Temporal distribution of gastroenteritis viruses in Ouagadougou, Burkina Faso: seasonality of rotavirus.

BACKGROUND: Acute gastroenteritis is one of the most common diseases among children and adults, and continues to cause a major problem of public health in Burkina Faso. The temporal pattern of rotavirus, norovirus, sapovirus, astrovirus, adenovirus and Aichivirus A was studied by examining prevalence of gastroenteritis viruses in association with meteorological variables in Ouagadougou, Burkina Faso. METHODS: Stool samples from 263 children under 5 years of age and 170 older children patients, adolescent and adults with gastroenteritis were collected in Ouagadougou, Burkina Faso from November 2011 to September 2012. Enteric viruses were detected using real-time or end-point (RT-) PCR. Temperature, humidity and monthly rainfall were recorded from the National Meteorological Direction. Categorical data were compared by Chi-square tests and the effect of weather variables and monthly prevalence were analyzed using Pearson Correlation Coefficient test. RESULTS: The prevalence of rotavirus infections was significantly higher in the dry season (Season S1) compared to the wet season (season S2) (p = 0.03) among the population of children under 5 years of age. No statistically significant difference was observed regarding other gastroenteritis viruses comparing the dry season and the wet season. Positive cases of rotavirus, norovirus, adenovirus and sapovirus in children under 5 years of age were correlated with temperature (r = -0.68, p = 0.01; r = -0.74, p < 0.001; r = -0.68, p = 0.01; r = -0.65, p = 0.02, respectively) and only rotavirus, adenovirus and astrovirus were correlated with relative humidity (r = -0.61, p = 0.04; r = -0.54, p = 0.08; r = -0.51, p = 0.1 respectively). No correlation was observed with rainfall. In older children, adolescent and adults patients, rotavirus and norovirus correlated with relative humidity (r = -0.58, p = 0.05; r = 0.54, p = 0.08 respectively), but, no correlation was observed between the temperature and the rainfall. CONCLUSION: This study extends knowledge on the monthly fluctuations on the prevalence of viral gastroenteritis. These results can provide valuable information necessary to alert health care providers when a period of infection in the community is likely to occur. The transmission of these viruses in Burkina Faso could depends on multiple factors including climatic variables.

Prevalence and Genetic Diversity of Enteric Viruses in Children with Diarrhea in Ouagadougou, Burkina Faso.

Enteric viruses are a major cause of diarrhea in children, especially those under five years old. Identifying the viral agents is critical to the development of effective preventive measures. This study aimed to determine the prevalence and genetic diversity of common enteric viruses in children under five years old in Burkina Faso. Stool samples from children with (n = 263) and without (n = 50) diarrhea disorders were collected in Ouagadougou, Burkina Faso from November 2011 to September 2012. Rotavirus, norovirus, sapovirus, astrovirus, adenovirus and Aichivirus A were detected using real-time or end-point (RT-)PCR. Rotavirus strains were G and P genotyped by multiplex RT-PCR and other viral strains were characterized by sequencing of viral subgenomic segements. At least one viral agent was detected in 85.6% and 72% of the symptomatic and asymptomatic patients, respectively. Rotavirus (63.5%), adenovirus (31.2%) and genogroup II norovirus (18.2%) were the most prevalent viruses in symptomatic patients, but only rotavirus and genogroup II norovirus were significantly associated with diarrhea (OR: 7.9, 95%CI: 3.7-17; OR: 3.5, 95%CI: 1-11.7, respectively). Sapovirus (10.3%), astrovirus (4.9%), genogroup I norovirus (2.7%) and Aichivirus A (0.8%) were less prevalent. The predominant genotype of rotavirus was G9P[8] (36.5%), and the predominant norovirus strain was GII.4 variant 2012 (71.4%). Among sapovirus, the genogroup II (87.5%) predominated. Astrovirus type 1 (41.7%) was the most frequent astrovirus identified. Aichivirus A belonged to the three genotypes (A, B and C). Enteric adenoviruses type 40 and 41 were identified in 10.2% and 5.1% respectively. Several cases of co-infections were detected. The results highlight the high prevalence and the high diversity of enteric viruses in Burkinabe children.