Study suggests human-to-human spread of bird flu likely

April 13th, 2008 - 1:56 pm ICT by admin  

Beijing, April 13 (IANS) A new study by Chinese scientists suggests that human-to-human transmission of the H5N1 bird flu virus is highly possible. The study is based on the analysis of two human cases of bird flu that occurred within the same family in eastern China’s Jiangsu province in December 2007, Scidev.Net reported.

A 24-year-old man died of H5N1 infection on Dec 2, 2007, the fifth day of his hospitalisation.

Two days after his death, his 52-year-old father developed bird flu symptoms such as fever, chill and cough. He was diagnosed with H5N1 infection and survived only after receiving early antiviral treatment.

The researchers, from the Chinese Center for Disease Control and Prevention (China CDC), investigated the men’s exposure to both poultry and people and found the son’s only plausible exposure to H5N1 was a visit to a poultry market six days before the onset of illness.

The father had substantial unprotected exposure to his ill son and the researchers could find no evidence of him coming into contact with live poultry or being exposed to H5N1 by any other transmission channel.

The H5N1 viruses isolated from father and son were also found to have virtually the same genetic structures.

“We believe that the son transmitted the H5N1 virus to his father while his father cared for him in the hospital,” the researchers wrote in the latest issue of the medical journal The Lancet.

But they have found it difficult to explain why the deceased’s mother and girlfriend - both of whom had substantial unprotected exposure to him during his hospitalisation - did not become infected.

“We could not find any apparent difference between the exposure forms of the father and the other two (the mother and girlfriend),” said co-author Shu Yuelong.

“The situation indicates that we are far from understanding the clear pathogenic mechanism of bird flu,” he said.

In an accompanying comment, Jeremy Farrar of the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam, and colleagues said all published incidents of possible or probable person-to-person transmission are currently between genetically related individuals.

“Whatever the underlying determinants, if we continue to experience widespread, uncontrolled outbreaks of H5N1 in poultry, the appearance of strains well adapted to human beings might just be matter of time,” Farrar said.

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