Flu Scan for Apr 23, 2015

Avian flu in Niger, Taiwan, South Africa
Cloth face masks
Gene tied to severe 2009 H1N1

Avian flu outbreaks confirmed in Niger, Taiwan, South Africa

Avian flu has struck domestic birds in Niger, Taiwan, and South Africa, according to separate reports posted yesterday by the World Organization for Animal Health (OIE).

Veterinary officials in Niger reported a highly pathogenic H5N1 avian flu outbreak at a poultry farm in Maradi, the country's third-largest city, in south-central Niger. It is the country's first H5N1 outbreak since 2006.

The outbreak began Apr 2 at a farm housing laying hens and breeding stock. The virus killed 2,290 of 2,440 susceptible birds, with the rest slated for culling. Results were confirmed on Apr 21 at the OIE reference lab in Padua, Italy. So far the source of the outbreak isn't known.

Two of Niger's neighboring countries—Nigeria and Burkina Faso— have recently reported H5N1 outbreaks.
Apr 22 OIE report on Niger outbreak

Elsewhere, Taiwan yesterday reported seven low-pathogenic H5N2 outbreaks, affecting four different counties and Tainan City, according to a second OIE report. The affected counties are Pingtung, Chiayi, Yunlin, and Changhua.

Though Taiwan has reported several highly pathogenic H5N2 outbreaks over the past few months in the same area, tests on Apr 1 at Taiwan's national laboratory confirmed the virus as low pathogenic, causing less than 75% mortality in the chickens tested. These seven outbreaks began in January and February.

All of the locations are commercial chicken farms. Of a total of 244,400 susceptible birds, the virus killed 75,319, with the remaining ones stamped out to curb the spread of the virus.
Apr 22 OIE report on Taiwan outbreaks

And South African veterinary authorities yesterday reported a low-pathogenic H5N2 outbreak at a commercial ostrich farm in Western Cape province, an area that has reported several such outbreaks over the past few years.

The virus sickened 2,212 of 6,204 susceptible birds. Response steps include quarantine, curbing bird movements, and screening.
Apr 22 OIE report on South Africa outbreak


Study: Cloth face masks raise infection risk in high-risk conditions

The use of cloth face masks by healthcare workers is not only not adequately protective in high-risk situations but may be harmful, setting users up for an increased risk of infection, according to a cluster-randomized, controlled clinical study published yesterday in BMJ Open.

The authors, from Australia and Vietnam, say their results are the first of their kind and that use of cloth masks should be discouraged globally.

The researchers randomly assigned 1,607 full-time healthcare workers in high-risk wards of 14 hospitals in Hanoi, Vietnam, to (1) use cloth (cotton) masks on every shift over a 4-week period, (2) use medical/surgical (disposable) masks on every shift, or (3) follow their customary practices, which may or may not include mask use.

On filtration testing of the masks, the penetration by particles was found to be almost 97% for the cloth and 44% for the medical masks.

The rate of all infections was highest in the cloth-mask group, with the rates for influenza-like infection (ILI) significantly higher in the cloth-mask group than the medical-mask group (relative risk [RR], 13.25; 95% confidence interval [CI], 1.74-100.97) and the control group (RR, 3.49; 95% CI, 1.00-12.7).

Cloth masks have been replaced by medical masks in many settings but are still commonly used in more than half the world because of the expense and supply/access problems associated with medical masks in many areas of the world, say the authors. They say the physical properties, moisture retention, reuse, and varying cleaning frequency and effectiveness of cloth masks may account for the increased risks they incur.

"Effective controls of outbreaks and pandemics at the origin impacts us directly, so it is important for global disease control that the use of cloth masks be discouraged in high-risk situations," said lead author Raina MacIntyre, PhD, in a press release from the University of New South Wales (UNSW).
Apr 22 BMJ Open study
Apr 22 UNSW press release


Study identifies gene tied to severe 2009 H1N1, H7N9 infection

Researchers have pinpointed a human gene that is associated with severe disease in 2009 H1N1 (pH1N1) flu and also with contracting H7N9 influenza.

An international team led by University of Hong Kong scientists evaluated genetic risk in 409 pH1N1 patients, 162 of whom had severe cases. They determined that the GG genotype of rs2070788, a higher-expression variant of TMPRSS2, doubled the risk of severe disease.

They also studied 102 H7N9 patients and 106 healthy controls and found that rs2070788 and rs383510 were significantly associated with susceptibility to H7N9 influenza.

The authors summarize: "We demonstrate that genetic variants with higher TMPRSS2 expression confer higher risk to severe A(H1N1)pdm09 influenza. The same variants also increase the susceptibility to human A(H7N9) influenza."
Apr 22 J Infect Dis abstract

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