This document was produced in response to the need for expert guidance to minimize the public health risk from exposure to dead birds with proven or suspected highly pathogenic avian influenza type A/H5N1 infection.
In March 2013, Chinese authorities announced the identification of a novel reassortant A(H7N9) influenza virus in patients in eastern China. Since then, human cases have continued to be reported, and as of 7 February 2014 (Figure 1), there have been 308 laboratory-confirmed cases: Zhejiang (122), Guangdong (54), Shanghai (42), Jiangsu (36), Fujian (19), Hunan (7), Jiangxi (5), Henan (4), Anhui (4) ,Beijing (3), Shandong (2), Hebei (1), Guangxi (2), Guizhou (1), Hong Kong (4) and Taiwan (2). In addition, the virus has been detected in one asymptomatic case in Beijing.
Since July 2011, 155 cases of the variant influenza A(H3N2) virus (A(H3N2)v) have been detected in the US: Hawaii (1), Indiana (113), Iowa (3), Maine (2), Ohio (30), Pennsylvania (3), Utah (1), and West Virginia (2). Most cases reported in Indiana and Ohio are recent cases. No human to human transmission has been determined among these recent cases.
This academic article describes virological findings and pathological consequences of a strain of influenza A(H3N8) recently identified as part of the investigations of an outbreak of pneumonia among harbour seals in New England in the autumn.
A report in the US Centers for Disease Control and Prevention (CDC) MMWR this week describes the investigation of mild respiratory illness among swine and people at a county fair in Indiana, USA between 8 and 14 July 2012. This is an important report as it is very clearly documents simultaneous detection of H3N2v influenza viruses in humans and swine in close contact.
Influenza pandemics occur when new influenza viruses appear that transmit efficiently between humans and to which a substantial proportion of the population is susceptible