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Bats have been implicated as reservoirs of emerging viruses. Bat species forming large social groups and roosting in proximity to human communities are of particular interest. In this study, we sampled a colony of ca. 350,000 individuals of the straw-colored fruit bat Eidolon helvum in Kumasi, the second largest city of Ghana. A novel rhabdovirus (Kumasi rhabdovirus [KRV]) was isolated in E. helvum cell cultures and passaged to Vero cells as well as interferon-competent human and primate cells (A549 and MA104). Genome composition was typical for a rhabdovirus. KRV was detected in 5.1% of 487 animals, showing association with the spleen but not the brain. Antibody prevalence was 11.5% by immunofluorescence and 6.4% by plaque reduction virus neutralization test (PRNT). Detection throughout 3 sampling years was pronounced in both annual wet seasons, of which only one overlaps the postparturition season. Juvenile bats showed increased viral prevalence. No evidence of infection was obtained in 1,240 female mosquitos (6 different genera) trapped in proximity to the colony to investigate potential vector association. Antibodies were found in 28.9% (5.4% by PRNT) of 107 swine sera but not in similarly large collections of sheep, goat, or cattle sera. The antibody detection rate in human subjects with occupational exposure to the bat colony was 11% (5/45 persons), which was significantly higher than in unexposed adults (0.8% [1/118]; chi square, P < 0.001). KRV is a novel bat-associated rhabdovirus potentially transmitted to humans and swine. Disease associations should be investigated. IMPORTANCE Bats are thought to carry a huge number of as-yet-undiscovered viruses that may pose epidemic threats to humans and livestock. Here we describe a novel dimarhabdovirus which we isolated from a large colony of the straw-colored fruit bat Eidolon helvum in Ghana. As these animals are exposed to humans and several livestock species, we looked for antibodies indicating infection in humans, cattle, swine, sheep, and goats. Signs of infection were found in swine and humans, with increased antibody findings in humans who are occupationally exposed to the bat colony. Our data suggest that it is worthwhile to look for diseases caused by the novel virus in humans and livestock.

The genome of bat adenovirus 2 was sequenced and analyzed. It is similar in size (31,616 bp) to the genomes of bat adenovirus 3 and canine adenoviruses 1 and 2. These four viruses are monophyletic and share an identical genome organization, with one E3 gene and four E4 genes unique to this group among the mastadenoviruses. These findings suggest that canine adenoviruses may have originated by interspecies transfer of a vespertilionid bat adenovirus.

A novel flavivirus was isolated from Uranotaenia mashonaensis , a mosquito genus not previously known to harbor flaviviruses. Mosquitoes were caught in the primary rain forest of the Taï National Park, Côte d'Ivoire. The novel virus, termed nounané virus (NOUV), seemed to grow only on C6/36 insect cells and not on vertebrate cells. Typical enveloped flavivirus-like particles of 60 to 65 nm in diameter were detected by electron microscopy in the cell culture supernatant of infected cells. The full genome was sequenced, and potential cleavage and glycosylation sites and cysteine residues were identified, suggesting that the processing of the NOUV polyprotein is similar to that of other flaviviruses. Phylogenetic analyses of the whole polyprotein and the NS3 protein showed that the virus forms a distinct cluster within the clade of mosquito-borne flaviviruses. Only a distant relationship to other known flaviviruses was found, indicating that NOUV is a novel lineage within the Flaviviridae .

Bunyaviruses are the largest known family of RNA viruses, infecting vertebrates, insects, and plants. Here we isolated three novel bunyaviruses from mosquitoes sampled in Côte d'Ivoire, Ghana, and Uganda. The viruses define a highly diversified monophyletic sister clade to all members of the genus Orthobunyavirus and are virtually equidistant to orthobunyaviruses and tospoviruses. Maximal amino acid identities between homologous putative proteins of the novel group and orthobunyaviruses ranged between 12 and 25%. The type isolates, tentatively named Herbert virus (HEBV), Taï virus (TAIV), and Kibale virus (KIBV), comprised genomes with L, M, and S segments of about 7.4 kb, 2.7 kb, and 1.1 kb, respectively. HEBV, TAIV, and KIBV encode the shortest bunyavirus M segments known and did not seem to encode NSs and NSm proteins but contained an elongated L segment with an ∼500-nucleotide (nt) insertion that shows no identity to other bunyaviruses. The viruses replicated to high titers in insect cells but did not replicate in vertebrate cells. The enveloped virions were 90 to 110 nm in diameter and budded at cellular membranes with morphological features typical of the Golgi complex. Viral RNA recovered from infected cells showed 5′-terminal nontemplated sequences of 9 to 22 nt, suggestive of cap snatching during mRNA synthesis, as described for other bunyaviruses. Northern blotting identified RNA species of full and reduced lengths, suggested upon analogy with other bunyaviruses to constitute antigenomic-sense cRNA and transcript mRNAs, respectively. Functional studies will be necessary to determine if this group of viruses constitutes a novel genus in the bunyavirus family.

The recently established family Mesoniviridae (order Nidovirales ) contains a single species represented by two closely related viruses, Cavally virus (CavV) and Nam Dinh virus (NDiV), which were isolated from mosquitoes collected in Côte d'Ivoire and Vietnam, respectively. They represent the first nidoviruses to be discovered in insects. Here, we report the molecular characterization of four novel mesoniviruses, Hana virus, Méno virus, Nsé virus, and Moumo virus, all of which were identified in a geographical region in Côte d'Ivoire with high CavV prevalence. The viruses were found with prevalences between 0.5 and 2.8%, and genome sequence analyses and phylogenetic studies suggest that they represent at least three novel species. Electron microscopy revealed prominent club-shaped surface projections protruding from spherical, enveloped virions of about 120 nm. Northern blot data show that the four mesoniviruses analyzed in this study produce two major 3′-coterminal subgenomic mRNAs containing two types of 5′ leader sequences resulting from the use of different pairs of leader and body transcription-regulating sequences that are conserved among mesoniviruses. Protein sequencing, mass spectroscopy, and Western blot data show that mesonivirus particles contain eight major structural protein species, including the putative nucleocapsid protein (25 kDa), differentially glycosylated forms of the putative membrane protein (20, 19, 18, and 17 kDa), and the putative spike (S) protein (77 kDa), which is proteolytically cleaved at a conserved site to produce S protein subunits of 23 and 57 kDa. The data provide fundamental new insight into common and distinguishing biological properties of members of this newly identified virus family.