Simian retroviruses in African apes

Addressing the illegal wildlife trade in the European Union as a public health issue to draw decision makers attention

The European Union is one of the most important markets for the trafficking of endangered species and a major transit point for illegal wildlife trade. The latter is not only one of the most important anthropogenic drivers of biodiversity loss, it also represents a growing risk for public health. Indeed, wildlife trade exposes humans to a plethora of severe emerging infectious diseases, some of which have contributed to the most dramatic global pandemics humankind has endured. Illegal wildlife trade is often considered as a problem of developing countries but it is first and foremost an international global business with a trade flow from developing to developed countries. The devastating effects of the ongoing SARS-CoV-2 outbreak should thus be an unassailable argument for European decision makers to change paradigm. Rather than deploying efforts and money to combat novel pathogens, mitigating the risk of spreading emerging infectious diseases should be addressed and be part of any sustainable socioeconomic development plan. Stricter control procedures at borders and policies should be enforced. Additionally, strengthening research in wildlife forensic science and developing a network of forensic laboratories should be the cornerstone of the European Union plan to tackle the illegal wildlife trade. Such proactive approach, that should further figure in the EU-Wildlife Action Plan, could produce a win-win situation: the curb of illegal wildlife trade would subsequently diminish the likelihood of importing new zoonotic diseases in the European Union.

Broad diversity of simian immunodeficiency virus infecting Chlorocebus species (African green monkey) and evidence of cross-species infection in Papio anubis (olive baboon) in Kenya

BACKGROUND

Simian immunodeficiency virus (SIV) naturally infects African non-human primates (NHPs) and poses a threat of transmission to humans through hunting and consumption of monkeys as bushmeat. This study investigated the as of yet unknown molecular diversity of SIV in free-ranging Chlorocebus species (African green monkeys-AGMs) and Papio anubis (olive baboons) within Mombasa, Kisumu and Naivasha urban centres in Kenya.

METHODS

We collected blood samples from 124 AGMs and 65 olive baboons in situ, and detected SIV by high-resolution melting analysis and sequencing of PCR products.

RESULTS

Simian immunodeficiency virus prevalence was 32% in AGMs and 3% in baboons. High-resolution melting (HRM) analysis demonstrated distinct melt profiles illustrating virus diversity confirmed by phylogenetic analysis.

CONCLUSIONS

There is persistent evolutionary diversification of SIVagm strains in its natural host, AGMs and cross-species infection to olive baboons is occurring. Further study is required to establish pathogenesis of the diverse SIVagm variants and baboon immunological responses.

Simian Foamy Virus Co-Infections

Foamy viruses (FVs), also known as spumaretroviruses, are complex retroviruses that are seemingly nonpathogenic in natural hosts. In natural hosts, which include felines, bovines, and nonhuman primates (NHPs), a large percentage of adults are infected with FVs. For this reason, the effect of FVs on infections with other viruses (co-infections) cannot be easily studied in natural populations. Most of what is known about interactions between FVs and other viruses is based on studies of NHPs in artificial settings such as research facilities. In these settings, there is some indication that FVs can exacerbate infections with lentiviruses such as simian immunodeficiency virus (SIV). Nonhuman primate (NHP) simian FVs (SFVs) have been shown to infect people without any apparent pathogenicity. Humans zoonotically infected with simian foamy virus (SFV) are often co-infected with other viruses. Thus, it is important to know whether SFV co-infections affect human disease.

