A vian flu appears to be spreading with increasing rapidity. In recent weeks, there have been confirmed reports of the disease in Europe and Africa, demonstrating that the H5N1 strain is hardier than thought and truly a global danger. While health officials call for continuing surveillance and vigilance, they also warn against overreacting to the threat. At the same time, those experts worry that other diseases may also emerge. Bird flu makes headlines, but other pathogens pose equal or greater dangers.
It is estimated that at least 200 million birds have died or been killed as a result of bird flu. Millions more are infected with the virus. Fifteen countries have reported outbreaks in the last month; more than 30 countries have reported cases since 2003. There have been more than 170 human infections in seven nations; more than 90 lives have been lost.
The sharp spike in the number of countries reporting infections is worrisome. Most recently, the disease has surfaced in India, Malaysia, Egypt, Bosnia, Croatia, Nigeria, Hungary, France and the Netherlands. Increasing awarness of the threat is one explanation, but the virus is plainly capable of traveling long distances — which suggests it is growing stronger — and adapting to a wide range of host environments. Especially worrisome is evidence that some “virus reservoirs,” such as wild ducks, can host the disease without getting sick themselves. That makes the disease harder to track, isolate and eliminate.
There is no evidence that it has mutated to the point where it can be transmitted from human to human. Human infections still only occur where people and fowl live in close proximity. Unfortunately, its appearance in India and Africa offers plenty of opportunities for infection. Health officials are struggling to prevent that and to prevent a panic. They are culling birds as quickly as possible and trying to quarantine individuals that might be infected with the disease.
Those efforts are complicated by a variety of factors. The isolation of many rural communities most at risk is one critical obstacle. Most of them do not have information about the threat, the risks and how to deal with the problem. Just as important is the reliance of families in those communities on birds for survival. It is estimated that in the developing world, some 70 percent of populations live in rural settings. They are reluctant to kill birds, even if infected, because they provide food and a livelihood.
This same problem surfaces in more developed countries. France and the Netherlands, two of Europe’s biggest poultry producers, have been hit by the disease. The Netherlands killed tens of millions of birds a few years ago when bird flu first surfaced. Those governments want to vaccinate millions of birds against the disease. The problem is that consumers in many countries are unwilling to eat vaccinated poultry for health reasons too. Thus a key component of any vaccination plan is the ability to distinguish vaccinated from unvaccinated birds.
The failure of avian flu to “jump species” is good news. But a mutation could occur at any time. As one World Health Organization spokesman noted, “as long as the virus is circulating it could jump to humans.” Bird flu has highlighted this threat, but it is not the only danger. About 1,400 pathogens — viruses, bacteria, fungi and parasites — cause human disease; some 800 originated in animals. TB, malaria and smallpox are among them.
Experts note that 38 pathogens have made the transition from animals to humans in the last quarter century. That means the rate at which diseases make this jump is increasing. The experts believe that bird flu may not be the only next animal disease to have a big impact on society.
Scientists blame a reduction in the buffer zone between people and animals due to increasing human encroachment on the environment and growing interactions between the two groups. Greater population densities facilitate the spread of disease within communities; greater mobility, courtesy of the ease of travel, facilitates its spread from one community to another.
Combating this threat requires work on many fronts. Surveillance must increase. There have to be better attempts to educate rural communities about the nature of the threat. There must also be funds available to them to compensate for the losses they incur when they cull birds. Governments have to work together to identify outbreaks as soon as they occur. There must be sharing of data so that vaccines are available and targeted to the proper strains. The “mobility” of viruses necessitates more cooperation between doctors and veterinarians. It will be a long and often frustrating struggle. But there is no alternative.
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