FAO Senior Officer, Vector-Borne Diseases, Brian Hursey talks about the Old World Screwworm epidemic in Iraq
The emergency situation currently happening in Iraq is due to the introduction of an insect called the Old World Screwworm, which is very seriously affecting the cattle and domestic animal population throughout the country. What is the screwworm and what are its effects on livestock? The screwworm is an obligate parasite [one that cannot lead a free-living existence without a host] of livestock and all warm-blooded animals. It lays its eggs on a wounded animal, and the eggs, when they hatch, form into larvae which penetrate into the animal and literally eat the animal alive. Unless they're treated, the wounds get so big and there are so many larvae involved that the animal is open to bacterial infections and the animal will die. How far has the infestation spread in Iraq? The Old World Screwworm first became apparent in Iraq in 1995. By December 1996, the number of recorded cases had reached something like 5 000 a month. One year later, in December 1997, the numbers had increased to about 50 000 a month. And those are only recorded cases. Unofficially, I think maybe we could double this number and say something like 100 000 animals a month are being affected. These figures reflect an emergency situation and probably this is caused to some extent by the situation in Iraq because not only has Iraq been infested but also Iran has been infested on its western border. But Iran has been able to control the disease through the use of insecticides and by having the infrastructure to do so. Iraq does not have the insecticides or the transport to be able to do very much about the problem. So we've now got a situation where month by month we have this increasing number of cases. What are the implications of the infestation in Iraq for other countries in the region? We've had consultants looking at the effects of this situation in Iraq on Iran. Their results went to a regional workshop, which FAO convened in conjunction with the Arab Organization for Agricultural Development (AOAD), held in Damascus in December last year. Veterinary authorities from all countries neighbouring Iran and Iraq were invited to attend this workshop. There were representatives from about eight countries. It became clear from the studies that the two main natural elements that are controlling the spread of the disease are the average temperatures and the amount of vegetation cover. In other words, there has to be a certain level of vegetation and a certain level of temperature present for the disease to flourish. If the temperature is too low the flies won't exist, which means that in the higher altitudes you probably won't find the flies. Also, where there is not enough vegetation you won't find the flies. Looking at the present distribution of the screwworm infections in Iraq and comparing it with what was predicted using the global information system approach, we found that the theoretical approach gave us something like a 91 percent correlation with the actual situation. That allows us to give some confidence to what are considered the high-risk countries that might be affected. So where do you see the greatest risk for further infestation? The lowlands of the Arabian Peninsula work out to be the area of possible infestation by the screwworm fly. It is very, very close to what we can expect to happen and, in fact, the area between the Euphrates River and the Tigris is the main area of infestation in Iraq and the lowlands in the southwestern part of the country]are the main infested area in Iran. We do not expect any further eastward movement in this direction because of the mountains and the associated low temperatures. But there is a risk of the fly spreading through the highlands along some of the lower level drainages to the neighbouring countries of Syria and maybe Jordan. That is the area of risk we're looking at at the moment. For that reason, FAO, together with AOAD, is trying to initiate a regional approach to this problem, so that we can deal with the disease not only where it is but can also ensure that it is not spread throughout the region. How is the epidemic spreading? One of the main risks is the movement of animals. It is not so much the movement of the fly which will cause the risk but the movement of animals. There is a lot of movement at the moment, mainly because of the economics of the animal trade in the region. The price of animals in Iraq is very depressed so there is a big incentive to export animals and sell them to neighbouring countries where the prices are higher. This something that we have to bear in mind. What is being done to control the epidemic? FAO first became aware of the situation in Iraq early last year and took measures to try and help. The Organization put in place a Technical Cooperation Programme, giving Iraq in the region of US$400 000 worth of assistance for the provision of chemicals, for diagnosis and for some training and instruction in how to control the disease. This wasn't a very large sum for a problem of this magnitude. But it was further enhanced by another $600 000 that was donated by the Government of the Netherlands. This has allowed more insecticides to be imported into the country and the situation is being controlled to an extent, although there is a very big problem still in the distribution of the insecticides and in the provision of large-scale spraying equipment, which is necessary to provide any sort of prevention. So at the moment we're only managing to keep the animals that are affected alive but are not able to control the disease and get it down to manageable proportions. With regard to the present financial assistance through the FAO TCP programme, some funds have been put aside to develop an emergency response to this problem which will take the form of an immediate two-year project to look at further prediction of the spread of the disease, the immediate reduction of the problem in Iraq and the development of better systems of diagnosis and more collaboration throughout the region. That is the position we're at at the moment. It could very well be that during that next two-year phase - which we estimate would cost within the region of $7 million to $8 million - the justification for considering the eradication of the problem could be investigated and that would entail introducing the Sterile Insect Technique, similar to what was done in Libya and North Africa. What is the Sterile Insect Technique? The only proven method of eradicating screwworm flies, the Sterile Insect Technique involves rearing insects in very, very large numbers - millions and millions - under factory conditions. The males that are produced are separated and sterilized using radiation. They are then taken and released over the area where the wild screwworms live and then they compete in mating with the females. Of course the females they mate with are then unproductive. By doing this regularly, breeding ability is gradually reduced and the population decreases until eventually, if it is carried out long enough, the insect is eradicated. This system was developed for the screwworm by scientists working in the United States because of the problems there some 30 or 40 years ago. The New World Screwworm was present at that time right through South America up into the south of United States where it had a significant impact on the cattle rearing areas in Texas and Florida. So this system was developed to eradicate and push the fly out of the United States, down through Mexico to the narrow peninsula, the Isthmus of Panama, where a continuous barrier of sterile insect release could be established to stop any reinvasion from the South American side. This programme was started some 30 years ago and is still ongoing today. It has cost billions and billions of dollars and yet has proved to be very cost-effective insofar as the losses it has contained and avoided for the livestock industries in that part of the country. How and when was this technique used in Libya and North Africa and how did that situation compare to what is happening now in Iraq? There are two species of screwworm: the Old World and the New World. It was the New World Screwworm that was introduced into Libya in the early 1990s. At that time FAO launched an extensive campaign to eradicate it from the shores of Libya using the Sterile Insect Technique. This successful campaign took three years and cost in the region of $75 million. The current situation in Iraq is similar in that again the screwworm fly has been introduced, but in this case it's the Old World Screwworm and it's probably come from Africa or from the eastern part of the continent. |
What is the nature of the
animal health emergency in Iraq?