Cynomolgus macaque IL37 polymorphism and control of SIV infection

The association between gene polymorphisms and plasma virus load at the set point (SP-PVL) was investigated in Mauritian macaques inoculated with SIV. Among 44 macaques inoculated with 50 AID50, six individuals were selected: three with SP-PVL among the highest and three with SP-PVL among the lowest. The exons of 390 candidate genes of these six animals were sequenced. Twelve non-synonymous single nucleotide polymorphisms (NS-SNPs) lying in nine genes potentially associated with PVL were genotyped in 23 animals. Three NS-SNPs with probabilities of association with PVL less than 0.05 were genotyped in a total of 44 animals. One NS-SNP lying in exon 1 of the IL37 gene displayed a significant association (p = 3.33 × 10⁻⁴) and a strong odds ratio (19.52). Multiple linear regression modeling revealed three significant predictors of SP-PVL, including the IL37 exon 1 NS-SNP (p = 0.0004) and the MHC Class IB haplotypes M2 (p = 0.0007) and M6 (p = 0.0013). These three factors in conjunction explained 48% of the PVL variance (p = 4.8 × 10⁻⁶). The potential role of IL37 in the control of SIV infection is discussed.

Potent neutralizing antibodies in humans infected with zoonotic simian foamy viruses target conserved epitopes located in the dimorphic domain of the surface envelope protein

Human diseases of zoonotic origin are a major public health problem. Simian foamy viruses (SFVs) are complex retroviruses which are currently spilling over to humans. Replication-competent SFVs persist over the lifetime of their human hosts, without spreading to secondary hosts, suggesting the presence of efficient immune control. Accordingly, we aimed to perform an in-depth characterization of neutralizing antibodies raised by humans infected with a zoonotic SFV. We quantified the neutralizing capacity of plasma samples from 58 SFV-infected hunters against primary zoonotic gorilla and chimpanzee SFV strains, and laboratory-adapted chimpanzee SFV. The genotype of the strain infecting each hunter was identified by direct sequencing of the env gene amplified from the buffy coat with genotype-specific primers. Foamy virus vector particles (FVV) enveloped by wild-type and chimeric gorilla SFV were used to map the envelope region targeted by antibodies. Here, we showed high titers of neutralizing antibodies in the plasma of most SFV-infected individuals. Neutralizing antibodies target the dimorphic portion of the envelope protein surface domain. Epitopes recognized by neutralizing antibodies have been conserved during the cospeciation of SFV with their nonhuman primate host. Greater neutralization breadth in plasma samples of SFV-infected humans was statistically associated with smaller SFV-related hematological changes. The neutralization patterns provide evidence for persistent expression of viral proteins and a high prevalence of coinfection. In conclusion, neutralizing antibodies raised against zoonotic SFV target immunodominant and conserved epitopes located in the receptor binding domain. These properties support their potential role in restricting the spread of SFV in the human population.

Bridging the gap: large animal models in neurodegenerative research

The world health organisation has declared neurological disorders as one of the greatest public health risks in the world today. Yet, despite this growing concern, the mechanisms underpinning many of these conditions are still poorly understood. This may in part be due to the seemingly diverse nature of the initiating insults ranging from genetic (such as the Ataxia's and Lysosomal storage disorders) through to protein misfolding and aggregation (i.e. Prions), and those of a predominantly unknown aetiology (i.e. Alzheimer's and Parkinson's disease). However, efforts to elucidate mechanistic regulation are also likely to be hampered because of the complexity of the human nervous system, the apparent selective regional vulnerability and differential degenerative progression. The key to elucidating these aetiologies is determining the regional molecular cascades, which are occurring from the early through to terminal stages of disease progression. Whilst much molecular data have been captured at the end stage of disease from post-mortem analysis in humans, the very early stages of disease are often conspicuously asymptomatic, and even if they were not, repeated sampling from multiple brain regions of "affected" patients and "controls" is neither ethical nor possible. Model systems therefore become fundamental for elucidating the mechanisms governing these complex neurodegenerative conditions. However, finding a model that precisely mimics the human condition can be challenging and expensive. Whilst cellular and invertebrate models are frequently used in neurodegenerative research and have undoubtedly yielded much useful data, the comparatively simplistic nature of these systems makes insights gained from such a stand alone model limited when it comes to translation. Given the recent advances in gene editing technology, the options for novel model generation in higher order species have opened up new and exciting possibilities for the field. In this review, we therefore explain some of the reasons why larger animal models often appear to give a more robust recapitulation of human neurological disorders and why they may be a critical stepping stone for effective therapeutic translation.

