Performance of a one-step quantitative duplex RT-PCR for detection of rotavirus A and noroviruses GII during two periods of high viral circulation

Rotavirus and bacterial diarrhoea among children in Ile-Ife, Nigeria: Burden, risk factors and seasonality

BACKGROUND

Diarrhoea is a leading cause of death among under-five children globally, with sub-Saharan Africa alone accounting for 1/3 episodes yearly. Viruses, bacteria and parasites may cause diarrhoea. Rotavirus is the most common viral aetiology of diarrhoea in children less than five years globally. In Nigeria, there is scarce data on the prevalence/importance, burden, clinical/risk factors and seasonality of rotavirus and bacteria and this study aims to determine the role of rotavirus and bacteria on diarrhoea cases in children less than five years in Ile-Ife, Nigeria.

METHODS

Socio-demographic data, environmental/risk factors and diarrhoiec stool samples were collected from children less than five years presenting with acute diarrhoea. Rotavirus was identified using ELISA. Bacteria pathogens were detected using cultural technique and typed using PCR. Diarrhoeagenic E. coli (DEC) isolates were subjected to antimicrobial susceptibility testing. Pathogen positive and negative samples were compared in terms of gender, age-group, seasonal distribution, and clinical/risk factors using chi-square with two-tailed significance. SPSS version 20.0.1 for Windows was used for statistical analysis.

RESULTS

At least one pathogen was detected from 63 (60.6%) children having gastroenteritis while 28 (44.4%) had multiple infections. Rotavirus was the most detected pathogen. Prevalence of rotavirus mono-infection was 22%, multiple infection with bacteria was 45%. Mono-infection prevalence of DEC, Shigella spp., and Salmonella spp. were 5.8% (6/104), 5.8% (6/104), and 2.9% (3/104) and co-infection with RVA were 23.1% (24/104), 21.2% (22/104) and 10.6% (11/104) respectively. All rotaviral infections were observed in the dry season. The pathotypes of DEC detected were STEC and EAEC. Parent earnings and mid-upper arm circumference measurement have statistical correlation with diarrhoea (p = 0.034; 0.035 respectively).

CONCLUSION

In this study, rotavirus was more prevalent than bacteria and occurred only in the dry season. Among bacteria aetiologies, DEC was the most common detected. Differences in seasonal peaks of rotavirus and DEC could be employed in diarrhoea management in Nigeria and other tropical countries to ensure optimal limited resources usage in preventing diarrhoea transmission and reducing indiscriminate use of antibiotics.

Norovirus infection and HBGA host genetic susceptibility in a birth community-cohort, Rio de Janeiro, Brazil

Norovirus has emerged as an important viral agent of acute pediatric gastroenteritis, with a growing genetic diversity reported in the last decades. Histo-blood group antigens (HBGAs) present on the surface of enterocytes are susceptibility factors for norovirus infection and differ between populations which could affects the epidemiology and evolution of these viruses. This study investigated the frequency, incidence and genetic diversity of noroviruses in a cohort of rotavirus A vaccinated children in association to the host HBGA (Secretor/Lewis) genetic susceptibility profile. Norovirus genogroups I and II (GI/GII) were screened by RT-qPCR in 569 stool samples from 132 children followed-up from birth to 11 months of age during 2014--2018. Noroviruses were identified in 21.2% of children enrolled in this study, with a norovirus detection rate of 5.6% (32/569), in 17.1% and 4.7% of acute diarrheic episodes (ADE) and non-ADE, respectively. The norovirus incidence was 5.8 infections per 100 child-months. Partial nucleotide sequencing characterized six different norovirus genotypes, with GII.4 Sydney 2012 being detected in 50% associated with three different polymerase genotypes (GII·P31, GII·P16 and GII·P4 New Orleans 2009). FUT3 genotyping was yielded seven new mutations in this population. A significant association between symptomatic norovirus infection and secretor profile could be inferred.

