Iowa Reports Novel Influenza Infections in Three Children

November 22, 2011 — The Iowa Department of Public Health today reported that a “novel strain of the influenza virus has been detected in three childrenexternal icon.” All three of the children were reportedly mildly ill and have recovered. Iowa has increased surveillance for influenza-like-illness to detect any additional cases of infection with this novel virus.

All three patients are young children who were in contact with one another. All cases were detected at the state public health laboratory through virologic surveillance. No additional cases have been identified.

Testing at CDC has confirmed that these viruses are similar to the swine-origin influenza A (H3N2) viruses identified in three other states. These viruses contain the “matrix (M) gene segment” from the pandemic 2009 H1N1 virus. This combination of genes was first identified in a person in July. Since then, several additional human infections with this virus have been detected, bringing the total number of human infections to 10 (Indiana 2, Pennsylvania 3, Maine 2, and Iowa 3). All 10 patients have recovered and the majority of cases had relatively mild illness, although 3 patients were hospitalized.

CDC has reported on the previous infections on its website, in the FluView activity report, and in the Morbidity and Mortality Weekly Report. Links to all previous reports related to this virus are available on the CDC swine influenza website.

These viruses are substantially different from human influenza A (H3N2) viruses, so the seasonal vaccine is expected to provide limited cross-protection among adults and no protection to children. However, laboratory testing so far indicates these viruses are susceptible to the antiviral drugs oseltamivir (Tamiflu®) and zanamivir (Relenza®). CDC recommends these drugs for treatment of seasonal and these swine-origin influenza viruses.

Prior to the three cases in Iowa, most human infections with this virus were associated with exposure to swine. In Iowa, however, no swine exposure has been identified. At this time, it appears that unsustained human-to-human transmission may have occurred. These viruses have been reported in swine in several states in the United States. Swine influenza viruses do not spread through contact with pork or pork products. Eating properly handled and cooked pork is safe.

As part of routine preparedness measures to counter possible pandemic threats posed by novel influenza viruses in the event that they gain the ability to spread easily from person-to-person, CDC has developed a candidate vaccine virus and provided it to manufacturers.
These cases will be officially reported in the MMWR and FluView.

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