Studying the virulence of bird flu in humans

New research has shown that the H5N1 avian influenza virus replicates much more aggressively in humans than other types of human influenza viruses, which means that quick diagnosis and treatment is vital to preventing fatalities from the disease.

The H5N1 avian influenza virus creates high viral levels that set off an overwhelming inflammatory response.This helps explain the infection's virulence, according to researchers M de Jong and others, who published their findings in the Journal of the American Medical Association.

Researchers at the Oxford University Clinical Research Unit at the Hospital for Tropical Disease in Ho Chi Minh City, Vietnam, studied 18 patients infected with H5N1 influenza and eight patients with two types of human influenza.

H5N1 patients had much higher levels of virus in their throats than other patients. Also, levels of some inflammatory cytokines and chemokines were correlated with viral load and were highest in the patients who died. One cytokine, interleukin 8, is produced by bronchial epithelial cells and may play a role in acute respiratory distress syndrome.

"Our observations indicate that high viral load, and the resulting intense inflammatory responses, are central to influenza H5N1 pathogenesis," the researchers said, noting that clinicians should focus on preventing this intense cytokine response by early diagnosis and antiviral treatment.

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Editor WorldPoultry