|<< Back to Safety and Health Information Bulletins - Table of Contents by Year
Safety and Health Information Bulletin
Avian influenza is a viral disease that can cause sickness and death among poultry. On rare occasions, avian influenza virus can be transmitted to poultry workers or others who come in contact with infected poultry or contact contaminated surfaces. Examples of such workers who could be at risk include poultry growers and their employees; service technicians of poultry processing companies; caretakers, layer barn workers, and chick movers at egg production facilities; and workers involved in disease control and eradication activities, including state, federal, contract, and company employees.
This Safety and Health Information Bulletin describes measures for protecting poultry workers when an avian influenza outbreak occurs. It presents basic information about avian influenza and describes measures for minimizing exposure to the virus. Links to Internet sites are provided for those wanting more detailed information on avian influenza, biosecurity measures, and personal protective equipment. This document complements avian population disease control and eradication strategies of state governments, industry, and the U.S. Department of Agriculture (USDA).
Avian influenza is a disease caused by infection of poultry with type A influenza viruses. The disease occurs worldwide, and all species of birds are thought to be susceptible to it. Strains of avian influenza are classified as being of either low pathogenicity (most strains) or high pathogenicity.
Low-pathogenic strains typically cause few or no signs in infected birds. When signs are seen, they may include respiratory problems, diarrhea, a decline in egg production, or an increase in mortality. However, under field conditions, some low-pathogenic strains (H5 and H7 subtypes) can mutate and become highly pathogenic, leading to the deaths of entire flocks. Highly pathogenic avian influenza is extremely contagious and a fatal form of the disease for poultry.
Although avian influenza A viruses rarely infect humans, since 1997, instances of human infection have occurred; some (outside the United States) have resulted in death. The virus is excreted in the droppings of infected birds and in their respiratory secretions. Transmission to humans is thought to have resulted from contact with infected sick or dead poultry or their droppings, or contact with contaminated litter or surfaces (e.g., egg flats). The suspected routes of entry of the virus to humans are the mouth, nose, eyes, and lungs. Although the human health risk of low-pathogenic avian influenza viruses is not well established, protective measures should be taken by persons likely to have prolonged direct or indirect exposure to any avian influenza virus in an enclosed setting.
Measures for Protecting Poultry Workers
Follow biosecurity practices
Poultry workers should know and follow biosecurity practices to prevent the introduction of avian influenza and other diseases into a poultry flock. An understanding of how infection can be spread is important for both effective biosecurity and worker safety and health practices. Poultry processing companies should provide a written copy of biosecurity practices to each of their contract growers.
A 2004 USDA fact sheet lists eight general biosecurity practices for poultry farms. Guidance is also available in the free biosecurity CD, Infectious Disease Risk Management: Practical Biosecurity Resources for Commercial Poultry Producers, which is available from the U.S. Poultry and Egg Association.
Depending on temperature and moisture conditions, avian influenza A viruses can survive in the environment for weeks. However, they are generally sensitive to most detergents and disinfectants and are inactivated by heating and drying. Contact with organic material such as dust, dirt, litter, and manure can decrease the effectiveness of some disinfectants, and thus the possibility persists that viruses will survive. U.S. Environmental Protection Agency
(EPA)-registered products that have a claim of being effective against influenza viruses should provide some measure of activity against avian influenza A viruses.
The label of an EPA-registered disinfectant describes how to use the product safely and effectively and includes measures that applicators should take to protect themselves. The personal protective equipment listed on a disinfectant label is based on the chemical's toxicity and may not be appropriate for all exposure conditions and handling activities. Thus, an exposure assessment should also be done when selecting personal protective equipment for applicators.
Know the signs indicating birds are infected with avian influenza viruses
The signs of illness seen in domestic poultry infected with avian influenza viruses are variable and affected by the virus strain, age and species of infected birds, concurrent bacterial disease, and the environment. Such signs may include -
Some birds might be otherwise healthy-looking but still infected with avian influenza virus. The severity of disease in poultry can also vary during an outbreak. Poultry workers should be aware of signs of disease in poultry so when necessary they can take immediate steps to protect themselves and other workers, quarantine the farm to prevent spread of disease, and report the disease to the responsible animal health authorities.
