Spatio-Temporal Dynamics of Circulating Rotavirus G1 Isolates Recovered from Children with Acute Flaccid Paralysis in Cameroon

Rotavirus (RV) is a virus that primarily affects the gastrointestinal tract of animals and humans. However, its extra-intestinal spread to the brain can lead to acute flaccid paralysis (AFP), a syndrome characterized by sudden weakness in one or more limbs. In Cameroon, the available data on RV come from cases of gastroenteritis and diarrhea. In children with AFP, there are no data on their genetic diversity and circulation. This study aims to determine the frequency of detection, genetic diversity, and circulation dynamics of RV in these children. A retrospective cross-sectional study was conducted among children aged 15 years or younger with AFP admitted to Cameroonian health facilities. RV detection was performed by real-time RT-PCR, genetic diversity by genotyping performed by Sanger sequencing of the VP7 and VP4 genes, and investigation of circulation dynamics through phylogeography. Data analysis and Pearson’s chi-square test were performed using Excel and SPSS version 29 software. Phylogenetic analysis, supported by 1000 bootstrap replications, was performed using MEGA version 11 software. A p-value less than or equal to 0.05 was considered statistically significant. RVA was detected in 38% of cases (76/200), with genotype G1 (82.1%), P[8] 3.6% and G/P combination of G1P[8] (14.3%). Genetic distance analysis of RVA G1 strains has revealed the circulation of slightly similar strains in some Regions of Cameroon, suggesting the emergence of RVA epidemics in 2018. Phylogenetic analyses determined an evolutionary rate of 9.13 × 10−4 (HDP 95%: 4.5 × 10−4 - 2.8 × 10−3) substitutions/site/year of RVA G1. Spatio-temporal circulation analysis revealed that Maputo in Mozambique was the country of origin of the Cameroonian strains, which are believed to have migrated to Cameroon and then spread to other Cameroon Regions, such as the Far North from the Littoral Region onwards, facilitated by human migration. Our results highlight that a silent RVA G1 epidemic circulated in Cameroon in 2018, providing valuable data for the surveillance and management of the emergence of RVA G1 strains not targeted by the vaccination in Cameroon.