Avian Flu Update

This week the Centers for Disease Control and Prevention (CDC) warned that the avian influenza (also known as the Bird Flu) could become a global epidemic if a new virulent strain of the virus emerges that can jump readily from human to human. If that happens health officials estimate that it would spread rapidly and could infect nearly one-third of the world's population and kill anywhere from 2 million to 50 million people. The recent statement by the CDC echoes a previous warning by the World Health Organization (WHO) and coincides with a new study on the virus published by the New England Journal of Medicine.

Avian has been known to mutate rapidly, and has resurfaced as an epidemic in eastern Asia. There are at least 15 different types of avian influenza that routinely infect birds around the world. The current outbreak is highly contagious among birds and rapidly fatal. Unlike many other strains of avian influenza, it can be transmitted to humans, causing severe illness and death. So far, the virus has only spread to those who came into close contact with infected birds or to people who have had close and prolonged exposure to infected humans. However, infectious disease experts fear the virus will soon mutate within a pig or some other animal which harbors both human and avian forms of the flu virus. The two viruses might then merge, creating an even more deadly virus that could spread rapidly among humans.

The current strain of avian flu has a mortality rate in humans of more than 33 percent - by comparison SARS (Severe Acute Respiratory Syndrome), which infected 8,400 and killed 800 in 2003, had a mortality rate of 15 percent. The avian flu killed approximately 32 people in the last year. Most of the humans were infected with the disease through direct contact with birds. However, there have been several isolated incidents in which the disease was reportedly transferred from human to human. According to the WHO the avian flu "...has gone through huge genetic changes and become more pathogenic. It has affected not only birds, but cats, pigs and tigers ..."

Researchers are currently working on a vaccine for the flu, but even if scientists are successful in finding a cure it may not stop the disease from becoming a pandemic. For financial reasons, the mass production of the vaccine would only happen after the onset of the epidemic and it would take time to distribute. Once an outbreak begins it could take months for the vaccine to reach the public. Public health specialists fear the next pandemic will likely be triggered in Asia, where health systems may not be able to cope.

Avian flu will likely be the cause of the next pandemic, which experts say will probably happen in the near future. There have been 4 pandemics during the last century, which emerge – on average – every 30 years. Between one and four million people died during the last flu pandemic, which hit Hong Kong in 1968. Health experts at the WHO have indicated that we are long overdue for an outbreak, the WHO spokesman recently made the statement that: "As with an earthquake or any other natural occurring phenomena, we cannot give an exact time but the situation now is particularly concerning in that we are so long after the last pandemic... and we have a virus circulating in Asia [speaking of avian]. We are living perhaps on borrowed time."

In 1918, just after the end of WWI, the so-called Spanish flu emerged. It was perhaps the most deadly pandemic in human history and killed between 20 and 50 million people, more than the Black Plague or AIDS. Surprisingly, new research suggests the 1918 flu epidemic was no more infectious than SARS. It was so deadly because the population was vulnerable and the virus was allowed to spread. If a new virulent form of the avian virus emerges health officials will need to act quickly to stop the pandemic in its earliest stages. A team of Harvard researchers concluded that an outbreak of the flu could only be combated effectively by vaccinating or distributing antiviral drugs to 50-75 percent of the population, but at present, vaccine production capacity and antiviral medication stockpiles are insufficient to provide such broad coverage, even in wealthy countries. The only option left is to isolate people with the disease, a time-honored tactic that worked well with the SARS outbreak in Asia last year. But SARS and the flu are different. People with SARS were only infectious when they had the symptoms. That meant people with fever, sneezing and coughing could be identified and isolated. The avian flu, however, can be substantially transmitted before the patient shows any symptoms. That problem is compounded by jet travel, which could help the virus to spread around the world within days.