Epidemiology and aetiology of moderate to severe diarrhoea in hospitalised patients ≥5 years old living with HIV in South Africa, 2018-2021: A case-control analysis.

Diarrhoea is a recognised complication of HIV-infection, yet there are limited local aetiological data in this high-risk group. These data are important for informing public health interventions and updating diagnostic and treatment guidelines. This study aimed to determine the pathogenic causes of diarrhoeal admissions in people living with HIV (PLHIV) compared to hospital controls between July 2018 and November 2021. Admitted diarrhoeal cases (n = 243) and non-diarrhoeal hospital controls (n = 101) ≥5 years of age were enrolled at Kalafong, Mapulaneng and Matikwana hospitals. Stool specimens/rectal swabs were collected and pathogen screening was performed on multiple platforms. Differences in pathogen detections between cases and controls, stratified by HIV status, were investigated. The majority (n = 164, 67.5%) of enrolled diarrhoeal cases with known HIV status were HIV-infected. Pathogens could be detected in 66.3% (n = 228) of specimens, with significantly higher detection in cases compared to controls (72.8% versus 50.5%, p<0.001). Amongst PLHIV, prevalence of Cystoisospora spp. was significantly higher in cases than controls (17.7% versus 0.0%, p = 0.028), while Schistosoma was detected more often in controls than cases (17.4% versus 2.4%, p = 0.009). Amongst the HIV-uninfected participants, prevalence of Shigella spp., Salmonella spp. and Helicobacter pylori was significantly higher in cases compared to controls (36.7% versus 12.0%, p = 0.002; 11.4% versus 0.0%, p = 0.012; 10.1% versus 0.0%, p = 0.023). Diarrhoeal aetiology differed by HIV status, with Shigella spp. (36.7%) and Salmonella spp. (11.4%) having the highest prevalence amongst HIV-uninfected cases and Shigella spp. (18.3%), Cystoisospora (17.7%), and Cryptosporidium spp. (15.9%) having the highest prevalence in cases amongst PLHIV. These differences should be considered for the development of diagnostic and treatment guidelines.

Diagnostic testing practices for diarrhoeal cases in South African public hospitals.

BACKGROUND: Stool samples submitted for diagnostic testing represent a proportion of diarrhoeal cases seeking healthcare, and an even smaller proportion of diarrhoeal cases in the community. Despite this, surveillance relies heavily on these laboratory results. This study described diarrhoeal diagnostic practices and aetiological agents of diarrhoea in patients admitted to three South African public hospitals in order to understand biases in surveillance data, and inform guidelines, diagnostic and laboratory practices to improve clinical management. METHODS: A doctors' survey was conducted to determine sample submission, diarrhoeal treatment and barriers to submitting samples for testing. Results for all samples submitted for routine diagnostics were obtained from the NHLS Central Data Warehouse. An enhanced surveillance study enrolled patients with acute diarrhoea at the same hospitals over the same period. Differences between routine culture results and molecular testing from the surveillance study were described. RESULTS: Stool samples were seldom submitted for diagnostic testing (median of 10% of admitted cases). Current diagnostic guidelines were not useful, hence most doctors (75.1%) relied on their own clinical judgement or judgement of a senior clinician. Although most doctors (90.3%) agreed that diagnostics were helpful for clinical management, they reported patients being unwilling to provide samples and long laboratory turnaround times. Routine diagnostic data represent cases with chronic diarrhoea and dysentery since doctors are most likely to submit specimens for these cases. Pathogen yield (number of pathogens detected for samples tested for specific pathogens) was significantly higher in the surveillance study, which used molecular methods, than through routine diagnostic services (73.3% versus 8.2%, p < 0.001), including for viruses (48.9% versus 2.6%, p < 0.001), bacteria (40.1% versus 2.2%, p < 0.001) and parasites (16.2% versus 3.6%, p < 0.001). Despite viruses being commonly detected in the surveillance study, viral testing was seldom requested in routine diagnostic investigations. CONCLUSIONS: Comprehensive diagnostic and treatment guidelines are required for diarrhoeal diseases. These guidelines should be informed by local epidemiological data, where diagnostic testing is reserved for cases most likely to benefit from specific treatment. Optimisation of current diagnostic processes and methods are required for these cases, specifically in terms of minimising turnaround times while maximising diagnostic acumen.

