Human To Human Transmission Of Bird Flu
April 9th, 2008 | by admin |
Testsindicate that a father diagnosed with bird flu in China probably caughtthe disease from his son, only increasing concern about transmission ofthe virus between humans. This was published early online and in theApril 2008 issue of The Lancet.
As of April 2, 2008,there have been 376 cases of infection with the highly pathogenic avianinfluenza A (H5N1) virus with 238 deaths reported in 14 differentcountries since November 2003. While most cases have been scattered,about one quarter of all cases have been in clusters of two or morepeople.
These two men, diagnosed within a week of one another,were investigated by Professor Yu Wang, Chinese Centre for DiseaseControl and Prevention, , China, and colleagues in December 2007in China’s Jiangsu Province. Both laboratory and field tests wereperformed immediately to determine a positive H5N1 infection in bothcases. Additionally, 91 people with whom they had come intocloseexposure, and more removed contacts who became at all ill were tested.
Theson, aged 24, died, while his 52 year old father survived afterreceiving early antiviral treatment and post-vaccination plasma from aparticipant in an H5N1 vaccine trial. The only potential point ofexposure of the son’s was a visit to a poultry market six days beforethe illness’s onset. In the meanwhile, the father had considerableunprotected exposure to his sick son.
All 91 exposed contactsgave consent for examination — of these, 78 were administeredanti-retroviral prophylaxis and two suffered from mild illness.However, all 91 tested negative for H5N1. The viruses isolated fromfather and son were genetically identical with the exception of onesmall base change in the nucleic acid chain making up the H5N1 geneticstructure.
The authors conclude that the transmissionwas probably between the two men. “Limited, non-sustainedperson-to-person transmission of H5N1 virus probably occurred in thisfamily cluster…Viral characteristics required for sustainedperson-to-person transmission remain unknown. H5N1 clusters requireurgent investigation because of the possibility that a change in theepidemiology of H5N1 cases could indicate that H5N1 viruses haveacquired the ability to spread more easily among people.”
DrJeremy Farrar, Hospital for Tropical Diseases, Ho Chi minh City,Vietnam, and colleagues, wrote an accompanying comment, in which theysay: “Whatever the underlying determinants, if we continue toexperience widespread, uncontrolled outbreaks of H5N1 in poultry, theappearance of strains well adapted to human beings might just be matterof time. In the meantime, all family contacts of a patient withprobable or confirmed H5N1 should be given chemoprophylaxis and placedunder surveillance. Personal protection and advice must be extended tothe family members and health workers visiting and looking afterpatients in hospital.”
“Today’s study is a superb piece ofwork showing the benefit of a longstanding and trusting internationalcollaboration that began during the severe acute respiratory syndromeepidemic. Such collaborations sustained over several years, centred inaffected countries, and closely linked with WHO are our best chance ofcombating current and future threats to international health andensuring that benefits are shared worldwide.”
Probable limited person-to-person transmission of highlypathogenic avian influenza A (H5N1) virus in China
HuaWang, Zijian Feng, Yuelong Shu, Hongjie Yu, Lei Zhou, Rongqiang Zu,Yang Huai, Jie Dong, Changjun Bao, Leying Wen, Hong Wang, Peng Yang,Wei Zhao, Libo Dong, Minghao Zhou, Qiaohong Liao, Haitao Yang, MinWang, Xiaojun Lu, Zhiyang Shi, Wei Wang, Ling Gu, Fengcai Zhu, Qun Li,Weidong Yin, Weizhong Yang, Dexin Li, Timothy M Uyeki, Yu Wang
The Lancet, April 8, 2008
DOI:10.1016/S0140-6736(08)60493-6
Click Here For Journal
Person-to-person transmission of influenza A (H5N1)
Nguyen Tran Hien, Jeremy Farrar, Peter Horby
The Lancet, April 8, 2008
DOI:10.1016/S0140-6736(08)60494-8
Click Here For Journal
Written by Anna Sophia McKenney
Copyright: Medical News Today
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