In this update:
[1] USA: WHO update
[2] USA (Michigan, West Virginia, Ohio)
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[1] USA: WHO update
Date: Fri 10 Aug 2012
Source: WHO Influenza at human-animal interface, monthly risk assessment summary [summ., edited]
http://www.who.int/influenza/human_animal_interface/HAI_Risk_Assessment/en/index.html
Human infection with other non-human influenza viruses
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The United States of America (USA) has recently reported an increase in the number of human cases of A(H3N2)v2 infection. As of 10 Aug 2012, the total number of confirmed human cases of influenza A(H3N2)v for 2012 increased to 154, mainly as a result of follow up investigations of the initial cases in Ohio and Indiana. One case was also reported from Hawaii and one in Illinois.
Most cases were children who had direct or indirect exposure to pigs in agricultural fairs, no further human to human transmission has been documented for the 2012 cases. Clinically, these cases are similar to seasonal influenza cases, and all patients have recovered from their illness. Investigations around cases and contacts is ongoing.
Limited serological studies indicate that adults may have some pre-existing immunity to this virus but children do not. Seasonal vaccines do not provide cross-protection to influenza A(H3N2)v in adults or children. 3 candidate vaccine viruses specific for A(H3N2)v have been developed in the USA and could be used to produce an (H3N2)v vaccine if needed.
Overall public health risk assessment for influenza A(H3N2)v viruses: further human cases and small clusters may be expected as this virus is circulating in the swine population in the USA. Sporadic human cases and small clusters of human infection with the virus are expected and do not change WHO's current assessment of pandemic risk at this point.
However, because influenza viruses evolve constantly and change characteristics and behavior unpredictably, WHO continues to stress the importance of global monitoring of variant influenza viruses and recommends to all member states to strengthen routine surveillance activities. Countries experiencing outbreaks of influenza virus infection in animals should implement appropriate biosafety measures to protect people working with or living nearby infected and potentially infected animals. Collaboration with animal health partners is necessary to optimally control this disease and decrease risks to public health.
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[2] USA (Michigan, West Virginia, Ohio)
Date: Thu 16 Aug 2012
Source: CIDRAP (Center for Infectious Disease Research & Policy) News [edited]
http://www.cidrap.umn.edu/cidrap/content/influenza/swineflu/news/aug1612variant.html
3 states report new cases of variant H3N2
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This summer [2012] 2 more states -- Michigan and West Virginia -- reported their 1st cases of variant swine-origin H3N2 influenza (H3N2v) that has been linked to exposure to pigs at fairs. Also, Ohio health officials are reporting 72 cases, an increase of 18 from the total the state released on 14 Aug 2012. The new cases from Ohio, plus the cases in Michigan and West Virginia, appear to push the national number of new H3N2v cases this summer to 198. The Michigan Department of Community Health (MDCH) said yesterday [15 Aug 2012] that its 1st patient is a child from Washtenaw County who was recently exposed to pigs at the Ingham County Fair. Dean Sienko, the MDCH's interim chief medical executive, said in the statement that although the virus is new to Michigan, simple steps, such as washing hands frequently with soap and water after exposure to animals, can be taken to avoid getting sick. Meanwhile, the Michigan's assistant state veterinarian, Nancy Frank, emphasized that the new virus doesn't pose a food safety risk, because influenza isn't transmitted by food, and people can't get sick with influenza from eating pork and pork products.
Meanwhile, West Virginia yesterday [15 Aug 2012] reported its 1st 3 H3N2v cases of the summer, which occurred in Mason County, according to a statement from the West Virginia Department of Health and Human Resources (WVDHHR). Marian Swinker, West Virginia's state health officer and commissioner for public health, said in the statement that the 3 cases were linked to attendance at the Gallia County Fair in Ohio, where swine were present. "We will not be surprised to identify more cases of H3N2v in West Virginia as surveillance efforts to detect this illness have increased," she said. The WVDHHR said it would post updates on new H3N2v cases in West Virginia each Thursday on its website. In December 2011, West Virginia reported 2 H3N2v infections, both in children who were daycare contacts and had no history of exposure to pigs, according to previous reports.
In other developments, the Ohio Department of Health (ODH) said today that the number of H3N2v cases in the state has risen to 72, up from 54 cases on 14 Aug 2012. Infections have been reported from 20 counties, though more than half of them are from 3 counties: Butler, Champaign, and Gallia.
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[The number of cases of influenza A(H3N2)v virus infection continues to increase probably mainly as a consequence of enhanced surveillance and the availability of appropriate diagnostic reagents. All patients have recovered and no onward transmission of the virus from human to human has been documented. Clinically, these cases are similar to seasonal influenza cases. Limited serological studies indicate that adults may have some pre-existing immunity to this virus whereas children do not. The current seasonal vaccines may not provide cross-protection to influenza A(H3N2)v virus infection in adults or children. Fortunately candidate vaccines are available now for use should the H3N2v influenza virus acquire the ability to spread from human to human. - Mod.CP
