Respiratory Protection and Avian Influenza Viruses - Frequently Asked Questions
Feb 05, 2007
The U.S. Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), the Health Protection Agency (HPA) and the Department for Environment, Food and Rural Affairs (DEFRA) have issued precautions that should be used with regard to avian influenza viruses. For the most current information see the following websites:
3M has also received a number of inquiries regarding respiratory protection and avian influenza viruses. Following are many of the most commonly asked questions and responses based on information provided by the CDC and WHO.
What is avian influenza or flu?
Influenza viruses that infect birds, such as the H5N1 virus, are called “avian influenza viruses.” Avian influenza viruses do not usually infect humans; however, influenza viruses are constantly changing, and several instances of human infections have been reported since 1997.
What are the symptoms of avian influenza?
Symptoms of bird flu in humans have ranged from typical flu-like symptoms (fever, cough, sore throat and muscle aches) to eye infections, pneumonia, severe respiratory diseases (such as acute respiratory distress), and other severe and life-threatening complications.
How is avian influenza transmitted?
Birds that are infected with avian influenza viruses can shed virus in saliva, nasal secretions, and faeces. It is believed that most cases of avian influenza infection in humans have resulted from contact with infected poultry or contaminated surfaces. In such situations, people should avoid contact with infected birds or contaminated surfaces, and should be careful when handling and cooking poultry. Strict hand hygiene must also be performed. Other means of transmission are possible, such as the virus becoming aerosolized and landing on exposed surfaces of the mouth, nose, eyes, or being inhaled.
Can avian influenza be transmitted from person to person?
To date the CDC and WHO have reported that although there is evidence of limited person-to-person spread of infection, sustained human-to-human transmission has not occurred.
How long can the avian influenza virus survive in the environment?
The duration that these viruses can survive in the environment depends on temperature and humidity conditions, but they may survive up to weeks in cooler and moister conditions.
What type of personal protective equipment (PPE) is recommended for those who are involved with disease control and eradication activities?
From www.defra.gov.uk: Current advice is that a FFP3 respirator with exhalation valve in conjunction with close fitting goggles or other equipment which gives similar levels of protection is necessary where protection against airborne transmission is required. Where a good seal cannot be achieved with other respirators e.g. because of facial hair, a full hood powered respirator should be considered. Lightweight disposable overalls with hoods should be worn to prevent contamination of personal clothing. Wellington boots, disposable surgical type rubber/vinyl gloves should be worn. Where available, toughened, tear resistant brands are preferred.
For respiratory protection 3M supply two EN149:2001 FFP3 respirators for industrial and consumer applications; the 3M 8835 and 3M 9332. A comprehensive range of 3M Powered Air Respirators is also available.
For eye protection the 3M 2790A goggles provide protection against fine dusts.
The 3M 4560 protective coveralls offer protection against fine particles and biological hazards.
What type of personal protective equipment (PPE) is recommended for health care workers who are exposed to patients with known or suspected avian influenza?
Current HPA advice for protection of Health Care Workers in the management of possible H5N1 Avian Influenza infected returning travellers is to wear a correctly fitted EN149:2001 FFP3 respirator, gown, gloves and eye protection.
3M supply two EN149 FFP3 respirators for health care applications; the 3M 1863 and 3M 1873V.
Should avian influenza patients wear a surgical mask?
Persons suspected of having avian influenza should be separated from others and asked to wear a surgical mask. If a surgical mask is not available, tissues should be provided and patients should be asked to cover their mouth and nose when coughing.
How do I clean my respirator after use?
Disposable respirators should not be cleaned; dispose of the respirator immediately after use according to facility policy. Reusable respirators may be disinfected using a mild bleach and water solution (0.1% sodium hypochlorite).
Can disposable respirators be shared between people?
No. Disposable respirators should never be shared.
Can respirators protect you from biological agents such as Bacteria or Viruses?
Respirators are designed to reduce exposures of the wearer to airborne hazards. Biological agents, such as viruses, are particles and can be filtered by particulate filters with the same efficiency as non-biological particles having the same physical characteristics (size, shape, etc.). However, unlike most industrial particles there are no exposure limits established for biological agents. Therefore, while respirators will help reduce exposure to avian influenza viruses, there is no guarantee that the user will not contract avian flu. Respirators may help reduce exposures to airborne biological contaminants, but they don't eliminate the risk of exposure, infection, illness, or death.
What is the difference between an approved respirator and a surgical mask?
Respirators are designed to help reduce the wearer’s exposure to airborne particles. The primary purpose of a surgical facemask is to help prevent biological particles from being expelled by the wearer into the environment. Some surgical masks are also designed to be fluid resistant to splash and splatter of blood and other infectious materials. Surgical facemasks are not necessarily designed to seal tightly to the face and therefore air leakage around the edges is likely. However, some respirators are designed to have the characteristics of both an approved respirator and a surgical mask.
How important is respirator fit?
Fit is very important. If a respirator does not seal properly to the face, airborne hazards can penetrate or enter underneath the face piece seal and into the breathing zone. It is very important to always follow the donning instructions and do a user seal-check or fit-check before entering the contaminated environment. Some countries, such as the US and UK, also require fit testing. A good fit can only be obtained if the face is clean-shaven in the area where the respirator seals against the face. Beards, long mustaches, and stubble may interfere with a good seal and cause leaks into the respirator. Many medical facemasks, not approved as respirators, do not seal tightly to the face allowing airborne hazards to enter the breathing zone. Even those medical facemasks that appear to seal tightly to the face have not been designed to protect the wearer from airborne hazards. Therefore, they should not be considered an equivalent substitute for approved respirators.
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