With the 5th & 6th known H5N6 human infections reported in neighboring Guangdong Province last week, an H5N6 positive dead egret found on their doorstep, and H7N9 starting to stir again on the mainland, it comes as little surprise that Hong Kong health authorities are increasing their vigilance against avian flu.
This from Reuters:
HONG KONG, Jan 6 (Reuters) - A woman in the southern Chinese city of Shenzhen has died after being infected with the highly contagious H5N6 bird flu virus, days after she was admitted to hospital, Hong Kong's Health Department said on Wednesday.(Continue . .. )
The 26-year-old woman's death last week comes ahead of the Chinese New Year holiday in early February when millions of Chinese travel to their home towns to celebrate with their families, with chicken a popular festive meal.
All border check points between Shenzhen and Hong Kong, and the airport, had already introduced disease prevention measures with thermal imaging systems in place, a department spokesman said.
As the above article indicates, adding to their avian flu concerns is the impending Lunar New Year's celebration. which in China is called Chunyun, Chinese New Year, or simply, The Spring Festival.
In Vietnam, it is called Tết Nguyên Đán or Feast of the First Morning (Tết for short), while in Korea it is called Seollal.
By whatever name, the lunar new year is no doubt the most important holiday in all of Asia; where hundreds of millions of people flee the big cities and return to their home towns for a few days to attend a reunion dinner with their families - preferably on the eve of the lunar New Year.
Each year Asia sees more than 3 billion passenger journeys – mostly by crowded train – over the extended holiday period (which runs from about two weeks before to two weeks after the new year).
So important is this holiday, and the accompanying traditional chicken feast, that many municipalities won't shut down live bird market vendors until the day of the lunar new year, despite the risks of avian flu.
Large migrations of people along with mass gatherings - such as we see each year with the Hajj, Carnival in Rio, and the Super Bowl - are of particular concern to public health officials and epidemiologists, as they have the potential to amplify a small infectious disease outbreak into a bigger one – both in terms of numbers and geographic spread.
And each year, it seems those risks grow greater.
In Asia, there are now four potentially deadly avian flu strains capable of infecting humans (H5N1, H5N6, H7N9, H10N8), whereas just three years ago there was really only one - H5N1 - to worry about.
We have also recently learned of the potential threat from EAH1N1, an evolving swine flu virus, which has become quite common in Chinese pigs (see PNAS: The Pandemic Potential Of Eurasian Avian-like H1N1 (EAH1N1) Swine Influenza).
There is also always the possibility (remote though it may be), that the mixing of people with different flu strains could spark a reassortment event, yielding a new flu strain or subtype (see J Clin Virol: Influenza Co-Infection Leading To A Reassortant Virus).
While novel influenza viruses are high on our watch list, events like Chinese New Years also have the potential to help distribute and proliferate other infectious diseases like tuberculosis, mosquito-borne illnesses like Dengue & Zika, measles, enteroviruses, and other respiratory pathogens.
In 2010, in The Impact Of Mass Gatherings & Travel On Flu Epidemics , we looked at a study published in BMC Public Health, that looked at and attempted to quantify the impacts of mass gatherings and holiday travel on the spread of an influenza epidemic.
Since then we've looked at additional studies, including the 2012 six-part series (see Lancet: Mass Gatherings And Health), that have looked at the dynamics of disease transmission in these internationally attended events.
This year - in addition to Chinese New Year's - other high risk events to watch include Carnival in Rio, the Super Bowl, the Mardi Gras, Summer Olympics in Rio de Janeiro, Umrah and the Hajj.
And you can be sure that behind the scenes at all of these venues (and around the world), publich health officials are gearing up to deal with a variety of anticipated, and unexpected heatlh threats (see How The ECDC Will Spend Your Summer Vacation).
While the risks of seeing a major disease outbreak in any given year are small, public health authorities must anticipate and prepare for the worst.
After all, we’ll never know the number of outbreaks that have been prevented by proactive measures over the years.
The old saying is true, `When public health works, nothing happens’.