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Separation of the island of Bioko from West Africa about 10,000 years ago dates the origins of simian immunodeficiency virus. Simian immunodeficiency virus (SIV) lineages have been identified that are endemic to Bioko Island. The time the island formed offers a geological time scale calibration point for dating the most recent common ancestor of SIV. The Bioko viruses cover the whole range of SIV genetic diversity, and each Bioko SIV clade is most closely related to viruses circulating in hosts of the same genus on the African mainland rather than to SIVs of other Bioko species. Our phylogeographic approach establishes that SIV is ancient and at least 32,000 years old. Our conservative calibration point and analyses of gene sequence saturation and dating bias suggest it may be much older.

Of 78 Gabonese individuals who had received bites from nonhuman primates (NHPs) while hunting, 7 were infected with human T lymphotropic virus (HTLV-1). Five had been bitten by gorillas and were infected with subtype strains; however, a 12-year-old girl who was severely bitten by a Cercopithecus nictitans was infected with a subtype D strain that was closely related to the simian T lymphotropic virus (STLV-1) that infects this monkey species. Her mother was infected with a subtype strain. These data confirm that hunters in Africa can be infected by HTLV-1 that is closely related to the strains circulating among local NHP game. Our findings strongly suggest that a severe bite represent a risk factor for STLV-1 acquisition.

Within the Flaviviridae, the recently designated genus Pegivirus has expanded greatly due to new discoveries in bats, horses, and rodents. Here we report the discovery and characterization of three simian pegiviruses (SPgV) that resemble human pegivirus (HPgV) and infect red colobus monkeys (Procolobus tephrosceles), red-tailed guenons (Cercopithecus ascanius) and an olive baboon (Papio anubis). We have designated these viruses SPgVkrc, SPgVkrtg and SPgVkbab, reflecting their host species' common names, which include reference to their location of origin in Kibale National Park, Uganda. SPgVkrc and SPgVkrtg were detected in 47% (28/60) of red colobus and 42% (5/12) red-tailed guenons, respectively, while SPgVkbab infection was observed in 1 of 23 olive baboons tested. Infections were not associated with any apparent disease, despite the generally high viral loads observed for each variant. These viruses were monophyletic and equally divergent from HPgV and pegiviruses previously identified in chimpanzees (SPgVcpz). Overall, the high degree of conservation of genetic features among the novel SPgVs, HPgV and SPgVcpz suggests conservation of function among these closely related viruses. Our study describes the first primate pegiviruses detected in Old World monkeys, expanding the known genetic diversity and host range of pegiviruses and providing insight into the natural history of this genus.

Adenoviruses play an important role as human pathogens, though most infections are believed to be asymptomatic. The over 100 human adenovirus types are classified into seven species (A-G), some of which include simian adenoviruses. Recent findings have highlighted that simian adenoviruses have a zoonotic potential and that some human adenoviruses are likely the result of relatively recent spillover events. In order to evaluate the risks associated with primates hunted and sold as bushmeat, multiple samples from 24 freshly killed monkeys were collected in the Republic of the Congo and tested for adenovirus DNA by PCRs targeting the conserved DNA polymerase and hexon genes. The DNA of a novel simian adenovirus was detected in a moustached monkey (Cercopithecus cephus) by the DNA polymerase PCR, but not by the hexon PCR. The 275 nucleotide amplicon was most closely related to members of the Human mastadenovirus F species (93% HAdV-40 and 89% HAdV-41 amino acid identity), rather than to other known simian adenoviruses. The phylogenetic clustering with Human mastadenovirus F sequences suggests a common ancestor, more recent than the last common ancestor of humans and moustached monkeys. The findings increase concerns about the zoonotic potential of simian adenoviruses and highlight the need for more research and surveillance on the issue.

The ancestry of HIV-1 has been traced to SIV cpz (simian immunodeficiency virus) infecting chimpanzees in west central Africa, but the origin of SIV cpz itself remains unknown. HIV's relation to SIV is discussed.

Climate change is predicted to result in changes in the geographic ranges and local prevalence of infectious diseases, either through direct effects on the pathogen, or indirectly through range shifts in vector and reservoir species. To better understand the occurrence of monkeypox virus (MPXV), an emerging Orthopoxvirus in humans, under contemporary and future climate conditions, we used ecological niche modeling techniques in conjunction with climate and remote-sensing variables. We first created spatially explicit probability distributions of its candidate reservoir species in Africa's Congo Basin. Reservoir species distributions were subsequently used to model current and projected future distributions of human monkeypox (MPX). Results indicate that forest clearing and climate are significant driving factors of the transmission of MPX from wildlife to humans under current climate conditions. Models under contemporary climate conditions performed well, as indicated by high values for the area under the receiver operator curve (AUC), and tests on spatially randomly and non-randomly omitted test data. Future projections were made on IPCC 4(th) Assessment climate change scenarios for 2050 and 2080, ranging from more conservative to more aggressive, and representing the potential variation within which range shifts can be expected to occur. Future projections showed range shifts into regions where MPX has not been recorded previously. Increased suitability for MPX was predicted in eastern Democratic Republic of Congo. Models developed here are useful for identifying areas where environmental conditions may become more suitable for human MPX; targeting candidate reservoir species for future screening efforts; and prioritizing regions for future MPX surveillance efforts.

