Catastrophes after crossing species barriers

Thursday 6th May: Scientists attending the 14th European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Prague were told that conventional medical textbooks were not to be trusted by Professor Albert Osterhaus of Erasmus University , Rotterdam .  He described the alarming trends seen in the last 20 years caused by more emerging viruses crossing species barriers - going against all currently held dogma.

When the symptoms of SARS first emerged, scientists believed it to be a new pandemic flu outbreak.  But under the auspices of the WHO, and following unprecedented collaboration between laboratories worldwide, SARS was eventually identified as a novel coronavirus whose natural reservoir is now believed to be the civet cats traded in the wild animal markets of Southern China . 

However, SARS is now recognised to be only the latest one of a number of respiratory viruses that have been shown to cross the species barriers.  Professor Osterhaus also described how the influenza A virus has a unique ability to reassort leading to the mutation of the low pathogenic virus in the wild bird and poultry population into highly virulent forms affecting poultry, domestic animals and humans.

Dr Ron Fouchier of Erasmus University , Rotterdam added, "Avian flu is now affecting humans much more frequently.  Last year in the Netherlands there were 89 cases with only one fatality.  This year to date we have seen 3 cases in N. America and 34 in SE Asia - with 23 fatalities.  In SE Asia , these cases could be the tip of the iceberg.  If we look we might find many more cases."

In the Netherlands there is now a policy of active surveillance of poultry to find the carriers before the virus mutates.

The Nipah and Hendra viruses have re-emerged in SE Asia , Australia and the Indian subcontinent, with possibly a first case of direct transmission from fruit bat host to human, and West Nile virus now affects virtually the whole of the North American bird population.

Professor Osterhaus firmly believes that such catastrophes will continue to occur and pose a serious threat to public health in the future due to a complex mix of societal, technological, ecological and viral changes.  To address this we must develop extensive diagnostic and surveillance networks as well as novel vaccines and antiviral therapy and protection strategies.  It will also be vital for laboratories worldwide to adopt the unique SARS cooperation model.  All this should provide the safeguards to limit their impact.