Avian Influenza - A Pandemic in the making? Part II
Cedric Lazarus
For the past couple of weeks, the focus on the Avian Influenza H5N1 virus has shifted sharply to Indonesia where in the small village of Kubu Simbelang seven members of one family died of the disease between the 2nd and 24th of May. As a result of this unusual cluster of cases, 54 surviving family members and other close contacts of the dead have been identified and placed under voluntary home quarantine. In addition, those quarantined are receiving the antiviral drug, Osetlamivir or Tamiflu, as a preventative measure and are visited daily by health officials. At the same time, house to house surveillance is being conducted throughout the village to look for influenza like illnesses among the villagers.
This Indonesian tragedy has prompted many scientists to be asking one important question, namely, "Does this cluster of cases represent a mutation in the virus with the ability to spread efficiently from person to person?" This is the so-called mutation to transmissibility concept that states that all it would take for H5N1 to become a pandemic would be for the virus to mutate so it could spread in a sustained way from person to person. The answer to this and other questions will probably be known in a few weeks after the investigations have been completed on the Indonesian cluster.
On another front, at a recent conference in Rome , the role that wild migrating birds play in the spread of the virus was rigorously debated. To quote one observer, "There hangs a cloud of mystery over the role these birds play in the spread of the virus." One view holds that migratory birds are the main culprit in the spread of the virus. A counterview is that both the legal and illegal trade in wildlife are to blame. Still a third view states that the most important spreader of the virus overall is man and the globalization of trade. It seems that the many experts have agreed to disagree on this important topic.
However, it is obvious that the answer to the question will assist countries in devising effective and appropriate preventative and control measures against the virus.
At the same time, the WHO recently announced that it has detected glaring deficiencies and weaknesses in the Avian Influenza Emergency Plans of many countries. According to the WHO, one of the Emergency Plans examined did not even mention the veterinary authorities despite the conventional wisdom that the key to preventing and controlling outbreaks in humans is to firstly control and prevent them in domestic poultry. A national Emergency Plan has to be multifaceted and its development and implementation must draw on the expertise of several groups and organizations such as health and veterinary officials, wild life organizations, poultry companies, universities, the police, army and many others.
In North America extensive surveillance continues in the wild bird populations and to date there has been no indication that the virus has arrived on the continent. Indeed there is now the feeling among some virologists that based on what they have seen so far the virus will not arrive on the continent any time soon. Let's hope that they are right. Despite this optimism we are all advised to educate ourselves on the virus, learn as much as we can about it and pay attention to what is happening in Asia . As one prominent Canadian economist recently said, "The problem is, a flu pandemic is just like a category 4 hurricane. There is a low probability. But when it happens, the probability is 100 per cent!"
In part 3, I will discuss the latest developments in vaccinating poultry and humans against the virus and the human antiviral drugs currently on the market.