Isolation of a simian immunodeficiency virus from a malbrouck (Chlorocebus cynosuros)

To investigate the diversity of simian immunodeficiency virus (SIV) among nonhuman primates (NHPs) in Zambia, next-generation sequencing was performed to determine the complete genome sequence of a novel SIV recovered by co-culturing African green monkey (AGM) peripheral blood lymphocytes with human CD4⁺ T-cell lines. We report the first described SIV (SIVagmMAL-ZMB) from a malbrouck (Chlorocebus cynosuros). SIVagmMAL-ZMB was detected by real-time PCR analysis of splenic RNA in 3.2% (3/94) of AGMs and was undetectable in baboons (0/105). SIVagmMAL-ZMB possessed <80% nucleotide sequence identity to known SIV isolates and was located basally to vervet monkey SIV strains in all phylogenies.

Bushmeat and Emerging Infectious Diseases: Lessons from Africa

Zoonotic diseases are the main contributor to emerging infectious diseases (EIDs) and present a major threat to global public health. Bushmeat is an important source of protein and income for many African people, but bushmeat-related activities have been linked to numerous EID outbreaks, such as Ebola, HIV, and SARS. Importantly, increasing demand and commercialization of bushmeat is exposing more people to pathogens and facilitating the geographic spread of diseases. To date, these linkages have not been systematically assessed. Here we review the literature on bushmeat and EIDs for sub-Saharan Africa, summarizing pathogens (viruses, fungi, bacteria, helminths, protozoan, and prions) by bushmeat taxonomic group to provide for the first time a comprehensive overview of the current state of knowledge concerning zoonotic disease transmission from bushmeat into humans. We conclude by drawing lessons that we believe are applicable to other developing and developed regions and highlight areas requiring further research to mitigate disease risk.

The detection of vector-borne-disease-related DNA in human stool paves the way to large epidemiological studies

The detection of Plasmodium spp. by the molecular analysis of human feces was reported to be comparable to detection in the blood. We believe that for epidemiological studies using molecular tools, it would be simpler to use feces, which are easier to obtain and require no training for their collection. Our aim was to evaluate the usefulness of feces for the detection of these pathogens towards developing a new tool for their surveillance. Between 2008 and 2010, 451 human fecal samples were collected in two Senegalese villages in which malaria and rickettsioses are endemic. Rickettsia and Plasmodium DNA were detected using quantitative PCR targeting Rickettsia of the spotted fever group, R. felis and Plasmodium spp. Two different sequences were systematically targeted for each pathogen. Twenty of the 451 fecal samples (4.4 %) were positive for Rickettsia spp., including 8 for R. felis. Inhabitants of Dielmo were more affected (18/230, 7.8 %; p = 0.0008) compared to those of Ndiop (2/221, 0.9 %). Children under 15 years of age were more often positive (19/285, 6.7 %) than were older children (1/166, 0.6 %; p = 0.005, odds ratio = 11.79). Only one sample was positive for Plasmodium spp. This prevalence is similar to that found in the blood of the Senegalese population reported previously. This preliminary report provides a proof of concept for the use of feces for detecting human pathogens, including microorganisms that do not cause gastroenteritis, in epidemiological studies.

Surveying the global virome: identification and characterization of HCV-related animal hepaciviruses

