Papio Anubis Research Articles

Antelope Predation by Nigerian Forest Baboons: Ecological and Behavioural Correlates

Baboons are well studied in savannah but less so in more closed habitats. We investigated predation on mammals by olive baboons (Papio anubis) at a geographical and climatic outlier, Gashaka Gumti National Park (Nigeria), the wettest and most forested site so far studied. Despite abundant wildlife, meat eating was rare and selective. Over 16 years, baboons killed 7 bushbuck (Tragelaphus scriptus) and 3 red-flanked duiker (Cephalophus rufilatus), mostly still-lying ‘parked' infants. Taking observation time into account, this is 1 predation per group every 3.3 months - far lower than at other sites. Some features of meat eating resemble those elsewhere; predation is opportunistic, adult males monopolize most prey, a targeted killing bite is lacking and begging or active sharing is absent. Carcass owners employ evasive tactics, as meat is often competed over, but satiated owners may tolerate others taking meat. Other features are unusual; this is only the second study site with predation records for bushbuck and the only one for red-flanked duiker. The atypical prey and rarity of eating mammals probably reflects the difficulty of acquiring prey animals when vegetation cover is dense. Our data support the general prediction of the socioecological model that environments shape behavioural patterns, while acknowledging their intraspecific or intrageneric plasticity.

Prevalence of gastrointestinal parasites of baboon (<i>Papio anubis</i>), warthog (<i>Phacochoerus africanus</i>) and waterbuck (<i>Kubus deffasa</i>) in Yankari game reserve, Bauchi state Nigeria

A total of ninety four (94) fresh faecal samples of baboons (Papio anubis), Warthogs (Phacochoerus africanus) and Waterbucks (Kubus deffasa) were collected from different strategic locations within Yankari Game Reserve in August, 2008. Samples were collected in sterilized specimen bottles containing 4% formalin and analyzed by simple floatation, sedimentation and concentration Mc master techniques. The sixty (63) fecal samples of baboons examined; 7(11.11%) had intestinal parasites, comprises of 260 (54.1%) metastrongylus eggs, 180 (37.50%) eggs of mites and 40 (8.33) of adult mites. A total of Seven 7 (28%) of the twenty five (25) fecal samples of warthogs had parasites which comprised of 4960 (98.0%) eggs of hyostrongylus eggs and 100 (2.0%) of monizia eggs. Only 2(33.3%) of the six (6) fecal samples of waterbucks had Hystrongylus eggs 180(1.1%).The infection rate was significantly higher (p<0.05) among Warthogs (98%) fallowed by Baboons (54.1%) and the least Waterbucks (1.1%). Exposure to posture may be the predisposing factor responsible for the prevalence rate recorded in the study area. This may posed a potential danger to visitors in Yankari Game Reserve and other wild animals. Implementation of control policy of helminthes parasites in the Reserve will reducethe prevalence of helminthes diseases.Key words: Baboon, Intestinal parasites, Waterbuck, Warthog, Yankari Game Reserve

Spatial and temporal patterns of home range use by olive baboons (Papio anubis) in eastern Laikipia, Kenya

AbstractThe study investigated the relationship between topography, seasonal food availability and home range use by a troop of olive baboons (Papio anubis) in a dry savannah environment. Valleys were the most utilized parts of the home range in dry seasons while old boma sites were more frequently used in the wet season. Herb‐layer food biomass decreased significantly in dry seasons. The flowers of both Acacia tortilis and Acacia etbaica were available only in dry seasons with valleys having the highest biomass. The biomass of Acacia nilotica seeds was higher in valleys than on other locations. Leaves of the shrub Lycium europaeum were available on all locations in the wet season but valleys had the highest biomass of this food type. Herb‐layer baboon food biomass at ridge tops, slopes, valleys and old boma sites showed similar trends in productivity between seasons. Baboons tracked food along the soil catenas by feeding at ridge tops and old boma sites where foods were available during the wet season and exploiting food sources at the valleys during the dry seasons. Food availability was related to the catena effect and baboons used the catenas in the home range in a predictable manner.

