Adenovirus gastroenteritis in Hungary, 2003-2006

Molecular analysis of adenovirus strains responsible for gastroenteritis in children, under five, in Tunisia

Purpose of work

Enteric Adenovirus (EAdV) is recognized as one of the most commonly identified agents responsible for severe acute gastroenteritis (AGEs) in the stools of infants.We sought to determine the rate of human adenovirus (HAdV) infections, and the genotypic characterization of circulating strains of HAdV in children under 5 years of age with AGEs in university and regional hospitals, located in the Center-East of Tunisia, from January 2014 to December 2016.

Methods

A classic PCR was performed on 582 stool samples taken within 5 days of the onset of symptoms. Chosen positive samples were sequenced, and some of the results were confirmed by the Next Generation Sequencing technique (NGS). Partial nucleotide sequences of the Hexon gene obtained in this study were compared with the NCBI GenBank database using BLAST. Multiple sequence alignment and phylogenetic analysis were conducted using MEGA6 software. The phylogenetic tree was generated using the maximum-likelihood method and bootstrap analysis was performed with 1000 replications.

Results

Out of 582 samples, 52 (8.93 %) cases were positive for HAdV, with a male predominance (57.4 %). Phylogenetic analyses showed that Tunisian HAdV strains clustered into five HAdV lineages corresponding to serotypes F41 (14/28), C2 (9/28), C5 (3/28), E4 (1/28), and A18 (1/28). HAdV was more frequent in children aged up to 12 months, as compared to the other age groups. The HAdV activity was noted in almost all the months of the year with a peak in autumn, in 2014 and 2015, and in winter in 2016.

Conclusion

This study showed that infections with HAdV species were frequent in children suffering from AGE with the predominance of HAdV F41 and C2. This result underlines the importance of regular monitoring of circulating genotypes, and it could be useful for future epidemiological research.

Molecular detection of human adenovirus in urban wastewater in Egypt and among children suffering from acute gastroenteritis

Incidence of enteric viruses in sewage, the efficacy of wastewater treatment plants to remove these viruses, and health effects from their release into the surface water are very important environmental issues in the microbiology field. One of the most pathogenic enteric viruses is adenovirus which can cause a serious disease such as gastroenteritis with low grade fever and mild dehydration in humans. In this study we performed qualitative polymerase chain reaction (PCR) analysis of HAdV on 60 stool samples from children with acute gastroenteritis admitted to Abu-Rish hospital and 96 environmental samples (32 raw sewage, 32 treated sewage, 32 sewage sludge) collected from Zenin wastewater treatment plant (WWTP). HAdV were detected in 17 (28.3%) of stool, 27 (84.4%) of raw sewage, 16 (50%) of treated sewage and 25 (78%) of sludge samples. The viral concentrations were in the range of 2.02 × 10⁶-7.23 × 10⁶, 8.7 × 10⁵-4.3 × 10⁶, 1.22 × 10⁴-3.7 × 10⁶ and 1.48 × 10⁶-1.77 × 10⁷ GC/mL in stool, raw sewage, treated sewage, and sludge, respectively. HAdV was detected throughout the whole year of sample collection. Moreover, our results suggested that males were more susceptible to adenovirus infections than females. The results indicate that the high incidence of HAdV in the treated sewage may cause adverse health effects.

The role of human adenoviruses type 41 in acute diarrheal disease in Minas Gerais after rotavirus vaccination

Human adenovirus species F (HAdV-F) type 40 and 41 are commonly associated with acute diarrheal disease (ADD) across the world. Despite being the largest state in southeastern Brazil and having the second largest number of inhabitants, there is no information in the State of Minas Gerais regarding the role of HAdV-F in the etiology of ADD. This study was performed to determine the prevalence, to verify the epidemiological aspects of infection, and to characterize the strains of human adenoviruses (HAdV) detected. A total of 377 diarrheal fecal samples were obtained between January 2007 and August 2011 from inpatient and outpatient children of age ranging from 0 to 12 years. All samples were previously tested for rotavirus, norovirus, and astrovirus, and 314 of 377 were negative. The viral DNA was extracted, amplified using the polymerase chain reaction and the HAdV-positive samples were sequenced and phylogenetically analyzed. Statistical analyses were performed using the Chi-square test (p < 0.05), considering two conditions: the total of samples tested (377) and the total of negative samples for the remaining viruses tested (314). The overall prevalence of HAdV was 12.47% (47/377); and in 76.60% (36/47) of the positive samples, this virus was the only infectious agent detected. The phylogenetic analysis of partial sequences of 32 positive samples revealed that they all clustered with the HAdV-F type 41. The statistical analysis showed that there was no correlation between the onset of the HAdV infection and the origin of the samples (inpatients or outpatients) in the two conditions tested: the total of samples tested (p = 0.598) and the total of negative samples for the remaining viruses tested (p = 0.614). There was a significant association in the occurrence of infection in children aged 0–12 months for the condition 1 (p = 0.030) as well as condition 2 (p = 0.019). The occurrence of infections due to HAdV did not coincide with a pattern of seasonal distribution. These data indicate the significant involvement of HAdV-F type 41 in the etiology of ADD in Minas Gerais, which demonstrates the importance of other viral agents in the development of the disease after the introduction of rotavirus vaccine immunization.

Development and Evaluation of a Loop-Mediated Isothermal Amplification Assay for the Detection of Adenovirus 40 and 41

Human adenoviruses (hAdVs) of subgroup F (enteric serotypes 40 and 41) display characteristic gut tropism, in vivo, fastidious growth characteristics in cell culture, and are estimated to be associated with 5-20% worldwide of acute gastroenteritis cases among infants and young children. Adequate hAdV gastroenteritis case management requires laboratory-based diagnosis. The present study aimed to the development and evaluation of a simple and cost-effective, one-step, single-tube adenovirus type 40/41 specific loop-mediated isothermal amplification (LAMP) assay for the detection of hAdV40/41 DNA in environmental and/or clinical samples, since no LAMP assay has previously been reported for the detection of these virus types. The assay targeted the hexon gene and had the advantages of being rapid, simple, specific, and sensitive. Results could be obtained within 60 min, under isothermal conditions at 69 °C. The detection limits for hAdV genomes were between 50 and 100 copies/reaction for hAdV40 and hAdV41, and no cross-reactions with other selected viruses, were found. The assay was evaluated with clinical as well as environmental samples. The developed assay is expected to provide a potential molecular tool in obtaining greater knowledge of the hAdV40/41 importance in the epidemiology and clinical manifestations of gastroenteritis.

Molecular detection of novel adenoviruses in fecal specimens of captive monkeys with diarrhea in China

Adenovirus (AdV) has been recently detected among monkeys with diarrhea in a major research primate colony in China. To better assess disease burden and epidemiology of adenoviruses in the colony, we examined the prevalence of this virus in fecal specimens by PCR using broadly reactive hexon gene-specific primers. Of the 29 strains that were characterized by sequence and phylogenetic analysis, we identified a broad spectrum of simian AdV (SAdV) types, including species SAdV-A (n=14) and HAdV-G (n=9). Six additional strains represented two genetic clusters distantly related to other known SAdVs. A better understanding of the epidemiology of SAdVs and their potential role in gastroenteritis is critical to the implementation of advanced prevention strategies against AdV infection in captive primates.