Evolutionary changes between pre- and post-vaccine South African group A G2P[4] rotavirus strains, 2003-2017.

The transient upsurge of G2P[4] group A rotavirus (RVA) after Rotarix vaccine introduction in several countries has been a matter of concern. To gain insight into the diversity and evolution of G2P[4] strains in South Africa pre- and post-RVA vaccination introduction, whole-genome sequencing was performed for RVA positive faecal specimens collected between 2003 and 2017 and samples previously sequenced were obtained from GenBank (n=103; 56 pre- and 47 post-vaccine). Pre-vaccine G2 sequences predominantly clustered within sub-lineage IVa-1. In contrast, post-vaccine G2 sequences clustered mainly within sub-lineage IVa-3, whereby a radical amino acid (AA) substitution, S15F, was observed between the two sub-lineages. Pre-vaccine P[4] sequences predominantly segregated within sub-lineage IVa while post-vaccine sequences clustered mostly within sub-lineage IVb, with a radical AA substitution R162G. Both S15F and R162G occurred outside recognised antigenic sites. The AA residue at position 15 is found within the signal sequence domain of Viral Protein 7 (VP7) involved in translocation of VP7 into endoplasmic reticulum during infection process. The 162 AA residue lies within the hemagglutination domain of Viral Protein 4 (VP4) engaged in interaction with sialic acid-containing structure during attachment to the target cell. Free energy change analysis on VP7 indicated accumulation of stable point mutations in both antigenic and non-antigenic regions. The segregation of South African G2P[4] strains into pre- and post-vaccination sub-lineages is likely due to erstwhile hypothesized stepwise lineage/sub-lineage evolution of G2P[4] strains rather than RVA vaccine introduction. Our findings reinforce the need for continuous whole-genome RVA surveillance and investigation of contribution of AA substitutions in understanding the dynamic G2P[4] epidemiology.

Identifying gaps in hand hygiene practice to support tailored target audience messaging in Soweto: A cross-sectional community survey.

Effective risk communication is essential for outbreak mitigation, as recently highlighted during the coronavirus disease 2019 (COVID-19) pandemic. Hand hygiene is one of the proposed public health interventions to protect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) acquisition and transmission along with social distancing, improved ventilation, environmental cleaning, and wearing of masks. Improving hand hygiene practices in the community requires an understanding of the socio-behavioural context. This cross-sectional community survey in Soweto identified gaps in hand hygiene, which can inform appropriate messaging at the community level. Only 42% of survey respondents practiced adequate hand hygiene. Tailored educational messaging should be targeted at young adults in particular, and the importance of soap for hand hygiene must be emphasised for all age groups. Risk communication should expand to focus on preventing multiple infectious diseases during and beyond the COVID-19 pandemic.

Diarrhoeal diseases in Soweto, South Africa, 2020: a cross-sectional community survey.