Recent advances in sequencing technologies have greatly enhanced our abilities to identify novel microbial sequences. Thus, our understanding of the global virome and the virome of specific host species in particular is rapidly expanding. Identification of animal viruses is important for understanding animal disease, the origin and evolution of human viruses, as well as zoonotic reservoirs for emerging infections. Although the human hepacivirus, hepatitis C virus (HCV), was identified 25years ago, its origin has remained elusive. In 2011, the first HCV homolog was reported in dogs but subsequent studies showed the virus to be widely distributed in horses. This indicated a wider hepacivirus host range and paved the way for identification of rodent, bat and non-human primate hepaciviruses. The equine non-primate hepacivirus (NPHV) remains the closest relative of HCV and is so far the best characterized. Identification and characterization of novel hepaciviruses may in addition lead to development of tractable animal models to study HCV persistence, immune responses and pathogenesis. This could be particular important, given the current shortage of immunocompetent models for robust HCV infection. Much remains to be learned on the novel hepaciviruses, including their association with disease, and thereby how relevant they will become as HCV model systems and for studies of animal disease. This review discusses how virome analysis led to identification of novel hepaci- and pegiviruses, their genetic relationship and characterization and the potential use of animal hepaciviruses as models to study hepaciviral infection, immunity and pathogenesis. This article forms part of a symposium in Antiviral Research on "Hepatitis C: Next steps toward global eradication."

Gorilla gorilla gorilla gut: a potential reservoir of pathogenic bacteria as revealed using culturomics and molecular tools

Wild apes are considered to be the most serious reservoir and source of zoonoses. However, little data are available about the gut microbiota and pathogenic bacteria in gorillas. For this propose, a total of 48 fecal samples obtained from 21 Gorilla gorilla gorilla individuals (as revealed via microsatellite analysis) were screened for human bacterial pathogens using culturomics and molecular techniques. By applying culturomics to one index gorilla and using specific media supplemented by plants, we tested 12,800 colonies and identified 147 different bacterial species, including 5 new species. Many opportunistic pathogens were isolated, including 8 frequently associated with human diseases; Mycobacterium bolletii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Serratia marcescens, Escherichia coli, Staphylococcus aureus and Clostridium botulinum. The genus Treponema accounted for 27.4% of the total reads identified at the genus level via 454 pyrosequencing. Using specific real-time PCR on 48 gorilla fecal samples, in addition to classical human pathogens, we also observed the fastidious bacteria Bartonella spp. Borrelia spp., Coxiella burnetii and Tropheryma whipplei in the gorilla population. We estimated that the prevalence of these pathogens vary between 4.76% and 85.7%. Therefore, gorillas share many bacterial pathogens with humans suggesting that they could be a reservoir for their emergence.

Pathogenic eukaryotes in gut microbiota of western lowland gorillas as revealed by molecular survey

Although gorillas regarded as the largest extant species of primates and have a close phylogenetic relationship with humans, eukaryotic communities have not been previously studied in these populations. Herein, 35 eukaryotic primer sets targeting the 18S rRNA gene, internal transcribed spacer gene and other specific genes were used firstly to explore the eukaryotes in a fecal sample from a wild western lowland gorilla (Gorilla gorilla gorilla). Then specific real-time PCRs were achieved in additional 48 fecal samples from 21 individual gorillas to investigate the presence of human eukaryotic pathogens. In total, 1,572 clones were obtained and sequenced from the 15 cloning libraries, resulting in the retrieval of 87 eukaryotic species, including 52 fungi, 10 protozoa, 4 nematodes and 21 plant species, of which 52, 5, 2 and 21 species, respectively, have never before been described in gorillas. We also reported the occurrence of pathogenic fungi and parasites (i.e. Oesophagostomum bifurcum (86%), Necator americanus (43%), Candida tropicalis (81%) and other pathogenic fungi were identified). In conclusion, molecular techniques using multiple primer sets may offer an effective tool to study complex eukaryotic communities and to identify potential pathogens in the gastrointestinal tracts of primates.

