China - epidemiology of 1st 120 cases on mainland (from ProMedMail.org, edited)

[Giuseppe]

China - epidemiology of 1st 120 cases on mainland (from ProMedMail.org, edited)

China - epidemiology of 1st 120 cases on mainland

Date: Sat 13 Jun 2009
From: Chen Jiming <jmchen66@yahoo.cn>

The epidemiology of the 1st 120 human A (H1N1) cases reported in China mainland


On [26 May 2009], we reported the epidemiology of the 1st 12 human A (H1N1) cases identified in China mainland. Now, we report the epidemiology of the 1st 120 human A (H1N1) cases identified in China mainland as of [12 Jun 2009] using the data mined from online news.
</jmchen66@yahoo.cn>

1. <jmchen66@yahoo.cn>Among the 120 cases, 104 were imported, 14 were domestic with known infection source, and 2 were domestic with unknown source.
   </jmchen66@yahoo.cn>
2. <jmchen66@yahoo.cn>China mainland identified the 1st A (H1N1) case on [10 May 2009], the 1st domestic case on [29 May 2009], and the 1st domestic case with unknown source on [12 Jun 2009]. The emergence of the cases of unknown source indicates that the risk of the disease spreading among communities in China mainland is rising. </jmchen66@yahoo.cn>
3. <jmchen66@yahoo.cn>Transmissions of the disease from only 5 of the imported 104 cases to others (that is, the 14 domestic cases with known infection source) were identified through clinical observation. That is to say, the reproduction rate is rather low (less than 0.2) as compared with the data from North America. This should be one of the results of the strict control measures implemented in China mainland so far. It is interesting that one imported case with little self-restriction in movement transmitted the disease to other 9 persons including members of her family and a sightseeing tour from multiple provinces.
   </jmchen66@yahoo.cn>
4. <jmchen66@yahoo.cn>Among the 104 imported cases, 92 were from North America (69 from USA and 23 from Canada), and 5 were from Australia. Others were from Yemen, Venezuela, the Philippines, Argentina, and Japan. This indicates that domestic cases might also have existed in Yemen, Venezuela, the Philippines, and Argentina. </jmchen66@yahoo.cn>
5. <jmchen66@yahoo.cn>Among the 120 cases, 118 were reported male (60) or female (58), that is, no gender difference was demonstrated.
   </jmchen66@yahoo.cn>
6. <jmchen66@yahoo.cn>Among the 120 cases, ages of 115 were reported. Most of them were very young (83 are less than 31 years old, and 54 are less than 21 years old). </jmchen66@yahoo.cn>
7. <jmchen66@yahoo.cn>The 120 cases were reported by 15 provinces or municipalities, and 100 were from 5 provinces or municipalities (Beijing 33, Guangdong 30, Fujian 14, Shanghai 13, Sichuan 10).
   </jmchen66@yahoo.cn>
8. <jmchen66@yahoo.cn>All of the 120 cases developed some flu-like symptoms, but none of them showed severe clinical signs, and till date, 62 have recovered. At least 4 human infections with the virus without any clinical signs were found and they were not included in the 120 cases.
   </jmchen66@yahoo.cn>
9. <jmchen66@yahoo.cn>15 of the 120 cases were found through airport temperature detection and 2 were found through train quarantine; the others were identified through other ways.
   </jmchen66@yahoo.cn>

<jmchen66@yahoo.cn>-- Ying-Xue Sun and Ji-Ming Chen China Animal Health and Epidemiology Center Qingdao, 266032 PR China <jmchen66@yahoo.cn>

[ProMED-mail would like to thank Drs Ying-Xue Sun and Ji-Ming Chen for sharing the report/information above. Of note is that one of the importations listed is from Yemen where to date there have not been official reports of influenza A (H1N1) infections to WHO. One wonders whether there might have been infection transmitted during airline travel vs as yet undocumented influenza A (H1N1) activity in Yemen. Given the ever increasing numbers of cases and countries reporting cases, either scenario is equally likely in this case. It is also curious that in the one case where there was unrestricted travel of an infected person, there were an additional 9 cases identified, in contrast with the observed reproductive rate of less than 0.2 in the other instances. - Mod.MPP]

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</jmchen66@yahoo.cn></jmchen66@yahoo.cn>

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