Credit CHP Communicable Disease Watch Vol10 Issue 16
# 7560
Hong Kong’s Centre For Health Protection (CHP) was created in the wake of the SARS epidemic of 2003, and has become well known for its timely, and detailed, public health messaging.
Among their many publications (listed here) is the CHP Communicable Diseases Watch, published every two weeks.
The latest edition contains information on this year’s influenza vaccination recommendations, local outbreaks of pertussis and listeriosis, and an epidemiological update of the H7N9 outbreak which was first reported at the end of March.
This review was written before the latest announced case in Guangdong Province, but is current as of August 2nd, 2013.
This update begins with a listing of cases by Province, followed by patient demographics and environmental and animal test results. This review then summarizes some of the recent research findings, and concludes with a call for continued public health vigilance and some prevention advice.
I’ve only included some excerpts, follow the link to read the report in its entirety.
Update on the situation of avian influenza A(H7N9)infection
Reported by Dr Conan Tsang, Medical Officer, Respiratory Disease Office, Surveillance and Epidemiology Branch, CHP.
On March 31, 2013, the National Health and Family Planning Commission (NHFPC) notified three fatal cases of avian influenza A(H7N9) infection in two separate provinces, two in Shanghai Municipality and one in Anhui Province of Mainland China. Since then, more cases were reported in other provinces.
As of August 2, a total of 133 cases, including 43 deaths, have been laboratory confirmed with avian influenza A(H7N9) virus in Zhejiang Province (46 cases including 9 deaths), Shanghai Municipality (33 cases including 16 deaths), Jiangsu Province (28 cases including 9 deaths), Jiangxi Province (6 cases including 1 death), Fujian Province (5 cases), Anhui Province (4 cases including 2 deaths), Henan Province (4 cases including 1 death), Shandong Province (2 cases), Hunan Province (2 cases including 1 death), Beijing Municipality (2 cases) and Hebei Province (1 case). Four fatal cases from unknown provinces were recorded.
One imported case from Jiangsu Province was also reported by the Centers for Disease Control of Taiwan, making a total of 134 cases. The last case was reported on July 20 affecting a 61-year-old woman in Hebei Province with onset of symptoms on July 10. The distribution of avian influenza A(H7N9) cases is summarized in Figure 1.
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Recent studies find that this avian influenza A(H7N9) virus may have greater ability to infect mammals, including humans, than other avian influenza viruses. The virus can replicate efficiently in human bronchus and lung ex-vivo cultures. It also predominantly infects type II alveolar epithelial cells and alveolar macrophages in the human lung.Type II alveolar epithelial cell is the key cell type supporting regeneration and repair of damaged lung tissues, infection and damage to these cells prevent the repair processes that allow the lung to recover from injury or infection1.
In addition, various ferret studies suggested that the virus was efficiently transmitted via direct contact2, and less efficiently by respiratory droplets2,3,4.These results indicate that avian influenza A(H7N9) viruses have the capacity for efficient replication in mammals and pose the risk of pandemic potential.
In addition, researchers of the Centers for Disease Control and Prevention of the United States also reported that the avian influenza A(H7N9) virus can pass through the eyes to infect respiratory tract in mouse studies2. This finding supports the Centre for Health Protection’s (CHP) existing influenza recommendations to avoid touching the eyes, nose or mouth to prevent spread of the virus. It also supports the recommendation for health care providers to wear eye protection when caring for patients with confirmed or suspected avian influenza A(H7N9) infection.
In view of the potential severity of avian influenza A(H7N9) infection, WHO recommended that all confirmed cases, probable cases, and cases under investigation receive antiviral treatment with a neuraminidase inhibitor drug as early as possible. Based on genetic and antigenic analyses of this novel avian influenza virus, knowledge and experience accumulated with existing avian influenza viruses, and risk assessment conducted by the WHO Collaborating Centres and Essential Regulatory Laboratories of Global Influenza Surveillance and Response System, WHO provisionally recommends that an A/Anhui/1/2013-like virus is used for the development of A(H7N9) vaccines for pandemic preparedness purposes.
For more on the recent H7N9 transmissibility studies, you may wish to revisit:
Nature: Limited Airborne Transmission Of H7N9 Between Ferrets
BMJ: `Probable Person-to-Person Transmission’ Of H7N9
NEJM Journal Watch: Characteristics of H7N9
Science: H7N9 Transmissibility Study In Ferrets