Human norovirus detection in bivalve shellfish in Brazil and evaluation of viral infectivity using PMA treatment

Noroviruses are the most common cause of gastroenteritis outbreaks in humans and bivalve shellfish consumption is a recognized route of infection. Our aim was to detect and characterize norovirus in bivalves from a coastal city of Brazil. Nucleic acid was extracted from the bivalve's digestive tissue concentrates using magnetic beads. From March 2018 to June 2019, 77 samples were screened using quantitative RT-PCR. Noroviruses were detected in 41.5%, with the GII being the most prevalent (37.7%). The highest viral load was 3.5 × 106 and 2.5 × 105 GC/g in oysters and mussels, respectively. PMA-treatment demonstrated that a large fraction of the detected norovirus corresponded to non-infectious particles. Genetic characterization showed the circulation of the GII.2[P16] and GII.4[P4] genotypes. Norovirus detection in bivalves reflects the anthropogenic impact on marine environment and serves as an early warning for the food-borne disease outbreaks resulting from the consumption of contaminated molluscs.

The effect of the waste disposal crisis on the rates of hospitalization due to acute diarrheal illness in a middle-income country: Retrospective chart review

BACKGROUND

A waste disposal crisis occurred in Lebanon leading to the accumulation of garbage in the streets of Beirut. It is not clear whether such a limited crisis of improper waste disposal will lead to more diarrhea illnesses. The purpose of this study is to compare the rates of admissions due to diarrhea and characterize the illness among adults and children before, during and after the garbage crisis.

MATERIALS AND METHODS

This study is an observational retrospective in-patient chart review extending over four time intervals: pre-crisis, major crisis, minor crisis, and post-crisis periods. Hospital admissions due to diarrhea or gastroenteritis were included. Descriptive analysis of the following was done: characteristics of the present illness at the time of admission, stool and lab tests ordered and management of the diarrhea illness.

RESULTS

There was an increase in admission rates due to diarrhea in the months of the crisis as compared to pre and post-crisis months. The severity of diarrheal illness and the management of admitted patients were almost the same across the four periods. Rota virus diarrheal outbreak was noted during the major crisis among children less than 2 years old, and adults above 18 years old.

CONCLUSIONS

Despite an increase in the rates of admissions due to diarrhea during the garbage crisis, the severity of the diarrhea illness did not differ. This may indicate that physicians and patients were more worried and utilized more health services. However, Rota outbreaks may be more prominent with improper garbage disposal.

Rotavirus A Infections in Community Childhood Diarrhea in the Brazilian Semiarid Region During Postvaccination Era

BACKGROUND

Rotavirus A (RVA) is one of the leading causes of acute gastroenteritis worldwide; however, few studies assessed RVA genetics with community surveillance.

OBJECTIVES

This study aimed to investigate clinical data, genetic diversity, and coinfection patterns of RVA infections in children from 2 to 36 months old with or without community childhood diarrhea in the Brazilian semiarid region during postvaccination era.

METHODS

We enrolled and collected socioeconomic/clinical information using a standardized questionnaire and fecal samples from 291 children. Viral RNA samples were extracted and analyzed using quantitative reverse transcription polymerase chain reaction to establish the diagnosis of RVA. Sequencing of VP7 and VP4 (VP8*) regions and phylogenetic analysis were performed.

RESULTS

RVA-negative diagnosis was associated with children 24 to 36 months old with complete vaccination schedule. Genotype G1P[8] was the most prevalent (57%), whereas unusual genotypes including G1P[4], G2P[8], and G3P[9] were also detected. G1- and P[8]-positive samples showed high degrees of similarity with the vaccine strain. RVA coinfections were frequently observed, and enteroaggregative Escherichia coli was the most prevalent copathogen.

CONCLUSIONS

These results demonstrate that genotype G1P[8] is the most prevalent strain. VP7 and/or VP8* gene segments arising from RV1 vaccine strain were documented in these children, suggesting shedding or herd vaccination. Moreover, our study indicates full vaccination is important for protection against RVA infections.

