Genetic diversity of G9, G3, G8 and G1 rotavirus group A strains circulating among children with acute gastroenteritis in Vietnam from 2016 to 2021

Rotavirus group A (RVA) is the most common cause of severe childhood diarrhea worldwide. The introduction of rotavirus vaccination programs has contributed to a reduction in hospitalizations and mortality caused by RVA. From 2016 to 2021, we conducted surveillance to monitor RVA prevalence and genotype distribution in Nam Dinh and Thua Thien Hue (TT Hue) provinces where a pilot Rotavin-M1 vaccine (Vietnam) implementation took place from 2017 to 2020. Out of 6626 stool samples, RVA was detected in 2164 (32.6%) by ELISA. RT-PCR using type-specific primers were used to determine the G and P genotypes of RVA-positive specimens. Whole genome sequences of a subset of 52 specimens randomly selected from 2016 to 2021 were mapped using next-generation sequencing. From 2016 to 2021, the G9, G3 and G8 strains dominated, with detected frequencies of 39%, 23%, and 19%, respectively; of which, the most common genotypes identified were G9P[8], G3P[8] and G8P[8]. G1 strains re-emerged in Nam Dinh and TT Hue (29.5% and 11.9%, respectively) from 2020 to 2021. G3 prevalence decreased from 74% to 20% in TT Hue and from 21% to 13% in Nam Dinh province between 2017 and 2021. The G3 strains consisted of 52% human typical G3 (hG3) and 47% equine-like G3 (eG3). Full genome analysis showed substantial diversity among the circulating G3 strains with different backgrounds relating to equine and feline viruses. G9 prevalence decreased sharply from 2016 to 2021 in both provinces. G8 strains peaked during 2019-2020 in Nam Dinh and TT Hue provinces (68% and 46%, respectively). Most G8 and G9 strains had no genetic differences over the surveillance period with very high nucleotide similarities of 99.2-99.9% and 99.1-99.7%, respectively. The G1 strains were not derived from the RVA vaccine. Changes in the genotype distribution and substantial diversity among circulating strains were detected throughout the surveillance period and differed between the two provinces. Determining vaccine effectiveness against circulating strains over time will be important to ensure that observed changes are due to natural secular variation and not from vaccine pressure.

Coding-complete genome sequences of rotavirus A reference strains EDIM, Ph158, and CC425

This study reports the coding-complete genome sequences of three rotavirus A (RVA) reference strains previously adapted in tissue culture: RVA/Mouse-tc/USA/EDIM/XXXX/G16P[16] with a G16-P[16]-I7-R7-C7-M8-A7-N7-T10-E7-H9 genotype constellation, RVA/Human-tc/USA/Ph158/1998/G9P[6] with a G9-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genotype constellation, and RVA/Human-tc/USA/CC425/1998/G3P[9] with a G3-P[9]-I2-R2-C2-M2-A3-N2-T1-E2-H3 genotype constellation.

Genotypic investigation of a rotavirus cluster at a quaternary-care pediatric hospital

Rotavirus (RV) was a common healthcare-associated infection prior to the introduction of the RV vaccine. Following widespread RV vaccination, healthcare-associated rotavirus cases are rare. We describe an investigation of a cluster of rotavirus infections in a pediatric hospital in which an uncommon genotype not typically circulating in the United States was detected.

Coding-Complete Genome Sequences of G6P[14] Rotavirus Strain Detected in a Human Stool Specimen within the United States

In this study, we report the detection of a G6P[14] rotavirus strain from a human stool sample within the United States. The full genotype constellation of the G6P[14] strain was identified as G6-P[14]-I2-R2-C2-M2-A11-N2-T6-E2-H3.

1218. Genotypic Investigation of a Rotavirus Cluster at a Pediatric Hospital in 2022

Background

Rotavirus group A (RVA) was the most common cause of infectious gastroenteritis among young children before introduction of rotavirus vaccine in the United States in 2006. Following widespread vaccination, U.S. hospital acquired (HA) rotavirus cases are rare. We describe a cluster of rotavirus infections in a pediatric hospital with a genotype uncommon among U.S. children.

Methods

Patient cases of HA gastrointestinal (GI) illness were detected through hospital-wide microbiology surveillance, performed by Infection Prevention and Control (IPC) practitioners per state requirements. Cluster procedures were implemented on a unit when 3 cases were identified by symptoms and/or laboratory tests within 48 hours. Due to the current rarity of rotavirus clusters, the hospital partnered with Centers for Disease Control and Prevention (CDC) laboratories to sequence strains in addition to instituting local control measures. RVA strains were genotyped by using the genotype specific qRT-PCR assays for VP7 and VP4 genes. Next Generation Sequencing (NGS) was performed for RVA strain characterization on Illumina MiSeq. Genotypes for all 10 RVA were determined by NCBI’s BLASTN program.

Results

Epidemiologic surveillance identified a rotavirus cluster of 10 patients aged 10 months to 10 years old, of whom 50% had received rotavirus vaccine. Symptoms included emesis and diarrhea. Cases could not be attributed to vaccine related shedding. All patients had epidemiologic links by contiguous bed spaces or shared care teams. Sequencing was conclusive for 9 of the 10 stool samples to be a G9P[4] genotype, which is rarely detected amongst U.S. children. Local control measures of increased education and cleaning, isolation of positive patients in single rooms, use of soap and water instead of alcohol-based hand sanitizer on room exit, and furlough of symptomatic healthcare workers halted transmission.

