Avian Flu Pandemic Concern

Concern About Avian Flu
Recently, there has been great concern about the virulence of the avian (bird) flu virus (H5N1) and the potential for its transmission to humans. The increased spread of the virus to wild birds, poultry, and mammals expands opportunities for human exposure and potential evolution of H5N1 into a virus capable of efficient human-to-human transmission. There has been some human-to-human spread of the H5N1 virus, but the spread has been limited and unsustained. Most recently, in June 2006, the World Health Organization (WHO) reported evidence of human-to-human transmission in Indonesia. Eight people from one family were infected. The first family member became ill through contact with infected poultry. This person infected family members. No spread outside of the exposed family was found. Health professionals believe that the continued spread of a highly pathogenic avian H5N1 virus across eastern Asia and Africa represents a significant threat to human health.

Confirmed Cases of Avian Flu

Since 2008 there have been 348 laboratory confirmed cases of avian flu in humans resulting in 216 deaths (January 3, 2007; Word Health Organization). However, this apparent high mortality rate does not provide a true picture of how lethal H5N1 may be in humans.  All of the known human cases have occurred in developing countries.  Only very severely ill individuals presented to hospitals where they were tested for the virus. 

It is likely that more mild cases not identified as H5N1 have occurred in the population.  Since the actual number of human infections is not known, it is not possible to accurately estimate the mortality rate associated with H5N1. 

The U.S. Department of Health and Human Services estimates that, under the most severe circumstances such as those that prevailed during the 1918 pandemic, the potential mortality rate from an avian flu pandemic could be 2.1%.

Symptoms of the Avian Flu
The symptoms of avian influenza may depend on which virus causes the disease. Symptoms of avian influenza in humans have ranged from typical human influenza-like symptoms:

• fever
• cough
• sore throat
• muscle aches

to more serious symptoms such as:

• eye infections
• pneumonia
• severe respiratory diseases (such as acute respiratory distress)
• and other severe and life-threatening complications

Prevention and Treatment for the Avian Flu Viruses
Avian flu viruses do not commonly infect humans, and there is little or no immune protection against them in the human population.  A human vaccine can be developed if a pandemic strain should come into existence.  If and when such a virus emerges, scientists will isolate it, characterize it, and develop and manufacture a vaccine.  Based on current vaccine production processes and capacities, it could take six months to begin producing pandemic vaccine once a pandemic strain emerges. A vaccine will be the most effective intervention to prevent transmission of avian flu when it becomes available. Anti-viral medications may also reduce transmission, but the supply of these medications is limited. Two important strategies that should be used to limit the spread of flu are infection control and social distancing.

Infection control measures include: keeping hands clean and germ-free, cough etiquette- covering your cough, remaining at home if you or a family member are sick (voluntary quarantine), and cleaning of the environment and routine disinfection.

Social distancing would be implemented during a pandemic. It involves increasing the physical distance among people, closing schools, canceling public events, reducing physical contact, and providing alternatives to face-to-face contact in the work place, such as telecommuting.

Four types of nonpharmaceutical measures to battle pandemic influenza have been recommended by the U. S. Centers for Disease Control and Prevention. The measures are tied to the Pandemic Severity Index (Interim Pre-pandemic Planning Guidance: Community Strategy for Pandemic Influenza Mitigation in the United States, U.S. Centers for Disease Control and Prevention, February, 2007. PDF) . The early, coordinated use of "community mitigation measures" such as isolating patients, sending students home, and canceling public gatherings can make a significant difference in the course of an epidemic. The four types of measures are: isolation and treatment of people in their homes, voluntary home quarantine, dismissing school and closing day-care centers, and social distancing for adults through changing work schedules and canceling public events.