Cross-species analyses unravel the complexity of H3K27me3 and H4K20me3 in the context of neural stem progenitor cells

Neural stem progenitor cells (NSPCs) in the human subventricular zone (SVZ) potentially contribute to lifelong neurogenesis, yet subtypes of glioblastoma multiforme (GBM) contain NSPC signatures that highlight the importance of cell fate regulation. Among numerous regulatory mechanisms, the posttranslational methylations onto histone tails are crucial regulator of cell fate. The work presented here focuses on the role of 2 repressive chromatin marks trimethylations on histone H3 lysine 27 (H3K27me3) and histone H4 lysine 20 (H4K20me3) in the adult NSPC within the SVZ. To best model healthy human NSPCs as they exist in vivo for epigenetic profiling of H3K27me3 and H4K20me3, we used NSPCs isolated from the adult SVZ of baboon brain (Papio anubis) with brain structure and genomic level similar to human. The putative role of H3K27me3 in normal NSPCs predominantly falls into the regulation of gene expression, cell cycle, and differentiation, whereas H4K20me3 is involved in DNA replication/repair, metabolism, and cell cycle. Using conditional knockout mouse models to diminish Ezh2 and Suv4-20h responsible for H3K27me3 and H4K20me3, respectively, we found that both repressive marks have irrefutable function for cell cycle regulation in the NSPC population. Although both EZH2/H3K27me3 and Suv4-20h/H4K20me3 have implication in cancers, our comparative genomics approach between healthy NSPCs and human GBM specimens revealed that substantial sets of genes enriched with H3K27me3 and H4K20me3 in the NSPCs are altered in the human GBM. In sum, our integrated analyses across species highlight important roles of H3K27me3 and H4K20me3 in normal and disease conditions in the context of NSPC.

Variation in the nasal cavity of baboon hybrids with implications for late Pleistocene hominins

Hybridization is increasingly proving to be an important force shaping human evolution. Comparisons of both ancient and modern genomes have provided support for a complex evolutionary scenario over the past million years, with evidence for multiple incidents of gene exchange. However, to date, genetic evidence is still limited in its ability to pinpoint the precise time and place of ancient admixture. For that we must rely on evidence of admixture from the skeleton. The research presented here builds on previous work on the crania of baboon hybrids, focusing on the nasal cavity of olive baboons, yellow baboons, and first generation (F1) hybrids. The nasal cavity is a particularly important anatomical region for study, given the clear differentiation of this feature in Neanderthals relative to their contemporaries, and therefore it is a feature that will likely differ in a distinctive manner in hybrids of these taxa. Metric data consist of 45 linear, area, and volume measurements taken from CT scans of known-pedigree baboon crania. Results indicate that there is clear evidence for differences among the nasal cavities of the parental taxa and their F1 hybrids, including a greater degree of sexual dimorphism in the hybrids. There is also some evidence for transgressive phenotypes in individual F1 animals. The greatest amount of shape variation occurs in the anterior bony cavity, the choana, and the mid-nasopharynx. Extrapolating our results to the fossil record, we would expect F1 hybrid fossils to have larger nasal cavities, on average, than either parental taxon, with overall nasal cavity shape showing the most profound changes in regions that are distinct between the parental taxa (e.g., anterior nasal cavity). We also expect size and shape differences to be more pronounced in male F1 hybrids than in females. Because of pronounced anterior nasal cavity differences between Neanderthals and their contemporaries, we suggest that this model might be effective for examining the fossil record of late Pleistocene contact.

Cellular Immune Responses against Simian T-Lymphotropic Virus Type 1 Target Tax in Infected Baboons.

