Insects malaria

MAJOR USES Used as a nonfood insecticide to control cockroaches, flies, lawn and turf insects malaria control flea collars. 

The value of insecticides in controlling human and animal diseases spread by insects has been dramatic. It has been shown that between 1942 and 1952, the use of DDT in pubHc health measures to control the mosquito vectors of malaria and the human body louse vector of typhus saved five million hves and prevented 100 million illnesses (4). Insecticides have provided the means to control such important human diseases as filariasis transmitted by Culex mosquitoes and onchocerciasis transmitted by Simulium blackflies. 

Lindane is used predominately as a seed dressing and soil insecticide, for the control of ectoparasites of humans and domestic animals, for the control of locusts and grasshoppers, and as a residual spray to control the Anopheles vectors of malaria. Because of its relatively high volatility it is useful to control wood-boring insects of timber, fmit trees, and ornamental plants. The mode of action is not well understood but is thought to be competitive blocking of the y-aminobutyric acid (GABA) transmitter of synaptic nerve transmission. 

Malaria. Malaria infection occurs in over 30% of the world s population and almost exclusively in developing countries. Approximately 150 X 10 cases occur each year, with one million deaths occurring in African children (87). The majority of the disease in humans is caused by four different species of the malarial parasite. Vaccine development is problematic for several reasons. First, the parasites have a complex life cycle. They are spread by insect vectors and go through different stages and forms (intercellular and extracellular sexual and asexual) as they grow in the blood and tissues (primarily fiver) of their human hosts. In addition, malaria is difficult to grow in large quantities outside the natural host (88). Despite these difficulties, vaccine development has been pursued for many years. An overview of the state of the art is available (89). 

Malaria is transmitted by the bite of an infected female Anopheles mosquito, one of the few species of the insect capable of carrying the human malaria parasite. The responsible protozoa ate from the genus P/asmodium of which only four of some 100 species can cause the disease in humans. The remaining species affect rodents, reptiles, monkeys, birds, and Hvestock. The species that infect humans are P/asmodium falciparum Plasmodium vivax Plasmodium malariae and Plasmodium ovale. Note that concomitant multiple malaria infections are commonly seen in endemic areas, a phenomenon that further compHcates choice of treatment. 

All travelers to endemic areas should be advised to remain in well-screened areas, to wear clothes that cover most of the body, and sleep in mosquito nets. Travelers should adhere to malaria chemoprophylaxis regimens and carry the insect repellant DEET (N, N,-diethylmetatoluamide) or other insect sprays containing DEET for use in mosquito-infested areas. 

The use of economic poisons has expanded in the field of public health since their indispensability has been shown in the control of insect-borne diseases. The organic insecticides, especially DDT, are now being used extensively in the control of malaria, yellow fever, dysentery, and other diseases. Their use in this field will certainly expand for years to come. 

Measures taken to control sources of larval emergence of sanitary pests are limited, and excessive treatments frequently induce the development of resistance in disease-transmitting insects. On the other hand, control measures by individuals are becoming a trend. For example, patients with malaria have decreased by the popularization of Olyset mosquito nets, which were developed by Sumitomo Chemical Co., Ltd. to deal with noctumally-active blood-sucking anopheles. 

Many hunters react to their prey s overall scent or some of its components, perhaps the smell of fur or some less complex odor. One of the world s most injurious insects, the African malaria mosquito (Anopheles gambiae), prefers humans to other sources of a blood meal. Oddly, whenever possible the mosquitoes bite people on their feet. This predilection reflects their strong attraction to the mixture of fatty acids that we associate with smelly feet. Humans may find the odor offensive, but these mosquitoes know it as a fragrant guide to blood. The same fatty acids also draw them to another odor that offends some people, the smell of Limburger cheese. 

Insects consume more than one third of the world s crops each year. In addition, insects such as mosquitoes spread life-threatening diseases, including malaria and encephalitis. Weeds reduce crop yields by taking over space, using up nutrients, and blocking sunlight. Some weeds even poison the animals that the crops are intended... 

An interesting footnote to history a Swiss physician, Paul Herman Muller, was awarded the Nobel Prize for medicine in 1948, for his work on DDT and its use in controlling insects that transmit malaria and typhus. 

Chlorinated hydrocarbons One example, DDT, is an insecticide. It was extensively used in World War II to delouse personnel and to prevent the spread of plague and other insect-borne diseases. Today, its use is restricted because of its toxicity and its very long life. Even though DDT is extremely effective, it is difficult to eliminate in nature. Its restricted use in some third-world countries has resulted in large increases in deaths due to malaria and other insect-borne diseases. 

Insecticide, used mostly to protect from diseases spread by insects. Also a byproduct in the production of dicofol, another insecticide. Limited use allowed under the Stockholm convention for areas where malaria is a significant health risk and economic constraints prevent the use of other pesticides... 

Pesticides were also valuable in bringing about the control of many insect-transmitted diseases. The use of DDT against the anopheles mosquito in the 1950s and 1960s, for example, was responsible for dramatic decreases in malaria infection rates in many parts of the world. The number of malaria cases in Venezuela dropped from more than 8 million in 1943 to 800 in 1958. Comparable results were reported in Italy, where the number of malaria cases dropped from 411,502 in 1945 to 37 in 1968, and in Taiwan, where the incidence dropped from more than 1 million cases in 1945 to just nine in 1969. 

Unlabeled Uses Demodicidosis, insect bite prophylaxis, leishmaniasis prophylaxis, malaria prophylaxis... 

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