Schistosoma mansoni and soil transmtted helminths in olive baboons and potential zoonosis.

Zoonotic pathogens are among the most important causes of ill health all over the world. The presence of these pathogens in free ranging baboons may have significant implications for humans. In Kenya, the encroachment of wildlife habitats has led to increased interaction between humans and wildlife especially non-human primates. The current study therefore aimed at investigating any possible zoonotic gastrointestinal helminths of olive baboons (Papio anubis) at the human-wildlife interface in two park borders and a ranch in Kenya, namely, Tsavo West National Park, Tana River Primate Reserve and Mutara Ranch, Laikipia, Kenya. One hundred and forty-seven baboons were used in the study. They were trapped in the wild, sampled for stool marked and then released back to the wild. Gastrointestinal (GIT) helminths identified were Strongyloides, Oesophagostomum, Enterobius spp and Trichuris Trichiura from all the three sites while Schistosoma mansoni was only detected from Tsavo baboons and with very low incidence (2.1%). The prevalence of these parasites varied among the sites but significant difference in prevalence was only noted in Strongyloides and Oesophagostomum (p < 0.05) among the three sites. This therefore implies that even with control measures instituted on the human population, baboons will always be a source of zoonotic GIT helminths especially S. mansoni even if the incidence are low. There is need to put in place measures aiming to reduce their interactions with humans and also try to control these infections in the baboons.

Zoonotic Gastrointestinal Parasites of Baboons (Papio anubis) in the Shai Hill Reserve in Ghana.

Several intestinal parasites of baboons are of zoonotic importance, especially where there is considerable interaction between the baboons and humans. The identification of gastrointestinal parasite infections of baboons (Papio anubis) was undertaken at the Shai Hills Reserve Resort, Ghana. A total of 51 faecal samples were collected randomly from individual baboons (51) and examined for cysts, eggs, and larvae of parasites of medical importance, using the direct saline smear and formol-ether concentration technique. The baboons were in 7 troops and were grouped into juveniles, subadults, and adults. The survey showed that 92% of the baboon samples examined were infected with at least one or more parasite(s) of medical importance. Hookworm had the highest prevalence of 38.39% followed by Ascaris lumbricoides (22.32%), whilst Diphyllobotrium latum recorded the lowest prevalence of 0.89%. Adults had the highest prevalence of A. lumbricoides (35.42%). Hookworm (47.92%) occurred most in the juveniles. This is the first report of intestinal parasitic infection in baboons within the Shai Hills Reserve. The results showed a high level of multiparasitism in the nonhuman primates, thus the need for possible interventions to maintain ecosystem health and control the infections as they may be a potential source of transmission to humans.

Micro Array-Assisted Analysis of Anti-Schistosome Glycan Antibodies Elicited by Protective Vaccination With Irradiated Cercariae.

Baboons vaccinated with radiation-attenuated cercariae develop high levels of protection against schistosome infection, correlating to high antibody titres towards schistosome antigens with unknown molecular identity. Using a microarray consisting of glycans isolated from different life-stages of schistosomes, we studied the anti-glycan immunoglobulin (Ig) G and IgM responses in vaccinated and challenged baboons over a time course of 25 weeks. Anti-glycan IgM responses developed early after vaccination, but did not rise in response to later vaccinations. In contrast, anti-glycan IgG developed more slowly, but was boosted by all five subsequent vaccinations. High IgM and IgG levels against O-glycans and glycosphingolipid glycans of cercariae were observed. At the time of challenge, while most antibody levels decreased in the absence of vaccination, IgG towards a subset of glycans containing multiple-fucosylated motifs remained high until 6 weeks post-challenge during challenge parasite elimination, suggesting a possible role of this IgG in protection.

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?

BACKGROUND: Nodular 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 FINDINGS: The 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/SIGNIFICANCE: Three 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.

Prevalence of Babesia microti in free-ranging baboons and African green monkeys.

Babesia microti-like parasites have been reported to infect captive non-human primates (NHPs). However, studies on the prevalence of Babesia spp. in free-ranging NHPs are lacking. This investigation aimed at determining the prevalence of B. microti in wild-caught Kenyan NHPs. In total, 125 animals were studied, including 65 olive baboons (Papio cynocephalus anubis) and 60 African green monkeys ([AGMs] Chlorocebus aethiops). Nested polymerase chain reaction targeting Babesia ß-tubulin genes was used to diagnose infection prevalence. Results indicated a prevalence of 22% (27/125) B. microti infection in free-ranging NHPs in Kenya. There was no statistically significant difference in B. microti infection prevalence between baboons and AGMs or male and female animals. This is the first report of the presence and prevalence of B. microti in free-ranging Kenyan NHPs.

Coprologic evidence of gastrointestinal helminths of forest baboons, Papio anubis, in Kibale National Park, Uganda.

