Re: Is H2H spread of a novel swine H3N2 occurring in the United States?
Re: Is H2H spread of a novel swine H3N2 occurring in the United States?
From Emerging Infectious Diseases Journal:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2876760/
Swine Influenza (H3N2) Infection in a Child and Possible Community Transmission, Canada
Joan L. Robinson,<SUP></SUP><SUP>*</SUP><SUP>?</SUP> Bonita E. Lee,<SUP>*</SUP> Jagdish Patel,<SUP>?</SUP> Nathalie Bastien,<SUP>?</SUP> Karen Grimsrud,<SUP>?</SUP> Robert F. Seal,<SUP>?</SUP> Robin King,<SUP>?</SUP> Frank Marshall,<SUP>#</SUP> and Yan Li<SUP>?</SUP><SUP>?</SUP>
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The mode of spread of SIV in humans is not established. Because of his young age, the index patient was not likely to have had unrecognized direct contact with swine. That aerosolization of influenza virus occurs is increasingly recognized (
25), but the child was reportedly never in the barns that housed the swine. However, other members of the farm reported that infants were sometimes taken for walks through the barn. The child also may have acquired the virus from person-to-person spread or from fomites. All 13 patients in the Fort Dix outbreak and 15 of 37 previously reported civilian case-patients also had no swine contact (
19,20).
The Fort Dix outbreak of SIV in humans lasted only 21 days and never spread outside the military base. The calculated basic reproductive rate (R<SUB>0</SUB>) was only 1.1 to 1.2. This suggests that person-to-person spread of the implicated H1N1 strain was not efficient enough to produce a major epidemic (
26). However, future strains of SIV could have a higher R<SUB>0</SUB>, and documentation of a case of swine influenza (H3N2) in a child with unrecognized transmission within the community adds another possible mechanism by which major epidemics of influenza could arise. Swine influenza infection in humans most commonly results in either no symptoms or a self-limited illness (
6). However, routine surveillance for cases among swine workers may enable early detection of a strain with the potential for person-to-person transmission, prompting institution of infection control measures and vaccine development.
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