New mad cow fears

German, Finnish, Lithuanian and Swedish laboratories has recently described the various forms of hantaviruses, which cause respiratory diseases, that infect small rodents in eastern Europe. Hantaviruses can pass to humans, particularly forest workers and farmers whose work brings them into contact with these animals. A particularly virulent form has been found in the Balkan states in Europe which has proved lethal in 12 per cent of human cases. The new analysis of the Hantavirus strains should help the development of analytical and diagnostic tests. Global warming is allowing certain species, in particular insects, to colonise new regions where they can further propagate pathogens. Tropical deforestation is bringing humans into contact with animals they have not encountered before. The Hendra and Nipah viruses, discovered in the 1990s, and deadly in some 50 per cent of cases, appear to originate in fruit-eating bats from south-east Asian forests. The increasing contact between humans and animal species is not matched by knowledge of the biochemical mechanisms that create a species barrier to infection. “Pathogen–host interactions are right now the subject of intense research. A better understanding of the pathogenesis mechanisms, facilitated by growing knowledge of genomes, should help us see more clearly,” says Alistair MacMillan of the UK’s Central Veterinary Laboratory. The USA-EU Biotechnology Research Task Force concluded at its meeting last summer that there was an urgent need to organize a meeting on this topic. This workshop will focus more particularly on experimental hypotheses and models that can potentially verify the molecular and environmental mechanism governing the transmission of infectious agents from one species to another, says Etienne Magnien, director for biotechnologies, food and agriculture at the European Commission’s research directorate. There is no doubt Sars has focused thinking on the challenges presented by the emergence of new human diseases arising from animals. Any many are pleased that WHO is strengthening its abilities. “The quick and effective response of WHO to the Sars crisis did much to restore faith amongst the many critics of the effectiveness of international agencies with large bureaucracies and limited resources for action,” says Anderson. “This strengthened approach to outbreak response will be reflected in the revised international health regulations, which set out roles and responsibilities for preventing transboundary spread of infectious diseases both on a routine basis and in crisis situations,” says David Heymann of the WHO. Magazine R93