Disease carrying vectors

MSW can aggravate different types of environmental pollution such as air, water, including groundwater, and soil pollution, which affects public health as the waste forms a breeding ground for various disease-carrying vectors such as flies, mosquitoes, rats and others, and indicates inappropriate and unscientific management [5]. 

Military personnel deployed in the field often suffer more casualties due to endemic vector-borne disease than to engagement with enemy combatants. The most dangerous of these are carried (vectored) by biting arthropod vectors mostly of the bloodsucking variety. Among the diseases encountered by soldiers are malaria, dengue fever and yellow fever, carried by certain mosquito species encephalitis and Lyme disease, carried by certain ticks and leishmaniasis, carried by some species of sand flies (Fig 14.1). 

In the United States in recent years several diseases with animal hosts are now infecting humans. The Arena virus has as its host certain desert rodents. Rodent droppings when dry and airborne as dust particles infect humans, often with lethal consequences. The West Nile virus appeared in the United States in 1999. Birds carry this virus, and mosquitoes are the vector to humans. In 1999 the virus was localized in the New York City area. By 2000 it has spread across New York State and into New Jersey and Massachusetts. The West Nile virus is especially lethal when it infects children, the elderly, or those with a compromised immune system. 

This bacteria has not yet been successfully cultured outside of citrus plants or the psyllid vectors that carry it. Once infected, vectors remain capable of transmitting the disease for their entire lives, but progeny are free of the bacterium. It causes symptoms only under relatively cool conditions (68-77°F) and generally has a milder effect than L. asiaticus (Cl7-A019). 

Flies and mosquitoes are vectors for a number of other diseases that constitute significant menaces to public health, but we do not yet know what role chemical signals play in all of them. Where natural chemicals are important, much additional research will be essential to establish whether they offer realistic approaches to managing these afflictions. The results with leishmaniasis and African trypanosomiasis indicate that such research can both increase our understanding of how fly vectors live and also lead to practical measures for fighting the diseases they carry. 

To report to the WHO evidence of a public health risk identified outside their territory, which may cause international disease spread, manifested by exported/imported human cases, vectors carrying infection or contamination, or contaminated goods... 

DDT was first synthesized in the 1870s, but its insecticidal properties were discovered only in 1940 by the Swiss chemist Paul Muller, who won a Nobel Prize in 1948 for his work. The U.S. military had introduced DDT for control of malaria, typhus, and other insect-carried disease by 1944, and after the end of World War II, DDT was used widely around the world for vector (mosquito) control and in agriculture. 

Vector control efforts were never fully implemented in Africa, even though that continent bore the greatest burden of disease. Many African countries had neither the infrastructure nor the human capacity to carry out spraying programs systematically and effectively. However, today the infrastructure is better and eradication programs would be more likely to succeed, if they were reinstituted. 

The timing of Muller s discovery insured its early application in the Mediterranean and South Pacific theaters of World War II to eliminate mosquito-vectored diseases malaria, filariasis, dengue fever also typhoid fever, carried by lice and fleas. 

Beginning with World War II, the armed forces have carried chlorinated hydrocarbon insecticides wherever they have gone for personnel protection, premise treatment, and area control (9). Many of these compounds have been manufactured in several countries and used for disease-vector control on the land, in the home, in water resources, and directly on people by a number of international agencies, as well as by individual nations. 

WHO should conduct studies to determine whether there are causal relationships between changes in the patterns of chemical control of vectors and variations in the incidence of certain vector-borne diseases. For reasons of safety and economy, studies should be carried out to determine the cost-effectiveness of current vector control practices and to find ways of using pesticides more judiciously. 

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