Molecular Identification of Enteric Viruses in Domestic Animals in Northeastern Gabon, Central Africa

Abstract

Astroviruses (AstVs), enteroviruses (EVs), and caliciviruses (CaVs) infect several vertebrate taxa. Transmitted through the fecal–oral route, these enteric viruses are highly resistant and can survive in the environment, thereby increasing their zoonotic potential. Here, we screened for AstVs, EVs, and CaVs to investigate the role of domestic animals in the emergence of zoonoses, because they are situated at the human/wildlife interface, particularly in rural forested areas in Central Africa. Rectal swabs were obtained from 123 goats, 41 sheep, and 76 dogs in 10 villages located in northeastern Gabon. Extracted RNA reverse-transcribed into cDNA was used to detect AstVs, EVs, and CaVs by amplification of the RNA-dependent RNA polymerase (RdRp), or capsid protein (VP1) gene using PCR. A total of 23 samples tested positive, including 17 goats for AstVs, 2 goats, 2 sheep, 1 dog for EVs, and 1 dog for CaVs. Phylogenetic analyses revealed that AstV RdRp sequences clustered with sheep-, goat-, or bovine-related AstVs. In addition, one goat and two sheep VP1 sequences clustered with caprine/ovine-related Evs within the Enterovirus G species, and the CaV was a canine vesivirus. However, human-pathogenic Evs, EV-B80 and EV-C99, were detected in goats and dogs, raising questions on the maintenance of viruses able to infect humans.

Characterization of enteroviruses circulating among farm animals and children in Central African Republic

“…This result could also be due to the small number of goats and sheep included in our study. Nonetheless, in another study, the screening of 164 rectal swabs from goats and sheep living in Gabon did not reveal EV-Es or EV-Fs either [ 7 ]. It is difficult to interpret these data since the prevalence of EV-Es and EV-Fs in healthy farm animals is unknown in Africa.…”

“…Alternatively, it could be passive carriage of human EVs by pigs after drinking contaminated water or even eating human stools, since pigs are coprophagous. It is noteworthy that one EV-B80 and one EV-C99 were previously reported in animal stools collected in Gabon, from a goat and a dog respectively [ 7 ]. It is therefore possible that some human EVs infect other hosts, even though the low number of human EVs detected in animal pools suggest that such infections are uncommon.…”