There are currently 5 million to 10 million human T-lymphotropic virus type 1 (HTLV-1)-infected people, and many of them will develop severe complications resulting from this infection. A vaccine is urgently needed in areas where HTLV-1 is endemic. Many vaccines are best tested in nonhuman primate animal models. As a first step in designing an effective HTLV-1 vaccine, we defined the CD8(+) and CD4(+) T cell response against simian T-lymphotropic virus type 1 (STLV-1), a virus closely related to HTLV-1, in olive baboons (Papio anubis). Consistent with persistent antigenic exposure, we observed that STLV-1-specific CD8(+) T cells displayed an effector memory phenotype and usually expressed CD107a, gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α). To assess the viral targets of the cellular immune response in STLV-1-infected animals, we used intracellular cytokine staining to detect responses against overlapping peptides covering the entire STLV-1 proteome. Our results show that, similarly to humans, the baboon CD8(+) T cell response narrowly targeted the Tax protein. Our findings suggest that the STLV-1-infected baboon model may recapitulate some of the important aspects of the human response against HTLV-1 and could be an important tool for the development of immune-based therapy and prophylaxis. HTLV-1 infection can lead to many different and often fatal conditions. A vaccine deployed in areas of high prevalence might reduce the incidence of HTLV-1-induced disease. Unfortunately, there are very few animal models of HTLV-1 infection useful for testing vaccine approaches. Here we describe cellular immune responses in baboons against a closely related virus, STLV-1. We show for the first time that the immune response against STLV-1 in naturally infected baboons is largely directed against the Tax protein. Similar findings in humans and the sequence similarity between the human and baboon viruses suggest that the STLV-1-infected baboon model might be useful for developing a vaccine against HTLV-1.

The average baboon brain: MRI templates and tissue probability maps from 89 individuals

The baboon (Papio) brain is a remarkable model for investigating the brain. The current work aimed at creating a population-average baboon (Papio anubis) brain template and its left/right hemisphere symmetric version from a large sample of T1-weighted magnetic resonance images collected from 89 individuals. Averaging the prior probability maps output during the segmentation of each individual also produced the first baboon brain tissue probability maps for gray matter, white matter and cerebrospinal fluid. The templates and the tissue probability maps were created using state-of-the-art, freely available software tools and are being made freely and publicly available: http://www.nitrc.org/projects/haiko89/ or http://lpc.univ-amu.fr/spip.php?article589. It is hoped that these images will aid neuroimaging research of the baboon by, for example, providing a modern, high quality normalization target and accompanying standardized coordinate system as well as probabilistic priors that can be used during tissue segmentation.

Morphometric characteristics of preantral and antral follicles and expression of factors involved in folliculogenesis in ovaries of adult baboons (Papio anubis).

Baboons are commonly utilized as an animal model for studies of human reproduction. However, folliculogenesis in this species has not been fully documented. The aim of this study was to assess follicle morphometry and expression of essential proteins involved in folliculogenesis in baboons. Ovaries were recovered from four adult baboons and processed for histological evaluation and immunohistochemical analyses. Follicle proportion, follicle and oocyte diameter, theca layer thickness, number of granulosa cells, and follicle density were calculated. Immunohistochemical staining was also carried out for connexin 43 (Cx43), aromatase, and zona pellucida 3 (ZP3). A total of 2221 follicles were counted and measured. Proportions of primordial, primary, secondary, small antral, and large antral follicles were 49, 26, 23, 1, and 1%, respectively. The increase in follicle diameter was due not only to the increase in oocyte diameter but also to granulosa cell proliferation. Almost all antral follicles were positive for Cx43 (89.8%), aromatase (84.8%), and ZP3 (100%). Most secondary follicles were positive for Cx43 (65%) and ZP3 (64.5%), and some primary follicles were positive only for Cx43. No primordial follicles stained positive in any of these immunohistochemical analyses. Only antral follicles showed aromatase activity. On the basis of these results, we can conclude that folliculogenesis in baboons appears to be similar to that in humans, and this animal therefore constitutes a valuable model.

An efficient model of human endometriosis by induced unopposed estrogenicity in baboons.

