Tanya Y. Murray

Novel norovirus recombinants detected in South Africa

BackgroundNoroviruses (NoV) are the leading cause of viral gastroenteritis worldwide. Recombination frequently occurs within and between NoV genotypes and recombinants have been implicated in sporadic cases, outbreaks and pandemics of NoV. There is a lack of data on NoV recombinants in Africa and therefore their presence and diversity was investigated in South Africa (SA).ResultsBetween 2010 and 2013, eleven types of NoV recombinants were identified in SA. Amplification of the polymerase/capsid region spanning the ORF1/2 junction and phylogenetic analysis confirmed each of the recombinant types. SimPlot and maximum x2 analysis indicated that all recombinants had a breakpoint in the region of the ORF1/2 junction (P < 0.05). The majority (9/11) were intergenotype recombinants, but two intragenotype GII.4 recombinants were characterised. Three combinations represent novel recombinants namely GII.P not assigned (NA)/GII.3, GII.P4 New Orleans 2009/GII.4 NA and GII.P16/GII.17. Several widely reported recombinants were identified and included GII.P21/GII.2, GII.P21/GII.3, GII.Pe/GII.4 Sydney 2012, and GII.Pg/GII.12. Other recombinants that were identified were GII.Pg/GII.1, GII.Pe/GII.4 Osaka 2007, GII.P4 New Orleans 2009/GII.4 Sydney 2012, GII.P7/GII.6. To date these recombinant types all have a reportedly restricted geographic distribution. This is the first report of the GII.P4 New Orleans 2009/GII.4 Sydney 2012 recombinant in Africa.ConclusionsOver the past four years, remarkably diverse NoV recombinants have been circulating in SA. Pandemic strains such as the GII.Pe/GII.4 Sydney 2012 recombinant co-circulated with novel and emerging recombinant strains. Combined polymerase- and capsid-based NoV genotyping is essential to determine the true diversity and global prevalence of these viruses.

Human calicivirus diversity in wastewater in South Africa

To investigate the diversity of human caliciviruses (HuCVs) in wastewater from small‐ to medium‐sized communities in five provinces of South Africa (SA).

Norovirus diversity in children with gastroenteritis in South Africa from 2009 to 2013: GII.4 variants and recombinant strains predominate

From 2009 to 2013 the diversity of noroviruses (NoVs) in children (⩽5 years) hospitalized with gastroenteritis in South Africa was investigated. NoVs were genotyped based on nucleotide sequence analyses of partial RNA-dependent RNA polymerase (RdRp) and capsid genes. Seventeen RdRp genotypes (GI.P2, GI.P3, GI.P6, GI.P7, GI.P not assigned (NA), GI.Pb, GI.Pf, GII.P2, GII.P4, GII.P7, GII.P13, GII.P16, GII.P21, GII.Pc, GII.Pe, GII.Pg, GII.PNA) and 20 capsid genotypes (GI.1, GI.2, GI.3, GI.5, GI.6, GI.7, GI.NA, GII.1, GII.2, GII.3, GII.4, GII.6, GII.7, GII.10, GII.12, GII.13, GII.14, GII.16, GII.17, GII.21) were identified. The combined RdRp/capsid genotype was determined for 275 GII strains. Fifteen confirmed recombinant NoV strains circulated during the study period. NoV GII.P4/GII.4 (47%) and GII.Pe/GII.4 (18%) predominated, followed by GII.PNA/GII.3 (10%) and GII.P21/GII.3 (7%). Other prevalent strains included GII.Pg/GII.12 (6%) and GII.Pg/GII.1 (3%). Two novel recombinants, GII.Pg/GII.2 and GII.Pg/GII.10 were identified. In 2013 the replacement of GII.4 New Orleans 2009 and GII.P21/GII.3, which predominated during the early part of the study, with GII.4 Sydney 2012 and GII.PNA/GII.3 was observed. This study presents the most comprehensive recent data on NoV diversity in Africa.

Human caliciviruses detected in HIV-seropositive children in Kenya.

