Although the number of H7N9 cases reported out of China has dropped markedly the past few weeks, the virus hasn't disappeared completely. Transmission is normally very rare during the summer months, and isn't expected to pick up until October or November.
First this report from Hong Kong's CHP, then I'll return with some excerpts from yesterday's MMWR.
CHP notified of human case of avian influenza A(H7N9) in Hunan(Continue . . . )
The Centre for Health Protection (CHP) of the Department of Health is today (September 8) monitoring a notification from the National Health and Family Planning Commission that an additional human case of avian influenza A(H7N9) was recorded from September 1 to 7 in Hunan, and strongly urged the public to maintain strict personal, food and environmental hygiene both locally and during travel.
The 67-year-old male patient in Zhangjiajie had onset on August 27 and was admitted to hospital for severe pneumonia. He had exposure to a live poultry market before onset.
Travellers to the Mainland or other affected areas must avoid visiting wet markets, live poultry markets or farms. They should be alert to the presence of backyard poultry when visiting relatives and friends. They should also avoid purchasing live or freshly slaughtered poultry, and avoid touching poultry/birds or their droppings. They should strictly observe personal and hand hygiene when visiting any place with live poultry.
Travellers returning from affected areas should consult a doctor promptly if symptoms develop, and inform the doctor of their travel history for prompt diagnosis and treatment of potential diseases. It is essential to tell the doctor if they have seen any live poultry during travel, which may imply possible exposure to contaminated environments. This will enable the doctor to assess the possibility of avian influenza and arrange necessary investigations and appropriate treatment in a timely manner.
While local surveillance, prevention and control measures are in place, the CHP will remain vigilant and work closely with the World Health Organization and relevant health authorities to monitor the latest developments.
Six months ago, in MMWR:Increase in Human Infections with Avian Influenza A(H7N9) In China's 5th Wave, we looked at the CDC's mid-season analysis of what was obviously going to be the biggest outbreak of H7N9 since the virus emerged in 2013.
In addition to the greatly increased number of human infections and expanded geographic range, we were just beginning to learn about a new, HPAI version of the virus along with the rapid spread of a second LPAI (Yangtze River Delta) lineage of the virus.While the summer lull has finally arrived, few expect the virus to remain quiet for very long. Yesterday the CDC's MMWR published a new review of the virus (see Update: Increase in Human Infections with Novel Asian Lineage Avian Influenza A(H7N9) Viruses During the Fifth Epidemic — China, October 1, 2016–August 7, 2017).
It's a long and detailed discussion, which you'll want to read in its entirety. Due to its length, I've only reproduced the summary below:
What is already known about this topic?
The current Asian lineage avian influenza A(H7N9) virus (Asian H7N9) epidemic in China is the fifth and largest epidemic on record.
What is added by this report?
Human infections with Asian H7N9 virus were reported from more provinces, regions, and municipalities in China during the fifth epidemic than in the previous four epidemics combined. Because of antigenic variation between the Yangtze River Delta lineage viruses, the newly emerged high pathogenic Asian H7N9 viruses, and 2013 candidate vaccine viruses, new candidate vaccine viruses have been produced.
What are the implications for public health practice?
These candidate vaccine viruses, as well as others being developed by other World Health Organization Collaborating Centers for Influenza, could be used for vaccine production, clinical trials, stockpiling, and other pandemic preparedness purposes, based on ongoing public health risk assessment. CDC has partnered with China CDC, and other China government organizations, United Nations organizations, and surrounding countries to enhance surveillance and laboratory capacity to detect and respond to Asian H7N9 in animals and humans.
You'll find additional details in last night's news round up from CIDRAP, in: