Bird flu virus H7N9 but more harmless?

Avian Influenza H7N9 safer than expected

07/12/2013

Researchers currently assume that the risk of the bird flu pathogen H7N9 is lower than originally feared. Studies have shown that the virus is poorly adapted to humans. Therefore, people are less at risk.

According to new findings, danger is overestimated
Apparently, the danger posed by the bird flu virus H7N9, greatly overestimated. As US researchers in the journal „Science“ report that the pathogen, which already killed around 40 people, is hardly adapted to humans. This contradicts the concern based on previous studies that the virus could become a pandemic in the winter. Molecular biologist James Paulson from The Scripps Research Institute (TSRI), La Jolla, California, is quoted in a statement from the facility: „Because studies have revealed that H7N9 has adapted to human receptors, we thought we should comment on it.“

Death rate of nearly 30 percent
The pathogen was first registered in eastern China in February and only a few days ago a first case of bird flu H7N9 in Hong Kong became known. Of the 132 H7N9 patients confirmed to May, 37 died, which represents a death rate of nearly 30 percent. In birds, the virus causes at best mild symptoms, but in humans this can cause respiratory distress and severe pneumonia. Since the epidemic largely subsided in May, only a few infections were registered. However, researchers continued to warn that cases could accumulate in winter. Studies, for example on ferrets or monkeys, have suggested that H7N9 can spread among mammals and also via human fecal matter.

Researchers do not give the all-clear
The US researchers Paulson and Ian Wilson, who also research at the Scripps Institute, contradict this now. At the pathogen type „Sh2“ they tested the ability to bind to human cells. The analysis by crystal structure analysis showed that the membrane protein hemagglutinin (HA), with which the virus attaches to human receptors, weakly docks, in contrast to some receptors of birds. The scientists do not want to give the all-clear and Wilson explains: „These results suggest that we should continue to monitor H7N9 and look for changes that make propagation among humans more likely.“

Typical symptoms of bird flu
Typical bird flu symptoms are initially similar to those of conventional flu and usually include high fever, cough, sore throat, and occasional shortness of breath. In rare cases, sufferers also suffer from diarrhea, abdominal pain, nausea and vomiting. It may take several weeks between exposure to the virus and the onset of the first symptoms. (Ad)