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# 7156
When it comes to proving human-to-human transmission of a virus not already known to transmit readily in that way, the bar is usually set pretty high.
If there are other, equally plausible explanations – such as a common environmental exposure – then H2H transmission cannot automatically be assumed.
This has been the standard used in evaluating H5N1 clusters for the past decade, and this seems to be the stance that experts in China have adopted regarding the suspected family cluster from early March, which Xinhua News is now reporting as being confirmed.
As you will recall, on March 31st (see More Details Emerge On Shanghai H7N9 Case) we first saw reports of three cases (2 in Shanghai, 1 in Anhui) that had been diagnosed with a new H7N9 virus.
While the two Shanghai cases were not linked, one of them – an 87 year old man - had two sons who were hospitalized with pneumonia around the same time.
The Shanghai Daily reported:
According to Shanghai No. 5 People's Hospital, the three members of the Li family were admitted between February 14 and 24 for symptoms including a high fever and coughing.
All three were diagnosed as having pneumonia.
The 69-year-old son recovered and was discharged but the 55-year-old died from severe pneumonia and respiratory failure in late February. The father died of multi-organ failure.
Neither son had the H7N9 virus, the bureau said.
While always `suspect’ cases, the sons have not been officially listed as having had the H7N9 virus. At least, not until today’s announcement.
This report from Xinhua News:
Family-clustered H7N9 cases unable to prove human-to-human transmission: expert
English.news.cn 2013-04-18 00:53:34
BEIJING, April 17 (Xinhua) -- The family-clustered H7N9 cases reported in Shanghai were unable to prove human-to-human transmission, an expert said Wednesday in an exclusive interview with Xinhua.
According to the National Health and Family Planning Commission, a man and one of his sons in Shanghai died from the bird flu, and his second son was also infected but has since recovered.
It has not been confirmed whether the three people contracted the virus from infected fowl or the contaminated environment or through human-to-human transmission, said Feng Zijian, an official with Chinese Center for Disease Control and Prevention.
Active screenings of human infections across the nation have not been required by the commission, and China will continue its current measures to prevent and control the spread of the H7N9, said Li Xingwang, an infectious disease expert of Beijing Ditan Hospital of the Capital Medical University.
Another, longer report, with a slightly different slant, appears today in China Daily.
Authorities test family infected by H7N9
Updated: 2013-04-18 01:59
By SHAN JUAN ( China Daily)
China's top health authority confirmed that a family infected by H7N9 in Shanghai might involve human-to-human transmission of the new bird flu strain.
The family involves two brothers and their 87-year-old father, who died on March 4 and was reportedly China's first human death from H7N9.
The elder son, who has recovered from the disease, was previously confirmed to have contracted the virus, the Chinese National Health and Family Planning Commission said on Wednesday at a media briefing.
However, the results of a test on the younger son were not available.
"Further investigations are still under way to figure out whether the family cluster involved human-to-human transmission," said Feng Zijian, director of the health emergency center of the Chinese Center for Disease Control and Prevention.
It seems likely that these two cases were among the 5 `retrospective diagnoses’ announced yesterday (see China: Six more H7N9 Cases - 77 Total, 16 Fatalities), although no identifying details were given at the time.
Given the suspicious circumstances, the revelation that the man and his two sons are now accepted as being part of a cluster is hardly a game changer.
While not proven in this case, we’ve seen limited human-to-human transmission of other avian viruses in the past, and so it would not be unexpected that we could see it with H7N9 as well.
The good news is that, what officials say they’ve not seen are any signs of ongoing, efficient, or sustained human transmission of this virus.
But at the same time, exactly how more than 80 people - across several provinces - have come to be infected by this emerging avian virus over the past month or so remains a mystery.
Stay tuned.
