Flu Scan for Aug 15, 2016

News brief

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

News Scan for Aug 15, 2016

News brief

Suspected yellow fever in Brazzaville prompts call for public health emergency

Infectious disease doctor Daniel Lucey, MD, MPH, penned an open letter to Director-General Margaret Chan, MD, MPH, of the World Health Organization (WHO), suggesting that the WHO reconsider declaring a Public Health Emergency of International Concern (PHEIC) over yellow fever cases in the Democratic Republic of the Congo (DRC) and the possibilities of an outbreak in the Republic of the Congo. The letter was posted on ProMED Mail, and written after Lucey returned from a recent trip to the DRC. ProMED Mail is the online reporting system of the International Society for Infectious Diseases. Lucey, an infectious disease specialist, is a senior scholar with Georgetown University's O'Neill Institute for National and Global Health Law.

Lucey requested Chan reconvene the WHO Emergency Committee on Yellow Fever that first met on May 19 to discuss the implications of fractional vaccine dosing, which is set to begin on Aug 17 in Kinshasa, DRC. Fractional dosing is meant to stretch the current supply of yellow fever vaccine and would confer immunity for 1 year.

Kinshasa, and its 11 million inhabitants, has been a focal point of concern ever since a yellow fever outbreak began last January in Luanda, Angola. As of Aug 8 the DRC had reported 2,269 cases, 74 of them confirmed, to the WHO.

Lucey also said there's growing concern over an uptick of yellow fever cases in Brazzaville, Republic of Congo which is near Kinshasa. Currently, there are no plans for a vaccine campaign in Brazzaville, but as of Aug 3 there were 193 suspected cases of yellow fever in that city. This is the first report of yellow fever in Brazzaville.
Aug 12 ProMED Mail post

UK viral meningitis cases drop after introduction of MMR vaccine

The Lancet recently published a study showing how pediatric hospital admissions in British children for viral meningitis dropped significantly after the measles-mumps-rubella (MMR) vaccine was introduced in 1988.

The authors of the study looked at 50 years of admissions records to analyze rates of viral meningitis. Bacterial meningitis is well-controlled with childhood immunizations, but this is the first study to track viral meningitis trends in the UK.

Between 1968 and 1985, viral meningitis admissions rates varied annually, with a mean of 13.5 admissions per 100,000 children (15 years-old or younger) each year. But between 1989 and 2011, that rate dropped to 5.2 per 100,000 children per year, a decrease linked to children ages 1 to 14 years old.

The authors said the National Health Service's introduction of the MMR vaccine in 1988 effectively stopped mumps-related meningitis transmission. More sensitive testing was also credited with case reduction.
Aug 12 Lancet Infect Dis abstract