Novel highly divergent reassortant bat rotaviruses in Cameroon, without evidence of zoonosis

Abstract

Bats are an important reservoir for zoonotic viruses. To date, only three RVA strains have been reported in bats in Kenya and China. In the current study we investigated the genetic diversity of RVAs in fecal samples from 87 straw-colored fruit bats living in close contact with humans in Cameroon using viral metagenomics. Five (near) complete RVA genomes were obtained. A single RVA strain showed a partial relationship with the Kenyan bat RVA strain, whereas the other strains were completely novel. Only the VP7 and VP4 genes showed significant variability, indicating the occurrence of frequent reassortment events. Comparing these bat RVA strains with currently used human RVA screening primers indicated that most of the novel VP7 and VP4 segments would not be detected in routine epidemiological screening studies. Therefore, novel consensus screening primers were developed and used to screen samples from infants with gastroenteritis living in close proximity with the studied bat population. Although RVA infections were identified in 36% of the infants, there was no evidence of zoonosis. This study identified multiple novel bat RVA strains, but further epidemiological studies in humans will have to assess if these viruses have the potential to cause gastroenteritis in humans.

Molecular characterization of a human G20P[28] rotavirus a strain with multiple genes related to bat rotaviruses

“…RVA genomic classification studies have revealed the emergence of novel or unusual RVAs carrying several novel gene segments or genotype constellations (Abe et al, 2011; Esona et al, 2010; Jere et al, 2014; Matthijnssens et al, 2011; Papp et al, 2012; Trojnar et al, 2013; Yinda et al, 2016). In this study, we identified and characterized a RVA strain with an unusual genotype constellation and carrying eight recently assigned novel gene segments.…”

“…The Rotavirus Classification Working Group (RCWG) has devised a complete genotype classification system, defining the genotype constellation of RVAs as follows: Gx-P[ x ]-Ix-Rx-Cx-Mx-Ax-Nx-Tx-Ex-Hx, representing VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 (Matthijnssens et al, 2011). To date, 35 G, 50 P, 26 I, 21 R, 19C, 19 M, 30 A, 20 N, 21 T, 26 E and 21H genotypes have been identified in human and non-human hosts and classified based on differences in the nucleotide sequence identities of each encoding gene segment, respectively (Abe et al, 2011; Esona et al, 2010; Estes and Greenberg, 2013; Guo et al, 2012; Jere et al, 2014; Matthijnssens et al, 2011; Papp et al, 2012; Trojnar et al, 2013; Yinda et al, 2016), http://rega.kuleuven.be/cev/viralmetagenomics/virus-classification). This classification system has accelerated the comparison of RVA genotypes and increased our understanding of the genetic diversity of RVA.…”

“…To date, a few RVA strains, each with distinct genetic diversity have been detected and reported in bats. The nucleotide sequences of these bat RVAs are typically distant from those of human and other mammalian RVAs and have been suggested to be bat specific (Esona et al, 2010; He et al, 2013; Xia et al, 2014; Yinda et al, 2016). However, the VP4 and NSP4 gene segments of bat RVA strain RVA/Bat-wt/KEN/KE4852/2007/G25P[6] detected in Kenya (Esona et al, 2010), gene segments VP7, VP4, VP3, NSP2 and NSP3 of bat RVA strain RVA/Bat-wt/ZMB/LUS12–14/2012/G3P[3] reported in Zambia (Sasaki et al, 2016) and VP6 gene segment of bat RVA strains 2980/BatRVA and 322/BatRVA detected in Kenya (Waruhiu et al, 2017) are highly similar to cognate gene sequences of human RVAs circulating in the same community.…”

Structural features of glycan recognition among viral pathogens

“…To date, they are classified into 32 G genotypes and 47 P genotypes based on their two antigenic outer capsid proteins, glycoprotein VP7 and protease-sensitive VP4, respectively [28,29]. VP4 is cleaved into VP8* and VP5*, with VP8* involved in glycan recognition.…”

Virus discovery in bats

“…The high throughput technique also allows efficient screening of a large number of bat specimens. This method was used to identify highly divergent novel rotaviruses in bats in Cameroon that were unlikely to have been successfully detected using the currently available primer combinations 26 . The sensitivity of high throughput sequencing is continuing to improve for virus discovery, employing techniques such as positive enrichment of samples for virus sequences using probes that cover the genomes of all the viral taxa known to infect vertebrates 27 .…”