Photo Credit CDC
# 6499
Even though no cases have been reported outside of the United States, Hong Kong - well known for their aggressive infectious disease surveillance system - has announced an addition to their Prevention and Control of Disease Ordinance to make the recently emerging H3N2v swine-origin flu virus a notifiable disease.
17 August 2012
Statutory reporting of variant influenza A (H3N2)
A spokesman for the Centre for Health Protection (CHP) of the Department of Health said today (August 17) that the Government has amended the Prevention and Control of Disease Ordinance (Cap. 599) to include variant influenza A (H3N2) as one of the statutorily notifiable diseases.
The spokesman said, "Recently in the US, a significant increase in the number of variant influenza A (H3N2) cases has been reported. In order to prepare in advance for possible importations of this infection into Hong Kong and their consequences, there is public health justification to strengthen the surveillance over this type of influenza to enable effective public health preventive and control measures be implemented locally. It is considered necessary to amend the Ordinance to include variant influenza A (H3N2) in the list of scheduled infectious diseases, with effect from August 17, 2012."
The amendment, which has been gazetted today, enables provisions of the Ordinance, such as medical surveillance, quarantine and isolation, to be applied as and when necessary.
"The law amendment will make Hong Kong better prepared against the disease by facilitating early disease detection and implementation of appropriate public health measures if they are called for, depending on public health risk assessment," he added.
Medical practitioners are required to notify the Director of Health if they have reason to suspect variant influenza A (H3N2). The CHP has sent letters to all medical practitioners to inform them of the legislative amendment and reporting criteria.
Twice a month the University of Hong Kong samples pigs arriving at Sheung Shui slaughterhouse for influenza viruses, and every few months we get a report on what they found.
The last report was in May (another should be due soon), and I covered it in Hong Kong Swine Flu Virus Surveillance). Of 1,100 samples tested between February and April of this year, 8 were found to be reassortments of swine flu viruses with genetic material from the 2009 H1N1 virus.
This is a lower number than the previous report (see Hong Kong Swine Influenza Surveillance) which detected a total of 27 reassortant viruses out of 1,500 samples.
Nevertheless, this type of surveillance shows that swine flu reassortments happen all over the world, and are not just an American problem. Most of the world, however, doesn’t test for these viruses and so they pretty much go undetected.
At least until they emerge in a big way, as we saw with the A/H1N1pdm virus in 2009.
While the jury is still out on the future course of the H3N2v virus, three more states have reported cases in the past 48 hours; Michigan (1), West Virginia (3), and Wisconsin (2).
The press release, overnight from the Wisconsin Health Department has the details on their two cases, both connected with a local fair.
FOR IMMEDIATE RELEASE
August 16, 2012CONTACT: Stephanie Smiley, (608) 260-5196
DEPARTMENT OF HEALTH SERVICES REPORTS FIRST HUMAN CASES OF H3N2v INFLUENZA
MADISON—State and local health officials report the Wisconsin State Laboratory of Hygiene confirmed two cases of the variant H3N2 (H3N2v) influenza virus in Wisconsin. Test results indicate one of the infections occurred in an adult from southeastern Wisconsin who worked at the Wisconsin State Fair. The individual did not report direct contact with swine. A second H3N2v infection has been detected in an adolescent who was a swine exhibitor at the Wisconsin State Fair and lives in western Wisconsin. The individuals are recovering from their illness and have not been hospitalized.
Since July 2012, the Centers for Disease Control and Prevention (CDC) has reported more than 150 cases of human infections with H3N2v influenza in Indiana, Ohio, Illinois, Hawaii, and Michigan. These human infections have all occurred in persons exposed to, or in proximity to, pigs.
It is very likely that as the county and state fair season proceeds, we will continue to see outbreaks of this swine-related influenza. And we should not be surprised to see its geographic range increase as well.
While limited human-to-human transmission may have have taken place, the CDC, as yet, has not announced evidence of sustained and efficient community transmission.
That could change over time, of course.
Each time the virus jumps from a pig to a human host, it gives it another opportunity to figure us out.
Maybe it never does, and this virus fizzles out. We’ll just have to wait and see.
But unless and until that happens, this virus will have a fairly limited public health impact. For the most part, infections have been mild to moderate, transmission has been limited, and no deaths have been reported.
For now the risks are primarily to those who come in contact with pigs, so the CDC is offering advice to fair goers, and those who raise swine, on how to best reduce the risk of infection.
We should get an update on this week’s H3N2v numbers later today from the CDC’s FluView report.
