Molecular epidemiology of norovirus outbreaks in Argentina, 2013-2018

Noroviruses are a leading cause of endemic and epidemic acute gastroenteritis in all age groups. However, in Latin America, there are limited and updated data regarding circulating genotypes. The aim of this study was to assess the prevalence and genetic diversity of norovirus outbreaks in Argentina from 2013 to 2018. Stool samples from 29 acute gastroenteritis (AGE) outbreaks were available for viral testing. Norovirus was detected in samples from 18 (62.1%) outbreaks (2 GI and 16 GII). Both GI outbreaks were typed as GI.6[P11] whereas 10 different GII genotypes were detected, in which GII.4 viruses were the most frequently detected (29.4%, associated with GII.P31 and GII.P16) followed by GII.1[P33] and GII.6[P7] (17.6% each). Like GII.4 viruses, GII.2 viruses were also detected in association with different polymerases (GII.P2 and GII.P16). Our findings underscore the importance of dual RNA-dependent RNA polymerase-VP1 typing since recombinant strains with new polymerase sequences emerge frequently suggesting a possible role in improved fitness of these viruses. This study represents the most recent multi-year assessment of the molecular epidemiology of norovirus strains associated with AGE outbreaks in Argentina. Molecular surveillance of norovirus has to be considered to monitor possible changes in dominant genotypes which may assist to inform the formulation of future vaccines.     

High prevalence of equine-like G3P[8] rotavirus in children and adults with acute gastroenteritis in Thailand

Group A rotavirus (RVA) is a major cause of acute gastroenteritis in infants and young children worldwide. This study aims to clarify the distribution of G/P types and genetic characteristics of RVAs circulating in Thailand. Between January 2014 and September 2016, 1867 stool specimens were collected from children and adults with acute gastroenteritis in six provinces in Thailand. RVAs were detected in 514/1867 (27.5%) stool specimens. G1P[8] (44.7%) was the most predominant genotype, followed by G3P[8] (33.7%), G2P[4] (11.5%), G8P[8] (7.0%), and G9P[8] (1.3%). Unusual G3P[9] (0.8%), G3P[10] (0.4%), G4P[6] (0.4%), and G10P[14] (0.2%) were also detected at low frequencies. The predominant genotype, G1P[8] (64.4%), in 2014 decreased to 6.1% in 2016. In contrast, the frequency of G3P[8] markedly increased from 5.5% in 2014 to 65.3% in 2015 and 89.8% in 2016. On polyacrylamide gel electrophoresis, most (135/140; 96.4%) of the G3P[8] strains exhibited a short RNA profile. Successful determination of the nucleotide sequences of the VP7 genes of 98 G3P[8] strains with a short RNA profile showed that they are all equine-like G3P[8] strains. On phylogenetic analysis of genome segments of two representative Thai equine-like G3P[8] strains, it was noteworthy that they possessed distinct NSP4 genes, one bovine-like and the other human-like. Thus, we found that characteristic equine-like G3P[8] strains with a short RNA electropherotype are becoming highly prevalent in children and adults in Thailand.     

一起疑似食源性诺如病毒暴发的流行病学调查

目的调查广州市某小学出现多名急性胃肠炎病例的感染来源、传播途径和危险因素。方法按照病例定义开展病例搜索,采用描述性流行病学和病例对照研究方法进行分析;样本采用RT．PCR方法检测诺如病毒核酸。结果2013年3月28～31日,共发生诺如病毒感染性腹泻27例,罹患率为3．31％（27／816）。3月28日14：00—22：00时为发病高峰,病例有班级聚集性,病例对照结果显示饭前洗手（OR=0．13,95％CI：0．03—0．63）和每天洗手次数≥5次（OR=0．26,95％CI：0．10～0．72）为保护因素。采集患者、厨工肛拭子、剩余食物及环境涂抹样等85份标本,其中5份检出诺如病毒GII-4型。结论这是一起由诺如病毒GII-4型引起的急性胃肠炎暴发,暴发原因是带毒厨工污染部分食物所致,以食源性传播为主。     

Evolution of norovirus

Norovirus (NoV) is now the dominant aetiological agent of acute gastroenteritis, and, with the recent introduction of rotavirus vaccines in many countries, this is likely to remain the case. NoV has a significant impact on human wellbeing in terms of morbidity, economic costs and mortality in developing countries. NoVs are divided into six genogroups (GI–GVI), but only GI, GII and GIV are known to infect humans, with GII being the most prevalent, causing >95% of human infections. The immune system is thought to drive selection of emerging pandemic NoVs through both antigenic drift and shift. This phenomenon results in the replacement of dominant circulating viruses approximately every 3 years, with new variants able to re-infect hosts previously infected with earlier viruses. This review explores the evolutionary aspects of contemporary NoVs.     