Looking in apes as a source of human pathogens

Because of the close genetic relatedness between apes and humans, apes are susceptible to many human infectious agents and can serve as carriers of these pathogens. Consequently, they present a serious health hazard to humans. Moreover, many emerging infectious diseases originate in wildlife and continue to threaten human populations, especially vector-borne diseases described in great apes, such as malaria and rickettsiosis. These wild primates may be permanent reservoirs and important sources of human pathogens. In this special issue, we report that apes, including chimpanzees (Pan troglodytes), bonobos (Pan paniscus), gorillas (Gorilla gorilla and Gorilla beringei), orangutans (Pongo pygmaeus and Pongo abelii), gibbons (Hylobates spp., Hoolock spp. and Nomascus spp) and siamangs (Symphalangus syndactylus syndactylus and Symphalangus continentis), have many bacterial, viral, fungal and parasitic species that are capable of infecting humans. Serious measures should be adopted in tropical forests and sub-tropical areas where habitat overlaps are frequent to survey and prevent infectious diseases from spreading from apes to people.

HIV-1 genetic variation and drug resistance development

Up until 10 years ago, basic and clinical HIV-1 research was mainly performed on HIV-1 subtype B that predominated in resource-rich settings. Over the past decade, HIV-1 care and therapy has been scaled up substantially in Latin America, Africa and Asia. These regions are largely dominated by non-B subtype infections, and especially the African continent is affected by the HIV pandemic. Insight on the potency of antiviral drugs and regimens as well as on the emergence of drug resistance in non-B subtypes was lacking triggering research in this field, also partly driven by the introduction and spreading of HIV-1 non-B subtypes in Europe. The scope of this article was to review and discuss the state-of-the-art on the impact of HIV-1 genetic variation on the in vitro activity of antiviral drugs and in vivo response to antiviral therapy; as well as on the in vitro and in vivo emergence of drug resistance.

FIV in cats--a useful model of HIV in people?

The feline immunodeficiency virus (FIV) shares genomic organization, receptor usage, lymphocyte tropism, and induction of immunodeficiency and increased susceptibility to cancer with the human immunodeficiency virus (HIV). Global distribution, marked heterogeneity and variable host adaptation are also properties of both viruses. These features render the FIV-cat model suitable to explore many aspects of lentivirus-host interaction and adaptation, and to explore treatment and prevention of infection. Examples of fundamental discoveries that have emerged from study in the FIV-cat model concern two-receptor entrance strategies that target memory T-lymphocytes, host factors that restrict retroviral infection, viral strategies for replication in non-dividing cells, and identification of correlates of immunity to the virus. This article provides a brief overview of strengths and limitations of the FIV-cat model for comparative biology and medicine.

A gorilla reservoir for human T-lymphotropic virus type 4

Of the seven known species of human retroviruses only one, human T-cell lymphotropic virus type 4 (HTLV-4), lacks a known animal reservoir. We report the largest screening for simian T-cell lymphotropic virus (STLV-4) to date in a wide range of captive and wild non-human primate (NHP) species from Cameroon. Among the 681 wild and 426 captive NHPs examined, we detected STLV-4 infection only among gorillas by using HTLV-4-specific quantitative polymerase chain reaction. The large number of samples analyzed, the diversity of NHP species examined, the geographic distribution of infected animals relative to the known HTLV-4 case, as well as detailed phylogenetic analyses on partial and full genomes, indicate that STLV-4 is endemic to gorillas, and that rather than being an ancient virus among humans, HTLV-4 emerged from a gorilla reservoir, likely through the hunting and butchering of wild gorillas. Our findings shed further light on the importance of gorillas as keystone reservoirs for the evolution and emergence of human infectious diseases and provide a clear course for preventing HTLV-4 emergence through management of human contact with wild gorillas, the development of improved assays for HTLV-4/STLV-4 detection and the ongoing monitoring of STLV-4 among gorillas and for HTLV-4 zoonosis among individuals exposed to gorilla populations.

