Major disease outbreaks have become more common around the globe in the past 40 years, according to a major investigation into emerging infections. Zoononses (diseases which can be transmitted from animals to humans) are an increasing threat to human health, while many infections have now become resistant to antibiotics. Tropical regions are likely to become a future hotspot for new diseases.

Researchers from the Zoological Society of London, the Wildlife Trust and Columbia University analysed databases of outbreaks and found 335 cases of emerging diseases between 1940 and 2004. Of these, 60.3% were infections which also affected animals, and 71.8% were known to have triggered disease in humans after spreading from wildlife. The research, published in Nature, identifies "hotspots" where new diseases are expected to come from wildlife, driven by the proximity of dense human populations and high levels of biodiversity.

The global pattern of diseases was closely linked to regions with high rainfall and biodiversity, alongside rapid growth in the human population. Europe and North America have experienced high numbers of outbreaks, but much of that is because those regions have invested heavily in detecting early signs of disease. Other countries, scientists fear, are less able to spot new diseases as they arise.

More diseases emerged in the 1980s than any other decade, according to the study. This was likely to be because of the emergence of HIV, which put vast numbers of people at risk of contracting other diseases. The great majority of outbreaks were triggered by bacteria and viruses, with 20% caused by antibiotic-resistant microbes.

Dr Kate Jones, of the zoological society, said areas of rich biodiversity harboured pools of pathogens, which were readily able to spread. "Humans are impacting on these areas and developing them, coming into contact with wildlife through bush meat, farming, domestication of animals. We're increasing our human impact on these areas and exposing ourselves to potential pathogens." Preserving wildlife-rich areas could help to protect people from new diseases, in the same way that conservation ensures cleaner water supplies and so on...

There doesn’t seem to be much greatly new in the findings of this research: I doubt anyone would be surprised to read that there had been an increase in outbreaks of new diseases, or that there are disease hotspots. On the other hand it is useful to have the obvious thrust under our noses.....