BACKGROUND: In South Africa, there are limited data on the burden of diarrhoea at a community level, specifically in older children and adults. This community survey estimated rates of and factors associated with diarrhoea across all ages and determined the proportion of cases presenting to healthcare facilities. METHODS: Households were enrolled from an existing urban health and demographic surveillance site. A household representative was interviewed to determine associated factors and occurrence of diarrhoea in the household, for all household members, in the past 2 weeks (including symptoms and health seeking behaviour). Diarrhoeal rate of any severity was calculated for < 5 years, 5-15 years and > 15 years age groups. Factors associated with diarrhoea and health seeking behaviour were investigated using binomial logistic regression. RESULTS: Diarrhoeal rate among respondents (2.5 episodes/person-year (95% CI, 1.8-3.5)) was significantly higher than for other household members (1.0 episodes/person-year (95% CI, 0.8-1.4); IRR = 2.4 (95% CI, 1.5-3.7) p < 0.001). Diarrhoeal rates were similar between age groups, however younger children (< 5 years) were more likely to present to healthcare facilities than adults (OR = 5.9 (95% CI, 1.1-31.4), p = 0.039). Oral rehydration solution was used in 44.8% of cases. Having a child between 5 and 15 years in the household was associated with diarrhoea (OR = 2.3 (95% CI, 1.3-3.9), p = 0.003) and, while 26.4% of cases sought healthcare, only 4.6% were hospitalised and only 3.4% of cases had a stool specimen collected. While the majority of cases were mild, 13.8% of cases felt they required healthcare but were unable to access it. CONCLUSION: Diarrhoeal rate was high across all age groups in this community; however, older children and adults were less likely to present to healthcare, and are therefore underrepresented through facility-based clinical surveillance. Current diarrhoeal surveillance represents a fraction of the overall cases occurring in the community.

A decade of rotavirus vaccination in Africa - Saving lives and changing the face of diarrhoeal diseases: Report of the 12th African Rotavirus Symposium.

The African Rotavirus Network organised the 12th African Rotavirus Symposium (ARS) from 30 July to 1 August 2019 in Johannesburg, South Africa. The symposium theme "A decade of rotavirus vaccination in Africa - Saving lives and changing the face of diarrhoeal diseases", included sessions aimed at sharing ideas and expertise on prevention and control of diarrhoeal disease in Africa. Inter alia, the delegates reviewed global and regional epidemiological trends on rotavirus diarrhoea, progress and experiences on rotavirus vaccine introduction, including vaccine safety monitoring and impact in Africa, scientific advances in developing newer rotavirus vaccines, surveillance and research on other diarrhoeal pathogens, and providing an enabling environment for networking. Importantly, the 12th ARS served to commemorate the 20th anniversary of the African Rotavirus Network (AfrRN) coinciding with the 50th anniversary of the South African Medical Research Council. Four oral, live-attenuated rotavirus vaccines are currently prequalified by the WHO (Rotarix, RotaTeq, Rotavac and RotaSiil). African countries utilising rotavirus vaccines in routine national immunisation programmes are realising their effectiveness and impact on diarrhoeal disease morbidity. An ~40% reduction in hospitalisations of <5-year-olds with acute gastroenteritis following rotavirus vaccine introduction, was reported between 2006 and 2018 in 92,000 children from the WHO-coordinated African Rotavirus Surveillance Network (AfrRSN) comprising 33 Member States. This was corroborated by a meta-analysis of published data, sourced from January 2000 to August 2018 that reported substantial reductions in rotavirus hospitalisations in countries using rotavirus vaccines. However, it was highlighted that the transition of some countries from Gavi-eligibility and vaccine supply shortfalls present significant challenges to achieving the full impact of rotavirus immunization in Africa. The wide diversity of rotavirus genotypes continues in Africa, with variation observed both geographically and temporally. There is currently no evidence to suggest that the emergence of rotavirus strains not included in the current vaccines do escape vaccine-induced immunity.

Circulation of classic and recombinant human astroviruses detected in South Africa: 2009 to 2014.