Endometriosis is a chronic estrogen-dependent disease that occurs in approximately 10% of reproductive age women. Baboons offer a clear benefit for studying the initiation and progression of endometriosis since baboon is very close to humans phylogenetically. Progestins are used in the treatment of endometriosis. The therapeutic window of progestins depends on the ratio of its affinity towards progesterone receptor agonism verses antagonism. The present study is to determine the role of pure antiprogestin in baboon endometriosis. We hypothesize that pure antiprogestin will induce unopposed estrogenicity and spontaneous endometriosis in baboons. The rate of endometrial invasion and attachment through modeled peritoneum in the presence and absence of progesterone and antiprogestin was evaluated in this study. A baboon model of endometriosis induced by unopposed estrogenicity using progesterone receptor antagonist (EC304) was used in this study. We observed EC304 has induced unopposed estrogenicity that deregulated proteins involved in attachment, invasion, cell growth, and steroid hormone receptors in this model. Our data suggest that depleting progesterone levels in the endometrium will increase estrogen hyper-responsiveness that leads to increased endometriotic lesion progression in the baboon (Papio anubis) model. This study reports a refined model of human endometriosis in baboons that could potentially be used to develop new diagnostic and therapeutic strategies for the benefit of women suffering from endometriosis.

Protective Effect of Chronic Schistosomiasis in Baboons Coinfected with Schistosoma mansoni and Plasmodium knowlesi.

Malaria and schistosomiasis coinfections are common, and chronic schistosomiasis has been implicated in affecting the severity of acute malaria. However, whether it enhances or attenuates malaria has been controversial due the lack of appropriately controlled human studies and relevant animal models. To examine this interaction, we conducted a randomized controlled study using the baboon (Papio anubis) to analyze the effect of chronic schistosomiasis on severe malaria. Two groups of baboons (n = 8 each) and a schistosomiasis control group (n = 3) were infected with 500 Schistosoma mansoni cercariae. At 14 and 15 weeks postinfection, one group was given praziquantel to treat schistosomiasis infection. Four weeks later, the two groups plus a new malaria control group (n = 8) were intravenously inoculated with 10(5) Plasmodium knowlesi parasites and monitored daily for development of severe malaria. A total of 81% of baboons exposed to chronic S. mansoni infection with or without praziquantel treatment survived malaria, compared to only 25% of animals infected with P. knowlesi only (P = 0.01). Schistosome-infected animals also had significantly lower parasite burdens (P = 0.004) than the baboons in the P. knowlesi-only group and were protected from severe anemia. Coinfection was associated with increased spontaneous production of interleukin-6 (IL-6), suggesting an enhanced innate immune response, whereas animals infected with P. knowlesi alone failed to develop mitogen-driven tumor necrosis factor alpha and IL-10, indicating the inability to generate adequate protective and balancing immunoregulatory responses. These results indicate that chronic S. mansoni attenuates the severity of P. knowlesi coinfection in baboons by mechanisms that may enhance innate immunity to malaria.

Two newly observed cases of fish-eating in anubis baboons

Most non-human primates are omnivorous and eat a wide variety of food types like as fruit, leaves, seeds, insects, gums or a mixture of these items. In spite of frequent eating of fish in human, there are few species to eat fishes in non-human primates. Observations of fish-eating in wild primates bring us an important cue for the question why humans have evolved appetite for fish. Here we report two new fish-eating cases observed in anubis baboons (Papio anubis) at the Mpala Research Centre, Kenya and the Gombe National Park, Tanzania. Both cases were observed in dry seasons, and two adult males and a young female ate recently dead or dying fishes in each case. In these two cases, the opportunity of fish-eating occurred by chance and it will be difficult for them to eat fishes ordinarily.

Next generation sequencing (NGS) database for tandem repeats with multiple pattern 2°-shaft multicore string matching.

Next generation sequencing (NGS) technologies have been rapidly applied in biomedical and biological research in recent years. To provide the comprehensive NGS resource for the research, in this paper , we have considered 10 loci/codi/repeats TAGA, TCAT, GAAT, AGAT, AGAA, GATA, TATC, CTTT, TCTG and TCTA. Then we developed the NGS Tandem Repeat Database (TandemRepeatDB) for all the chromosomes of Homo sapiens, Callithrix jacchus, Chlorocebus sabaeus, Gorilla gorilla, Macaca fascicularis, Macaca mulatta, Nomascus leucogenys, Pan troglodytes, Papio anubis and Pongo abelii genome data sets for all those locis. We find the successive occurence frequency for all the above 10 SSR (simple sequence repeats) in the above genome data sets on a chromosome-by-chromosome basis with multiple pattern 2° shaft multicore string matching.

