More H3N2v Cases In Michigan With H1N1pdm09 PA & MP?
September 6, 2013
One additional infection with influenza A (H3N2) variant (H3N2v) virus was reported to CDC during week 35 from Michigan. A total of 18 H3N2v cases have been reported this summer (Illinois , Indiana , Michigan , and Ohio ). So far during 2013, one person has been hospitalized as a result of H3N2v illness;
The above comments from the CDC week 35 FluView cite a second confirmed H3N2v case in Michigan. Recombinomics was referred to the Berrien County Department of Health for more information, since the second case was linked to Barrien County (see map). However, there is also appears to be an Ingham County case, so it is unclear if the second case resides in Ingham County or there are now three cases in Michigan.
The CDC has released full sequences from the first Michigan case (designated A/Indiana/21/2013 because Indiana collected the sample and made the diagnosis), which like the three prior cases had change at position 145 and had H1N1pdm09 PA and MP gene segments. The linkage to Barrien County suggests the second case in Michigan will also have H1N1pdm09 PA and MP genes, extending the number of human cases with that constellation to five (and extending the number of 2013 H3N2v cases with N145K or K145R to 18 – all cases confirmed in 2013).
The increasing number of human cases with H1N1pdm09 PA and MP genes and the absence of this constellation in H3N2v swine sequences, including collection in July, 2013, have not been addressed by the CDC.