مقالات پذیرفته شده در سومین کنگره بین المللی زیست پزشکی
An Overview of Acute Gastroenteritis associated with Noroviruses in Children and Adults.
An Overview of Acute Gastroenteritis associated with Noroviruses in Children and Adults.
mahdiye ardeshiri,1,*mahtab dehbozorgi,2Hanie abbasi ,3
1. Faculty of Midwifery , Islamic Azad University, Masjed Soleyman Branch 2. Departmant of Microbiology , Faculty of Biological Sciences , Shahid Beheshti University , Tehran , Iran 3. Tehran University of Medical Sciences and Health Services
Introduction: Noroviruses (NoVs) are a major cause of sporadic and epidemic acute gastrointestinal illness worldwide. Norovirus affects people of all ages, and most healthy individuals resolve symptoms within 48–72 h, whereas immunocompromised, very young, and elderly individuals have severe outcomes. Norovirus is a non-enveloped, positive-sense, single-stranded RNA virus of approximately 7.5 kb in length within the family Caliciviridae. The genome is organized into three open reading frames (ORFs). ORF1 encodes a large polyprotein that is cleaved into six nonstructural proteins and ORF2 and ORF3 encode major (VP1) and minor (VP2) capsid proteins. Based on VP1, noroviruses are classified into at least seven genogroups (GI to GVII), which can be further divided into at least 30 genotypes. Recombination events along with point mutations within the norovirus genome are well-documented forces that drive norovirus evolution and possibly herd immunity. Norovirus recombination most frequently occurs between the junction of ORF1 and ORF2. The prevalence of norovirus has a peak in cold seasons and people in closed settings and restaurants are more susceptible to be infected. Norovirus infection has generally an incubation period of 24-48 hours and is characterized by acute onset of nausea, vomiting, abdominal cramps, myalgia and non bloody diarrhea. Although extensive research has been carried out worldwide in this field, few studies have been conducted in Iran on genetic characteristics and circulating genogroups and genotypes.
Methods: In this review, we summarized over 45 different studies on human norovirus from 2010 to 2019 in Iran and the rest of the world. The overall protocol is to extract the RNA of virus with special kits and the genome is amplified with RT-PCR followed by nucleotide sequencing, that has been particularly useful in molecular epidemiology studies to identify point-source of infection. Real-time quantitative RT-PCR, which is faster and more sensitive than conventional RT-PCR, has recently been developed for rapid detection of NoV in large numbers of stool samples during epidemic and endemic gastroenteritis.
Results: According to these epidemiological studies in Iran and the rest of the world, 30 of the 45 articles, were included for a norovirus prevalence and genotyping data. The infection causes by norovirus GII is more than GI. Since 2002, GII.4 strains have caused the majority of norovirus outbreaks worldwide. Although in recent years, non-GII.4 strains, such as GII.17 and GII.2, have replaced GII.4 strains in several Asian countries. New GII.4 strains emerge about every 2 to 4 years. Norovirus prevalence in cases of acute gastroenteritis was estimated at 18% world wide.
Conclusion: The rapidly expanding scientific literature on norovirus shows that this pathogen contributes substantially to the global burden of acute gastroenteritis across all settings and age groups. In agreement with previous reports, most infections in these review articles, were caused by GII viruses. Overall incidence of acute gastroenteritis is increased because of a wider diversity of bacterial and parasitic pathogens in low-income settings, so that among cases of acute gastroenteritis, norovirus might be less prevalent. The prevalence of norovirus in European and American countries, because of different feeding patterns may be different with Middle Eastern countries. Although the prevalence of Norovirus in Iran is lower than other developing countries, promoting public health education and preparation of health care setting for controlling the Norovirus sporadic cases and outbreaks are strongly recommended.