Supplemental Material for Hand Preferences for Unimanual and Bimanual Coordinated Actions in Olive Baboons (Papio anubis): Consistency Over Time and Across Populations

Supplemental Material for Hand Preferences for Unimanual and Bimanual Coordinated Actions in Olive Baboons (Papio anubis): Consistency Over Time and Across Populations

Sero-Prevalence of Herpesvirus Papio 2 in Wild-Caught Olive Baboons from Selected Regions in Kenya

Sero-Prevalence of Herpesvirus Papio 2 in Wild-Caught Olive Baboons from Selected Regions in Kenya

A Preclinical Non-Human Primate Model to Test Reversible Myeloablation Following IV Busulfan Therapy without Stem Cell Rescue

Busulfan is a standard drug utilized in stem cell transplantation for myeloid malignancies, however it is not used in any induction or salvage chemotherapy regimen in these diseases. Non-human primates (NHP) represent a useful model for preclinical evaluation of chemotherapy-related toxicity. In order to identify what dose of IV busulfan could be tested in clinical studies for acute myeloid leukemia, we utilized NHP to determine the highest dose of IV busulfan needed to achieve reversible myelosuppression in unperturbed bone marrow (BM). Nine adult baboons (Papio anubis) were divided into three groups (n=3/group) for this study. Group A received the lowest dose of busulfan 6.4 mg/kg (1.6 mg/kg/day x 4 days), Group B received 8 mg/kg (3.2 mg/kg on day 1 and 1.6 mg/kg on day 2-4) and Group C received 9.6 mg/kg (3.2 mg/kg/day day 1-2 and 1.6 mg/kg/day day 3-4). Peripheral blood (PB) complete blood count (CBC), and BM CD34+ cells, colony forming unit (CFU) were monitored over 90 days after busulfan. Maximum suppression of WBC count, hemoglobin (Hb) and platelet counts in the PB of baboons in all 3 groups were observed around day 15. The suppression of WBC was 57 ± 4%, 58 ± 4% and 53 ±10% in group A, B and C respectively (group A: p = 0.006, group B: p = 0.03, group C: p = 0.07). The suppression of absolute neutrophil counts (ANC) in group A, B and C were 85 ± 2%, 8 4± 1% and 82± 5% respectively. Similarly the minimum post-busulfan Hb levels were 10± 0.6 g/dl, 10± 1g/dl, 10± 0.6g/dl in group A, B and C respectively. The suppression of platelet counts were 84 ± 6%, 81 ± 7% and 81 ± 9% in group A, B and C respectively. Taken together, PB CBC results indicate that at day 15, despite administering a higher dose of busulfan the maximum depletion of ANC, Hb and platelet was comparable among the three groups. At day 90, the PB WBC, Hb and platelet counts returned within normal ranges. Notably, in the group receiving the highest dose of busulfan (Group C) the PB WBC counts at day 90 displayed 76 ± 9% recovery and platelets a 79 ± 13% recovery. Extra-hematopoietic toxicity, including weight loss, was not significant in any group of animals. Then we examined CD34+ cells and CFU content of BM prior to and following busulfan therapy. Baboons receiving the lowest dose of busulfan (Group A) displayed 75 ± 19% CD34+ cell suppression, while the intermediate group B had 90 ± 9%, and the group C which received the highest dose of busulfan had 98 ± 0.6 % suppression. The CD34+ cell recovery at day 90 was 56%, 35% and 24% in group A, B and C, respectively, suggesting that the BM CD34+ cell compartment requires more time to recover despite near normal CBC numbers. Similarly, at day 15 the suppression of BM CFU in group A, B and C was 71 ± 10% , 86 ± 8% and 91 ± 5% respectively. Although the suppression in PB WBC count was not distinct the absolute number of CD34+ cells and CFU content of BM varied based on busulfan dose administered. At day 90 the recovery of BM CFU in group A, B & C were 51 ± 15% , 79 ± 15% and 53 ± 9%, respectively. Although there was no significant intergroup difference in degree of CFU plating efficiency, pre-busulfan versus day 90 CFU recovery in group C was statistically significant (p = 0.02) . These results further validate the hierarchy of CD34+ cells and CFU in contrast to more mature PB cells and the cell populations targeted by busulfan, emphasizing regulatory systems governing homeostasis are likely maintained by reserved BM precursors and progenitor cells. Despite near normalization of blood counts, the relatively primitive BM CD34+ cells and CFU content require longer time to return to pre treatment levels. BM biopsy results indicate a return of cellularity and tri-lineage hematopoiesis comparable to pre-treatment levels in all three groups by day 90. Taken together, our study showed that when busulfan is administered in a dose range of 6.4 to 9.6 mg/kg in an NHP model, it is capable of inducing reversible myeloablation with tolerable toxicity without requiring stem cell rescue or blood transfusions. Our results also indicate that about 30 to 40% BM reserve is capable of maintaining normal PB cell counts. Based on the results, we plan to design a phase 1/2 clinical trial where non-myeloablative doses of IV busulfan will be tested as salvage therapy in patients with acute myeloid leukemia. DisclosuresNo relevant conflicts of interest to declare.

