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Tuesday, December 27, 2011

New swine flu virus (H3N2v) infected human !!

New Swine-Origin Flu Cases Reported By Todd Neale, Senior Staff Writer, MedPage Today Published: December 27, 2011 Since the middle of August, the CDC has received 12 reports of human infections with a swine-origin influenza A (H3N2) virus, the agency announced. The cases come from five states -- Indiana (two), Iowa (three), Maine (two), Pennsylvania (three), and West Virginia (two), Douglas Jordan, MA, of the CDC's influenza division, and colleagues reported online in Morbidity and Mortality Weekly Report. All but one of the affected individuals were younger than 18, and half had had no contact with pigs. Three were hospitalized, and all have fully recovered. Although there is still limited information available on how efficiently the virus is transmitted between pigs, between humans, or between species, evidence indicates at least minimal human-to-human transmission of the variant, which contains genes from avian, human, and swine flu strains. The report, which follows previous MMWR dispatches on two cases in Indiana and Pennsylvania and the three in Iowa, focused on the three most recent cases -- an adult male in Indiana and two children in West Virginia. The infecting strain was similar to the previous cases. It was a swine-origin influenza A (H3N2) virus with the matrix (M) gene from the pandemic influenza A (H1N1) virus. To distinguish the virus from the circulating seasonal H3N2, health officials have dubbed it H3N2v. The man in Indiana, who had direct occupational contact with swine, was hospitalized for four days after developing fever, cough, shortness of breath, nausea, vomiting, and body aches. After preliminary testing by state health officials revealed infection with an inconclusive influenza A virus, samples were sent to the CDC, which confirmed that it was the new variant. The two children in West Virginia, both younger than 5, attended the same daycare facility. One had been hospitalized for an unrelated condition two days before developing fever. The other developed fever, cough, diarrhea, and rhinorrhea and recovered fully without receiving any medical care. Neither of the children had traveled recently nor had exposure to swine. Even though they had been in contact with each other, the CDC said it was unlikely the virus was passed directly from one to the other because illness onset in the two cases was separated by more than 10 days."This represents a scenario of limited human-to-human transmission occurring in a daycare setting," the authors wrote. "Therefore, clinicians also should consider the possibility of influenza A (H3N2)v infections in patients who have not had exposure to swine, particularly young children in those states where ... cases have been reported."All of the variant viruses tested so far have been susceptible to oseltamivir (Tamiflu) and zanamivir (Relenza), and resistant to amantadine and rimantadine. Young children likely have little preexisting immunity to the viruses, although older children and adults who have been exposed to other H3N2 viruses in the past might have limited immunity, according to the authors. The trivalent seasonal vaccine, which protects against an H3N2 strain, is not expected to provide significant protection against the variant.

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