轻度胃肠炎伴婴幼儿良性惊厥患儿血清硫化氢水平变化的研究

目的 研究轻度胃肠炎伴婴幼儿良性惊厥(BICE)患儿血清硫化氢(H2S)水平的变化及意义.方法 选择住院治疗的42 例BICE 患儿为观察组,同期因单纯急性胃肠炎入院治疗的46 例患儿为对照组.使用分光光度计法检测其血清H2S 水平.结果 观察组患儿血清H2S 水平显著低于对照组(28±12 μmol/L vs45±10 μmol/L,P<0.O1).惊厥发作次数≥ 2 次患儿血清H2S 水平显著低于发作次数<2 次患儿(P<0.O5).BICE 患儿惊厥发作次数与血清H2S 水平呈负相关(r=-0.485,P=0.001);惊厥持续时间≥ 5 min 组患儿的发作时间与血清H2S 水平呈负相关(r=-0.736,P=0.004).结论 内源性H2S 水平的降低可能是BICE 患儿发病原因之一;血清H2S 水平下降程度与惊厥发生的次数及发作超过5 min 的持续时间有关,其临床意义有待于更多的研究证实.     

Wheat - Dependent Exercise-Induced Anaphylaxis Occurred With a Delayed Onset of 10 to 24 hours After Wheat Ingestion: A Case Report

Wheat-dependent exercise-induced anaphylaxis (WDEIA) usually occurs 1 to 4 hours after wheat ingestion and the pathophysiology of WDEIA remains unknown. It is recommended that WDEIA patients refrain from exercise for 4 to 6 hours after wheat ingestion. We report a case of a 51-year-old man who experienced 5 anaphylaxis attacks; two of which occurred 10 to 24 hours after wheat ingestion and exercise. He has a history of chronic gastroenteritis that responds well to antihistamine drugs but not proton pump inhibitors (PPIs) and prokinetic agents. Abdominal CT results implied the possibility of superior mesenteric artery syndrome. We suggest that WDEIA occurs 6 hours after wheat ingestion in cases compounded by obstructive gastrointestinal diseases.     

嗜酸细胞性胃肠炎的临床特点及误诊分析

目的 探讨嗜酸细胞性胃肠炎(EG)的临床特点和分析其误诊原因。方法 对6例EG的临床特点、实验室检查、内镜表现和治疗随诊情况进行分析。结果 ①)黏膜型EG患者常以腹痛和腹泻为首发症状,而浆膜型以腹痛、腹胀和腹水为首发症状,可伴恶心呕吐、低热等,肌型以肠梗阻表现为主。②外周血和骨髓中嗜酸细胞计数明显增高(43.5％±20.5％,33.4％±15.6％),以成熟型为主,其变化与症状有关。③血沉、反应蛋白、纤维蛋白原等指标正常,IgG可下降。④腹水为渗出液,可见嗜酸细胞。⑤内镜表现多为黏膜片状糜烂和水肿,以胃窦和回盲部明显,活检可证实大量嗜酸细胞浸润。⑥激素可在1周内迅速缓解症状,并使嗜酸细胞恢复正常。⑦病情可有反复,但预后良好。结论 EG临床和内镜表现无特异性,外周血嗜酸细胞、腹水嗜酸细胞、胃肠黏膜组织中嗜酸细胞增多是诊断的关键。误诊原因:①对EG认识不足;②临床表现无特异性;③未注意外周血嗜酸细胞;④未及时行内镜检查并多点活检;⑤腹水未行EG检查;⑥腹腔镜检查未普及;⑦病理医师未注意到嗜酸细胞;⑧未行人工嗜酸细胞分类计数。     

Eosinophilic gastroenteritis and graft‐versus‐host disease induced by transmission of Norovirus with fecal microbiota transplant

Fecal microbiota transplantation (FMT) was performed to decolonize gastrointestinal tract from antibiotic‐resistant bacteria before allogeneic hematopoietic cells transplantation (alloHCT). AlloHCT was complicated by norovirus gastroenteritis, acute graft‐versus‐host disease, and eosinophilic pancolitis. Norovirus was identified in samples from FMT material. Symptoms resolved after steroids course and second norovirus‐free FMT from another donor.