| Though the avian influenza virus is hosted by | | | | and are hence labeled as, N (non-resistant to oil), |
| birds, some particular subtype might affect other | | | | R (oil resistant) and P (oil proof). Each individual |
| mammals too, including humans. In a direct | | | | mask is tested in laboratory settings before being |
| manner the virus is contacted from infected birds, | | | | approved for sale. But N95 ones are disposable |
| mostly domestic poultry but sometimes wild birds | | | | and cannot be cleaned. |
| also can infect hunters, tribal people, etc. In an | | | | The most common ones are N-95 filtering |
| indirect manner the infection can enter the human | | | | respirators which have been approved by NIOSH |
| system via edibles infected with the virus, polluted | | | | (also called as Filtering Facepieces) as being |
| water, objects, air, food, etc. by the bodily | | | | effective drastically cutting down exposure risks |
| secretions or excretions of infected birds. The flu | | | | to airborne viruses like SARS or Avian Influenza. |
| virus being airborne, the contamination in the air | | | | The usage of masks is recommended to people |
| could be reasonably high, in cases of epidemic or | | | | working in high contamination situations, like health |
| pandemic proportions. Infected people carry the | | | | care workers attending to patients, or field |
| flu virus with them wherever they travel and | | | | workers involved in destroying the infection |
| spread it in air and on objects they touch via their | | | | sources, etc. |
| nasal secretions and bodily discharges. | | | | Another set of very powerful, protective masks |
| Personal Protective Equipment or PPE as they are | | | | are Powered Air-Purifying Respirators (PAPRs). |
| called are equipments designed for health | | | | They are more effective than N-95 masks in |
| professionals to use if they are working in | | | | offering better protection. These are used by |
| contaminated environments. Nose and mouth | | | | persons who cannot wear N-95 masks, like people |
| respirators or 'Masks' are the ones most widely | | | | with facial hair. This battery operated mask has a |
| used. Bird flu masks are very specific pertaining to | | | | face piece with breathing tube and filters. |
| the fact that the bird flu virus is microscopic and | | | | Even though any mask is not a guarantee against |
| is not easily filtered out from the environment | | | | influenza infection, they dramatically cut down the |
| using conventional filters. | | | | chances of infection from airborne viruses. It |
| These masks are designed on the guidelines given | | | | remains to be said however, that the capabilities |
| by National Institute for Occupational Safety and | | | | of the masks degrade over time from usage. |
| Health (NIOSH). Based on filtering efficiency, the | | | | Aerosols, if present in the working environments, |
| filters used in the masks fall under 3 categories, | | | | degrade the filters even more. Hence, bird flu |
| namely Type 95, Type 99 and Type 100. The | | | | masks should not be used with 100% reliance, but |
| proportions of microscopic (0.3 micron wide) | | | | only as one of the preventive tool. More so, there |
| particles filtered out by these filters are 95%, | | | | are guidelines that need to be adhered to while |
| 99% and 99.7%, respectively. Also the filters are | | | | (re)using such PPE. |
| categorized based on filter efficiency degradation | | | | |