Emerging infectious diseases will get worse

Emerging infectious diseases pose a global threat to human and animal health, and the problem is likely to worsen, warns an expert in the British Medical Journal (BMJ).

The recent emergence of diseases, such as AIDS, SARS and avian flu, have catapulted emerging infectious diseases to the top of the medical and political agendas, and have highlighted the importance of wildlife as reservoirs or vectors for disease, writes Dr Andrew Cunningham.

Of pathogens causing emerging infectious diseases, 75% are zoonotic (able to transmit from animals to humans), with wildlife being an increasingly important source.

But why are we now seeing an apparently rapid increase in the emergence of new zoonoses from wildlife?

One of the major drivers is closer human contact with wildlife, primarily caused by human encroachment into, and modification of, wildlife habitat. For example, Ebola virus outbreaks often are linked to hunting for "bushmeat" or to mining development, and the AIDS pandemic originated from human encroachment into African forests for food.

The rise in international trade and travel is also important. The emergence of West Nile virus in North America, and AIDS and SARS globally, for example, arose from such travel and trade.

This globalisation of people and products is difficult to control and is largely related to increasing air transportation. With world air travel expected to grow at about 5% a year for at least the next 20 years, the problem of emerging infectious diseases will continue to grow, he warns.

Emerging infectious diseases are not only a problem for human health but are a major threat to animal welfare and to species conservation. Some emerging infectious diseases also threaten domesticated species.

Through emerging infectious diseases, therefore, the medical, veterinary, and wildlife conservation professions, share a common agenda. The problem is not small, and tackling it will not be easy, but recognising a common problem is, at least, a start, he concludes.