Researchers find possible biomarker for severe H7N9 infection
Researchers who analyzed the blood of Chinese patients infected with H7N9 influenza found markedly elevated levels of angiotensin 2, which be a severity marker for the disease. The team from China reported its findings yesterday in Nature Communications.
They compared plasma from 47 patients infected with H7N9 from Hangzhou, Nanjing, and Shanghai with that of 21 patients from Beijing who were sick with the 2009 H1N1 virus from December 2012 to February 2013. Their comparison also included samples from healthy volunteers and people with coronary heart disease (CHD). For the patients with flu, samples were collected at different times: within the first 7 days of disease onset, 8 to 14 days after disease onset, and from 15 days after disease onset.
The angiotensin 2 plasma levels were much higher in H7N9 patients than in 2009 H1N1 patients, CHD patients, and CHD patients with hypertension.
To focus on disease outcome patterns in H7N9 patients, the group looked at 22 patients who had samples taken from both the first and second week of illness. For those discharged from the hospital in less than 28 days, angiotensin 2 levels decreased significantly during the second week of infection. The level, however, remained high during the second week for those who had longer hospitalizations or who died.
They found that in H7N9 patients, angiotensin 2 levels during the second week of illness highly correlated with severity scores, with levels during the first week showing a weaker but still significant correlation. Similarly, researchers found that patients who have high angiotensin 2 levels during the second week were more likely to die.
Researchers concluded that angiotensin 2 is a biomarker for lethal flu infections and that the findings lend support for potential therapies.
May 6 Nat Commun abstract
Scientists detect H11N2 in Antarctic penguins
Researchers have for the first time identified avian flu viruses in Antarctic penguins, and the H11N2 strain they found differed considerably from existing strains, according to a study yesterday in mBio.
An international team took 301 swabs from windpipes and posterior openings (cloaca) of Adelie penguins in two locations in Antarctica in January and February 2013. They also drew 270 blood samples.
They found that 8 (2.7%) of the swab samples were positive for H11N2 avian flu via polymerase chain reaction. Phylogenetic analysis showed a high degree of similarity among the viruses.
When the researchers compared the full genome sequences of four of the viruses to influenza virus sequences in public databases, they found that they were unique. Lead author Aeron Hurt, PhD, of the World Health Organization's influenza center in Melbourne, said in a news release from the American Society for Microbiology (ASM), "When we drew phylogenetic trees to show the evolutionary relationships of the virus, all of the genes were highly distinct from contemporary [avian flu viruses] circulating in other continents in either the Northern or Southern Hemisphere." The ASM publishes mBio.
Further analysis revealed that the virus diverged from other avian flu viruses between 49 and 80 years ago, with several genes showing similarity and shared ancestry with H3N8 equine influenza viruses.
In addition, 43 of 270 penguins (16%) had influenza A antibodies in their blood. The investigators also found that the cultured H11N2 virus did not replicate well in experimentally inoculated ferrets.
May 6 mBio study
May 6 ASM news release
