China reports H5N6 in poultry; study finds high H5N1 seroprevalence

Chinese officials yesterday reported two outbreaks of highly pathogenic H5N6 avian flu, while a study out of Indonesia reports that 84% of Indonesian poultry workers have evidence of previous infection with H5N1 avian flu in their bloodstream.

Elsewhere, the World Health Organization (WHO) confirmed two recent H5N1 human cases in Egypt.

H5N6 in China

The two H5N6 outbreaks are in separate provinces and have affected more than 100,000 poultry, Chinese officials reported in a World Organization for Animal Health (OIE) report.

The largest outbreak, near Jinchang City in Gansu province, struck a farm of 95,172 birds on Oct 2. The virus caused 30,000 avian flu infections and 18,000 deaths.

The second outbreak, near Xiaogan City in Hubei province, involved a farm of 6,100 birds, of which 4,338 poultry were sickened and 3,924 died. That outbreak also began on Oct 2.

All told, 101,272 birds either died from the disease or were culled to prevent disease spread. Tests from both farms came back positive 2 days ago for highly pathogenic H5N6 avian flu. Response steps have been activated at both farms.

Gansu province is in the north-central part of China, south of Mongolia. Hubei province lies southeast of that, in the east-central part of the country. Xiaogan City is about 800 miles west of Shanghai.

China has reported 15 H5N6 cases in humans, which is the global total. Nine of them have been confirmed this year, the most recent on May 31.

Evidence in blood of H5N1

The report from Indonesia involved 101 workers at a live-poultry market in East Java whose blood was tested in early 2014, according to a Journal of Infectious Diseases study.

Using the hemagglutination inhibition (HI) assay, the researchers found that 84% of the sera tested positive for antibodies to H5N1 avian flu virus. The team also noted that the average HI titer among the samples was about three times higher than in 2012 and that seroconversion occurred in 44% of paired sera (11 of 25) from 2012 to 2014.

None of the poultry workers indicated on a questionnaire that they had had severe acute respiratory illness.

H5N1 cases in Egypt

The Egyptian H5N1 cases were noted in a brief update yesterday from the WHO Regional Office for the Eastern Mediterranean. The agency simply noted 2 additional cases since its previous update in July, bringing the country's 2016 total to 10. No details on the new cases, the most recent of which occurred on Jul 28, were provided.

The WHO regional office said that Egyptian officials have confirmed 183 cases since Jan 2, 2014, the vast majority in late 2014 and early 2015—the most active period of human H5N1 cases ever in any country. Of the 183 cases, 60% were in female patients, with children under 5 (30%) and those 30 to 45 years old (31%) especially affected. Young children, however, had the lowest case-fatality rate (CFR), which increased with age.

Since the disease was first reported in Egypt in 2006, officials have confirmed 356 H5N1 cases, including 121 deaths, for a CFR of 34%. The WHO also reported that those who received antiviral drugs within 48 hours of symptom onset had a CFR of 17%, compared with 34% in those who didn't.

See also:

Oct 9 OIE report

Oct 7 J Infect Dis study

Oct 9 WHO report

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