High Viral Load, Cytokines Linked to Fatal H5N1 Infections
Early diagnosis and effective treatment important
MONDAY, Sept. 11 (HealthDay News) -- Individuals infected with the H5N1 strain of the influenza A virus have high viral loads and an intense inflammatory cytokine response, suggesting the importance of early diagnosis and effective treatment, according to study results published online Sept. 10 in Nature Medicine.
Menno D. de Jong, M.D., Ph.D., from the Oxford University Clinical Research Unit in Ho Chi Minh City, Vietnam, and colleagues characterized the basis of the virulence of the H5N1 virus in 18 individuals hospitalized after H5N1 infection in 2004 and 2005, of whom 13 died. Eight individuals hospitalized after infection with the H3N2 or H1N1 influenza strains were used as a comparison.
The researchers found that patients infected with H5N1 had much higher viral loads in the pharynx, which were highest in those who died. H5N1 viral RNA was only found in the blood of fatal cases. Levels of some cytokines and chemokines were also high, and peripheral T cell counts were low in H5N1-infected patients, according to the study.
"Our observations indicate that high viral load, and the resulting intense inflammatory responses, are central to influenza H5N1 pathogenesis," de Jong and colleagues conclude. "The focus of clinical management should be on preventing this intense cytokine response, by early diagnosis and effective antiviral treatment."