The gastrointestinal parasites of baboons have been well characterized from savannah and desert habitats, but little is known about their gastrointestinal parasites in forest habitats. From May to June 2004, we collected 41 fecal samples from free-ranging olive baboons (Papio anubis) within the forested Kibale National Park, Uganda. Samples were examined to determine the prevalence of gastrointestinal helminths in this forest dwelling population of olive baboons. The prevalence of nematodes identified from fecal flotation was Oesophagostomum sp. (85%), Trichostrongylus sp. (22%), Trichuris sp. (46%), Strongyloides sp. (44%), Ternidens sp. (5%), Abbreviata sp. (2%), and Molineus sp. (2%). Flotation techniques also recovered unidentified eggs, probably of hookworm origin (22%). No parasite eggs were recovered by sedimentation of eight samples. Coproculture techniques using 13 of the 41 samples recovered larvae from Oesophagostomum sp., Strongyloides sp., and Trichostrongylus sp. The high prevalence of nematodes recovered in this study seems to support previous theories of high nematode infections in forested habits.

The detection limits for estimates of infection intensity in schistosomiasis mansoni established by a study in non-human primates.

In human schistosomiasis mansoni, it is impossible to directly determine worm burden and hence infection intensity, so surrogates must be used. Studies on non-human primates revealed a linear relationship between worm burden and three surrogates, faecal egg output, circulating anodic and circulating cathodic antigens. By regression, the thresholds of detection were determined as 40, 24 and 47 worms, respectively. These observations provide a quantitative basis for the contention that low intensity infections in humans are being missed. The significance for estimates of disease prevalence, evaluation of the effects of chemotherapy and the implementation of vaccine trials is emphasised.

Insights into the epidemiology and genetic make-up of Oesophagostomum bifurcum from human and non-human primates using molecular tools.

The nodule worm Oesophagostomum bifurcum (Nematoda: Strongylida) is a parasite of major human health importance predominantly in northern Togo and Ghana. Currently, it is estimated that 0.25 million people are infected with this nematode, and at least 1 million people are at risk of infection. Infection with this parasite causes significant disease as a consequence of encysted larvae in the wall of the large intestine. In spite of the health problems caused by O. bifurcum, there have been significant gaps in the knowledge of the biology, transmission and population genetics of the parasite. This review provides an account of some recent insights into the epidemiology and genetics of the parasite from human and non-human primate hosts in specific regions of Africa using molecular tools. Recent research findings are discussed mainly in relation to non-human primates being reservoirs of infection, and the consequences for the prevention and control of oesophagostomiasis in humans are briefly discussed.

Oesophagostomum bifurcum in non-human primates is not a potential reservoir for human infection in Ghana.

In northern Togo and Ghana, human infection with the parasitic nematode Oesophagostomum bifurcum is of major health importance. Elsewhere, oesophagostomiasis is considered a zoonotic infection, non-human primates being the natural host. We examined 349 faecal samples of the olive baboon, mona monkey and black and white colobus monkey from two geographically distinct areas in Ghana, outside the region endemic for O. bifurcum in humans. Using both microscopy and species-specific PCR, we found a high prevalence of O. bifurcum (75-99%) in olive baboons and mona monkeys. The majority of the test-positive faecal samples contained large numbers of larvae after copro-culture (>100). No O. bifurcum was detected in the faeces of the black and white colobus monkeys. Observational studies on the behaviour of the non-human primates, focusing on defecation, food consumption and the sharing of habitat with the local human population, indicated favourable conditions for zoonotic transmission. Given that no human infection with O. bifurcum has been reported from either study area, the present findings support the hypothesis that O. bifurcum from humans in the north of Ghana, and O. bifurcum from olive baboons and/or mona monkeys are distinct.

Definition of genetic markers in nuclear ribosomal DNA for a neglected parasite of primates, Ternidens deminutus (Nematoda: Strongylida)--diagnostic and epidemiological implications.

Ternidens deminutus (Strongylida) is a parasitic nematode infecting non-human and human primates in parts of Africa, Asia and the Pacific islands. The present study genetically characterized T. deminutus and defined genetic markers in nuclear ribosomal DNA (rDNA) as a basis for developing molecular-diagnostic tools. The sequences of the second internal transcribed spacer (ITS-2) of rDNA were determined for adult specimens of T. deminutus (Nematoda: Strongylida: Oesophagostominae) from the Olive baboon and the Mona monkey. The length and G+C content of the ITS-2 sequences was 216 bp and approximately 43%, respectively. While there was no sequence variation among individual T. deminutus specimens from the baboon, 6 (2.8%) nucleotide differences were detected in the ITS-2 between the parasite from baboon and that of the Mona monkey, which is similar to the difference (3.2%) between 2 other species of Oesophagostominae (Oesophagostomum bifurcum and O. stephanostomum) from non-human primates, suggesting significant population variation or the existence of cryptic (i.e. hidden) species within T. deminutus . Pairwise comparisons of the ITS-2 sequences of the 2 operational taxonomic units of T. deminutus with previously published ITS-2 sequences for selected members of the subfamilies Oesophagostominae and Chabertiinae indicated that species from primates (including those representing the subgenera Conoweberia and Ihleia) are closely related, in accordance with previous morphological studies. The sequence differences (27-48.3%) in the ITS-2 between the 2 taxonomic units of T. deminutus and hookworms (superfamily Ancylostomatoidea) enabled their identification and delineation by polymerase chain reaction (PCR)-based mutation scanning. The genetic markers in the ITS-2 provide a foundation for improved, PCR-based diagnosis of T. deminutus infections and for investigating the life-cycle, transmission patterns and ecology of this parasite.