BACKGROUND: Astroviruses (AstVs) are associated with diarrhoeal and extra-intestinal infections in human, animal and avian species. A prevalence of 7% was reported in selected regions in SA while AstVs detected from clinical stool specimens were almost identical phylogenetically to strains identified in environmental and water samples. This study investigated the molecular diversity of astroviruses circulating between 2009 and 2014 in South Africa (SA). METHODS: Astroviruses detected in stool specimens collected from hospitalised children were investigated retrospectively. Astroviruses were characterised using type-specific RT-PCR, partial nucleotide sequence analyses in ORF1 and ORF2 and whole genome sequencing. Different genotypes were compared with clinical features to investigate genotype-related associations. The Vesikari severity scale (VSS) was evaluated for scoring astrovirus diarrhoeal infections. RESULTS: Of 405 astroviruses detected, 49.9 % (202/405) were characterised into 32 genotypes comprising 66.3 % (134/202) putative-recombinants and 33.7 % (68/202) classic strains. No trends by year of collection, age or site were observed. Whole genome analysis in eight strains revealed that genotypes assigned by partial nucleotide sequence analyses to five astroviruses were incorrect. Bivariate analyses showed there were no significant associations between genotypes and clinical symptoms or severity of infection. A comparison of Vesikari parameters with astrovirus-positive proxy values demonstrated that Vesikari scores for duration of diarrhoea and admission temperatures would result in a milder infection rating in astrovirus-positive cases. CONCLUSIONS: Diverse genotypes co-circulated with putative-recombinants predominating. Astrovirus classification was complicated by the lack of a consistent characterisation system and reliable reference database. The VSS should be used cautiously to rate astrovirus diarrhoea. While surveillance in communities and out-patient clinics must be continued, screening for human astroviruses in alternate hosts is needed to determine the reservoir species.

Outbreak of Listeriosis in South Africa Associated with Processed Meat.

BACKGROUND: An outbreak of listeriosis was identified in South Africa in 2017. The source was unknown. METHODS: We conducted epidemiologic, trace-back, and environmental investigations and used whole-genome sequencing to type Listeria monocytogenes isolates. A case was defined as laboratory-confirmed L. monocytogenes infection during the period from June 11, 2017, to April 7, 2018. RESULTS: A total of 937 cases were identified, of which 465 (50%) were associated with pregnancy; 406 of the pregnancy-associated cases (87%) occurred in neonates. Of the 937 cases, 229 (24%) occurred in patients 15 to 49 years of age (excluding those who were pregnant). Among the patients in whom human immunodeficiency virus (HIV) status was known, 38% of those with pregnancy-associated cases (77 of 204) and 46% of the remaining patients (97 of 211) were infected with HIV. Among 728 patients with a known outcome, 193 (27%) died. Clinical isolates from 609 patients were sequenced, and 567 (93%) were identified as sequence type 6 (ST6). In a case-control analysis, patients with ST6 infections were more likely to have eaten polony (a ready-to-eat processed meat) than those with non-ST6 infections (odds ratio, 8.55; 95% confidence interval, 1.66 to 43.35). Polony and environmental samples also yielded ST6 isolates, which, together with the isolates from the patients, belonged to the same core-genome multilocus sequence typing cluster with no more than 4 allelic differences; these findings showed that polony produced at a single facility was the outbreak source. A recall of ready-to-eat processed meat products from this facility was associated with a rapid decline in the incidence of L. monocytogenes ST6 infections. CONCLUSIONS: This investigation showed that in a middle-income country with a high prevalence of HIV infection, L. monocytogenes caused disproportionate illness among pregnant girls and women and HIV-infected persons. Whole-genome sequencing facilitated the detection of the outbreak and guided the trace-back investigations that led to the identification of the source.

Molecular epidemiology of human bocavirus infection in hospitalized children with acute gastroenteritis in South Africa, 2009-2015.

Human bocavirus (HBoV) is known to be associated with a variety of clinical manifestation including acute gastroenteritis (AGE). Despite their global prevalence, no data is available on the epidemiology of HBoV associated with AGE in South Africa (SA). Between April 2009 and April 2015, 3765 stool specimens were collected from children less than 5 years of age hospitalized with diarrhea. Specimens were screened for selected enteric viruses by enzyme immunoassay and quantitative polymerase chain reaction, bacteria by culture and parasites by staining and microscopy. HBoV was detected in 5.63% (212 of 3765) of cases, the majority of which were children ≤2 years (92%, 195 of 212), and were common in the summer and autumn months (60%; 128 of 212). Further investigations of coinfections showed that bacteria (adjusted odds ratio [aOR] = 2.20; 95% confidence interval [CI], 1.41-3.45; P = .001) and sapovirus (aOR = 2.05; 95% CI, 1.08-3.86; P = .027) were significantly associated with HBoV in multivariate analysis. HBoV genotyping was successful in 191 of the 212 samples with HBoV-1 being the most prevalent genotype observed (79.6%; 152 of 191) followed by HBoV-3 (13.6%; 26 of 191), HBoV-2 (5.2%; 10 of 191), and HBoV-4 (1.6%; 3 of 191). The high prevalence of HBoV-1, a virus known to be associated with respiratory infections, and the association between HBoV-positive specimens and already established AGE agents, suggests that HBoV may play a limited role in the observed AGE cases in SA.

