#H7N9 – A disease of many puzzles – lots of why’s and how’s and not many answers

Lots of questions and not many answers seem to be the current theme regarding H7N9. Helen Branswell wrote a great article in the Canadian Press, as has CIDRAP on this very issue.

• Why men? 57 of 82 patients are men (Those with available gender data). For H5N1, the gender balance has been more even.
• Why older? Why are most of the patients older, a sharp contrast to the pattern seen with H5N1? The median age is 61.5 years, with a range of 2 to 89 years
• Why so fast? Why have more than 96 cases popped up in just a few weeks in China versus and just 45 H5N1 cases in the country in about 10 years?
• Why minimal illness in birds? Why the virus seems to cause little or no sickness in birds but makes humans seriously ill?
• How does it infect? How exactly is the virus is getting into humans? About 40 percent of the victims had no clear history of exposure to poultry.
• What is the source? This is perhaps the million-dollar question. The suspected source is poultry, however Chinese authorities reported this week that only 39 of about 48 000 samples from more than 1000 poultry markets, farms, and other sites contained the virus.

The moderator of ProMed begged the question at the end of post # 187…maybe the prefix “Avian” is unjustified?

http://www.canada.com/health/positives+tests+poultry+pigs+question+Where+H7N9/8258923/story.html

http://www.cidrap.umn.edu/cidrap/content/influenza/h7n9/news/apr1913ageh7.html