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NIOSH - National Institute for Occupational Safety and Health

NIOSH Safety and Health Topic:

West Nile Virus


West Nile Virus

mosquito biting finger

The West Nile virus (WNV) is most often spread to humans from the bite of an infected mosquito. The WNV normally cycles between mosquitoes and birds. However, people may also be infected if they are bitten by a WNV-infected mosquito. Most cases of WNV are probably not acquired in the workplace but there are some workers at risk of WNV infection. Outdoor workers are at risk of WNV infection from the bite of an infected mosquito. Workers who perform necropsies of infected birds or handle WNV-infected tissues or fluids are also at risk of WNV infection if their skin is penetrated or cut.

Workers at risk of exposure to WNV include those working outdoors when mosquitoes are biting. Outdoor workers at risk include farmers, foresters, landscapers, groundskeepers and gardeners, painters, roofers, pavers, construction workers, laborers, mechanics, and other outdoor workers. Entomologists and other field workers are also at risk while conducting surveillance and other research outdoors.

Although WNV is most often transmitted by the bite of infected mosquitoes, the virus can also be transmitted through contact with infected animals, their blood, or other tissues. Thus laboratory, field, and clinical workers who handle tissues or fluids infected with WNV or who perform necropsies are at risk of WNV exposure.

Workers at risk should receive training that describes and reinforces the potential occupational hazards and risks of WNV exposure and infection. The importance of timely reporting of all injuries and illnesses of suspected occupational origin should be emphasized. A medical surveillance system should be in place which includes the reporting of symptoms consistent with WNV infection, laboratory incidents or accidents involving possible WNV exposures, and employee absenteeism.

Page last updated: October 22, 2008
Page last reviewed: May 16, 2008
Content Source: National Institute for Occupational Safety and Health (NIOSH)

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