Thursday, September 26, 2013

Chinese CDC: Be Alert For H7N9



# 7812


Zeng Guang, chief epidemiologist for China’s CDC  has issued a warning that  the recently emerged avian H7N9 virus – which has pretty much disappeared over the summer – is likely to return this winter.  His statement is similar to one we saw issued last week by the UN’s Food and Agriculture Organization (see  FAO Warns On Bird Flu) and complements the report yesterday indicating that due to concerns over  H7N9: Beijing Orders Hospital Surveillance For Flu-Like Illnesses.


Although avian flu infection is occasionally reported during the summer months,  the past decade has shown a clear seasonality to H5N1 outbreaks in poultry (see chart below).  It is believed that H7N9, which emerged last February and circulated among human in China through mid-May, is likely to follow the same pattern.


Seasonality of H5N1 in poultry 

Source FAO  H5N1 HPAI Global Overview


We’ve also watched a parade of studies published over the summer that have painted this emerging virus as being better suited to mammalian hosts, and processing greater pandemic potential, than any other avian flu studied to date.  A few examples include:


Nature: Limited Airborne Transmission Of H7N9 Between Ferrets
BMJ: `Probable Person-to-Person Transmission’ Of H7N9
Lancet: Tropism Of H7N9 In the Human Respiratory Tract
Science: H7N9 Transmissibility Study In Ferrets


While it is impossible to predict how much of a threat this virus will pose this winter, public health officials around the world are prudently preparing . . . just in case


Last week, in NIH Begins Phase II Clinical Trials On H7N9 Vaccine Candidates, we saw that vaccine research is underway, but any sizable quantity of vaccine would take at least 6 months to produce once the go-ahead to manufacture has been issued. Last spring, in H7N9 Preparedness: What The CDC Is Doing, we looked at some of the steps the CDC is taking, and in late May, the CDC issued  Pandemic Planning Tips For Public Health Officials.


Influenza viruses are considered unpredictable by nearly everyone that studies them.


A prime example came in 2009 - while we were focused on avian flu H5 viruses in Asia - we were blindsided by a pandemic virus that emerged from the wrong species (swine), on the wrong continent (North America), and from an improbable subtype (H1). 


The good news is improved surveillance and pandemic preparedness will pay dividends regardless of the next emerging pandemic’s subtype or place of origin.




Experts: Be alert of H7N9 amid flu seasons   2013-09-26 08:52:32

BEIJING, Sept. 26 (Xinhuanet) -- The avian influenza strain of H7N9 is highly likely to return and affect humans in the autumn and winter on the Chinese mainland, warned Zeng Guang, chief epidemiologist at the Chinese Center for Disease Control and Prevention.


China has remained free of new human H7N9 cases for more than a month since the last fatality — a 51-year-old woman who died of multiple organ failure caused by the virus on Aug 12 in Huizhou, Guangdong province — according to the National Health and Family Planning Commission.


The woman, who was transferred from Langfang, Hebei province, in mid July, worked in slaughtering poultry at a local market.


China has reported 134 human infections of H7N9 on the mainland, including 45 deaths, official statistics show.


"Given that the virus never stopped circulating among birds, humans are also at risk of infection, particularly in the common peak flu season, which usually lasts till spring,"Zeng said.


An overlap of the peak flu season and more frequent smoggy weather could make the situation even worse and intervention efforts more complicated, he said.


Flu prevention requires good ventilation, which can't be easily supplied in smoggy weather, he explained.


He urged the public to take precautions such as to avoid staying in public places for long and to be aware of good personal hygiene, including frequent hand-washing.


In addition, to prevent H7N9 infection, "people shouldn't go to live poultry markets", he said.


Feng Zijian, director of the health emergency center of China CDC, echoed the need for public awareness but dismissed the possibility of a widespread human outbreak.


Close surveillance of the virus has so far detected no major mutations that would enable H7N9 to easily spread among humans, he said.


"We'll have joint consultation on Friday with the agriculture departments which oversee virus surveillance of animals to evaluate the epidemic risk in the autumn and winter season to guide more targeted interventions,"he said.


(Continue . . .)

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