<Note>Savanna Chimpanzees (Pan troglodytes schweinfurthii) Consume and Share Blue Duiker (Philantomba monticola) Meat in the Issa Valley, Ugalla, Western Tanzania

Meat eating is pervasive across chimpanzee populations in Africa, with red colobus monkey (Piliocolobus spp.) being the most common prey (Boesch & Boesch 1989; Stanford et al. 1994a; Watts et al. 2012, Hosaka 2015) if sympatric in the same habitat. Besides colobus monkeys, chimpanzees consume a variety of other primates, including olive and yellow baboons (Papio spp.) and bushbabies (Galago spp.). In the forest habitats of western Tanzania chimpanzees have been reported to consume numerous different mammalian species: 18 at Mahale Mountains National Park (Uehara 1997; Hosaka 2015) and eight at Gombe National Park, whilst in the miombo woodland dominated Ugalla Region no direct observations have been recorded to date (Table 1). In West Africa, chimpanzees from Tai Forest, Ivory Coast consume eight different mammal species, all primates (Boesch & Boesch 1989). Wherever chimpanzees consume meat, it is almost always via hunting, as they rarely scavenge (Watts 2008).

Impala (Aepyceros melampus) associate with olive baboons (Papio anubis) for feeding and security in Tarangire National Park, Tanzania

Impala (<i>Aepyceros melampus</i>) associate with olive baboons (<i>Papio anubis</i>) for feeding and security in Tarangire National Park, Tanzania

High Prevalence of Antibodies against the Bacterium Treponema pallidum in Senegalese Guinea Baboons (Papio papio).

The bacterium Treponema pallidum is known to cause syphilis (ssp. pallidum), yaws (ssp. pertenue), and endemic syphilis (ssp. endemicum) in humans. Nonhuman primates have also been reported to be infected with the bacterium with equally versatile clinical manifestations, from severe skin ulcerations to asymptomatic. At present all simian strains are closely related to human yaws-causing strains, an important consideration for yaws eradication. We tested clinically healthy Guinea baboons (Papio papio) at Parc National Niokolo Koba in south eastern Senegal for the presence of anti-T. pallidum antibodies. Since T. pallidum infection in this species was identified 50 years ago, and there has been no attempt to treat non-human primates for infection, it was hypothesized that a large number of West African baboons are still infected with simian strains of the yaws-bacterium. All animals were without clinical signs of treponematoses, but 18 of 20 (90%) baboons tested positive for antibodies against T. pallidum based on treponemal tests. Yet, Guinea baboons seem to develop no clinical symptoms, though it must be assumed that infection is chronic or comparable to the latent stage in human yaws infection. The non-active character is supported by the low anti-T. pallidum serum titers in Guinea baboons (median = 1:2,560) versus serum titers that are found in genital-ulcerated olive baboons with active infection in Tanzania (range of medians among the groups of initial, moderate, and severe infected animals = 1:15,360 to 1:2.097e+7). Our findings provide evidence for simian infection with T. pallidum in wild Senegalese baboons. Potentially, Guinea baboons in West Africa serve as a natural reservoir for human infection, as the West African simian strain has been shown to cause sustainable yaws infection when inoculated into humans. The present study pinpoints an area where further research is needed to support the currently on-going second WHO led yaws eradication campaign with its goal to eradicate yaws by 2020.

