|FAO H7N9 Epidemic Waves - June 14th|
After falling to only 5 cases announced in last week's report, today China's NHFPC has notified Hong Kong of 10 H7N9 infections (2 fatal) during the past week. Since June 1st, China has announced 35 cases, already making this the most active H7N9 summer by far.
The 10 patients, all male, range in age from 31 to 79, and all had onsets on or after June 5th. They span 8 provinces/regions; Beijing (2), Sichaun (2), Anhui (1), Guizhou (1), Hebei (1), Inner Mongolia (1), Jiangsu (1), Tianjian (1).The pronounced skewing towards older males is once again evident in this week's report, and 9 of the 12 reportedly had recent contact with live poultry. We should get more details in next week's HK Avian Flu Report.
In past years, the heat of summer has forced a nearly complete shutdown of H7N9 activity in China, and seeing more than a dozen cases reported over the June-July-August period was a rarity. Last year, that pattern changed very slightly, prompting speculation that the virus was becoming more `heat tolerant'.
Those concerns were echoed again last March in Eurosurveillance: Preliminary Epidemiology & Analysis Of Jiangsu's 5th H7N9 Wave, when researchers reported ` . . . . increased detection rate of H7N9 in environmental samples suggests that the virus might become more resistant to high ambient temperature'While the expansion of H7N9 into more northern provinces might account for some of this year's late season persistence, we continue to see activity in some of China's southern provinces (Sichuan, Guizhou) as well, and temperatures reported this month in China's north have been running at or above average for much of June (see Chart below).
|Beijing Weather - Credit Accuweather|
Between the rapid expansion of a new LPAI H7N9 lineage (Yangtze River Delta) over this past winter, the emergence and spread of a new HPAI H7N9 strain, and the continual evolution of dozens of genotypes in the wild - some changes in the virus's behavior over time are to be expected.
So far, no significant mutations have been reported that would account for increased `heat tolerance' in the virus, and so much of this speculation remains based on anecdotal evidence.The level of viral activity (both in birds, and in humans) over the summer should shed more light on the matter. Some excerpts from today's HK CHP announcement follow:
The Centre for Health Protection (CHP) of the Department of Health today (June 23) is monitoring a notification from the National Health and Family Planning Commission that 10 additional human cases of avian influenza A(H7N9), including two deaths, were recorded from June 16 to 22, and strongly urged the public to maintain strict personal, food and environmental hygiene both locally and during travel.
The 10 male patients, aged from 31 to 79, had onset from June 5 to 19. Two each are from Beijing and Sichuan, and one each from Anhui, Guizhou, Hebei, Inner Mongolia Autonomous Region, Jiangsu and Tianjian. Among them, nine were known to have exposure to poultry or poultry markets.
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 a 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.
The CHP's Port Health Office conducts health surveillance measures at all boundary control points. Thermal imaging systems are in place for body temperature checks on inbound travellers. Suspected cases will be immediately referred to public hospitals for follow-up.
The display of posters and broadcasting of health messages in departure and arrival halls as health education for travellers is under way. The travel industry and other stakeholders are regularly updated on the latest information.
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