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From the safety inside vehicles, Knowsley Safari offers visitors a close-up encounter with captive olive baboons. As exiting vehicles may be contaminated with baboon stool, a comprehensive coprological inspection was conducted to address public health concerns. Baboon stools were obtained from vehicles, and sleeping areas, inclusive of video analysis of baboon–vehicle interactions. A purposely selected 4-day sampling period enabled comparative inspections of 2662 vehicles, with a total of 669 baboon stools examined (371 from vehicles and 298 from sleeping areas). As informed by our pilot study, front-line diagnostic methods were: QUIK-CHEK rapid diagnostic test (RDT) ( Giardia and Cryptosporidium ), Kato–Katz coproscopy ( Trichuris ) and charcoal culture ( Strongyloides ). Some 13.9% of vehicles were contaminated with baboon stool. Prevalence of giardiasis was 37.4% while cryptosporidiosis was <0.01%, however, an absence of faecal cysts by quality control coproscopy, alongside lower than the expected levels of Giardia -specific DNA, judged RDT results as misleading, grossly overestimating prevalence. Prevalence of trichuriasis was 48.0% and strongyloidiasis was 13.7%, a first report of Strongyloides fuelleborni in UK. We advise regular blanket administration(s) of anthelminthics to the colony, exploring pour-on formulations, thereafter, smaller-scale indicator surveys would be adequate.

Background: Primates can harbor parasites that could be pathogenic or not for humans and primates themselves. It is necessary to know the parasitological situation of the primates that are under surveillance in the park., Aim: To estimate the prevalence and diversity of gastrointestinal parasites, including zoonotic potential parasites, in baboons in the Niokolo-Koba National Park located in Senegal., Method: Fecal samples ( n = 50) from two groups of baboons (A and B) were collected in October 2019. The samples were processed using the flotation technique and the modified Ritchie method. Slides were examined microscopically and the parasite identification was based on morphology, color, and parasite content., Results: A total of seven nematodes ( Strongyloides sp., Trichirus sp., Ancylostoma sp., Mammo monogamus, Enterobius sp., Strongyloides stercoralis , Strongyle digestif), one cestode ( Bertiella sp.), and one trematode ( Fasciolopsis sp.) were identified. The overall prevalence was 78%, while the prevalence of poly-infected samples was 49%. The parasite with zoonotic potential, S. stercoralis , was identified in group B samples. Trichuris sp., which is common and pathogenic to humans and primates, was present with prevalence of 52% and of 32% in groups A and B, respectively., Conclusion: These results suggest that baboons are infested with zoonotic parasites and this situation could expose people working in this park to infection. Contact between humans and these baboons or their feces could expose them to infection with zoonotic parasites., Competing Interests: The authors declare that there is no conflict of interest.

The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was funded in 2008 to conduct research that would support country schistosomiasis control programs. As schistosomiasis prevalence decreases in many places and elimination is increasingly within reach, a sensitive and specific test to detect infection with Schistosoma mansoni and Schistosoma haematobium has become a pressing need. After obtaining broad input, SCORE supported Leiden University Medical Center (LUMC) to modify the serum-based antigen assay for use with urine, simplify the assay, and improve its sensitivity. The urine assay eventually contributed to several of the larger SCORE studies. For example, in Zanzibar, we demonstrated that urine filtration, the standard parasite egg detection diagnostic test for S. haematobium , greatly underestimated prevalence in low-prevalence settings. In Burundi and Rwanda, the circulating anodic antigen (CAA) assay provided critical information about the limitations of the stool-based Kato-Katz parasite egg-detection assay for S. mansoni in low-prevalence settings. Other SCORE-supported CAA work demonstrated that frozen, banked urine specimens yielded similar results to fresh ones; pooling of specimens may be a useful, cost-effective approach for surveillance in some settings; and the assay can be performed in local laboratories equipped with adequate centrifuge capacity. These improvements in the assay continue to be of use to researchers around the world. However, additional work will be needed if widespread dissemination of the CAA assay is to occur, for example, by building capacity in places besides LUMC and commercialization of the assay. Here, we review the evolution of the CAA assay format during the SCORE period with emphasis on urine-based applications.

Entamoeba histolytica is an enteric parasite that infects approximately 50 million people worldwide. Although E. histolytica is a zoonotic parasite that has the potential to infect nonhuman primates, such transmission is poorly understood. Consequently, this study examined whether E. histolytica is present among humans, chimpanzees and baboons living in the Greater Gombe Ecosystem (GGE), Tanzania. The primary aims were to determine patterns of E. histolytica infection in a system with human-nonhuman primate overlap and to test associations between infection status and potential risk factors of disease. Entamoeba spp. occurred in 60.3% of human, 65.6% of chimpanzee and 88.6% of baboon samples. Entamoeba histolytica occurred in 12.1% of human, 34.1% of chimpanzee and 10.9% of baboon samples. Human E. histolytica infection was associated with gastrointestinal symptoms. This was the first study to confirm the presence of E. histolytica in the GGE. The high sample prevalence of E. histolytica in three sympatric primates suggests that zoonotic transmission is possible and stresses the need for further phylogenetic studies. Interventions targeting better sanitation and hygiene practices for humans living in the GGE can help prevent E. histolytica infection in humans, while also protecting the endangered chimpanzees and other primates in this region.

