Wednesday, March 23, 2011

PLoS One: Epidemiological & Molecular Analysis Of Egyptian H5N1

 

 

# 5434

 

 

Over the past couple of years we’ve received more reports of human infections from the H5N1 bird flu virus out of Egypt than from any other place on earth. 

 

Thus far in 2011, there have been 12 cases publically confirmed by the Ministry of Health, with 5 fatalities.  (Note: the newshounds on the flu forums are awaiting details & official confirmation of several more, as yet unannounced cases.)

 

Unlike some Asian countries, where the virus has proved fatal in 80% of reported cases, the CFR (Case fatality ratio) in Egypt has ranged from 10% (2009) to 34% (2010).

 

The spread of what appears to be a `milder’ Egyptian version of the virus has sparked particular concern, since that could be a sign of better adaptation to human physiology.   

 

At the very least, those less sickened are more likely to have increased social contacts while infected, and more opportunities to spread the virus.

 

Yesterday a study appeared in PLoS One  that looks at how the virus in Egypt differs from that which we’ve seen circulating in other parts of the world.

 

First a link to the study and abstract, and then a link to an excellent overview by Robert Roos of CIDRAP.

 

 

The Epidemiological and Molecular Aspects of Influenza H5N1 Viruses at the Human-Animal Interface in Egypt

Ghazi Kayali, Richard J. Webby, Mariette F. Ducatez, Rabeh A. El Shesheny, Ahmed M. Kandeil, Elena A. Govorkova, Ahmed Mostafa, Mohamed A. Ali

 

With 119 confirmed cases between March 2006 and December 2010, Egypt ranks second among countries reporting human H5N1 influenza virus infections. In 2009–2010, Egypt reported 68 new human cases and became the new epicenter for H5N1 infections.

 

We conducted an epidemiological and molecular analysis in order to better understand the situation in Egypt. The onset of new cases peaked annually during the winter and spring months, with majority of cases reported in the Nile Delta region.

 

Most cases were less than 18 years old (62%) and females (60%). The overall case-fatality rate was 34% and significantly increased by age. There was a significant difference between the case-fatality rates among females and males. We observed a significant drop (p = 0.004) in case fatality rate in 2009 (10%) as compared to higher rates (36%–56%) in other years.

 

Hospitalization within 2 or 3 days after onset of symptoms significantly decreased mortality. Molecular analysis showed that variations do occur among viruses isolated from birds as well as from humans in Egypt, and these mutations were especially noted in 2009 viruses.

 

As the epidemiological profile of Egyptian cases differs from other countries, there is an urgent need to conduct prospective studies to enhance our understanding of incidence, prevalence, and determinants of virulence of human infections with avian H5N1 influenza viruses.

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While I would normally be tempted to summarize the rest of this study, there is no need since Robert Roos of CIDRAP has already done a terrific job for us.

 

Study profiles human H5N1 burden in Egypt

Robert Roos * News Editor

Mar 22, 2011 (CIDRAP News) – A study of human H5N1 influenza cases in Egypt, including a genetic analysis of some of the isolates, shows that most cases have occurred in children and females but does not explain why the fatality rate there is significantly lower than in other countries.

 

Writing in PLoS One, a team of US and Egyptian scientists says Egypt became the epicenter of human H5N1 cases in 2009 and 2010, with 68 of the 121 cases reported worldwide. But the country's H5N1 case-fatality rate (CFR) is 34%, versus 60% for other countries with human cases.

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Both the study and the CIDRAP synopsis are highly recommended.