Hajj is the annual gathering of Islam practitioners in Mecca, Saudi Arabia. During the
event, gastrointestinal infections are usually experienced and outbreaks have always
been a concern; nevertheless, a deep and integrative study of the etiological agents has
never been carried out. Here, I describe for the first time the epidemiology of
pathogenic enteric viruses during Hajj 2011, 2012 and 2013.
The focus of this study was the common enteric viruses Astrovirus, Norovirus, Rotavirus
and Adenovirus. An enzyme Immunoassay established their presence in 14.9%, 15.0%
and 6.6% of the reported cases of acute diarrhea for 2011, 2012 and 2013, respectively.
For the three years of study, Astrovirus accounted for the majority of the viral
infections. To our knowledge, this is the first time an epidemiological study depicts
Astrovirus as the main viral agent of gastroenteritis in a mass gathering event.
Hajj is rich in strains of Astrovirus, Norovirus and Rotavirus. A first screening by RT-PCR
resulted in ten different genotypes. Strains HAstV 2, HAstV 1 and HAstV 5 were
identified for Astrovirus. GI.6, GII.3, GII.4 and GII.1 were described for Norovirus and
G1P, G4P and G3P were found for Rotavirus.
The majority of the Astrovirus isolates could not be genotyped suggesting the presence
of a new variant(s). Cases like this encourage the use of metagenomics (and nextgeneration
sequencing) as a state-of-the-art technology in clinical diagnosis. A sample
containing Adenovirus particles is being used to standardize a process for detection
directly from stool samples and results will be obtained in the near future.
The overall findings of the present study support the concept of Hajj as a unique mass
gathering event that potentiates the transmission of infectious diseases. The finding of
Norovirus GII.4 Sydney, a variant originated from Australia, suggests that Hajj is a
receptor of infectious diseases worldwide.
This work is part of the Hajj project, a collaborative effort with the Ministry of Health of
the Kingdom of Saudi Arabia in order to describe entirely the epidemiology of
gastrointestinal diseases in Hajj. It is expected that the results of this study will serve in
the refinement of public health policies.
|Date of Award||May 2014|
|Original language||English (US)|
- Biological, Environmental Science and Engineering
|Supervisor||Arnab Pain (Supervisor)|