Background Human immunodeficiency virus (HIV) type 1 and 2, the causative agents of acquired immunodeficiency syndrome (AIDS), emerged from African non-human primates (NHPs) through zoonotic transmission of simian immunodeficiency viruses (SIV). Among African NHPs, the Cercopithecus genus contains the largest number of species known to harbor SIV. However, our understanding of the diversity and evolution of SIVs infecting this genus is limited by incomplete taxonomic and geographic sampling, particularly in East Africa. In this study, we screened blood specimens from red-tailed guenons ( Cercopithecus ascanius schmidti ) from Kibale National Park, Uganda, for the presence of novel SIVs using unbiased deep-sequencing. Findings We describe and characterize the first full-length SIV genomes from wild red-tailed guenons in Kibale National Park, Uganda. This new virus, tentatively named SIVrtg_Kib, was detected in five out of twelve animals and is highly divergent from other Cercopithecus SIVs as well as from previously identified SIVs infecting red-tailed guenons, thus forming a new SIV lineage. Conclusions Our results show that the genetic diversity of SIVs infecting red-tailed guenons is greater than previously appreciated. This diversity could be the result of cross-species transmission between different guenon species or limited gene flow due to geographic separation among guenon populations.

Tick-borne flaviviruses (TBFV) are sustained in nature through cycling between mammalian and tick hosts. In this study, we used African green monkey kidney cells (Vero) and Ixodes scapularis tick cells (ISE6) to compare virus-induced changes in mammalian and arthropod cells. Using confocal microscopy, transmission electron microscopy (TEM), and electron tomography (ET), we examined viral protein distribution and the ultrastructural changes that occur during TBFV infection. Within host cells, flaviviruses cause complex rearrangement of cellular membranes for the purpose of virus replication. Virus infection was accompanied by a marked expansion in endoplasmic reticulum (ER) staining and markers for TBFV replication were localized mainly to the ER in both cell lines. TEM of Vero cells showed membrane-bound vesicles enclosed in a network of dilated, anastomosing ER cisternae. Virions were seen within the ER and were sometimes in paracrystalline arrays. Tubular structures or elongated vesicles were occasionally noted. In acutely and persistently infected ISE6 cells, membrane proliferation and vesicles were also noted; however, the extent of membrane expansion and the abundance of vesicles were lower and no viral particles were observed. Tubular profiles were far more prevalent in persistently infected ISE6 cells than in acutely infected cells. By ET, tubular profiles, in persistently infected tick cells, had a cross-sectional diameter of 60-100 nm, reached up to 800 nm in length, were closed at the ends, and were often arranged in fascicle-like bundles, shrouded with ER membrane. Our experiments provide analysis of viral protein localization within the context of both mammalian and arthropod cell lines as well as both acute and persistent arthropod cell infection. Additionally, we show for the first time 3D flavivirus infection in a vector cell line and the first ET of persistent flavivirus infection.

Nipah virus (NiV) is a paramyxovirus (genus Henipavirus) that emerged in the late 1990s in Malaysia and has since been identified as the cause of sporadic outbreaks of severe febrile disease in Bangladesh and India. NiV infection is frequently associated with severe respiratory or neurological disease in infected humans with transmission to humans through inhalation, contact or consumption of NiV contaminated foods. In the work presented here, the development of disease was investigated in the African Green Monkey (AGM) model following intratracheal (IT) and, for the first time, small-particle aerosol administration of NiV. This study utilized computed tomography (CT) and magnetic resonance imaging (MRI) to temporally assess disease progression. The host immune response and changes in immune cell populations over the course of disease were also evaluated. This study found that IT and small-particle administration of NiV caused similar disease progression, but that IT inoculation induced significant congestion in the lungs while disease following small-particle aerosol inoculation was largely confined to the lower respiratory tract. Quantitative assessment of changes in lung volume found up to a 45% loss in IT inoculated animals. None of the subjects in this study developed overt neurological disease, a finding that was supported by MRI analysis. The development of neutralizing antibodies was not apparent over the 8-10 day course of disease, but changes in cytokine response in all animals and activated CD8+ T cell numbers suggest the onset of cell-mediated immunity. These studies demonstrate that IT and small-particle aerosol infection with NiV in the AGM model leads to a severe respiratory disease devoid of neurological indications. This work also suggests that extending the disease course or minimizing the impact of the respiratory component is critical to developing a model that has a neurological component and more accurately reflects the human condition.

The Simian Immunodeficiency Virus (SIV) mus/mon/gsn lineage is a descendant of one of the precursor viruses to the HIV-1/SIVcpz/gor viral lineage. SIVmus and SIVgsn were sequenced from mustached and greater spot nosed monkeys in Cameroon and SIVmon from mona monkeys in Cameroon and Nigeria. In order to further document the genetic diversity of SIVmus, we analyzed two full-length genomes of new strains identified in Gabon. The whole genomes obtained showed the expected reading frames for gag, pol, vif, vpr, tat, rev, env, nef, and also for a vpu gene. Analyses showed that the Gabonese SIVmus strains were closely related and formed a monophyletic clade within the SIVmus/mon/gsn lineage. Nonetheless, within this lineage, the position of both new SIVmus differed according to the gene analyzed. In pol and nef gene, phylogenetic topologies suggested different evolutions for each of the two new SIVmus strains whereas in the other nucleic fragments studied, their positions fluctuated between SIVmon, SIVmus-1, and SIVgsn. In addition, in C1 domain of env, we identified an insertion of seven amino acids characteristic for the SIVmus/mon/gsn and HIV‑1/SIVcpz/SIVgor lineages. Our results show a high genetic diversity of SIVmus in mustached monkeys and suggest cross-species transmission events and recombination within SIVmus/mon/gsn lineage. Additionally, in Central Africa, hunters continue to be exposed to these simian viruses, and this represents a potential threat to humans.