Group A rotaviruses circulating prior to a national immunization programme in Nigeria: Clinical manifestations, high G12P[8] frequency, intra-genotypic divergence of VP4 and VP7

Nigeria having approximately 50 000 Rotavirus A (RVA) deaths annually is yet to introduce RVA vaccine into routine national immunization; therefore surveillance of RVA strains circulating before vaccine introduction is essential in evaluating impact of the intervention. Stool samples and sociodemographic data of diarrhoeic children, <5 years were collected between August 2012 and December 2013. While a high prevalence of RVA infection (47.6%; 49/103) was observed by quantitative reverse transcription real time PCR, only 25% (26/103) had high RVA genome concentrations and were antigen positive. G and P types were obtained for 31 and 37 samples respectively. G12P[8] strains were predominant (30.6%; 16/31); Other genotypes found included G9, G3, G2 and P[4], P[6], P[8]. A G12 + G2/P[8] + P[6] mixed infection was detected. The P[8] genotype showed divergence with strains distributed in lineage III and IV. Compared to the vaccines, changes in antigenic sites of VP8* and VP7 were found. The finding of the G2P[6] genotype combination and emergence of G12 strains support observations in most of the recent RVA studies from Africa. P[6] is common in many African countries, in contrast to countries in Europe and the Americas. In conclusion, this study shows the circulation of other RVA genotypes compared to the common RVA genotypes in Nigeria. PCR results should be interpreted with caution to avoid significant bias from samples with low RVA genome concentrations. These findings provide important information on the detection and molecular epidemiology of RVA prior to vaccination and contribute as a baseline for future evaluations after possible vaccine introduction.

Environmental transmission of diarrheal pathogens in low and middle income countries

Every year, more than half a million children die due to diarrheal diseases. Recent studies have identified the most important etiologies of diarrheal disease are enterotoxigenic and enteropathogenic E. coli, Shigella spp., rotavirus, norovirus and Cryptosporidium spp. These etiologies are unsurprisingly characterized by a combination of high shedding, high infectivity, and transmissibility through multiple environmental reservoirs. The relative importance of the transmission routes is likely site-specific. So the impact of interventions, which typically target only one or two environmental reservoirs, is likely also site-specific. The factors influencing the transmission routes most important for diarrheal disease are complex, including - at a minimum - etiology of endemic disease; and water, sanitation, and hygiene infrastructure and practices. The site-specific nature - and complexity of transmission - helps explain the observed variation in impacts of water, sanitation, and hygiene interventions. It may also render efforts to estimate or quantify global means for interventions' impacts irrelevant. The theme of this Perspective is that greater reductions in diarrheal disease transmission in LMICs can be achieved by designing interventions to interrupt the most important environmental transmission pathways. Intervention choice should be informed by site-specific conditions, most notably: diarrheal etiology and existing water, sanitation, and hygiene infrastructure and practices. The theme is discussed through the lens of the characteristics of the most important diarrheal diseases (shedding, infectivity, growth, and persistence) and the general characteristics of environmental reservoirs (exposure pathways and fecal contamination). The discussion highlights when interventions - and combinations of interventions - will be most effective at reducing diarrheal disease burden.

VP7 and VP8* genetic characterization of group A rotavirus genotype G12P[8]: Emergence and spreading in the Eastern Brazilian coast in 2014

Group A rotavirus (RVA) genotype G12 is habitually associated with diarrhea disease (DD) in African children and recently its detection has increased worldwide. A total of 970 stool samples collected from individuals with DD in the Northeastern, Southeastern, and Southern Brazilian regions, Eastern coast, were analyzed and 321 (33%) were positive for RVA and of these, 241 (75%) genotyped as G12P[8]. The rate of RVA positivity was higher among children aged 5-10 years old (60%). All RVA infections observed in adults aged >21 years were G12P[8] (n = 27) showing that this genotype affected older age groups during the year of 2014 in Brazil. Phylogenetic analysis of VP7 and VP8* G12P[8] strains demonstrated an elevated similarity among Brazilian and G12-III prototypes strains circulating worldwide recently, suggesting that this lineage is associated with the global spread of the G12 genotype, considered as the 6th most prevalent human RVA genotype nowadays; while other G12 lineages remain sporadically detected and usually detected in association with other P genotypes. VP8* analysis revealed that Brazilian strains belong to P[8]-3 lineage, the single P[8] lineage presently detected in the country. No major nucleotide/amino acid disparities were observed among strains recovered from children and adults for VP7 and VP8* genes. These data are essential to support the surveillance studies, particularly in countries where the RVA vaccine was introduced in their National Immunization Program enabling identification of potential alterations in the epidemiological profile that can impact its efficacy in vaccination programs. J. Med. Virol. 89:64-70, 2017. © 2016 Wiley Periodicals, Inc.