Norovirus prevalence and estimated viral load in symptomatic and asymptomatic children from rural communities of Vhembe district,South Africa

BackgroundHuman Norovirus (NoV) is recognized as a major etiological agent of sporadic acute gastroenteritis worldwide.ObjectivesThis study describes the clinical features associated with Human NoV occurrence in children and determines the prevalence and estimated viral burden of NoV in symptomatic and asymptomatic children in rural South Africa.Study designBetween July 2014 and April 2015, outpatient children under 5 years of age from rural communities of Vhembe district, South Africa, were enrolled for the study. A total of 303 stool specimens were collected from those with diarrhea (n = 253) and without (n = 50) diarrhea. NoVs were identified using real-time one-step RT-PCR.ResultsOne hundred and four (41.1%) NoVs were detected (62[59.6%] GII, 16[15.4%] GI, and 26[25%] mixed GI/GII) in cases and 18 (36%) including 9(50%) GII, 2(11.1%) GI and 7(38.9%) mixed GI/GII in controls. NoV detection rates in symptomatic and asymptomatic children (OR = 1.24; 95% CI 0.66⿿2.33) were not significantly different. Comparison of the median C_T values for NoV in symptomatic and asymptomatic children revealed significant statistical difference of estimated GII viral load from both groups, with a much higher viral burden in symptomatic children.ConclusionsThough not proven predictive of diarrhea disease in this study, the high detection rate of NoV reflects the substantial exposure of children from rural communities to enteric pathogens possibly due to poor sanitation and hygiene practices. The results suggest that the difference between asymptomatic and symptomatic children with NoV may be at the level of the viral load of NoV genogroups involved.     

Identification of viral and atypical bacterial pathogens in children hospitalized with acute respiratory infections in Hong Kong by multiplex PCR assays

Acute respiratory tract infection is a leading cause of hospital admission of children. This study used a broad capture, rapid and sensitive method (multiplex PCR assay) to detect 20 different respiratory pathogens including influenza A subtypes H1, H3, and H5; influenza B; parainfluenza types 1, 2, 3, and 4; respiratory syncytial virus (RSV) groups A and B; adenoviruses; human rhinoviruses; enteroviruses; human metapneumoviruses; human coronaviruses OC43, 229E, and SARS‐CoV; Chlamydophila pneumoniae; Legionella pneumophila; and Mycoplasma pneumoniae; from respiratory specimens of 475 children hospitalized over a 12‐month period for acute respiratory tract infections. The overall positive rate (47%) was about twice higher than previous reports based on conventional methods. Influenza A, parainfluenza and RSV accounted for 51%, and non‐cultivable viruses accounted for 30% of positive cases. Influenza A peaked at March and June. Influenza B was detected in January, February, and April. Parainfluenza was prevalent throughout the year except from April to June. Most RSV infections were found between February and September. Adenovirus had multiple peaks, whereas rhinovirus and coronavirus OC43 were detected mainly in winter and early spring. RSV infection was associated with bronchiolitis, and parainfluenza was associated with croup; otherwise the clinical manifestations were largely nonspecific. In general, children infected with influenza A, adenovirus and mixed viruses had higher temperatures. In view of the increasing concern about unexpected outbreaks of severe viral infections, a rapid multiplex PCR assay is a valuable tool to enhance the management of hospitalized patients, and for the surveillance for viral infections circulating in the community. J. Med. Virol. 81:153–159, 2009. © 2008 Wiley‐Liss, Inc.     

Cytokines in nasopharyngeal secretions; evidence for defective IL-1 beta production in children with recurrent episodes of acute otitis media.

The host-parasite relationship in the nasopharynx of young children with bacterial colonization and antigen uptake in the mucosa and lymphatic tissue provides an opportunity to investigate infectious/inflammatory processes and responses. IL-1 beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) were analysed in nasopharyngeal secretions and serum from children with or without recurrent episodes of acute otitis media, from healthy adults and adults with or without recurrent episodes of acute otitis media, from healthy adults and adults with hypogammaglobulinaemia or selective deficiency of IgG3. Nasopharyngeal secretions generally contained substantial amounts of IL-1 beta, IL-6 and TNF-alpha. In contrast, IL-1 beta, IL-6 and TNF-alpha were not detectable in sera on the same occasion. Children were found to have higher levels of IL-1 beta, IL-6 and TNF-alpha than healthy adults and than adults with immunodeficiency. High levels of IL-1 beta were associated with low or undetectable levels of IL-6 and TNF-alpha, whereas the opposite pattern was seen in association with low levels of IL-1 beta. This was especially true for children with recurrent episodes of acute otitis media (RAOM). In children with nasopharyngeal colonization with Haemophilus influenzae, significantly higher levels of IL-1 beta, IL-6 and TNF-alpha (P = 0.0001, respectively) were found compared with non-colonized children. Notably, the RAOM children exhibited significantly lower levels of IL-1 beta, IL-6, and TNF-alpha in nasopharyngeal secretions (P = 0.0001, 0.01 and 0.0001, respectively) than healthy children. These results demonstrate local production of inflammatory cytokines in nasopharynx, related to bacterial colonization, and suggest that children with RAOM are poor nasopharyngeal cytokine producers.     

Simultaneous trisomy 9q3 and monosomy 5p in two children with der(5),t(5;9)(p15.1;q34.13): report of an extended family.

We present a family segregating for t(5;9)(p15.1;q34.13). Two cases with der(5),t(5;9), resulting in a partial duplication 9q34.13----qter and partial deletion of 5p15.12----pter, were ascertained. The phenotypes were consistent with features of both the cri du chat and trisomy 9q3 syndromes.     

Diverse origin of P[19] rotaviruses in children with acute diarrhea in Taiwan: Detection of novel lineages of the G3, G5, and G9 VP7 genes

We previously reported the detection of genotype P[19] rotavirus strains from children hospitalized with acute dehydrating diarrhea during a 5-year surveillance period in Taiwan. The characterization of five P[19] strains (0.4% of all typed), including three G3P[19], a novel G5P[19], and a unique G9P[19] genotype is described in this study. Phylogenetic analysis of the VP4, VP7, VP6, and NSP4 genes was performed, which demonstrated novel lineages for respective genotypes of the VP4 and the VP7 genes. The sequence similarities of the P[19] VP4 gene among Taiwanese human strains was higher (nt, 91.5-96.2%; aa, 93.7-97.6%) than to other P[19] strains (nt, 83.5-86.6%; aa, 89.4-94.1%) from different regions of the world. The VP7 gene of the three G3P[19] Taiwanese strains shared up to 93.4% nt and 97.5% aa identity to each other but had lower similarity to reference strain sequences available in GenBank (nt, <90.1%; aa, <95.6%). Similarly, the VP7 gene of the novel G5P[19] strain was only moderately related to the VP7 gene of reference G5 strains (nt, 82.2-87.3%; aa, 87.0-93.1%), while the VP7 gene of the single G9P[19] strain was genetically distinct from other known human and animal G9 rotavirus strains (nt, ≤ 92.0%; aa, ≤ 95.7%). Together, these findings suggest that the Taiwanese P[19] strains originated by independent interspecies transmission events. Synchronized surveillance of human and animal rotaviruses in Taiwan should identify possible hosts of these uncommon human rotavirus strains.