Entries in Vietnam (2)
Why Na Tao matters, despite apparent lack of human bird flu transmission
Scott McPherson
in 1918 pandemic, H5N1, Na Tao, Politics and government, Vietnam, bird flu, influenza and infectious diseases
|
1 Comment
A reader of this Blogsite, Jonathan Singleton, asked me to comment on the recent proMED report regarding Na Tao, Vietnam. As you may know, Na Tao is at the heart of a possible cluster of human cases of bird flu. My previous two blogs have covered this developing situation.
The proMED report in question is below.
Influenza A (H5N1) is not transmitted from human to human
---------------------------------------------------------------------------
Yesterday afternoon [14 Apr 2010], at a meeting of the National Steering Committee for pandemic influenza control and prevention, Dr Tran Nhu Duong, Deputy Director of the National Institute of Hygiene and Epidemiology confirmed that influenza A (H5N1) has not been transmitted from human to human.
The investigation of the Institute on 2 cases of influenza A (H5N1) in Na Tao village, Nhu Co commune, Cho Moi District, Bac Kan province did not detect human to human virus transmission.
Reports of two investigation teams of the Institute in Bac Kan showed that the two patients were living about 100 meters apart, and they had never been in direct contact with each other.
All 33 people who had contact with the patients, including relatives, visitors, neighbors, nurses, and physicians, were tested and monitored for 16 days. There has been no case with symptoms of the disease. All the test results were negative.
Communicated by:
PRO/MBDS
As we now know, there are three suspected human cases, not two. But that is not material to our discussion. What is material is that two persons, living about a little more than a football field's distance apart, contracted H5N1 bird flu.
The report seems to conclude that distance alone, coupled with a lack of direct contact of one with another, eliminates the possibility of human-to-human (H2H) transmission. That sounds logical enough.
But the larger issue -- the proverbial elephant in the room -- is this: Has the virus itself changed enough in Na Tao, Vietnam, to allow for an easier method of transmission from avian to human respiratory cells? If so, that disclosure would prove to be almost as big (and ultimately more potentially troublesome) than another H2H cluster.
That is a question that the Vietnamese report does not answer.
Let's consider the facts. Three persons in one district contract bird flu. Apparently they all contracted it via contact with diseased poultry. That tells me that either the virus in that area of Vietnam is more potent, and/or the ability of the virus to favor human epithelial cells as much as it favors chicken epithelial cells.
We all know from reading the research papers that this proclivity toward one species or another is primarily driven by temperature. The fact that both diseased poultry and diseased villagers have been detected in a cluster bears investigating by the WHO. For a cluster is a cluster whenever you get multiple persons in a close area, H2H or no H2H. Three B2H bird flu cases in one hamlet should be significant enough to want to gather many samples and look at them very, very carefully.
All eyes on Vietnam for potential human bird flu cluster
Scott McPherson
in Egypt, H1N1, H5N1, Politics and government, Vietnam, bird flu, cluster case, influenza and infectious diseases, pandemic, swine flu
|
1 Comment
Yesterday, Vietnam confirmed yet another human bird flu case. This time, however, this case bears watching, because it could signal something far more disconcerting than just a single human case.
From the proMED report:
The Director of the Bac Kan provincial Health Department, Nong Quoc Chi, confirmed an A (H5N1)-infected case on [5 Apr 2010]. The patient, [male], 22, from Na Tao hamlet, Nhu Co commune, Cho Moi district, is currently in critical condition. He is being treated at the [National Institute of Tropical and Infectious Diseases]. The patient got sick on [30 Mar 2010] with symptoms of high fever and cough. He was admitted to Bac Kan provincial hospital, and then sent to the [National Institute of Tropical and Infectious Diseases] on [3 Apr 2010] where he tested positive for the lethal strain of A (H5N1) virus.
At present, 4 other people in Nhu Co commune show similar symptoms of high fever and cough. They are under quarantine and being treated at Bac Kan provincial hospital.
The patient in question was taken ill on the 30th of March, and then sent to Hanoi when his condition worsened. The four suspected human bird flu cases are currently in quarantine at the provincial hospital in the provincial capital of Bak Kan. (Or Bac Can, as shown on map at left).
There are many unanswered questions. The most obvious of these is whether these four suspected cases are bird flu, or swine flu?
If these cases are indeed bird flu, has there been human-to-human chain transmission, or were these people all infected during the same timeframe by a single vector? Were they all infected by sick poultry, or were they sickened by a human infection?
OK, let's assume these four people were all H1N1/swine flu infections. That is not good news! That would mean that, once again, bird flu and swine flu had "rubbed elbows" in rural Vietnam. Search my Blogsite for the earlier known case, back in 2009.
According to the Vietnamese Department of Preventive Medicine and the Environment, there are no outbreaks of H1N1 anywhere in Vietnam. From VOA News:
No more A/H1N1 outbreaks in Vietnam
At a meeting reviewing the flu epidemic situation in Hanoi on March 31, the Deputy Director of the Department of Preventive Medicine and the Environment, Tran Khac Phu, confirmed that 11,208 people in the country had been infected with the virus as of March 31 and 58 of them had died.
Regarding the A/H5N1 flu, Phu said that there were no more confirmed cases last week, and the total number of such cases so far this year stands at five, including two deaths.
The A/H1N1 virus epidemic appears to have subsided and the country has not detected any mutations in the virus, said Associate Professor Dr. Nguyen Tran Hien, Director of the Central Institute of Hygiene and Epidemiology.
However, Hien urged localities to closely monitor for the A/H5N1 virus as it is still being found on poultry in several areas.
According to the World Health Organisation (WHO), by March 30, there had been 492 confirmed cases of A/H5N1 infection in 15 countries, resulting in 291 deaths.
Vietnam is actively looking for bird flu cases, so perhaps this is why they feel so confident that no H1N1 outbreaks have occurred. But this may be at odds with the WHO Vietnam report of February 10, 2010. that WHO report stated, matter-of-factly:
Pandemic (H1N1) 2009 is continuing to spread throughout Viet Nam. The spread of 
the virus to all countries, worldwide, is considered inevitable.
As of 10 February 2010, Viet Nam's Ministry of Health has received reports of 11,186 laboratory confirmed cases, including 58 deaths. (Bold WHO's)
It is important to note that this pandemic is currently referred to as of “moderate” severity based upon the global situation. The overwhelming majority of patients are recovering without the need for hospitalization or even medical care, the levels of severe cases are similar to the levels we expect for seasonal influenza, and the health care systems are able to cope with the number of people seeking care.
With the increasing spread of H1N1 in Viet Nam, we expect that there will be a number of people who have serious complications and some will die.
All-righty then! Is Vietnam's swine flu rate climbing or falling? This is not an unimportant question, because it is becoming apparent that Vietnam, more than any other nation save Egypt, may have the potential to be that flashpoint where H5 and H1 reassort. Vietnam has had, to date, prior to this report, 5 bird flu cases with 2 deaths. Egypt, in contrast, has had 18 human bird flu cases with 6 deaths. Both areas are of huge concern.
Let's all keep our eyes on this developing situation.