Control Efforts: Preventing Contact with Vector



One subset of control strategies  tries to prevent human contact with mosquitoes, the vector that carries malaria.  Insecticide treated bednets, or ITNs have worked extremely well for protecting humans when they are most susceptible to mosquito bites—in their sleep.  A new net developed late November 2003 uses a combination of insecticides bifentrhrin and carbosulfane to kill twice as many mosquitoes as single insecticide nets. [1] ITNs are limited, however, because individuals are not protected when they are outside their nets in the evening or during daytime.  Families may also be unwilling to use the nets or maintain them by reapplying insecticide every six months.  Travelers to Malaria endemic regions may also use insect repellents to prevent contact with mosquitoes.  The use of insect repellents is not a viable strategy for my families at risk for malaria who are near the poverty line and need to use all available funds to purchase food. [2] In addition, to be effective, the substance must be constantly reapplied, which might pose an unnecessary hassle for many individuals. 

Fogging and IRS


A few strategies work by spreading insecticides around an area to discourage mosquitoes.  In fogging, workers release a thin mist either indoors or outdoors in an area that mosquitoes are known to frequent.  For an effective fogging campaign, sprayers must coordinate fogging with times that the insects fly in greatest numbers.  This technique is also impractical because the chemical does not remain in the air for an extended period of time. [3]   An alternative to fogging that malaria control experts prefer is Indoor Residual Spraying (IRS).  IRS consists of spraying a substance like DDT on the walls of a residence or business.  This has three functions: to kill mosquitoes, to prevent them from entering an area, and to encourage them to leave without biting.  Because of its known environmental consequences and possible harm to humans in large doses, the use of DDT is now debated, although it was a major force in the eradication efforts in Europe, North America, and Asia. 

Control Efforts: Elimination of Vector

Larval Control and Environmental Management

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Another control strategy focuses on killing the mosquitoes of an endemic area.  One way to achieve this is by destroying the aquatic forms of the insects.  This can involve examining areas with sources of standing water with larval forms and eliminating or controlling them.  In addition to using an insecticide such as temephos, bacterial toxins such as Bti, and larvivorous fish may be introduced. [4]

A complex, but highly effective vector control strategy is environmental management which includes analyzing and altering the features of an area that encourage proliferation of mosquitoes.  An example of this is draining a swamp which mosquitoes frequent.  A considerable challenge with this method, in addition to the significant planning involved, is the risk of interfering with development efforts or the natural ecology of a region. [5]   One consequence, for example, could be the introduction of a new parasite that thrives in the altered environment. 


[1] Masood, 2003

[2] Malaria Foundation International

[3], [5] WHO (2005) Malaria Control Today

[4] Curtis