[Mechanisms of viral emergence and interspecies transmission: the exemple of simian foamy viruses in Central Africa]

A large proportion of viral pathogens that have emerged during the last decades in humans are considered to have originated from various animal species. This is well exemplified by several recent epidemics such as those of Nipah, Severe Acute Respiratory Syndrome, Avian flu, Ebola, Monkeypox, and Hantaviruses. After the initial interspecies transmission per se, the viruses can disseminate into the human population through various and distinct mechanisms. Some of them are well characterized and understood, thus allowing a certain level of risk control and prevention. Surprisingly and in contrast, the initial steps that lead to the emergence of several viruses, and of their associated diseases, remain still poorly understood. Epidemiological field studies conducted in certain specific high-risk populations are thus necessary to obtain new insights into the early events of this emergence process. Human infections by simian viruses represent increasing public health concerns. Indeed, by virtue of their genetic andphysiological similarities, non-human primates (NHPs) are considered to be likely the sources of viruses that can infect humans and thus may pose a significant threat to human population. This is well illustrated by retroviruses, which have the ability to cross species, adapt to a new host and sometimes spread within these new species. Sequence comparison and phylogenetic studies have thus clearly showed that the emergence of human immunodeficiency virus type 1 (HIV-1) and HIV-2 in humans have resulted from several independent interspecies transmissions of different SIV types from Chimpanzees and African monkeys (including sooty mangabeys), respectively, probably during the first part of the last century. The situation for Human T cell Lymphotropic virus type 1 (HTLV-1) is, for certain aspects, quite comparable. Indeed, the origin of most HTLV-1 subtypes appears to be linked to interspecies transmission between STLV-1-infected monkeys and humans, followed by variable periods of evolution in the human host. In this review, after an introduction on emerging viruses, we will briefly present the results of a large epidemiological study performed in groups of Bantus and Pygmies living in villages and settlements located in the rain forest of the South region of Cameroon. These populations are living nearby the habitats of several monkeys and apes, often naturally infected by different retroviruses including SIV, STLV and simianfoamy virus. Most of the persons included in this study were hunters of such NHPs, thus at high risk of contact with infected body fluids (blood, saliva,...) during hunting activities. After reviewing the current available data on the discovery, cross-species transmission from monkeys and apes to humans of the simian foamy retroviruses, we will report the results of our study. Such infection is a unique natural model to study the different mechanisms of restriction of retroviral emergence in Humans.

Co-circulation of enteroviruses between apes and humans

A total of 139 stool samples from wild chimpanzees, gorillas and bonobos in Cameroon and Democratic Republic of Congo (DRC) were screened for enteroviruses (EVs) by reverse transcription PCR. Enterovirus RNA was detected in 10 % of samples, comprising eight from 58 sampled chimpanzees (13.8 %), one from 40 bonobos (2.5 %) and five from 40 gorillas (12.2 %). Three viruses isolated from chimpanzees grouped with human isolate EV-A89 and four (four chimpanzees, one gorilla) represented a newly identified type, EV-A119. These species A virus types overlapped with those circulating in human populations in the same area. The remaining six strains comprised a new species D type, EV-D120, infecting one chimpanzee and four gorillas, and a single EV variant infecting a bonobo that was remarkably divergent from other EVs and potentially constitutes a new enterovirus species. The study demonstrates both the circulation of genetically divergent EV variants in apes and monkeys as well as those shared with local human populations.

Massive depletion of bovine leukemia virus proviral clones located in genomic transcriptionally active sites during primary infection

Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection that remains generally asymptomatic but can also lead to leukemia or lymphoma. These viruses replicate by infecting new lymphocytes (i.e. the infectious cycle) or via clonal expansion of the infected cells (mitotic cycle). The relative importance of these two cycles in viral replication varies during infection. The majority of infected clones are created early before the onset of an efficient immune response. Later on, the main replication route is mitotic expansion of pre-existing infected clones. Due to the paucity of available samples and for ethical reasons, only scarce data is available on early infection by HTLV-1. Therefore, we addressed this question in a comparative BLV model. We used high-throughput sequencing to map and quantify the insertion sites of the provirus in order to monitor the clonality of the BLV-infected cells population (i.e. the number of distinct clones and abundance of each clone). We found that BLV propagation shifts from cell neoinfection to clonal proliferation in about 2 months from inoculation. Initially, BLV proviral integration significantly favors transcribed regions of the genome. Negative selection then eliminates 97% of the clones detected at seroconversion and disfavors BLV-infected cells carrying a provirus located close to a promoter or a gene. Nevertheless, among the surviving proviruses, clone abundance positively correlates with proximity of the provirus to a transcribed region. Two opposite forces thus operate during primary infection and dictate the fate of long term clonal composition: (1) initial integration inside genes or promoters and (2) host negative selection disfavoring proviruses located next to transcribed regions. The result of this initial response will contribute to the proviral load set point value as clonal abundance will benefit from carrying a provirus in transcribed regions.

