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NIOSH Document Details Worker Protections Against West Nile Virus

Proper personal protective equipment, education and training and vigilant reporting of injuries and illnesses are among the keys to keeping at-risk workers safe from the dangers of West Nile Virus, according to a new document issued by the National Institute for Occupational Safety and Health.

The document provides recommendations to laboratory, field and clinical workers and their employers for protection from West Nile Virus exposure. Among the topics addressed are identifying which workers may be exposed to WNV, who is at risk, how to handle dead animals, how WNV affects pregnancy and what to do if you suspect you may have been infected with WNV.

According to NIOSH, occupational exposures to WNV which is most often spread to humans from the bite of an infected mosquito have been documented. Laboratory, field and clinical workers who handle tissues or fluids infected with WNV or who perform necropsies are at risk of WNV, but the document adds that a number of other occupations may be exposed to WNV, including health care workers and emergency response and public safety personnel.

According to the NIOSH document, employers of laboratory, field, and clinical workers should protect their workers from WNV exposure by taking the following steps:

  • Provide training that describes how WNV is transmitted and reinforces knowledge about the risks of WNV exposure and infection.
  • Supply workers with appropriate personal protective equipment that provides barrier protection such as gloves, gowns, masks, goggles or glasses with solid side shields and/or chin-length face shields.
  • Provide alternatives to latex gloves for workers who need or want to avoid latex.
  • Stress to workers the importance of reporting all work-related injuries and illnesses in a timely manner.
  • Provide a medical surveillance system that monitors, records and assesses the following:
    • Symptoms consistent with WNV infection;
    • Laboratory incidents involving possible WNV exposure; and
    • Absenteeism associated with WNV infection.

Recommendations for Workers

Laboratory, field and clinical workers should avoid handling dead animals when possible. If they must handle them, NIOSH advises them to take the following precautions:

  • Use tools such as shovels to avoid direct contact with the animals.
  • Wear medical examination gloves that provide a protective barrier between blood or other body fluids and your skin:
    • Wear two pairs of gloves if one pair alone might tear.
    • Make sure that latex gloves are reduced-protein, powder-free gloves to reduce workers' exposure to allergy-causing proteins.
    • Wear cotton or leather work gloves as the outer pair when heavy work gloves are needed.
    • Wear the medical examination gloves as the inner pair.
    • Discard both inner and outer gloves immediately after use.
    • Remember that cotton, leather and other absorbent gloves are not protective when worn alone.
  • Avoid skin and mucous membrane contact with blood and other tissues by using personal protective equipment that provides barrier protection such as gloves, gowns, masks, goggles or glasses with solid side shields and/or chin-length face shields.
  • Wash hands and other skin surfaces with soap and water immediately after contact with blood or other tissues, after removing gloves and before leaving the workplace.
  • Take precautions when using scalpels, forceps and other sharp instruments.
  • Use medical devices with safety features to avoid sharps-related injuries.
  • Do not recap, bend or remove contaminated needles and sharps. Never shear or break contaminated needles.
  • Dispose of sharp devices in labeled, puncture-resistant, leak-proof sharps disposal containers immediately after use.
  • Immediately after use, dispose of materials contaminated by infected animals, their blood or other tissues in containers approved for biohazardous wastes.
  • Minimize the generation of aerosols when working with infected tissues, samples and animals.
  • Immediately report the following to the supervisor:
    • All needlestick and other sharps-related injuries;
    • Any laboratory incidents involving possible WNV exposure; and
    • Any symptoms consistent with WNV infection.

Severe Cases of WNV Are Rare

According to the NIOSH document, most human infections with WNV (about 80 percent) cause no symptoms, and about 20 percent cause flu-like symptoms, including fever, fatigue, headache and muscle or joint pain.

Fewer than 1 percent of humans infected with WNV become severely ill, according to NIOSH. Severe symptoms include high fever, stiff neck, disorientation, tremors, muscle weakness and paralysis.

Severely affected persons may develop encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes of the brain or spinal cord). Severe cases may be fatal.

The NIOSH document can be accessed at

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