Genetic diversity of STLV-2 and interspecies transmission of STLV-3 in wild-living bonobos.

There are currently four known primate T-cell lymphotropic virus groups (PTLV1-4), each of which comprises closely related simian (STLV) and human (HTLV) viruses. For PTLV-1 and PTLV-3, simian and human viruses are interspersed, suggesting multiple cross-species transmission events; however, for PTLV-2 this is not so clear because HTLV-2 and STLV-2 strains from captive bonobos (Pan paniscus) form two distinct clades. To determine to what extent bonobos are naturally infected with STLV, we screened fecal samples (n = 633) from wild-living bonobos (n = 312) at six different sites in the Democratic Republic of Congo (DRC) for the presence of STLV nucleic acids. STLV infection was detected in 8 of 312 bonobos at four of six field sites, suggesting an overall prevalence of 2.6% (ranging from 0 to 8%). Six samples contained STLV-2, while the two others contained STLV-3, as determined by phylogenetic analysis of partial tax and Long Terminal Repeats (LTR) sequences. The new STLV-2 sequences were highly diverse, but grouped with previously identified STLV-2 strains as a sister clade to HTLV-2. In contrast, the new STLV-3 sequences did not cluster together, but were more closely related to STLVs from sympatric monkey species. These results show for the first time that fecal samples can be used to detect STLV infection in apes. These results also show that wild-living bonobos are endemically infected with STLV-2, but have acquired STLV-3 on at least two occasions most likely by cross-species transmission from monkey species on which they prey. Future studies of bonobos and other non-human primate species in Central Africa are needed to identify the simian precursor of HTLV-2 in humans.

African origin of the malaria parasite Plasmodium vivax.

Plasmodium vivax is the leading cause of human malaria in Asia and Latin America but is absent from most of central Africa due to the near fixation of a mutation that inhibits the expression of its receptor, the Duffy antigen, on human erythrocytes. The emergence of this protective allele is not understood because P. vivax is believed to have originated in Asia. Here we show, using a non-invasive approach, that wild chimpanzees and gorillas throughout central Africa are endemically infected with parasites that are closely related to human P. vivax. Sequence analyses reveal that ape parasites lack host specificity and are much more diverse than human parasites, which form a monophyletic lineage within the ape parasite radiation. These findings indicate that human P. vivax is of African origin and likely selected for the Duffy-negative mutation. All extant human P. vivax parasites are derived from a single ancestor that escaped out of Africa.

Devastating decline of forest elephants in central Africa.

African forest elephants- taxonomically and functionally unique-are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002-2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced.

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.

Effects of epidemic diseases on the distribution of bonobos.

This study examined how outbreaks and the occurrence of Anthrax, Ebola, Monkeypox and Trypanosomiasis may differentially affect the distribution of bonobos (Pan paniscus). Using a combination of mapping, Jaccard overlapping coefficients and binary regressions, the study determined how each disease correlated with the extent of occurrence of, and the areas occupied by, bonobos. Anthrax has only been reported to occur outside the range of bonobos and so was not considered further. Ebola, Monkeypox and Trypanosomiasis were each reported within the area of occupancy of bonobos. Their respective overlap coefficients were: J = 0.10; Q(α = 0.05) = 2.00 (odds ratios = 0.0001, 95% CI = 0.0057; Z = -19.41, significant) for Ebola; J = 1.00; Q(α = 0.05) = 24.0 (odds ratios = 1.504, 95% CI = 0.5066-2.6122) for Monkeypox; and, J = 0.33; Q(α = 0.05) = 11.5 (Z = 1.14, significant) for Trypanosomiasis. There were significant relationships for the presence and absence of Monkeypox and Trypanosomiasis and the known extent of occurrence of bonobos, based on the equations y = 0.2368Ln(x)+0.8006 (R(2) = 0.9772) and y = -0.2942Ln(x)+0.7155 (R(2) = 0.698), respectively. The positive relationship suggested that bonobos tolerated the presence of Monkeypox. In contrast, the significant negative coefficient suggested that bonobos were absent in areas where Trypanosomiasis is endemic. Our results suggest that large rivers may have prevented Ebola from spreading into the range of bonobos. Meanwhile, Trypanosomiasis has been recorded among humans within the area of occurrence of bonobos, and appears the most important disease in shaping the area of occupancy of bonobos within their overall extent of occupancy.

