Full genome characterization of human Rotavirus A strains isolated in Cameroon, 2010-2011: diverse combinations of the G and P genes and lack of reassortment of the backbone genes.

Over the past few years whole genome sequencing of rotaviruses has become a routine laboratory method in many strain surveillance studies. To study the molecular evolutionary pattern of representative Cameroonian Rotavirus A (RVA) strains, the semiconductor sequencing approach was used following random amplification of genomic RNA. In total, 31 RVA strains collected during 2010-2011 in three Cameroonian study sites located 120 to 1240 km from each other were sequenced and analyzed. Sequence analysis of the randomly selected representative strains showed that 18 RVAs were Wa-like, expressing G1P[6], G12P[6], or G12P[8] neutralization antigens on the genotype 1 genomic constellation (I1-R1-C1-M1-A1-N1-T1-E1-H1), whereas 13 other strains were DS-1-like, expressing G2P[4], G2P[6], G3P[6], and G6P[6] on the genotype 2 genomic constellation (I2-R2-C2-M2-A2-N2-T2-E2-H2). No inter-genogroup reassortment in the backbone genes was observed. Phylogenetic analysis of the Cameroonian G6P[6] strains indicated the separation of the strains identified in the Far North region (Maroua) and the Northwest region (Bamenda and Esu) into two branches that is consistent with multiple introductions of G6P[6] strains into this country. The present whole genome based molecular characterization study indicates that the emerging G6P[6] strain is fully heterotypic to Rotarix, the vaccine introduced during 2014 in childhood immunization program in Cameroon. Continuous strain monitoring is therefore needed in this area and elsewhere to see if G6s, besides genotype G1 to G4, G8, G9 and G12, may become a new, regionally important genotype in the post vaccine licensure era in Africa.

Detection of novel porcine bocaviruses in fecal samples of asymptomatic pigs in Cameroon.

Improvements and widespread use of nucleic acid amplification and sequencing methods have led to the recognition of new virus diversity in various domestic animals, including pigs. In this study we utilized either virus species specific or broadly reactive PCR assays to describe the occurrence and genetic diversity of selected DNA viruses belonging to families Adenoviridae, Circoviridae, Anelloviridae and Parvoviridae in Cameroonian pigs. Fecal specimens were collected during spring of 2011. No adenoviruses, circoviruses and anelloviruses were detected, however, high prevalence and remarkable genetic diversity within the identified parvoviruses and, particularly, within bocaviruses was observed. PPV4 was the most prevalent virus (20%), followed by PBoV3 (18%), PBoV4 (18%), PBoV5 plus 6V/7V (16%), and PBoV1 plus PBoV2 (6%). The frequency of mixed infections with various combinations of these virus species reached 20%. Genetic analysis of the identified viruses showed that the capsid gene of PBoV1 and PBoV2 strains shared up to 91% and 94%nt sequence similarities to reference PBoV1 and PBoV2 strains, respectively. The identified PBoV3 and PBoV4 strains shared ≤ 95% and ≤ 98%nt identities with reference PBoV3 and PBoV4 strains, respectively, along the NS gene, whereas the PBoV5 strains shared 86%nt identities with Hungarian and 87%nt identities with Chinese PBoV5 strains along the capsid gene. In addition, a single PBoV5-like strain shared ≤ 71%nt sequence identity with other PBoV5 strains. This is the first study to report evidence of the circulation of bocaviruses in Africa and contributes to our understanding of the impact of globalization on the dispersal of new and emerging viruses.