Abstract
Group A rotavirus (RVA) infections form a major public health problem, especially in low-income countries like the Democratic Republic of the Congo (COD). However, limited data on RVA diversity is available from sub-Saharan Africa in general and the COD in particular. Therefore, the first aim of this study was to determine the genetic diversity of 99 RVAs detected during 2007–2010 in Kisangani, COD. The predominant G-type was G1 (39%) and the most predominant P-type was P[6] (53%). A total of eight different G/P-combinations were found: G1P[8] (28%), G8P[6] (26%), G2P[4] (14%), G12P[6] (13%), G1P[6] (11%), G9P[8] (4%), G4P[6] (2%) and G8P[4] (1%). The second aim of this study was to gain insight into the diversity of P[6] RVA strains in the COD. Therefore, we selected five P[6] RVA strains in combination with the G1, G4, G8 (2x) or G12 genotype for complete genome analysis. Complete genome analysis showed that the genetic background of the G1P[6] and G12P[6] strains was entirely composed of genotype 1 (Wa-like), while the segments of the two G8P[6] strains were identified as genotype 2 (DS-1-like). Interestingly, all four strains possessed a NSP4 gene of animal origin. The analyzed G4P[6] RVA strain was found to possess the unusual G4-P[6]-I1-R1-C1-M1-A1-N1-T7-E1-H1 constellation. Although the majority of its genes (if not all), were presumably of porcine origin, this strain was able to cause gastro-enteritis in humans. The high prevalence of unusual RVA strains in the COD highlights the need for continued surveillance of RVA diversity in the COD. These results also underline the importance of complete genetic characterization of RVA strains and indicate that reassortments and interspecies transmission among human and animal RVAs strains occur regularly. Based on these data, RVA vaccines will be challenged with a wide variety of different RVA strain types in the COD.
Highlights
Group A rotaviruses (RVAs) are the world’s leading cause of severe diarrhea in children,5 years of age and form a major public health problem, with an estimated 453,000 deaths per year worldwide
The G- and P-genotypes of 99 antigen-positive samples were characterized by reverse-transcription polymerase chain reaction (RT-PCR) using the QIAGEN OneStep RT-PCR kit (QIAGEN/Westburg) using primers Beg9 and End9 (VP7), and VP4_1-17F and Con2 (VP4)
In this study a high proportion of P[6] RVA strains was observed together with a large number of unusual strains (G8P[6], G12P[6], G1P[6], G4P[6] and G8P[4]). These unusual genotype combinations may represent potential reassortants between human and animal RVA strains as a result of zoonotic infection
Summary
Group A rotaviruses (RVAs) are the world’s leading cause of severe diarrhea in children ,5 years of age and form a major public health problem, with an estimated 453,000 deaths per year worldwide. The COD, together with India, Nigeria, Pakistan and Ethiopia, is one of the countries that bear the highest RVA mortality rates worldwide. When focusing on the differences in the genetic setup of RVA strains circulating in Africa, compared to the ones circulating in industrialized countries, multiple studies have reported the high detection rate of RVA strains containing the P[6] and G8 genotypes. Both genotypes are believed to be of animal origin: P[6] RVA strains (most likely) originated from pigs, while G8 is a genotype often detected in cows or other members of the mammalian order of the Artiodactyla [3,4,5,6,7,8,9,10]. The majority of known human G8 RVAs strains have been described all over the African continent in combination with a large number of VP4 specificities and with different genetic backgrounds [11,12,13,14,15,16,17,18,19,20,21,22,23]
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