H5N1 hospitalizes Egyptian man

Egypt's ministry of health (MOH) has announced another H5N1 avian influenza infection, this one in a 51-year-old man from Assiut governorate who is hospitalized, according to the ministry's translated statement posted today by Avian Flu Diary. The latest case lifts Egypt's total  this year to 26, 10 of which were fatal, the MOH said.

Meanwhile, it's still not clear if avian influenza is involved in a rash of severe respiratory infections, some of them fatal, in neighboring Libya. Updates on the Libyan health ministry's Facebook page, translated and posted by FluTrackers, said there have been 10 cases of severe pneumonia, 5 of them fatal, but samples have apparently tested negative for H5N1 avian flu; 1 may involve the 2009 H1N1 strain.
Dec 30 Avian Flu Diary post
FluTrackers thread

China reports another H7N9 case

Another H7N9 avian flu case has been reported in China, in a 35-year-old woman from the Guangdong province city of Shenzhen who is hospitalized in critical condition, Hong Kong's Centre for Health Protection (CHP) reported today, citing an official report from the provincial health department.

The report said the woman's illness is the first H7N9 case reported in Shenzhen this winter. However, a woman recently diagnosed with an H7N9 infection in Hong Kong had reportedly traveled to the Shenzhen area before she got sick.

The new case raised the global H7N9 total to 475 infections, according to a case list kept by FluTrackers, an infectious disease news message board.

A World Health Organization (WHO) statement today on the earlier case said the patient,68, got sick on Dec 19 and saw two doctors on Dec 19 and 23 before she was hospitalized on Dec 25.; She is in critical condition.

Investigators found she had traveled to Shenzhen on Dec 13, returning to Hong Kong the same day. She didn't visit any wet markets or have any contact with poultry in Hong Kong during her incubation period, so her illness is considered to have been contracted outside Hong Kong.

The woman's illness, the first detected in Hong Kong this winter, prompted the region to increase its pandemic alert level.

In a separate announcement today, Hong Kong's government said results of serology tests on some live chickens imported from the mainland suggests the birds were exposed to an H7 avian flu virus, and further testing is under way to determine if they are carrying live virus. Authorities will release the birds for sale if results are negative.
Dec 30 CHP statement
FluTrackers H7N9 case list
Dec 30 WHO statement
Dec 30 Hong Kong government statement

Study: Vaccine-evading H9N2 strain in chickens paved way for H7N9

One strain of H9N2 avian influenza virus that achieved predominance in China's chicken flocks from 2010 to 2013 served as the forerunner of the H7N9 virus that emerged in humans in 2013, contributing six of the latter virus's eight genes, according to a study published online yesterday in the Proceedings of the National Academy of Sciences.

H7N9 emerged as a human pathogen in China in 2013, and more than 470 cases have been recorded so far, including more than 100 deaths.

In the report, a Chinese-American research team writes that it was previously known that H9N2 viruses contributed all six of the H7N9 virus's internal genes, but how the evolution of H9N2 viruses facilitated the emergence of H7N9 was not fully understood.

The researchers used whole-genome sequencing to track the evolution of H9N2 in chickens from 1994 to 2013, according to a press release from St. Jude Children's Research Hospital, which employs some of the authors. By examining thousands of sequences, they found that the genetic diversity of H9N2 viruses fell sharply in 2009. From 2010 through 2013 one particular H9N2 strain emerged as predominant and flourished despite widespread vaccination of chickens against H9N2.

Vaccination against H9N2 prevented outbreaks in Chinese chicken flocks for more than a decade, but by 2010 the vaccine was no longer working, according to the authors. They concluded that the virus strain that became predominant did so largely by evolving to evade the vaccine.

The authors suggested that chickens infected with this H9N2 strain probably served as mixing vessels in which the virus and other flu viruses from wild birds and domestic ducks traded genes, leading to the emergence of H7N9, according to the release.

"The insights gained from this collaboration suggest that tracking genetic diversity of H9N2 on poultry farms could provide an early warning of emerging viruses with the potential to spark a pandemic," said St. Jude's Robert Webster, PhD, in the release.
Dec 29 PNAS abstract
Dec 29 St. Jude press release