Human T-lymphotropic Virus 1 (HTLV-1) induces a persistent infection that remains generally asymptomatic. Nevertheless, in a small proportion of individuals and after a long latency, HTLV-1 infection leads to leukemia or lymphoma. Onset of clinical manifestations correlates with a persistently elevated number of infected cells. Because the vast majority of cells are infected at early stages, primary infection is a crucial period for HTLV-1 persistence and pathogenesis. Since HTLV-1 is transmitted through breast feeding and because systematic population screenings are rare, there is a lack of available samples at early infection. Therefore, we addressed this question in a closely related animal model by inoculating cows with Bovine Leukemia Virus (BLV). We show that the vast majority of cells becoming infected during the first weeks of infection and do not survive later on. We also demonstrate that the initial host selection occurring during primary infection will specifically target cells that carry a provirus inserted in genomic transcribed regions. This conclusion thus highlights a key role exerted by the host immune system during primary infection and indicates that antiviral treatments would be optimal when introduced straight after infection.

Molecular evidence for the presence of Rickettsia Felis in the feces of wild-living African apes

BACKGROUND

Rickettsia felis is a common emerging pathogen detected in mosquitoes in sub-Saharan Africa. We hypothesized that, as with malaria, great apes may be exposed to the infectious bite of infected mosquitoes and release R. felis DNA in their feces.

METHODS

We conducted a study of 17 forest sites in Central Africa, testing 1,028 fecal samples from 313 chimpanzees, 430 gorillas and 285 bonobos. The presence of rickettsial DNA was investigated by specific quantitative real-time PCR. Positive results were confirmed by a second PCR using primers and a probe targeting a specific gene for R. felis. All positive samples were sequenced.

RESULTS

Overall, 113 samples (11%) were positive for the Rickettsia-specific gltA gene, including 25 (22%) that were positive for R. felis. The citrate synthase (gltA) sequence and outer membrane protein A (ompA) sequence analysis indicated 99% identity at the nucleotide level to R. felis. The 88 other samples (78%) were negative using R. felis-specific qPCR and were compatible with R. felis-like organisms.

CONCLUSION

For the first time, we detected R. felis in wild-living ape feces. This non invasive detection of human pathogens in endangered species opens up new possibilities in the molecular epidemiology and evolutionary analysis of infectious diseases, beside HIV and malaria.

HTLV-3/4 and simian foamy retroviruses in humans: discovery, epidemiology, cross-species transmission and molecular virology

Non-human primates are considered to be likely sources of viruses that can infect humans and thus pose a significant threat to human population. This is well illustrated by some retroviruses, as the simian immunodeficiency viruses and the simian T lymphotropic viruses, which have the ability to cross-species, adapt to a new host and sometimes spread. This leads to a pandemic situation for HIV-1 or an endemic one for HTLV-1. Here, we present the available data on the discovery, epidemiology, cross-species transmission and molecular virology of the recently discovered HTLV-3 and HTLV-4 deltaretroviruses, as well as the simian foamy retroviruses present in different human populations at risk, especially in central African hunters. We discuss also the natural history in humans of these retroviruses of zoonotic origin (magnitude and geographical distribution, possible inter-human transmission). In Central Africa, the increase of the bushmeat trade during the last decades has opened new possibilities for retroviral emergence in humans, especially in immuno-compromised persons.