Take antiviral medication and get the current season's influenza vaccine if appropriate
In the event of an avian influenza outbreak, workers who will be involved in disease control and eradication activities should consult their healthcare provider about the advisability of taking antiviral medications for influenza. The Centers for Disease Control and Prevention (CDC) has recommended that workers receive an influenza antiviral drug daily for the entire time they are in direct contact with infected poultry or contaminated surfaces. In the absence of sensitivity testing, oseltamavir is the antiviral drug currently of choice because the likelihood that the virus will be resistant to it is less than with amantadine or rimantadine.
The CDC recommends that workers involved in avian influenza disease control and eradication activities should get the current season's human influenza vaccine. Human influenza vaccine will not prevent infection with low pathogenic or highly pathogenic avian influenza A viruses, but this precautionary measure could reduce the possibility of dual infection with avian and human influenza viruses. Although dual infection is unlikely, it is plausible that such a situation might cause new and different viral strains to be created; such new strains might be transmissible among people and lead to more widespread infections. Although this CDC recommendation is only for workers involved in disease control and eradication activities, other poultry workers should consider getting the current season's influenza vaccine for the same reason.
Current information suggests that limited human-to-human transmission of avian influenza A viruses has occurred but is very uncommon. Public health authorities are monitoring outbreaks of human illness associated with avian influenza, and to date, human infections with avian influenza viruses identified since 1997 have not resulted in sustained human-to-human transmission.
Additional CDC information on concerns about dual infection, the use of antiviral medications, and vaccination of poultry workers is available at Interim Guidance for Protection of Persons Involved in U.S. Avian Influenza Outbreak Disease Control and Eradication Activities [103 KB PDF, 3 pages].
Know the signs and symptoms of human infection with avian influenza viruses
All poultry workers should know the signs and symptoms of avian influenza virus infection in humans so that measures can be taken for immediate treatment. The signs and symptoms may include fever, cough, sore throat, conjunctivitis (eye infections), and muscle aches. Infection with avian influenza viruses can also lead to pneumonia, acute respiratory distress, and other severe and life-threatening complications. A worker who experiences any of these symptoms or illnesses, or who might have been exposed to avian influenza virus should seek medical care and tell the healthcare provider before arrival that exposure to avian influenza virus may have occurred.
More information concerning human infection with avian influenza viruses is available at Information on Avian Influenza and Influenza at the Human-Animal Interface (HAI) (Note: Links have been updated - 01/09/2013).
Wear personal protective equipment
People, including children, working daily in poultry confinement units are at risk of exposure to a variety of contaminants including organic dusts, gases such as ammonia, and microorganisms (viruses, bacteria, and fungi) that can cause illness. Thus, for many poultry workers, wearing personal protective equipment is a routine practice. For example, wearing a respirator can reduce exposures to airborne organic dusts that
might pose a risk of respiratory disease and decreased breathing capacity. These exposures in the poultry industry can lead to chronic lung disease and premature death. The National Institute for Occupational Safety and Health (NIOSH) recommends that children should not do any work that requires wearing a respirator. Respirators are designed to fit adults and the likelihood that they will fit and protect children is doubtful. (See NIOSH Recommendations to the U.S. Department of Labor for Changes to Hazardous Orders. This document and others concerning young workers can be found at Young Worker Safety and Health.)
Most cases of avian influenza virus infection in humans are thought to have resulted from contact with infected poultry or contacting contaminated surfaces followed by self-inoculation of the virus into the eyes, nose or mouth. Other means of transmission are possible, such as airborne material containing the virus entering a person's mouth, nose, or eyes, or being inhaled into the lungs.
The CDC and the Occupational Safety and Health Administration (OSHA) have made recommendations for protecting workers involved in avian influenza outbreak disease control and eradication activities concerning the respiratory protection, eye protection, and protective clothing that should be worn and the hand-hygiene practices that should be followed. (See Avian Flu.)