Epidemiology of human astroviruses among children younger than 5 years: Prospective hospital-based sentinel surveillance in South Africa, 2009-2014.

BACKGROUND: The epidemiology of human astroviruses (HAstVs) in hospitalised patients less than 5 years of age from selected sites in South Africa was investigated. Diarrheagenic stool specimens collected from April 2009 to May 2014 were screened retrospectively for selected viruses, bacteria and parasites. METHOD: Patient data were analysed to identify epidemiologic factors most frequently detected with HAstV infections. The following case-comparisons were investigated; HAstV-positive and HAstV-negative children, human immunodeficiency virus (HIV)-infected and HIV-uninfected (HAstV-positive) children and HIV-exposed and unexposed (HAstV-positive HIV-uninfected) children. RESULTS: Astrovirus was identified in 7.0% (234/3340) of cases and most frequently in ages 7 to 12 months (9.2%; 90/975) compared with 5.8% to 6.6% in other 6-month age groups. No seasonal trends were observed. More HAstVs were detected in children from homes that used outdoor water sources (7.6%) compared to indoor sources [5.7%; adjusted odds ratio (aOR), 1.5; 95% CI, 1.1-2.1; P = 0.009]. Astroviruses were detected in 8.4% (67/799) of HIV-uninfected patients that were exposed to HIV compared with 5.9% (74/1257) of HIV-unexposed patients ( P = 0.032). CONCLUSION: Astroviruses were most prevalent in children aged 7 to 12 months and were detected throughout the study period. The study was limited as only hospitalised patients were investigated and no comparisons were made to diarrhoea-free control groups. Future HAstV surveillance should include community-based studies and children presenting at outpatient facilities.

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.

Complete genome analyses of the first porcine rotavirus group H identified from a South African pig does not provide evidence for recent interspecies transmission events.

Rotaviruses (RVs) are classified into eight species/groups (RVA-RVH) according to the migration patterns of their 11 genome segments, as well as by serological and molecular properties of Viral Protein 6 (VP6). In 1997 a new unclassified RV was reported infecting adults in Bangladesh and China. This virus was initially named novel adult diarrhoea rotavirus (ADRV-N), but later renamed as RVH. Since then, RVH has been detected in humans only very sporadically. However, RVH is increasingly being detected in pig populations in the USA, Brazil and Japan, but not yet in Africa. Unfortunately, whole genome sequence data of porcine RVH strains in GenBank is currently restricted to a single strain (SKA-1) from Japan. Porcine diarrhoeic samples were collected in South Africa and analysed for rotavirus using an RVA ELISA and electropherotyping by PAGE. One sample displayed a 4:2:1:1:1:1:1 migration pattern, typical for RVH. In order to further investigate this strain, sequence-independent amplification followed by random sequencing using the 454/Roche GS FLX Sequencer was performed, resulting in the second complete porcine RVH strain (MRC-DPRU1575) available in databases. Phylogenetically, all segments of MRC-DPRU1575 clustered closely with the SKA-1 strain and in some segments with known porcine RVH strains from Brazil and the USA. In contrast, the porcine RVH strains were only distantly related to human RVH strains from Asia and a partial RVH-like strain recently detected in bats from Cameroon. Overall, strain MRC-DPRU1575 is the first complete genome of a porcine RVH from Africa and allows for the development of improved RVH screening methods. Our analyses indicate that RVH strains cluster according to their host species, not suggesting any evidence of recent interspecies transmission events. However, more RVH genomes from a wider host range are needed to better understand their evolutionary pathways and zoonotic potential.

