A unique human rotavirus (non vaccine) G9P4 genotype infection in a child with gastroenteritis

Unusual G9P[4] Rotavirus Emerged After the Dynamic Changes in Rotavirus Genotypes From Equine-Like G3 to Typical Human G1/G3 in Indonesia

Inter-genogroup reassortment of Rotavirus A (RVA) strains has highlighted the spread of unusual RVA strains worldwide. We previously reported the equine-like G3 RVA as the predominant strain in Indonesia in 2015-2016. However, since July 2017, typical human genotypes G1 and G3 have replaced these strains completely. To understand how dynamic changes in RVA occur in Indonesia, we performed a detailed epidemiological study. A total of 356 stool specimens were collected from hospitalized children in Sidoarjo, Indonesia between 2018 and 2022. Whole-genome sequencing was performed for all 26 RVA-positive samples using next-generation sequencing. Twenty-four samples were determined to be the unusual RVA G9P[4], while two were G9P[6]. Detailed analysis revealed that seven G9P[4] strains had the typical DS-1-like backbone, while the other strains exhibited a double-reassortant profile (G9-N1) on the DS-1-like backbone. The Bayesian evolutionary analyses suggested that the Indonesian G9P[4] strains share a common ancestor with previously reported G9P[4] strains in the VP7 and VP4 genes. G9P[4] DS-1-like strains were identified as the predominant genotype in Indonesia in 2021 for the first time. These results suggest that the G9P[4] strains were generated from the previous G9P[4] strains that had undergone further intra-reassortments with the other circulating strains.

Hospital based surveillance and molecular characterization of rotavirus in children less than 5 years of age with acute gastroenteritis in Nepal

BACKGROUND

Rotavirus remains a significant causative agent of childhood acute gastroenteritis, particularly among children less than 5 years of age. Although precise data on childhood mortality associated with diarrheal disease in Nepal is not available, it is estimated that22% of all rotavirus deaths globally occurs in neighboring country of India. In spite of the substantial burden of rotavirus gastroenteritis in the Indian subcontinent, rotavirus vaccine has not been introduced in Nepal. Continuous surveillance for monitoring rotavirus disease burden and molecular characterization is needed prior to rotavirus vaccine introduction in Nepal.

METHODS

A total of 3310 stool samples (2849 hospitalized cases and 461 non-hospitalized cases), were collected from patients <5 years of age from January 2013 to December 2016 and tested for rotavirus antigen by ELISA (ProSpecT, USA). A subset of ELISA positive stool samples was genotyped. Demographic data were collected.

RESULTS

During the four-year surveillance period, the overall burden of rotavirus infection was 24% among hospitalized children which was much higher than among non-hospitalized children (12%). The majority of children hospitalized with rotavirus gastroenteritis were less than 2 years of age (86%). Rotavirus-associated gastroenteritis hospitalizations occur year-round in Nepal, but a distinct peak in winter (up to 40% among hospitalized) was observed. Of 735 ELISA positive samples, 492 were genotyped by RT-PCR. The most prevalent genotype was G12P[6] (45.3%), followed byG2P[4](12.2%), G1P[8] (9.6%), G9P[4](7.3%), and G9P[8](4.5%). Mixed infection accounted for 4.4% of cases, 6.2% were partially typed and 10.5% of the samples were G and P untypable.

CONCLUSIONS

A high burden of rotavirus gastroenteritis and a diversity of circulating rotavirus strains in Nepal were observed. Recommendation to introduce a rotavirus vaccine with known vaccine effectiveness would help in reducing the severity of Rotavirus diarrheal disease in children less than 5 years of age.

Multi-center surveillance of rotavirus diarrhea in hospitalized children <5 years of age in India, 2009-2012

Diarrheal disease due to Group A rotaviruses continues to be an important cause of morbidity in the developing world and India contributes significantly to the disease burden. Surveillance carried out between July 2009 and June 2012 at two medical centers in south India and one center in north India estimated 39% of all diarrheal admissions to be due to rotavirus. The most prevalent genotype isolated was G1P[8](33%) followed by G2P[4](17%). G9P[4] has also emerged as a significant cause of rotavirus diarrhea. No seasonal variation was noticed from the centers in south India, whereas we observed increased rotavirus diarrhea in the center in north India during March and April.

Review of global rotavirus strain prevalence data from six years post vaccine licensure surveillance: is there evidence of strain selection from vaccine pressure?

Comprehensive reviews of pre licensure rotavirus strain prevalence data indicated the global importance of six rotavirus genotypes, G1P[8], G2P[4], G3P[8], G4P[8], G9P[8] and G12P[8]. Since 2006, two vaccines, the monovalent Rotarix (RV1) and the pentavalent RotaTeq (RV5) have been available in over 100 countries worldwide. Of these, 60 countries have already introduced either RV1 or RV5 in their national immunization programs. Post licensure vaccine effectiveness is closely monitored worldwide. This review aimed at describing the global changes in rotavirus strain prevalence over time. The genotype distribution of the nearly 47,000 strains that were characterized during 2007-2012 showed similar picture to that seen in the preceding period. An intriguing finding was the transient predominance of heterotypic strains, mainly in countries using RV1. Unusual and novel antigen combinations continue to emerge, including some causing local outbreaks, even in vaccinated populations. In addition, vaccine strains have been found in both vaccinated infants and their contacts and there is evidence for genetic interaction between vaccine and wild-type strains. In conclusion, the post-vaccine introduction strain prevalence data do not show any consistent pattern indicative of selection pressure resulting from vaccine use, although the increased detection rate of heterotypic G2P[4] strains in some countries following RV1 vaccination is unusual and this issue requires further monitoring.