Bird Flu And What It Means For You, Sylvester and Tweety
By Professor Jock McLean
There is an old saying that good news doesn’t sell newspapers. This is certainly the case with some human diseases, where reports of doom and gloom are the order of the day. However the facts are quite different. There have been only 774 deaths from SARS and about 200 from “Mad Cow Disease”. The interesting feature of these two diseases is that humans require a specific genetic make up if they are to be susceptible to infection.
AIDS kills about three million people a year while malaria is responsible for around a million deaths a year. The high death rate from these two diseases gets little press coverage these days. In addition, many Australians take holidays in countries with high rates of malaria infection and don’t give the disease a second thought.
Bird Flu is a topic which regularly surfaces in the media and so far it has killed only 129 people, mainly in Asia. Let us look at some features of Bird Flu. It is not the same disease as the one which causes epidemics of human influenza. The Bird Flu virus does not easily cause disease and spread in humans. Infection requires close contact with sick or dead poultry. It is unlikely that an epidemic of human flu in Australia will come from migrating birds carrying the Bird Flu virus to this country. If the Bird Flu virus does mutate or mixes with human flu viruses to create an agent which can cause an epidemic of human flu, this process is most likely to occur somewhere overseas and the infection carried to Australia by humans.
Much has been made of the risk of an outbreak of Bird Flu in Australian domestic poultry. While the threat is real, the risk remains low for a number of reasons. Waterfowl, such as ducks and geese are the most important carriers of Bird Flu viruses. However these birds do not migrate back and forth to Australia. Shorebirds and waders do migrate from infected regions, but are less likely to carry Bird Flu.
Wandering birds such as Magpie geese and ducks found in northern Australia and southern New Guinea but don’t generally travel into Asia. So for Bird Flu to get into Australian domestic poultry it would most likely come from a migrating shore bird on to a wandering wild bird and then on to our local poultry. This convoluted path reduces the risk of Bird Flu coming to Australia.
However, we should not be too complacent. There have been five outbreaks of Bird Flu in Australia in the years between 1976 and 1997. Fortunately all five were successfully brought under control. As a result of these experiences, Australian commercial poultry farmers have in place strict security systems to eliminate the risk of Bird Flu getting into their poultry.
The Australian quarantine authorities also have well established procedures which are designed to prevent Bird Flu infecting our local poultry. These include monitoring the disease in other countries, surveillance programs in Australian and disaster plans to deal with outbreaks.
So what does all this mean for you? There is little risk of humans in Australia becoming infected with Bird Flu through normal contact with birds. To become infected, humans have to come in contact with a large amount of virus that gets deep into the lungs. Normal hygiene measures, such as washing your hands after handling birds and putting on gloves when handling sick or dead birds is all that is required. It is up to you whether you continue to kiss Tweety or Sylvester good night. Poultry meat and eggs purchased in shops have not been shown to cause infection in humans.
What about Tweety? He has very little risk of infection, but to be on the safe side it is best to cut him off from his wild mates and don’t allow them access to his food or water.
Sylvester doesn’t get off scot-free. Domestic and feral cats and other members of the cat family may become infected and die following eating infected birds. They can pass the virus on to other cats but probably not back to birds. Fortunately, the risk of cats infecting humans is low. Nevertheless, good hygiene should be observed after handling cats and cleaning litter boxes. All this means that Sylvester must be stopped from killing and eating wild birds, which is a good idea anyway.
Dogs, pigs and other species are unlikely to present a problem by becoming infected with Bird Flu.
So what is the bottom line? Bird Flu rarely infects humans and then only under special circumstances. However, there is always a small chance that it can convert to a strain that will infect humans and this change will probably take place overseas. You are safe for the moment, but need to be aware of the situation, especially if traveling outside Australia. Sylvester and Tweety are also safe for now.
Now for some doom and gloom. The worst case is that Tweety could pick up Bird Flu after meeting with one of his wild mates. Suffering from an attack of the flu he would be a bit slow and then wicked Sylvester would pounce, devour the poor bird and become next victim of Bird Flu. But this is too awful to contemplate!
Professor McLean has held various academic positions, has experience in the regulation of agricultural and veterinary chemicals, been involved in research and has published in a number of areas. He has also worked in small and large animal practice.