The human caliciviruses (HuCVs) are important causes of gastroenteritis worldwide. Norovirus (NoV) and sapovirus (SaV) have been detected in HIV‐seropositive children but the genetic diversity of HuCVs circulating in these individuals is largely unknown. In this study the prevalence and genotype diversity of HuCVs circulating in Kenyan HIV‐positive children, with or without diarrhea, from the year 1999 to 2000 was investigated. The overall prevalence of HuCVs was 19% with NoV predominating at 17% (18/105) and SaV present in 5.7% (6/105) of specimens. Human CVs were detected in both symptomatic (24%) and asymptomatic (16%) children. Co‐infections with other enteric viruses were detected in 21.6% of children with diarrhea but only in 4.4% of children without diarrhea. Remarkable genetic diversity was observed with 12 genotypes (7 NoV, 5 SaV) being identified in 20 HuCV‐infected children. NoV genogroup II (GII) strains predominated with GII.2 and GII.4 each representing 27% of the NoV‐positive strains. The GII.4 strain was most closely related to the nonepidemic GII.4 Kaiso 2003 variant. Other NoV genotypes detected were GI.3, GII.6, GII.12, GII.14, and GII.17. Five different SaV genotypes (GI.2, GI.6, GII.1, GII.2, and GII.4) were characterized from six specimens. Diarrheal symptoms were not associated with any specific HuCV genotype. Overall the HuCV genotype distribution detected in this study reflects those in other studies worldwide. The strains detected are closely related to genotypes that have circulated on several continents since the year 2000. J. Med. Virol. 86:75–81, 2014.

Sapovirus prevalence in children less than five years of age hospitalised for diarrhoeal disease in South Africa, 2009-2013

BACKGROUND Although sapovirus (SaV) has been detected in 2.2-12.7% of gastroenteritis cases globally, there are limited data on SaV epidemiology. OBJECTIVES Describe the epidemiology, clinical characteristics and factors associated with SaV gastroenteritis in hospitalised children <5 years of age in South Africa. STUDY DESIGN Between 2009 and 2013 during prospective diarrhoeal surveillance, stool specimens were collected from four sites and screened for SaVs and associated enteric pathogens using ELISA, microscopy, conventional and real-time PCR. Epidemiological and clinical data were compared in patients with or without SaV. Odds ratios were assessed by bivariate and stepwise multivariable logistic regression analysis. RESULTS Sapoviruses were detected in 7.7% (238/3103) of children admitted to hospital and 11.4% (9/79) of deaths. Sapovirus was detected more commonly in children 19-24 months compared to<6months (aOR=2.3; p=0.018) and in males (aOR=2.0; p=0.001). Additional factors associated with SaV detection included residing with≥7 inhabitants compared to ≤3 (aOR=2.2; p=0.011) and concomitant norovirus infections (aOR=3.0; p=0.003). HIV-infected children with SaV were more likely to have bloody stools (aOR=16.8; p<0.001), low birth weight (<2.5kg; aOR=5.8; p=0.007) and live in environments without flush toilets (aOR=8.1; p=0.003) compared to HIV-uninfected children. CONCLUSIONS Sapoviruses, which are perceived to cause mild diarrhoea, were detected in hospitalised children and diarrhoeal deaths in South Africa. Determinants increasing the odds of SaV included overcrowding and concomitant infections while HIV-infected children with SaV displayed bloody stools, low birth weight and reduced access to proper sanitation. Mitigation strategies against SaV infections include improved sanitation.

Diverse sapovirus genotypes identified in children hospitalised with gastroenteritis in selected regions of South Africa.

BACKGROUND Sapoviruses (SaVs) are recognised as causative agents of gastroenteritis worldwide. However, data on the genetic diversity of this virus in Africa are lacking, particularly in the form of current long-term studies. OBJECTIVE To determine the genetic diversity of SaVs in children hospitalised with gastroenteritis in South Africa (SA). STUDY DESIGN From April 2009 to December 2013, SaVs were characterised from stool specimens from children hospitalised with gastroenteritis in four provinces of SA. RESULTS Fourteen different SaV genotypes were identified from the 221 strains that were characterised. Genogroup (G) IV predominated overall and was detected in 24% (53/221) of specimens. The other identified genotypes included six belonging to GI (GI.1-GI.3, GI.5, GI.6, and GI.7) and seven belonging to GII (GII.1-GII.7). CONCLUSION This study has provided the first comprehensive data on the genetic diversity of SaVs in a clinical setting in SA, contributing to the global knowledge of this virus.

Quantification and molecular characterisation of human sapoviruses in water sources impacted by highly polluted discharged wastewater in South Africa

Sapoviruses (SaVs) were detected and quantified in 8/10 water samples collected from wastewater treatment works (WWTWs) and water sources impacted by these WWTWs in Limpopo Province, South Africa. The median SaV concentration was 2.45 × 10⁶ copies/L and SaV genotypes I.2 and IV were characterised. This study provides new data on the high concentrations of clinically relevant SaVs in rivers and dams impacted by poor-performing WWTWs.