Molecular epidemiology of norovirus variants detected in children under five years of age in Hyderabad, India

Norovirus Epidemiology and Genotype Circulation during the COVID-19 Pandemic in Brazil, 2019-2022

Norovirus stands out as a leading cause of acute gastroenteritis (AGE) worldwide, affecting all age groups. In the present study, we investigated fecal samples from medically attended AGE patients received from nine Brazilian states, from 2019 to 2022, including the COVID-19 pandemic period. Norovirus GI and GII were detected and quantified using RT-qPCR, and norovirus-positive samples underwent genotyping through sequencing the ORF1/2 junction region. During the four-year period, norovirus prevalence was 37.2%, varying from 20.1% in 2020 to 55.4% in 2021. GII genotypes dominated, being detected in 92.9% of samples. GII-infected patients had significantly higher viral concentrations compared to GI-infected patients (median of 3.8 × 107 GC/g and 6.7 × 105 GC/g, respectively); and patients aged >12-24 months showed a higher median viral load (8 × 107 GC/g) compared to other age groups. Norovirus sequencing revealed 20 genotypes by phylogenetic analysis of RdRp and VP1 partial regions. GII.4 Sydney[P16] was the dominant genotype (57.3%), especially in 2019 and 2021, followed by GII.2[P16] (14.8%) and GII.6[P7] (6.3%). The intergenogroup recombinant genotype, GIX.1[GII.P15], was detected in five samples. Our study is the first to explore norovirus epidemiology and genotype distribution in Brazil during COVID-19, and contributes to understanding the epidemiological dynamics of norovirus and highlighting the importance of continuing to follow norovirus surveillance programs in Brazil.

Norovirus gastroenteritis in children under-five years hospitalized for diarrhea in two cities of northeast India: A retrospective study

PURPOSE

Norovirus gastroenteritis, known to cause 'winter vomiting disease' is increasingly being identified as a major cause of viral gastroenteritis worldwide. The impact and prevalence of this viral disease are lacking in many parts of India including northeast India. This study aimed to determine the prevalence and association of norovirus gastroenteritis among under-five-year-old hospitalized children in two cities in northeast India (Dibrugarh in Assam & Dimapur in Nagaland).

MATERIALS AND METHODS

A retrospective analysis of 407 randomly selected diarrheal stool samples was conducted using a commercial multiplex probed-based real-time RT-PCR assay capable of detecting six-viral gastroenteritis pathogens including Norovirus GI, Norovirus GII, Rotavirus, Human Adenovirus, Human Astrovirus, and Sapovirus.

RESULTS

Results showed that norovirus was detected in 18.4% of the samples (75/407; 95% CI: 14.8%-22.5%), with norovirus genogroup II being the predominant group in 97.3% of norovirus cases. A significant association of norovirus diarrhea was found with seasonality, with higher prevalence in colder months compared to warmer months (22.4% vs 9.1%, p-value:0.002). Additionally, 66.7% (50/75) of cases of norovirus gastroenteritis had reported vomiting as the major symptom and had a shorter duration of diarrhea (p-value 0.03). Co-infections with other viral pathogens were seen in 45.9% (187/407) of the cases. The detection of rotavirus was 67.1% (273/407), human adenovirus (45.9%; 187/407), sapovirus and astrovirus (5.9%, 24/407 each), and norovirus GI (0.5%, 2/407) among the cases.

CONCLUSION

This study reports the prevalence of norovirus gastroenteritis in northeast India and further highlights that norovirus gastroenteritis is responsible for substantial cases of hospitalization of under-five years children in the region.

Epidemiological investigation of norovirus infections in Punjab, Pakistan, through the One Health approach

Introduction

Norovirus, mainly associated with acute gastroenteritis, is very contagious and can affect a vast range of species ranging from cattle, pigs, dogs, mice, cats, sheep, and lions to humans. It is a foodborne pathogen that mainly transmits through the fecal–oral route.

Methods

This is the first-ever study conducted in Lahore and Sheikhupura districts of Punjab, Pakistan, to investigate noroviruses through the One Health approach. From January 2020 to September 2021, 200 fecal samples were collected from clinical cases of hospitalized patients and 200 fecal samples from sick animals at veterinary hospitals and local farms. In addition, 500 food and beverage samples were collected from street vendors and retail stores. A predesigned questionnaire was used to assess the risk factors and clinical characteristics of sick people and animals.

Results and discussion

Overall, 14% of the human clinical samples were positive by RT-PCR for genogroup GII. All bovine samples were negative. Food and beverage samples were tested in pools, resulting in sugarcane juice samples positive for genogroup GII. Previous contact with acute gastroenteritis patients, sex, and presence of vomiting were found to be significant risk factors (p ≤ 0.05). The substantial number of diarrhea cases associated with noroviruses calls for additional studies to investigate the epidemiology and transmission and to improve surveillance.