The following information describes why respiratory protection, eye protection, protective clothing, and hand-hygiene practices are recommended for disease control and eradication activities and gives guidance on selecting personal protective equipment for workers responding to outbreaks of avian influenza. This information was prepared as an aid to the development of biosecurity guidelines and standard operating procedures for the various sectors of the poultry industry.
The process of selecting an appropriate ensemble of personal protective equipment requires an understanding of the work activities associated with possible exposures; the health effects that may result from exposure; properties of the virus (such as whether it is low pathogenicity or high pathogenicity); host factors (e.g., a worker's susceptibility and immunization status); and the advantages, disadvantages, and protective capabilities of the different types of personal protective equipment. Because changes to the initial ensemble may occur during the course of a response to an outbreak, the persons with responsibility for making revisions should be identified in the biosecurity guidelines.
Because infectious diseases such as avian influenza may be transmitted by breathing contaminated dust, poultry workers should wear respirators. Respirators that have filters or cartridges are called air-purifying respirators. These types are the most practical and appropriate choices for poultry workers to wear when they might be exposed to infected birds or during day- to-day activities in poultry barns. The table below lists the advantages, disadvantages, and costs of the five types of air-purifying respirators in order of increasing levels of protection. More information on the advantages and disadvantages of different respirators and guidance on selecting
respirators for infectious agents can be found in the respirator selection section of the CDC/NIOSH histoplasmosis guidelines. Also, for guidance on the protective capabilities of respirators, see 2004 NIOSH Respirator Selection Logic.
While all of the listed respirators can protect poultry workers, they will not be protective unless all of the elements of a written respiratory protection program are followed. Examples include providing respirator training to workers and fit testing tight-fitting facepieces to ensure a secure and comfortable face seal. Also, every respiratory protection program must have an administrator who is responsible for overseeing the program?s functioning and who can answer questions workers might have about respirator use; workers need to
be informed about who the program administrator is.
The need for respiratory protection presents a challenge to many poultry workers, such as contract poultry growers and their employees. Workers at risk of prolonged direct or indirect exposure to any avian influenza virus in an enclosed setting should always be included in a respiratory protection program.
Information describing all of the elements of a complete respiratory protection program and the use of respirators can be found at OSHA's Respiratory Protection Safety and Health Topics Page.
Eye protection will reduce direct exposure of the eyes to contaminated dust and aerosols and help keep workers from touching their eyes with contaminated fingers. To prevent the mucous membranes of the eyes from being exposed to the avian influenza virus, poultry workers should wear safety goggles or a respirator that has a full facepiece, hood, helmet, or loose-fitting facepiece. If safety goggles are worn, they should be nonvented (eyecup goggles, for example) or, at a minimum, indirectly vented.
Properly fitted, indirectly vented safety goggles with a good antifog coating may be a good choice for poultry workers who have lower risks of exposure. However, such goggles are not airtight, and consequently, they will not completely prevent exposures to airborne material. Directly vented goggles and safety glasses will provide limited protection, but are not recommended for protection against fine particles, splashes, or aerosols such as required in situations when workers will be exposed to infected birds.
Workers who wear prescription lenses should wear eye protection that has the correction built into the safety lenses of the protective eyewear, has lens inserts, or can be fitted over regular street- wear prescription glasses without compromising eye or respiratory protection. Although regular prescription glasses cannot be worn with full facepiece respirators, they can be worn with some types of powered air-purifying respirators (those with hoods and some with helmets) and some styles of goggles. However, for goggles to be effective they must fit snugly, especially from the corners of the eyes across the brow. Additionally, protective eyewear should be selected that does not interfere with the worker?s vision by disturbing the proper position of the prescription lenses. Contact lenses may be worn with goggles, safety glasses, or any respirator and thus provide excellent corrective vision while maximizing the protective eyewear selected.
Eye protection should be fitted together with a respirator because some goggles can alter the fit of a half-facepiece respirator. To ensure that the eye protection does not interfere with a facepiece seal, it should be worn when half-facepiece respirators are fit tested and when workers conduct seal checks each time they put on the respirator.
