From a case-control survey to a diagnostic viral gastroenteritis panel for testing of general practitioners' patients

Semi-quantitative assessment of gastrointestinal viruses in stool samples with Seegene Allplex gastrointestinal panel assays: a solution to the interpretation problem of multiple pathogen detection?

PURPOSE

The aim of the study was to determine and evaluate the clinical usefulness of pathogen specific semi-quantitative cut-offs in stool samples with multiple pathogen detections.

METHODS

The PCR (Seegene Allplex Gastrointestinal Virus Assay) data from 4527 positive samples received over 16 months were retrospectively analyzed to investigate the distribution of the Ct values of each individual viral pathogen. By using interquartile ranges for each viral pathogen, pathogen specific semi-quantitative cut-offs were determined.

RESULTS

After a thorough analysis of the Ct values, a well-founded decision to exclude all results with a Ct value higher than 35 was made. This approach made it possible to generate a more nuanced report and to facilitate clinical interpretation in case of mixed infections by linking a lower Ct value of a pathogen to a greater likelihood of being a relevant causative pathogen. Moreover, not reporting viral pathogens with a Ct value higher than 35 led to a significant reduction (p < 0.0001) of reported mixed infections compared to oversimplified qualitative or qualitative reporting.

CONCLUSION

By omitting very high Ct values and reporting semi-quantitatively, value was added to the syndromic reports, leading to an easier to read lab report, especially in mixed infections.

Is it time to switch to a formulation other than the live attenuated poliovirus vaccine to prevent poliomyelitis?

The polioviruses (PVs) are mainly transmitted by direct contact with an infected person through the fecal-oral route and respiratory secretions (or more rarely via contaminated water or food) and have a primary tropism for the gut. After their replication in the gut, in rare cases (far less than 1% of the infected individuals), PVs can spread to the central nervous system leading to flaccid paralysis, which can result in respiratory paralysis and death. By the middle of the 20th century, every year the wild polioviruses (WPVs) are supposed to have killed or paralyzed over half a million people. The introduction of the oral poliovirus vaccines (OPVs) through mass vaccination campaigns (combined with better application of hygiene measures), was a success story which enabled the World Health Organization (WHO) to set the global eradication of poliomyelitis as an objective. However this strategy of viral eradication has its limits as the majority of poliomyelitis cases today arise in individuals infected with circulating vaccine-derived polioviruses (cVDPVs) which regain pathogenicity following reversion or recombination. In recent years (between January 2018 and May 2023), the WHO recorded 8.8 times more cases of polio which were linked to the attenuated OPV vaccines (3,442 polio cases after reversion or recombination events) than cases linked to a WPV (390 cases). Recent knowledge of the evolution of RNA viruses and the exchange of genetic material among biological entities of the intestinal microbiota, call for a reassessment of the polio eradication vaccine strategies.

Worldwide prevalence and genotype distribution of human astrovirus in gastroenteritis patients: A systematic review and meta-analysis

AIM

Human astrovirus (HAstV) is an important causative agent of gastroenteritis in humans, which mainly infects young children and the elderly. The goal of this study was to conduct a meta-analytic review of the prevalence of HAstV amongst patients with gastroenteritis, and to shed light on the connection between HAstV infection and gastroenteritis.

METHODS

Systematic literature searches were conducted to identify all potentially relevant studies recorded up to April 8th, 2022. For study weighting, the inverse variance method was employed and the random-effects model was applied to evaluate data. For case-control studies, the pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to establish the relationship between HAstV infection and gastroenteritis.

RESULTS

Among 302423 gastroenteritis patients from 69 different countries, the overall pooled prevalence of HAstV infection was 3.48% (95% CI: 3.11%-3.89%). Case-control approach was used in 39 investigations, and the overall prevalence of HAstV infection among the 11342 healthy controls was 2.01% (95% CI: 1.40%-2.89%). Gastroenteritis and HAstV infection were associated with a pooled OR of 2.16 (95% CI: 1.72-2.71; P < 0.0001; I² = 33.7%). The most commonly found HAstV genotypes in gastroenteritis patients were HAstV1 (62.18%), HAstV7 (33.33%), and HAstV-MLB1 (17.43%).

CONCLUSION

The frequency of HAstV infection was the highest in children under the age of five, and in developing countries. The prevalence rate of HAstV was not influenced by gender. Semi-nested and nested RT-PCR were highly sensitive assays for detecting HAstV infections.