Conclusion

Routine surveillance of HA GI illness identified a cluster; RVA strain genotyping and characterization identified unusual rotavirus genotype G9P[4] as the cause. Partnership between IPC practitioners and laboratorians with CDC demonstrated the need to enhance infection prevention measures to halt transmission and identified a rare rotavirus strain as the likely cause of the cluster.

Disclosures

Courtney E. Comar, PhD, Pfizer: Stocks/Bonds|Viatris: Stocks/Bonds.

Dermoscopy of porokeratosis: results from a multicentre study of the International Dermoscopy Society

BACKGROUND

The diagnosis of porokeratosis can be challenging, and knowledge about its dermoscopic features is limited.

OBJECTIVES

To describe the dermoscopic features of porokeratosis of Mibelli and disseminated superficial actinic porokeratosis (DSAP) and the frequency of these features in a larger case series. The interobserver concordance was also assessed.

METHODS

In this retrospective cohort study, members of the International Dermoscopy Society contributed macroscopic and dermoscopic images of histopathologically verified cases of porokeratosis of Mibelli or DSAP. Three observers independently reviewed the collected images to identify the presence of predefined dermoscopic features. Following this, a consensus meeting was held to agree upon which dermoscopic features were present in each lesion.

RESULTS

In total, 78 clinical and dermoscopic images of porokeratoses were collected. The most common dermoscopic feature was keratin rim, which was present in 74 lesions (92.3%). The most common vascular structures were dotted or glomerular vessels which were present in almost half of the cases (48.7%). Other relatively frequent dermoscopic findings were as follows: non-peripheral scales (44.9%), grey-brown dots or pigmentation along the keratin rim (38.5%), and light-brown pigmentation within the keratin rim (33.3%). Shiny white structures and blood spots or erosions along the keratin rim were findings never before described in porokeratosis and were detected in 16.7% and 17.9% of the lesions, respectively. Dermoscopic findings in porokeratosis of Mibelli and DSAP were similar except for fewer blood spots or erosions along the keratin rim and more light-brown pigmentation within the keratin rim in DSAP. The interobserver concordance ranged from 0.44 (moderate) to 0.84 (almost perfect).

CONCLUSIONS

The dermoscopic hallmark of porokeratosis is the keratin rim, a finding also allowing for almost perfect interobserver agreement. Pigmentation or erosions along the keratin rim, vascular structures, as well as scales, pigmentation or shiny white structures within the keratin rim are additional dermoscopic clues.

Whole gene analysis of a genotype G29P[6] human rotavirus strain identified in Central African Republic

OBJECTIVE

Rotavirus A (RVA) remains the main causative agent of gastroenteritis in young children and the young of many mammalian and avian species. In this study we describe a RVA strain detected from a 6-month-old child from Central African Republic (CAR).

RESULTS

We report the 11 open reading frame sequences of a G29-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2 rotavirus strain, RVA/Human-wt/CAR/CAR91/2014/G29P[6]. Nine genes (VP1-VP3, VP6, NSP1-NSP5) shared 90-100% sequence similarities with genogroup 2 rotaviruses. Phylogenetically, backbone genes, except for VP3 and NSP4 genes, were linked with cognate gene sequences of human DS-1-like genogroup 2, hence their genetic origin. The VP3 and NSP4 genes, clustered genetically with both human and animal strains, an indication genetic reassortment human and animal RVA strains has taken place. The VP7 gene shared nucleotide (93-94%) and amino acid (95.5-96.7%) identities with Kenyan and Belgian human G29 strains, as well as to buffalo G29 strain from South Africa, while the VP4 gene most closely resembled P[6]-lineage I strains from Africa and Bangladesh (97%).

Determinants of TRPV4 activity following selective activation by small molecule agonist GSK1016790A

TRPV4 (Transient Receptor Potential Vanilloid 4) channels are activated by a wide range of stimuli, including hypotonic stress, non-noxious heat and mechanical stress and some small molecule agonists (e.g. phorbol ester 4α-PDD). GSK1016790A (GSK101) is a recently discovered specific small molecule agonist of TRPV4. Its effects on physical determinants of TRPV4 activity were evaluated in HeLa cells transiently transfected with TRPV4 (HeLa-TRPV4). GSK101 (10 nM) causes a TRPV4 specific Ca(2+) influx in HeLa-TRPV4 cells, but not in control transfected cells, which can be inhibited by ruthenium red and Ca(2+)-free medium more significantly at the early stage of the activation rather than the late stage, reflecting apparent partial desensitization. Western blot analysis showed that GSK101 activation did not induce an increase in TRPV4 expression at the plasma membrane, but caused an immediate and sustained downregulation of TRPV4 on the plasma membrane in HeLa-TRPV4 cells. Patch clamp analysis also revealed an early partial desensitization of the channel which was Ca(2+)-independent. FRET analysis of TRPV4 subunit assembly demonstrated that the GSK101-induced TRPV4 channel activation/desensitization was not due to alterations in homotetrameric channel formation on the plasma membrane. It is concluded that GSK101 specifically activates TRPV4 channels, leading to a rapid partial desensitization and downregulation of the channel expression on the plasma membrane. TRPV4 subunit assembly appears to occur during trafficking from the ER/Golgi to the plasma membrane and is not altered by agonist stimulation.