Eastern chimpanzees, but not bonobos, represent a simian immunodeficiency virus reservoir.

Chimpanzees in west central Africa (Pan troglodytes troglodytes) are endemically infected with simian immunodeficiency viruses (SIVcpzPtt) that have crossed the species barrier to humans and gorillas on at least five occasions, generating pandemic and nonpandemic forms of human immunodeficiency virus type 1 (HIV-1) as well as gorilla SIV (SIVgor). Chimpanzees in east Africa (Pan troglodytes schweinfurthii) are also infected with SIVcpz; however, their viruses (SIVcpzPts) have never been found in humans. To examine whether this is due to a paucity of natural infections, we used noninvasive methods to screen wild-living eastern chimpanzees in the Democratic Republic of the Congo (DRC), Uganda, and Rwanda. We also screened bonobos (Pan paniscus) in the DRC, a species not previously tested for SIV in the wild. Fecal samples (n = 3,108) were collected at 50 field sites, tested for species and subspecies origin, and screened for SIVcpz antibodies and nucleic acids. Of 2,565 samples from eastern chimpanzees, 323 were antibody positive and 92 contained viral RNA. The antibody-positive samples represented 76 individuals from 19 field sites, all sampled north of the Congo River in an area spanning 250,000 km(2). In this region, SIVcpzPts was common and widespread, with seven field sites exhibiting infection rates of 30% or greater. The overall prevalence of SIVcpzPts infection was 13.4% (95% confidence interval, 10.7% to 16.5%). In contrast, none of the 543 bonobo samples from six sites was antibody positive. All newly identified SIVcpzPts strains clustered in strict accordance to their subspecies origin; however, they exhibited considerable genetic diversity, especially in protein domains known to be under strong host selection pressure. Thus, the absence of SIVcpzPts zoonoses cannot be explained by an insufficient primate reservoir. Instead, greater adaptive hurdles may have prevented the successful colonization of humans by P. t. schweinfurthii viruses.

Identification and molecular characterization of new simian T cell lymphotropic viruses in nonhuman primates bushmeat from the Democratic Republic of Congo.

Four types of human T cell lymphotropic viruses (HTLV) have been described (HTLV-1 to HTLV-4) with three of them having closely related simian virus analogues named STLV-1, -2, and -3. To assess the risk of cross-species transmissions of STLVs from nonhuman primates to humans in the Democratic Republic of Congo, a total of 330 samples, derived from primate bushmeat, were collected at remote forest sites where people rely on bushmeat for subsistence. STLV prevalences and genetic diversity were estimated by PCR and sequence analysis of tax-rex and LTR fragments. Overall, 7.9% of nonhuman primate bushmeat is infected with STLVs. We documented new STLV-1 and STLV-3 variants in six out of the seven species tested and showed for the first time STLV infection in C. mona wolfi, C. ascanius whitesidei, L. aterrimus aterrimus, C. angolensis, and P. tholloni. Our results provide increasing evidence that the diversity and geographic distribution of PTLVs are much greater than previously thought.

Novel multiplexed HIV/simian immunodeficiency virus antibody detection assay.

Like most emerging infectious disease viruses, HIV is also of zoonotic origin. To assess the risk for cross-species transmission of simian immunodeficiency viruses (SIVs) from nonhuman primates to humans in the Democratic Republic of Congo, we collected 330 samples derived from nonhuman primate bushmeat at 3 remote forest sites. SIV prevalences were estimated by using a novel high-throughput assay that included 34 HIV and SIV antigens in a single well. Overall, 19% of nonhuman primate bushmeat was infected with SIVs, and new SIV lineages were identified. Highest SIV prevalences were seen in red-tailed guenons (25%) and Tshuapa red colobus monkeys (24%), representing the most common hunted primate species, thus increasing the likelihood for cross-species transmission. Additional studies are needed to determine whether other SIVs crossed the species barrier. With the newly developed assay, large-scale screening against many antigens is now easier and faster.