life cycle and the fact that sterile flies were not arriving in the island during the two-week strike in Mexico, re-infestation took place. He adds that efforts to continue the eradication programme were further retarded by electricity shortage and flooding after Hurricane Ivan.
“We had no electricity to cool the pupae, so they were hatching at a faster than required rate,” he points out.

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