Gastrointestinal adenovirus infections in a tertiary referral centre in Saudi Arabia

Rotavirus and adenovirus in children evaluated for viral gastroenteritis at a single healthcare center in the Eastern Province of Saudi Arabia: A perspective of two decades

BACKGROUND

The aim of this study was to determine the distribution of rotavirus and adenovirus in pediatric patients evaluated for viral gastroenteritis in a hospital in the Eastern Province of Saudi Arabia for 22 years.

MATERIALS AND METHODS

This was a retrospective study based in a secondary healthcare center in Saudi Arabia. Laboratory and demographic data were collected from hospital records for all pediatric patients (up to 14 years old) evaluated for viral gastroenteritis by rotavirus/adenovirus antigen detection kit from January 2000 to December 2022. Data were analyzed utilizing SPSS version 28.0. Categorical data were presented as frequency and percentages, whereas mean and standard deviations were computed for continuous variables. Chi-square test and t-test were used to determine statistical significance.

RESULTS

The overall yields of antigen detection were 13.6% for rotavirus and 2.6% for adenovirus. Coinfection with both viruses was documented in 0.5% of the study population. Rotavirus was persistently detected in the past two decades with varying frequency, but the detection of adenovirus showed intervals of at least three consecutive years of zero confirmed cases. Before 2013, when the rotavirus vaccine was introduced in Saudi Arabia, rotavirus was much more prevalent than adenovirus (30% compared to 3.8% in 2010), but they became equally prevalent a decade after the introduction of the vaccine. Rotavirus gastroenteritis showed three different peaks in the year, in March, July, and December. Each peak was followed by a gradual decrease in prevalence before the next peak. Adenovirus, in contrast, was detected consistently around the year at rates between 2% and 5%.

CONCLUSION

Rotavirus and adenovirus gastroenteritis have changed in prevalence in the past two decades. We found distinct seasonal patterns associated with rotavirus and adenovirus gastroenteritis. The utilization of virological testing for pediatric gastroenteritis with syndromic testing panels is to be encouraged to improve the knowledge of the true prevalence of enteric viruses.

Molecular Epidemiology and Surveillance of Human Adenovirus and Rotavirus A Associated Gastroenteritis in Riyadh, Saudi Arabia

In Saudi Arabia, acute gastroenteritis (GE) is a common illness affecting children and adults; however, the extent to which human rotavirus A (HRV) and human adenovirus (HAdV) strains contribute to the condition is unclear. The surveillance of the GE-causing viruses, HRV and HadV, was performed using polymerase chain reaction, sequencing, and phylogenetic analysis at King Khalid University Hospital. The associations between virus prevalence and meteorological factors were analyzed. The prevalence of HAdV was recorded (7%), followed by HRV (2%). On a gender basis, HAdV infections were found to be dominant in females (5:2) (U = 407.5; p < 0.0001), whereas HRV was only detected in males (U = 50; p < 0.0001). A significantly higher HAdV prevalence was recorded at the age of 3.5 ± 0.63 years (21.1%; p = 0.00047), whereas HRV cases were found equally distributed between <3 years and 3-5 years. The highest HAdV prevalence was recorded in autumn, followed by winter and spring. A significant correlation was detected between humidity and the total number of recorded cases (p = 0.011). Phylogenetic analysis depicted the dominance of HAdV type 41 and the G2 lineage of HRV among circulating strains. The current study uncovered the epidemiology and genotypes of HRV and HadV, and provided forecasting equations for monitoring climatic-mediated outbreaks.

Molecular epidemiology, genetic diversity, and vaccine availability of viral acute gastroenteritis in the middle East and North Africa (MENA) region

Acute gastroenteritis is the cause of considerable mortality and morbidity worldwide, particularly among children under five years in underdeveloped countries. Most acute gastroenteritis (AGE) cases are attributed to viral etiologies, including rotavirus, norovirus, adenovirus, astrovirus, and sapovirus. This paper aimed to determine the prevalence rate of different viral etiologies of AGE in the Middle East and North Africa (MENA) region. Moreover, this paper explored rotavirus phylogenetic relatedness, compared VP7 and VP4 antigenic regions of rotavirus with vaccine strains, and explored the availability of vaccines in the MENA region. The literature search identified 160 studies from 18 countries from 1980 to 2019. The overall prevalence of rotavirus, norovirus, adenovirus, astrovirus, and sapovirus were 29.8 %, 13.9 %, 6.3 %, 3.5 %, and 3.2 % of tested samples, respectively. The most common rotavirus genotype combinations in the MENA region were G1P[8], G9P[9], and G2P[4], whereas GII.4 was the predominant norovirus genotype all of which were reported in almost all the studies with genotyping data. The comparison of VP7 and VP4 between circulating rotavirus in the MENA region and vaccine strains has revealed discrete divergent regions, including the neutralizing epitopes. Rotavirus vaccine was introduced to most of the countries of the MENA region; however, only a few studies have assessed the effectiveness of vaccine introduction. This paper provides a comprehensive update on the prevalence of the different viral agents of AGE in the MENA region.

