Flu Scan for Aug 15, 2016

More H3N2v in Michigan pigs
MRSA and fatal flu infections

Additional H3N2v in pigs at Michigan county fairs

Two more Michigan county fairs, one in Cass County and one in Ingham County, are reporting variant H3N2 (H3N2v) influenza in pigs, according to a media release from the Van Buren/Cass District Health Department. No ill human contacts have been reported, according to state health officials.  

Twenty pigs tested positive for H3N2v at the Cass County fair, which took place from Jul 31 to Aug 6. More than 300 pigs were exhibited.  The first pig tested positive on Aug 9.

On Aug 6 one pig that was exhibited at the Ingham County tested positive for swine flu. Last month a pig at the Muskegon county fair also tested positive for H3N2v.

Humans are at risk for swine flu if they come in close contact with infected pigs, but H3N2v usually causes only mild illness when transmitted to people.
Aug 12 Van Buren/Cass District Health Department release

Study sheds more light on deadly MRSA complications in flu patients

In an ongoing investigation into why secondary methicillin-resistant Staphylococcus aureus (MRSA) infections are often so fatal to patients with flu, researchers who did lab studies on mice found that flu infection alters the antibacterial response of white blood cells, prompting them to damage patients' lungs instead of the bacteria.

The team from the University of Nebraska Medical Center and Albany Medical College described their findings today in the Journal of Experimental Medicine (JEM).

In an earlier study, one of the researchers had found mice with flu were susceptible to MRSA because the infection seemed to suppress the ability of macrophages and neutrophils to kill bacteria by releasing hydrogen peroxide and suppress other reactive oxygen species.

In the new study, researchers found that in coinfected mice, reactive oxygen species released by macrophages and neutrophils induced the death of inflammatory cells in the lungs, damaging surround tissue, according a press release today from Rockefeller University Press, the publisher of JEM. Also, they found that inhibiting NADPH oxidase 2 (Nox2), the enzyme that produces reactive oxygen species in macrophages and neutrophils, reduced lung damage and when added to antibiotics, improved survival of the mice.

Keer Sun, PhD, study coauthor and assistant professor at the University of Nebraska Medical Center, said in a press release, "Our results demonstrate that influenza infection disrupts the delicate balance between Nox2-dependent antibacterial immunity and inflammation. This not only leads to increased susceptibility to MRSA infection but also extensive lung damage." He said treatment that targets both MRSA and reactive oxygen species may yield important benefits for flu patients who have MRSA pneumonia.
Aug 15 J Exper Med abstract
Aug 15 Rockefeller University press release

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