Vector control

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Vector control taking place in the Southern United States during the 1920s. Vector Control.jpg
Vector control taking place in the Southern United States during the 1920s.

Vector control is any method to limit or eradicate the mammals, birds, insects or other arthropods (here collectively called "vectors") which transmit disease pathogens. The most frequent type of vector control is mosquito control using a variety of strategies. Several of the "neglected tropical diseases" are spread by such vectors.

Contents

Importance

For diseases where there is no effective cure, such as Zika virus, West Nile fever and Dengue fever, vector control remains the only way to protect human populations.[ citation needed ]

However, even for vector-borne diseases with effective treatments the high cost of treatment remains a huge barrier to large amounts of developing world populations. Despite being treatable, malaria has by far the greatest impact on human health from vectors. In Africa, a child dies every minute of malaria; this is a reduction of more than 50% since 2000 due to vector control. [1] In countries where malaria is well established the World Health Organization estimates countries lose 1.3% annual economic income due to the disease. [2] Both prevention through vector control and treatment are needed to protect populations.[ citation needed ]

As the impacts of disease and virus are devastating, the need to control the vectors in which they carried is prioritized. Vector control in many developing countries can have tremendous impacts as it reduces mortality rates, especially among infants. [3] Because of the high movement of the population, disease spread is also a greater issue in these areas. [4]

As many vector control methods are effective against multiple diseases, they can be integrated together to combat multiple diseases at once. [5] The World Health Organization therefore recommends "Integrated Vector Management" as the process for developing and implementing strategies for vector control. [6]

Methods

Vector control focuses on utilizing preventive methods to control or eliminate vector populations. Common preventive measures are:

Habitat and environmental control

Removing or reducing areas where vectors can easily breed can help limit their growth. For example, stagnant water removal, destruction of old tires and cans which serve as mosquito breeding environments, and good management of used water can reduce areas of excessive vector incidence.[ citation needed ]

Further examples of environmental control is by reducing the prevalence of open defecation or improving the designs and maintenance of pit latrines. This can reduce the incidence of flies acting as vectors to spread diseases via their contact with feces of infected people.[ citation needed ]

Reducing contact

Limiting exposure to insects or animals that are known disease vectors can reduce infection risks significantly. For example, bed nets, window screens on homes, or protective clothing can help reduce the likelihood of contact with vectors. To be effective this requires education and promotion of methods among the population to raise the awareness of vector threats.

Chemical control

Insecticides, larvicides, rodenticides, Lethal ovitraps and repellents can be used to control vectors. For example, larvicides can be used in mosquito breeding zones; insecticides can be applied to house walls or bed nets, and use of personal repellents can reduce incidence of insect bites and thus infection. The use of pesticides for vector control is promoted by the World Health Organization (WHO) and has proven to be highly effective. [7]

Biological control

The use of natural vector predators, such as bacterial toxins or botanical compounds, can help control vector populations. Using fish that eat mosquito larvae, the use of cat fish to eat up mosquito larvae in ponds can eradicate the mosquito population, or reducing breeding rates by introducing sterilized male tsetse flies have been shown to control vector populations and reduce infection risks. [8]

Legislation

United States

In the United States, cities or special districts are responsible for vector control. For example, in California, the Greater Los Angeles County Vector Control District is a special district set up by the state to oversee vector control in multiple cities. [9]

See also

Related Research Articles

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<span class="mw-page-title-main">Malaria</span> Medical condition

Malaria is a mosquito-borne infectious disease that affects humans and other vertebrates. Human malaria causes symptoms that typically include fever, fatigue, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin 10 to 15 days after being bitten by an infected mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria.

<span class="mw-page-title-main">Yellow fever</span> Viral disease common in tropical Africa and South America

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<span class="mw-page-title-main">Arbovirus</span> Common name for several species of virus

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<i>Anopheles</i> Genus of mosquito

Anopheles or Marsh Mosquitoes is a genus of mosquito first described and named by J. W. Meigen in 1818. About 460 species are recognized; while over 100 can transmit human malaria, only 30–40 commonly transmit parasites of the genus Plasmodium, which cause malaria in humans in endemic areas. Anopheles gambiae is one of the best known, because of its predominant role in the transmission of the most dangerous malaria parasite species – Plasmodium falciparum.

Tropical diseases are diseases that are prevalent in or unique to tropical and subtropical regions. The diseases are less prevalent in temperate climates, due in part to the occurrence of a cold season, which controls the insect population by forcing hibernation. However, many were present in northern Europe and northern America in the 17th and 18th centuries before modern understanding of disease causation. The initial impetus for tropical medicine was to protect the health of colonial settlers, notably in India under the British Raj. Insects such as mosquitoes and flies are by far the most common disease carrier, or vector. These insects may carry a parasite, bacterium or virus that is infectious to humans and animals. Most often disease is transmitted by an insect bite, which causes transmission of the infectious agent through subcutaneous blood exchange. Vaccines are not available for most of the diseases listed here, and many do not have cures.

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<span class="mw-page-title-main">Indoor residual spraying</span> Process of spraying insecticides inside residences to prevent malaria

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References

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  3. "10 Facts on Malaria". World Health Organization. 2009.
  4. Walsh, Julia A.; Kenneth S. Warren (1980). "Selective primary health care: An interim strategy for disease control in developing countries". Social Science & Medicine. Part C: Medical Economics. 14 (2): 145–63. doi:10.1016/0160-7995(80)90034-9. PMID   7403901.
  5. Golding, Nick; Wilson, Anne L.; Moyes, Catherine L.; Cano, Jorge; Pigott, David M.; Velayudhan, Raman; Brooker, Simon J.; Smith, David L.; Hay, Simon I.; Lindsay, Steve W. (October 2015). "Integrating vector control across diseases". BMC Medicine. 13 (1): 249. doi: 10.1186/s12916-015-0491-4 . PMC   4590270 . PMID   26423147.
  6. "Handbook for Integrated Vector Management" (PDF). World Health Organization . Retrieved 3 December 2015.
  7. "Pesticides and their application for the control of vectors and pests of public health importance" (PDF). World Health Organization. 2006.
  8. Vreysen, MJ; et al. (2000). "Glossina austeni (Diptera: Glossinidae) eradicated on the island of Unguja, Zanzibar, using the sterile insect technique". Journal of Economic Entomology. 93 (1): 123–135. doi: 10.1603/0022-0493-93.1.123 . PMID   14658522. S2CID   41188926.
  9. "HEALTH AND SAFETY CODE SECTION 2010-2014". California Health and Safety Code. California. Retrieved 18 December 2013.