Parasitological, Hematological and Biochemical Characteristics of a Model of Hyper-microfilariaemic Loiasis (Loa loa) in the Baboon (Papio anubis).

BackgroundLoiasis, a filarial infection caused by Loa loa usually thought to cause relatively minor morbidity, can cause serious and often fatal reactions in patients carrying very high levels of circulating Loa loa microfilariae (mf) following administration of microfilaricidal drugs. An experimental model of this condition would greatly aid the definition of the optimal management of this important clinical presentation.Methodology/Principle FindingsFifteen baboons (Papio anubis) were infected with 600 infective larvae (L3) isolated from Chrysops vector flies. Animals were observed for any clinical changes; blood samples were collected every 1–2 months for 22 months, and analysed for parasitological, hematological and biochemical profiles using standard techniques. All animals became patent but remained clinically normal throughout the study. The parasitological pre-patent period was between 4–8 months, with a majority (60%) of animals becoming patent by 5 months post infection (MPI); all animals were patent by 8 MPI. Microfilarial loads increased steadily in all animals and reached a peak at 18 MPI. By 10 MPI >70% of animals had mf >8,000 mf/mL, and at 18 MPI >70% of animals had mf >30,000mf/mL with 50% of these animals with mf >50,000mf/mL. Absolute eosinophil, creatinine, Ca2+ and K+ levels were generally above normal values (NV). Positive associations were seen between microfilariaemia and eosinophilia, Hb, Ca2+, and gamma-GT values, whilst significant negative associations were seen between microfilariaemia and potassium, glucose and mononuclear leukocyte levels.ConclusionsInfection of splenectomised baboons with L. loa can induce levels of circulating microfilariae, and corresponding haematological profiles, which parallel those seen in those humans in danger of the severe post-microfilariacide clinical responses. Utilization of this experimental model could contribute to the improved management of the loiasis related adverse responses in humans.

Nodular Worm Infections in Wild Non-human Primates and Humans Living in the Sebitoli Area (Kibale National Park, Uganda): Do High Spatial Proximity Favor Zoonotic Transmission?

BackgroundNodular Oesophagostomum genus nematodes are a major public health concern in some African regions because they can be lethal to humans. Their relatively high prevalence in people has been described in Uganda recently. While non-human primates also harbor Oesophagostomum spp., the epidemiology of this oesophagostomosis and the role of these animals as reservoirs of the infection in Eastern Africa are not yet well documented.Methodology/Principal FindingsThe present study aimed to investigate Oesophagostomum infection in terms of parasite species diversity, prevalence and load in three non-human primates (Pan troglodytes, Papio anubis, Colobus guereza) and humans living in close proximity in a forested area of Sebitoli, Kibale National Park (KNP), Uganda. The molecular phylogenetic analyses provided the first evidence that humans living in the Sebitoli area harbored O. stephanostomum, a common species in free-ranging chimpanzees. Chimpanzees were also infected by O. bifurcum, a common species described in human populations throughout Africa. The recently described Oesophagostomum sp. found in colobine monkeys and humans and which was absent from baboons in the neighboring site of Kanyawara in KNP (10 km from Sebitoli), was only found in baboons. Microscopic analyses revealed that the infection prevalence and parasite load in chimpanzees were significantly lower in Kanyawara than in Sebitoli, an area more impacted by human activities at its borders.Conclusions/SignificanceThree different Oesophagostomum species circulate in humans and non-human primates in the Sebitoli area and our results confirm the presence of a new genotype of Oesophagostomum recently described in Uganda. The high spatiotemporal overlap between humans and chimpanzees in the studied area coupled with the high infection prevalence among chimpanzees represent factors that could increase the risk of transmission for O. stephanostomum between the two primate species. Finally, the importance of local-scale research for zoonosis risk management is important because environmental disturbance and species contact can differ, leading to different parasitological profiles between sites that are close together within the same forest patches.