Caution should also be used when removing eye protection to ensure that contaminated equipment does not come in contact with the eyes or other mucous membranes. Eye protection that is properly selected and used will help prevent conjunctivitis (redness, swelling and pain in the
eyes and eyelids). Poultry workers exposed to birds infected with avian influenza should see a physician at the first signs of conjunctivitis.
More information on eye protection for infection control and other documents concerning eye safety are available at CDC/NIOSH - Eye Safety.
Protective Clothing and Hand-hygiene Practices
Protective clothing (which includes gloves, aprons, outer garments or coveralls, and boots or boot covers) should be used to prevent direct skin contact with contaminated materials and surfaces and reduce the likelihood of transferring contaminated material outside a poultry barn or work site. Disposable protective clothing is preferred.
Because protective clothing can be more insulating than regular work clothing, precautions should be taken to protect workers from the effects of heat stress. For example, wearing a lightweight cotton coverall might create less of a heat stress risk for a worker than a chemical resistant suit. Additionally, workers should know the symptoms of heat-stress- related illnesses and be able to take appropriate measures to ensure that such illnesses do not occur. Information concerning heat stress and possible solutions can be found at OSHA's Occupational Heat Exposure Safety and Health Topics Page.
When selecting gloves, whether disposable ones made of nitrile or vinyl that are lightweight (a thickness of 8 to 12 mil) or ones that are heavy duty (a thickness of 18 mil or greater) that can be reused after being disinfected, factors to consider include a worker?s activities, the importance of dexterity, and whether the gloves need to be durable and resistant to tearing and abrasion. Regardless of the type of glove selected, care is needed to ensure that wearing protective gloves does not aggravate existing dermatitis or damage healthy skin because of prolonged exposure to water or sweating hands. For example, a thin cotton glove can be worn beneath a glove to protect against dermatitis, which can occur from prolonged skin exposure to moisture in gloves caused by perspiration.
Workers should always remove protective clothing (except for gloves) first and discard or secure the clothing for disinfection before removing their respirators and goggles. It is important that workers understand the importance of strict adherence to hand washing after contacting infected birds or surfaces that might be contaminated. Having suitable hand-washing facilities and a good supply of soap and disposable towels is essential. Before removing their gloves, workers should wash their gloved hands thoroughly with soap and water, and after removing the gloves, they should wash their hands again. If hand-washing facilities are unavailable at the site of an outbreak response, alternative hand-disinfection procedures will be specified. If waterless soaps or alcohol-based sanitizers are provided, care should be taken because they are very harsh on the skin, which might lead to dermatitis if used too frequently.
It is important to take measures for preventing the avian influenza virus from being spread to other areas. To do this, disposable items of personal protective equipment should be discarded properly, and non- disposable items should be cleaned and disinfected according to outbreak-response guidelines.
Where to get more Information
Links to Internet sites are provided in this Safety and Health Information Bulletin for those wanting more detailed information on the topics presented. In addition, for those wanting sources of personal protective equipment, manufacturers of protective clothing, respirators, eye protection, and other items of personal protective equipment are listed in the Buyer's Guide of the International Safety Equipment Association.
For answers to workplace safety and health questions, check the Web sites of NIOSH or OSHA, or telephone NIOSH at (800) 356-4674 or OSHA at (800) 321-6742.
This Safety and Health Information Bulletin is a product of the OSHA-NIOSH Issues Exchange Group. Appreciation is extended for the insightful reviews of this document by scientists from the National Center for Infectious Diseases of the CDC and the Animal and Plant Health Inspection Service of the U.S. Department of Agriculture. Appreciation is also extended to Ms. Priscilla Wopat of the NIOSH Spokane Research Laboratory for editing the document.
Mention of company names or products does not constitute endorsement by the National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention
Accessibility Assistance: Contact the OSHA Directorate of Technical Support and Emergency Management at (202) 693-2300 for assistance accessing PDF materials.