Rotavirus vaccination within the South African Expanded Programme on Immunisation.

Diarrhoeal diseases are ranked the third major cause of childhood mortality in South African children less than 5 years, where the majority of deaths are among black children. Acute severe dehydrating rotavirus diarrhoea remains an important contributor towards childhood mortality and morbidity and has been well documented in South Africa. As the preventive strategy to control rotavirus diarrhoea, South Africa became the first country in the WHO African Region to adopt the rotavirus vaccine in the national childhood immunisation programme in August 2009. The rotavirus vaccine in use, Rotarix, GSK Biologicals, is given at 6 and 14 weeks of age, along with other vaccines as part of Expanded Programme on Immunisation (EPI). Studies which facilitated the introduction of rotavirus vaccine in South Africa included the burden of rotavirus disease and strain surveillance, economic burden of rotavirus infection and clinical trials to assess the safety and efficacy of vaccine candidates. This paper reviews the epidemiology of rotavirus in South Africa, outlines some of the steps followed to introduce rotavirus vaccine in the EPI, and highlights the early positive impact of vaccination in reducing the rotavirus burden of disease based on the post-marketing surveillance studies at Dr George Mukhari hospital, a sentinel site at University of Limpopo teaching hospital in Pretoria, South Africa, which has conducted rotavirus surveillance for >20 years.

Whole genome analysis of multiple rotavirus strains from a single stool specimen using sequence-independent amplification and 454® pyrosequencing reveals evidence of intergenotype genome segment recombination.

Infection of a single host cell with two or more different rotavirus strains creates conditions favourable for evolutionary mechanisms like reassortment and recombination that can generate novel strains. Despite numerous reports describing mixed rotavirus infections, whole genome characterisation of rotavirus strains in a mixed infection case has not been reported. Double-stranded RNA, exhibiting a long electropherotype pattern only, was extracted from a single human stool specimen (RVA/Human-wt/ZAF/2371WC/2008/G9P[8]). Both short and long electropherotype profiles were however detected in the sequence-independent amplified cDNA derived from the dsRNA, suggesting infection with more than one rotavirus strain. 454® pyrosequencing of the amplified cDNA revealed co-infection of at least four strains. Both genotype 1 (Wa-like) and genotype 2 (DS-1-like) were assigned to the consensus sequences obtained from the nine genome segments encoding NSP1-NSP5, VP1-VP3 and VP6. Genotypes assigned to the genome segments encoding VP4 were P[4] (DS-1-like), P[6] (ST3-like) and P[8] (Wa-like) genotypes. Since four distinct genotypes [G2 (DS-1-like), G8, G9 (Wa-like) and G12] were assigned to the four consensus nucleotide sequences obtained for genome segment 9 (VP7), it was concluded that at least four distinct rotaviruses were present in the stool. Intergenotype genome recombination events were observed in genome segments encoding NSP2, NSP4 and VP6. The close similarities of some of the genome segments encoding NSP2, VP6 and VP7 to artiodactyl rotaviruses suggest that some of the infecting strains shared common ancestry with animal strains, or that interspecies transmission occurred previously. The sequence-independent genome amplification technology coupled with 454® pyrosequencing used in this study enabled the characterisation of the whole genomes of multiple rotavirus strains in a single stool specimen that was previously assigned single genotypes, i.e. G9P[8], by sequence-dependent RT-PCR.

Whole genome analyses of African G2, G8, G9, and G12 rotavirus strains using sequence-independent amplification and 454® pyrosequencing.

