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Ann Saudi MedAnn Saudi MedAnnals of Saudi Medicine0256-49470975-4466King Faisal Specialist Hospital and Research Centre 10.5144/0256-4947.2013.634asm-6-634LettersRE: The burden of Rotavirus gastroenteritis among hospitalized pediatric patients in a tertiary referral hospital in Jeddah Al-Mendalawi Mahmood Dhahir From the Pediatrics, Al-Kindy College of Medicine, Baghdad University, Baghdad, IraqCorrespondence: Dr. Mahmood Dhahir Al-Mendalawi, Pediatrics, Al-Kindy College of Medicine, Baghdad University, PO Box 55302, Baghdad Post Office, Baghdad 1111, Iraq, mdalmendalawi@yahoo.comNov-Dec 2013 33 6 634 635 Copyright © 2013, Annals of Saudi Medicine2013This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
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To the Editor: I have 2 comments on the interesting paper by Afifi and Nabiha.1

First, despite the implementation of Rotavirus (RV) vaccine in Saudi Arabia in 2006, the prevalence of RV gastroenteritis (RVGE) (42.9%) reported by Afifi and Nabiha1 is still worrisome. I presume that that the worrying prevalence can be attributed to the following 2 points: (1) Saudi pediatric population is not yet completely covered with RV vaccine. This is obvious on noticing that only 2.3% of the studied RV positive GE and 6.1% of the studied RV negative GE received RV vaccine (Table 1).1 (2) It is obvious that temporal and spatial fluctuations in the genotype distribution of human RV are continuously observed worldwide in surveillance studies. New genotypes, such as G9 and G12, have emerged and spread worldwide in a very short time span. In addition, reassortment events have the potential to contribute substantially to genetic diversity among human and animal RV.2 Recent data on the molecular epidemiology of RVGE in Saudi children are scarce. Kheyami3 addressed the distribution of G and P types of RV circulating in the population of Saudi Arabia and demonstrated the presence of serotypes G1-G4, G9, G12, P [4], P [6], and P [8]. However, Obeid4 in his study found that subgroup I (serotype 2) constituted 5.4% of the isolates in comparison to 56.7% for subgroup II (serotypes 1, 3, and 4), whereas 37.8% were nontypeable. Regular surveillance and characterization of RV are, therefore, warranted to confirm RV genotype fluctuations. This, in turn, might partly explain the prevalence of RVGE in Saudi children compared to other viruses. It also helps identify unusual types that could be incorporated into future RV vaccines.

Second, Norovirus (NV) is currently recognized as one of the emerging viruses causing infection in humans. It is the leading cause of the outbreaks of viral GE worldwide. In children, NV plays an increasing and important role in enteric infection, apart from RV, especially in the post-RV vaccine era.5 Afifi and Nabiha1 categorized their studied GE cases into 4 groups: RV infection alone (33.6%), adenovirus (AV) infection alone (7%), combined RV and AV infection (9.3%), and other causes of GE (50.2%). I wonder whether they detected the cases of NVGE in their studied cohort and probably included them within the latter group. This is critical to comment that NVGE shares many characteristics of RVGE, namely similar clinical presentation, significant morbidity, mortality and economic burden, and the need for regular molecular and genetic surveillance of the circulating virus.
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REFERENCES
1 Afifi R  Nabiha M   The burden of Rotavirus gastroenteritis among hospitalized pediatric patients in a tertiary referral hospital in Jeddah Ann Saudi Med 2013 33 241 6 23793425 
2 Matthijnssens J  Bilcke J  Ciarlet M  Martella V  Bányai K  Rahman M    Rotavirus disease and vaccination: impact on genotype diversity Future Microbiol 2009 4 1303 16 19995190 
3 Kheyami AM   Rotavirus gastroenteritis and strain diversity in Saudi Arabia. Current status and future prospects Saudi Med J 2010 31 276 9 20231932 
4 Obeid OE   Characterization of human rotavirus subgroups and serotypes in children under five with acute gastroenteritis in a Saudi Hospital Family Community Med 2011 18 22 5 
5 Chen SY  Chiu CH   Worldwide molecular epidemiology of norovirus infection Paediatr Int Child Health 2012 32 128 31 22824658