Human Adenovirus Molecular Characterization in Various Water Environments and Seasonal Impacts in Riyadh, Saudi Arabia

The regular monitoring of water environments is essential for preventing waterborne virus-mediated contamination and mitigating health concerns. We aimed to detect human adenovirus (HAdV) in the Wadi Hanifah (WH) and Wadi Namar (WN) lakes, King Saud University wastewater treatment plant (KSU-WWTP), Manfouha-WWTP, irrigation water (IW), and AnNazim landfill (ANLF) in Riyadh, Saudi Arabia. HAdV hexon sequences were analyzed against 71 HAdV prototypes and investigated for seasonal influence. ANLF had the highest HAdV prevalence (83.3%). Remarkably, the F species of HAdV, especially serotype 41, predominated. Daily temperature ranges (22–45 °C and 10–33 °C) influenced the significance of the differences between the locations. The most significant relationship of ANLF and IW to WH and KSU-WWTP was found at the high-temperature range (p = 0.001). Meanwhile, WN was most correlated to ANLF at the low-temperature range (p < 0.0001). Seasonal influences on HAdV prevalence were insignificant despite HAdV’s high prevalence in autumn and winter months, favoring low temperatures (high: 22–25 °C, low: 14–17 °C) at five out of six locations. Our study provides insightful information on HAdV prevalence and the circulating strains that can address the knowledge gap in the environmental impacts of viruses and help control viral diseases in public health management.

Molecular characterization of human adenoviruses in urban wastewaters using next generation and Sanger sequencing

Human adenoviruses (HAdVs) are of major public health importance and are associated with a variety of clinical manifestations, including gastroenteritis, respiratory, ocular and urinary tract infections. To study the occurrence, prevalence and diversity of HAdV species and types circulating in Italy, we conducted a large-scale molecular-epidemiological investigation, a yearlong monitoring of 22 wastewater treatment plants, covering 10 Italian regions, representative of northern, central, and southern Italy. A total of 141 raw sewage samples were collected from January to December 2013, and processed to detect and characterize by phylogenetic analysis a fragment of the hexon coding region of HAdVs. Nested PCR results showed the presence of HAdVs in 85 out of 141 samples (60% of samples). Fifty-nine samples were characterized by conventional Sanger sequencing as belonging to four HAdV species and four types: A (type 12, 5 samples), B (type 3, 8 samples), C (type 5, 1 sample) and F (type 41, 45 samples). The remaining 26 samples could not be characterized because of uninterpretable (mixed) electropherograms suggesting the presence of multiple species and/or types. Pools of characterized and uncharacterized PCR amplicons were further analyzed by next-generation sequencing (NGS). NGS results revealed a marked HAdV diversity with 16 additional types detected beyond the four types found by Sanger sequencing. Overall, 19 types were identified, belonging to HAdV species A-F: types 12 and 31 (species A), type 3 (species B), types 1, 2, and 5 (species C), types 9, 17, 24, 26, 37, 38, 42, 44, 48, and 70 (species D), type 4 (species E), and types 40 and 41(species F). An untypeable HAdV was also detected, showing similar percentages of identity with more than one prototype (types 15, 30, 56, and 59). Our findings documented the circulation of a wide variety of species and types in raw sewage, potentially able to affect other surface water environments and hence human health. Next-generation sequencing proved to be an effective strategy for HAdV genotyping in wastewater samples. It was able to detect a wide range of "less prevalent" types unidentified by conventional Sanger sequencing, confirming that studies based on conventional technologies may grossly underestimate the existence of some, possibly less common, types. Knowledge of the distribution of HAdV species and types would improve our understanding of waterborne HAdV-related health risks.