High mortality rates caused by rotaviruses are associated with several strains such as G2, G8, G9, and G12 rotaviruses. Rotaviruses with G9 and G12 genotypes emerged worldwide in the past two decades. G2 and G8 rotaviruses are however also characterized frequently across Africa. To understand the genetic constellation of African G2, G8, G9, and G12 rotavirus strains and their possible origin, sequence-independent cDNA synthesis, amplification, and 454(®) pyrosequencing of the whole genomes of five human African rotavirus strains were performed. RotaC and phylogenetic analysis were used to assign and confirm the genotypes of the strains. Strains RVA/Human-wt/MWI/1473/2001/G8P[4], RVA/Human-wt/ZAF/3203WC/2009/G2P[4], RVA/Human-wt/ZAF/3133WC/2009/G12P[4], RVA/Human-wt/ZAF/3176WC/2009/G12P[6], and RVA/Human-wt/ZAF/GR10924/1999/G9P[6] were assigned G8-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2, G2-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2, G12-P[4]-I1-R1-C1-M1-A1-N1-T1-E1-H1, G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1, and G9-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genotypes, respectively. The detection of both Wa- and DS-1-like genotypes in strain RVA/Human-wt/ZAF/3133WC/2009/G12P[4] and Wa-like, DS-1-like and P[6] genotypes in strain RVA/Human-wt/ZAF/GR10924/1999/G9P[6] implies that these two strains were generated through intergenogroup genome reassortment. The close similarity of the genome segments of strain RVA/Human-wt/MWI/1473/2001/G8P[4] to artiodactyl-like, human-bovine reassortant strains and human rotavirus strains suggests that it originated from or shares a common origin with bovine strains. It is therefore possible that this strain might have emerged through interspecies genome reassortment between human and artiodactyl rotaviruses. This study illustrates the swift characterization of all the 11 rotavirus genome segments by using a single set of universal primers for cDNA synthesis followed by 454(®) pyrosequencing and RotaC analysis.

Characterization of 2 human genotype G10 rotavirus strains, 3008CM and 1784/CI/1999, isolated in Cameroon and Cote d'Ivoire during the 1999-2000 rotavirus season.

During routine rotavirus surveillance projects in Cameroon and Cote d'Ivoire, 2 fecal samples collected from 2 children <5 years of age who presented with symptoms of gastroenteritis were found to give anomalous G typing results. These specimens were strongly rotavirus positive by enzyme immunoassay, displayed VP6 subgroup II specificity and long RNA electropherotypes, and were typed as rotavirus serotype G2 with monoclonal antibodies. In addition, the strains were typed as rotavirus VP7 genotype G3 and VP4 genotype P[8] by reverse-transcription polymerase chain reaction. Further investigation of the polymerase chain reaction G-typing results with a second set of primers revealed that the specimens were not genotype G3, and both samples were sequenced to elucidate the problem. Both strains were found to be genotype G10 by nucleotide sequence. Comparison of nucleotide and amino acid sequences and phylogenetic analysis of the African G10 strains revealed that these strains are closely related to the human G10 strains that were detected during the 2001-2003 rotavirus season in Ghana. The detection of G10 rotavirus in Africa adds to the global distribution of this strain and strengthens the need to continue strain surveillance in developing countries to understand the extent of strain distribution and diversity.

Rotavirus strain types circulating in Africa: Review of studies published during 1997-2006.

Rotavirus is responsible for more than half a million deaths among infants and young children worldwide each year; many of these deaths could be prevented by widespread use of an effective rotavirus vaccine. The diversity of rotavirus strains in many developing countries, where most rotavirus deaths occur, could represent a significant challenge to the efficacy of current vaccines. In anticipation of rotavirus vaccine introduction, we examined studies published over a 10-year period (1997-2006) from countries in Africa that examined the distribution of VP7 (G) and VP4 (P) rotavirus strain types in symptomatic children and in neonates, together with studies that undertook a more detailed characterization of unusual rotavirus strains. Compared with recently published global reviews of rotavirus strain types and a previous review of the African literature published before 1997, the current data indicate a substantially increased diversity of rotavirus strains across the continent. Notable findings included a reduction in the proportion of globally common serotypes; a high proportion of unusual P/G combinations, suggesting viral reassortment; evidence for zoonotic rotavirus transmission; the emergence and spread across Africa of serotype G9; and a high prevalence of the P[6] VP4 genotype. These data imply that rotavirus vaccines will need to confer protection against a wide variety of strain types in Africa and emphasize the importance of continued strain surveillance before and after the introduction of routine rotavirus vaccination.