Has Deadly Bird Flu Spread Beyond Asia?
Recombinomics Commentary
April 7, 2005
>> "The potential for the disease to spread to other continents is real and the international scientific community cannot remain insensitive to the challenge of preventing this happening," OIE Director-General Bernard Vallat told a conference in Paris on Thursday. <<
Although the potential for H5N1 bird flu to spread to other continents is real, the possibility that it has already spread to other continents is high. Reports of bird flu in the three northeastern provinces of Vietnam, Thai Binh, Haiphong, and Quang Ninh, show clear patterns of human-to-human transmissions. Reports of H5N1 infected poultry in these provinces have historically been very low and there has been little evidence to link many, if any, of these cases to poultry. The evidence for human-to-human transmission within the clusters is overwhelming, and the clustering of these clusters leaves little doubt that the transmission to humans is becoming increasingly efficient, as transmission chains grow longer and clusters grow larger.
However, many of the cases have been much milder than those reported in the south, where the case fatality remains at 100%. In the north, many of the patients improve within days after hospitalization and are released after 1-2 weeks. This mild course suggests many H5N1 patients simply recover at home, assuming that they have a bad case of human flu.
As the number of the milder cases increases, so does the likelihood that some H5N1 infected people will travel outside of Asia and transmit H5N1 to contacts in other continents. These milder cases will go unnoticed unless the symptoms worsen to a point where testing is ordered. However, milder cases will not be tested, so the flow of H5N1 outside of Asia will remain undetected.
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