Avian Flu Scan for Feb 25, 2015

More H7N9 cases in China
H9N2 seroprevalence

H7N9 sickens two in China's Guangdong province

China's Guangdong province reported two new H7N9 avian influenza cases today, according to a report from Hong Kong's Centre for Health Protection (CHP).

One of the H7N9 case-patients is a 3-year-old boy from the city of Heyuan, who is hospitalized in stable condition. The other infection occurred in an 18-year-old woman from the city of Foshan. She is currently hospitalized in critical condition.

The two new cases bring the global H7N9 total to 613, according to a case list maintained by FluTrackers, an infectious disease tracking message board.
Feb 25 CHP report
H7N9 case list


Study finds low prevalence of H9N2 infection in people exposed to birds

Seroprevalence of H9N2 avian flu antibodies among people exposed to birds was fairly low, although the virus still poses a pandemic threat, according to a study in the Journal of Infectious Diseases.

Researchers conducted a meta-analysis involving 25 studies on the results of hemagglutination inhibition (HI) and microneutralization (MN) assays presented in 25 studies from 1997 to 2003. Results were compared with the World Health Organization (WHO)–recommended case definition for seroprevalence, which is a median 1.3% via HI and 0.3% via MN.

Use of the HI assay in people exposed to birds resulted in an overall H9N2 seroprevalence of 4.9% (range, 0.6%-42.6%), which did not differ significantly from the WHO estimate. The MN assay returned a median seroprevalence of 2.7% (range, 0.5%-9%), which was significantly higher than the WHO definition.

Researchers found that H9N2 infections were detected mainly in China, Hong Kong, and Bangladesh, although infection has also been detected in other Asian regions, the Middle East, Africa, and North America. The virus has an almost global distribution in domestic poultry.

H9N2 infection in people generally causes mild or asymptomatic disease, and the study said that surveillance efforts are likely missing infections in people exposed regularly to birds. Because H9N2 poses a pandemic threat, researchers recommended standardized sampling protocols and the development of new diagnostic assays.
Feb 23 J Infect Dis abstract

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