Development of enhanced primer sets for detection of norovirus

Development of enhanced primer sets for detection of Norovirus and Hepatitis A in food samples from Guayaquil (Ecuador) by reverse transcriptase-heminested PCR

Norovirus (NV) is an infectious biological agent that causes gastrointestinal problems of the original nonbacterial appearance of foodborne illnesses. The genotype of NV responsible for the most frequent NV disease outbreaks is GII, accounting for 60–80% of the cases. Moreover, original and new NV variants are continuously emerging, concurrent with the recent global increase in NV infections. Hepatitis A virus (HAV) is another foodborne pathogen frequently implicated in acute gastroenteritis cases around the world. The virus is transmitted among humans via the fecal-oral route, and infection by HAV causes the most severe form of viral illness acquired from foods. In this study, we implemented primer sets to detect NV genotypes I and II. We also developed primer sets for the detection of HAV. The primers were used in a heminested reverse transcriptase PCR (hnRT-PCR) protocol that was rapid and sensitive for detecting NVG1, NVGII and HAV virus in food. The hnRT-PCR was applied successfully to strawberries and spinach obtained from a local fresh-food market, where we could see NVGI, NVGII and HAV. Keywords: Norovirus1; Hepatitis A2; gastroenteritis3; genotypes4; NVG15; NVGII6; hnRT-PCR7.

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

PURPOSE

Noroviruses are common viral agents in acute diarrhea in all age groups worldwide. Norovirus has been classified into 10 genogroups, GI to GX with over 48 genotypes among them the GII.4 genotype has evolved over time with a clear pattern of periodic variant replacement. Immunity is strain or genotype specific with little or no protection conferred across genogroups. The present study was aimed to determine the epidemiology, prevalent genotypes of norovirus in children below five years of age in the Hyderabad region, India.

METHODS

The stool samples and clinical data were collected from 458 children below 5 years of age comprising of cases with acute gastroenteritis (n ​= ​366) and a control group (n ​= ​92) admitted to the pediatric ward. All the samples were tested for Norovirus by ELISA and RT-PCR. Sequencing was done for predominant strains.

RESULTS

10.3% (n ​= ​38) of cases and 3.2% (n ​= ​3) of the control group were found to be Norovirus positive. Predominant genotypes were GII-82.5% followed by GI-12.5%.

CONCLUSION

Sequencing and Phylogenetic analyses of 20 GII.4 strains was done. All of the isolates are clustered away from published the GII.4 variants thus suggesting the appearance of a new variant.

Bacteria Associated with Healthcare-Associated Infections on Environmental Samples Obtained from Two Fire Departments

(1) Background: Firefighters spend about 64% of their time responding to medical emergencies and providing medical care without a patient history, which can render them vulnerable to healthcare-associated infections (HAI). Infection prevention, control, and surveillance systems have been instituted at hospitals. However, the prevalence of firefighters’ exposure to HAI is unknown. The objective of this study was to document evidence of HAI on surfaces in fire stations and engines to inform disinfection procedures and identify which pathogens might contribute to occupational exposures. (2) Methods: High-touch or high-use surfaces of two fire departments were sampled during five separate occasions. One fire station from one fire department was sampled over a 4-week period, whereas four fire stations were sampled from a different fire department only once. Sampled surfaces included: entryway floor, washing machine, medical bag, back seat of engine, keyboard of reporting computer, engine console, and uniform pants. (3) Results: Multiple statistical models determined that bacterial contamination was similar between the two fire departments and their stations. Keyboards were the most contaminated surface for all fire stations and departments, E. coli was the most common bacteria detected, and C. difficile was the least detected bacteria. Adjustments for rates of contamination found that contamination rates varied between fire stations. (4) Conclusions: Comprehensive environmental sampling and clinical studies are needed to better understand occupational exposures of firefighters to HAI.

Norovirus and human adenovirus occurrence and diversity in recreational water in a karst aquifer in the Yucatan Peninsula, Mexico

AIMS

To determine the seasonal occurrence and diversity of norovirus (NoV) and human adenovirus (HAdV) in groundwater from sinkholes, and brackish water used for recreational activities in the karst aquifer of the Yucatan Peninsula, Mexico.

METHODS AND RESULTS

Hollow fibre ultrafiltration was used to concentrate viruses and standard plaque assay methods were used to enumerate somatic and F+ specific coliphages as viral indicators. Real-time quantitative polymerase chain reaction assays were used to estimate the number of genome copies for NoV strains GI, and GII, and HAdVs. The predominant NoV genotypes and HAdV serotypes were identified by comparative sequence analysis. Somatic and male F+ specific coliphages were detected at concentrations up to 94 and 60 plaque-forming units per 100 ml respectively. The NoV genogroup I (GI) was associated with 50% of the sampled sites during the rainy season only, at concentrations ranging from 120 to 1600 genome copies per litre (GC l^-1 ). The NoV genogroup II (GII) was detected in 30 and 40% of the sampled sites during the rainy and dry seasons, respectively, at concentrations ranging from 10 to 290 GC l^-1 . During the rainy and dry seasons, HAdVs were detected in 20% of the sites, at concentrations ranging from 24 to 690 GC l^-1 . Identification of viral types revealed the presence of NoV GI.2, GII.Pe, GII.P16 and GII.P17, and HAdV F serotypes 40 and 41.

CONCLUSIONS

These findings demonstrate that NoVs and HAdVs are prevalent as virus contaminants in the karst aquifer, representing potential health risks particularly during the rainy season, in one of the most important areas used for tourism in Mexico.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is one of the few studies conducted in karst aquifers that provide a foundational baseline of the distribution, concentrations and diversity of NoVs and HadVs in these particular environments.

Genetic and epidemiological analysis of norovirus from children with gastroenteritis in Botswana, 2013-2015

Background

Norovirus is a leading cause of viral gastroenteritis worldwide with a peak of disease seen in children. The epidemiological analysis regarding the virus strains in Africa is limited. The first report of norovirus in Botswana was in 2010 and currently, the prevalence and circulating genotypes of norovirus are unknown, as the country has no systems to report the norovirus cases. This study investigated the prevalence, patterns and molecular characteristics of norovirus infections among children ≤5 years of age admitted with acute gastroenteritis at four hospitals in Botswana.

Methods

A total of 484 faecal samples were collected from children who were admitted with acute gastroenteritis during the rotavirus vaccine impact survey between July 2013 and December 2015. Norovirus was detected using real-time RT-PCR. Positive samples were genotyped using conventional RT-PCR followed by partial sequencing of the capsid and RdRp genes. Norovirus strains were determined by nucleotide sequence analysis using the online Norovirus Genotyping Tool Version 1.0, and confirmed using maximum likelihood tree construction as implemented in MEGA 6.0.

Results

The prevalence of norovirus was 9.3% (95% CI 6.7–11.9). The genotype diversity was dominated by the GII.4 strain at 69.7%. This was followed by GII.2, GII.12 each at 9.1%, GI.9 at 6.6% and GII.6, GII.10 each at 3.0%. The most common combined RdRp/Capsid genotype was the GII.Pe/GII.4 Sydney 2012. Norovirus was detected during most part of the year; however, there was a preponderance of cases in the wet season (December to March).

Conclusion

The study showed a possible decline of norovirus infections in the last 10 years since the first report. An upward trend seen between 2013 and 2015 may be attributable to the success of rotavirus vaccine introductions in 2012. Knowledge of circulating genotypes, seasonal trends and overall prevalence is critical for prevention programming and possible future vaccine design implications.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3157-y) contains supplementary material, which is available to authorized users.