China. Epidemiology of the first 12 human cases of A/H1N1-swl influenza (from ProMedMail.org, edited)

[Giuseppe]

China. Epidemiology of the first 12 human cases of A/H1N1-swl influenza (from ProMedMail.org, edited)

<http: www.promedmail.org=""><http: www.isid.org="">Date: Tue 26 May 2009
From: Chen Jiming <jmchen66@yahoo.cn>

The epidemiology of the first 12 human A (H1N1) cases reported in mainland China


</jmchen66@yahoo.cn></http:></http:><http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn>From 11 May to 25 May 2009, 12 human A (H1N1) Influenza cases were reported mainland. </jmchen66@yahoo.cn></http:></http:>
<http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn></jmchen66@yahoo.cn></http:></http:>
<http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn>

Through the original data from China CDC (<http: www.chinacdc.net.cn="">http://www.chinacdc.net.cn/), the cases show the following epidemiological features:
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1. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">they are all imported cases through international airplanes;
   </http:></jmchen66@yahoo.cn></http:></http:>
2. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">the airplanes departed from USA (7 cases), Canada (4 cases), or Australia (1 case);
   </http:></jmchen66@yahoo.cn></http:></http:>
3. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">the airplanes arrived in Beijing (8 cases), Shanghai (2 cases), or Hong Kong (2 cases);
   </http:></jmchen66@yahoo.cn></http:></http:>
4. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">7 of the 12 cases had moved to other provinces or municipalities in China before they were identified;
   </http:></jmchen66@yahoo.cn></http:></http:>
5. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">They are 2-69 years of age;
   </http:></jmchen66@yahoo.cn></http:></http:>
6. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">10 of them are male and 2 are female, presumably due to the fact that the majority of the passengers in the airplanes were male;
   </http:></jmchen66@yahoo.cn></http:></http:>
7. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">only 2 were considered suspected cases on arrival at the airport through body temperature scanning;
   </http:></jmchen66@yahoo.cn></http:></http:>
8. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">only the above 2 felt uncomfortable during the flight, and the others felt uncomfortable or had a fever only after they arrived at their final destinations (several hours to 6 days later);
   </http:></jmchen66@yahoo.cn></http:></http:>
9. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">the confirmations were reported 1-6 days (mean: 3.55 days, SD: 1.97 days) after they arrived in their destination airport;
   </http:></jmchen66@yahoo.cn></http:></http:>
10. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">none of them developed severe illnesses, and up to the present, 4 have recovered and left hospital.
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<http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">
These epidemiological data are interesting as they suggest that
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1. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">if the prevalence of the A (H1N1) infection among the international airplane passengers is comparable to that in the departure countries, there should be many more cases in USA and Canada than the official records (more than millions?);
   </http:></jmchen66@yahoo.cn></http:></http:>
2. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">if the prevalence of the A (H1N1) infection in the international airplane passengers is higher than in the departure countries, some of the 12 cases should have become infected during traveling. Therefore, airplane passengers should take some measures to prevent themselves becoming infected during the journey;
   </http:></jmchen66@yahoo.cn></http:></http:>
3. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">some domestic cases have probably emerged in Australia since one of the 12 cases had traveled from Melbourne on 21 May 2009 and had developed fever during the flight. He had no traveling history to other countries recently. Therefore, he is not only an imported case in China mainland, but also a domestic case in Australia;
   </http:></jmchen66@yahoo.cn></http:></http:>
4. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">considering only 2 of the 12 cases were identified as suspected cases at the arrival airports, it is not possible to block future imported cases coming to mainland China through air traveling;
   </http:></jmchen66@yahoo.cn></http:></http:>
5. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">considering 7 of the 12 cases had dispersed to other provinces or municipalities in China before they were identified, and some of them felt uncomfortable and confirmed only several days after they arrived, it should be of quite high possibility for the imported cases to transfer the virus to other people living around them and spark outbreaks in mainland China in the near future;
   </http:></jmchen66@yahoo.cn></http:></http:>
6. <http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">currently, the 12 cases suggest that people in China are susceptible to [H1N1 virus] infection and that the infection is not that severe at least up to the present.
   </http:></jmchen66@yahoo.cn></http:></http:>

<http: www.promedmail.org=""><http: www.isid.org=""><jmchen66@yahoo.cn><http: www.chinacdc.net.cn="">-- Ji-Ming Chen, PhD
Head of the Laboratory of Animal Epidemiological Surveillance
China Animal Health and Epidemiology Center
Qingdao, 266032 PR China <jmchen66@yahoo.cn>


[This lucid epidemiological analysis of the 1st cases of influenza A (H1N1) virus infection in mainland China confirms some of the basic features of the outbreak. The rapid global spread of infection is determined in large part by the short duration and ubiquity of commercial air travel. Other features are the general mildness of the illness and the high proportion of inapparent to apparent infections. Also, as commented previously, the absence of fever in the early stages of illness renders the use of temperature scanners at airports ineffective in identification of carriers of infection. The analysis above indicates that the infection is likely to take hold widely in mainland China. Furthermore the prediction of the existence of cryptic cases of infection in Australia has been confirmed. - Mod.CP]

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