Screwworm Should be Eradicated by Year-End


The Ministry of Agriculture and Lands is projecting that by the end of this year, the screwworm pest will be eliminated from the island.
Executive Director of the Veterinary Services Division, Dr. Headley Edwards, told JIS News that since March of this year, the Ministry has been employing a new approach in eradicating the pest, by using the box fly to disperse sterile flies into the wild, as opposed to the chill fly system, which was previously used by the Ministry.
He explained that the box fly system utilizes pupae acquired from Mexico, which are packaged into boxes containing some 1,800 pupae per box.
According to Dr. Edwards upon arrival of the insects, “feed is placed into the boxes and once they (the flies) emerge, they are dispersed. This means they are not exposed to the chill fly chamber whereby the flies would have been chilled, made immobile, collected and then dispersed,” he informed.
He said the advantage of using this method is that the flies would have already been active, fed and therefore much stronger when they are released. The Ministry’s eradication effort is being supported by officials from the United States and Mexico. The Mexican officials, Dr. Edwards informed, not only supply the flies, but also provide technical assistance, equipment and manpower. Both countries have already won the fight against the pest, which collectively took some 29 years to be eradicated.
The effectiveness of the Ministry’s eradication programme, he said, can be measured based on the rate of infestation, but noted that “one fly could produce a number of infestations because a fertile fly can produce batches of 300 to 500 eggs per batch within a three week-period.” Real gains, he pointed out, are made when lesser incidences of infestation are reported.
In the meantime, he informed that the Division is looking into the collection of egg masses to determine the number of fertile eggs that are being produced. This is one method of determining the effectiveness of the programme.
“The higher the percentage of fertile egg masses show that you have more of the wild flies and the higher degree of sterility produced from those egg masses means that the sterile and wild flies .are mating but they are producing infertile eggs so that would reduce the population,” he said.
According to Dr. Edwards the process is costly, not only to buy the sterile flies but also to disperse them. “It’s about 90 hours per month of flying time and that is a costly exercise as the flies are dispersed island wide about four times per week,” he emphasized.
The programme consists not only of dispersing sterile flies, but infested farm animals are treated free of cost. Another aspect of the programme is a public awareness campaign, which is currently underway. Dr. Edwards reported that although the screwworm predominantly affects animals, in recent times, a number of human cases have been identified. “We have had quiet a number of human cases over the period of the programme and that also poses a problem because sometimes, the incidences are not reported,” he said.
To totally eradicate the insect, the Executive Director is encouraging farmers to check all their animals for possible cuts and conduct corrective action where infestation is found, as well as report all cases of infestation to the Screwworm Eradication Programme.

JIS Social