Background: Gastrointestinal parasites are neglected infections, yet they cause significant burden to animal and human health globally. To date, most studies of gastrointestinal parasites focus on host-parasite systems that involve either a single parasite or a host species. However, when hosts share habitat and resources, they may also cross-transmit generalist gastrointestinal parasites. Here we explore multi-host-parasite interactions in a single ecosystem to understand the infection patterns, especially those linked to livestock-wildlife interfaces and zoonotic risk., Methods: We used both coprological methods (flotation and sedimentation; N = 1,138 fecal samples) and molecular identification techniques (rDNA and mtDNA; N = 18 larvae) to identify gastrointestinal parasites in nine sympatric host species (cattle, sheep, goats, wildebeest, Grant's gazelles, Thomson's gazelles, impala, vervet monkeys and baboons) in the Amboseli ecosystem, Kenya., Results: We found that the host community harbored a diverse community of gastrointestinal helminths, including 22 species and/or morphotypes that were heterogeneously distributed across the hosts. Six zoonotic gastrointestinal helminths were identified: Trichuris spp., Trichostrongylus colubriformis, Enterobius spp. Oesophagostomum bifurcum, Strongyloides stercoralis and Strongyloides fuelleborni. The dominant parasite was Trichuris spp, whose ova occurred in two morphological types. Baboons were co-infected with Strongyloides fuelleborni and S. stercoralis., Conclusions: We found that the interface zone shared by wild ungulates, livestock and non-human primates is rich in diversity of gastrointestinal helminths, of which some are extensively shared across the host species. Closely related host species were most likely to be infected by the same parasite species. Several parasites showed genetic sub-structuring according to either geography or host species. Of significance and contrary to expectation, we found that livestock had a higher parasite richness than wild bovids, which is a health risk for both conservation and livestock production. The zoonotic parasites are of public health risk, especially to pastoralist communities living in areas contiguous to wildlife areas. These results expand information on the epidemiology of these parasites and highlights potential zoonotic risk in East African savanna habitats., Competing Interests: The authors have declared that no competing interests exist.

Background & Objectives: The transmission of schistosomiasis, caused by trematodes of the genus Schistosoma, relies on freshwater snails that act as an intermediate host while human and other mammalian act as the definitive hosts. Many non-human primates (NHPs) such as Chlorocebus aethiops (vervet) and Papio anubis (baboon) are reported to be infected with Schistosoma mansoni in Ethiopia, but the role they play in parasite maintenance and transmission is still not clear. The objective of this study was, therefore, to determine the prevalence of S. mansoni infection in human and NHPs living in close proximities to villages in selected endemic areas of Ethiopia., Methods: In this cross-sectional study, stool specimens were collected from 911 humans, and fresh faecal droppings from 106 NHPs from Bochesa (Ziway), Bishan Gari (Kime) and Finchaa (Camp 7) endemic localities in Oromia Regional State, and examined for S. mansoni and other helminth infections using Kato-Katz method for human participants and direct microscopic examination for NHPs., Results: The prevalence of helminthiasis among the human study population was 42.4% (386/911), and for soil-transmitted helminth infections (A. lumbricoides, hookworms, and T. trichiura) it was 13.4% (122/911). In humans S. mansoni was the predominant parasite, 23.1% (210/911) followed by A. lumbricoides, 8.7% (79/911); hookworms, 5.8% (53/911); T. trichiura, 4.8% (44/911); Taenia species, 2.2% (20/911); E. vermicularis, 2.1% (19/911); and H. nana, 3.2% (29/911). NHPs were found positive for Trichuris species and Strongyloides species besides S. mansoni., Interpretation & Conclusion: NHPs might play a significant role in local transmission and maintenance of S. mansoni infection even in the absence of human hosts. This calls for supplementation of chemotherapy for schistosomiasis along with measures such as snail control to interrupt transmission of the disease from humans to NHPs, and vice-versa., Competing Interests: The authors declare that no conflict of interests exist

Oesophagostomum sp. is a parasitic nematode that frequently infects wild chimpanzees. Although nodular lesions are commonly associated with infection, some wild chimpanzee populations seem to tolerate Oesophagostomum nodular lesions while those at Gombe and other sites suffer from associated morbidity and mortality. From August 2004 to December 2013, we examined demographic (i.e., age, sex) and individual correlates (i.e., fecal consistency, Oesophagostomum egg production) to Oesophagostomum-associated pathology in 14 individually recognized chimpanzees at Gombe Stream National Park, Tanzania. In addition, we characterized Oesophagostomum-associated pathology in 14 individual sympatric primates including baboons, colobus, and cercopithecid monkeys. In five chimpanzees, there was no evidence of any significant underlying disease aside from oesophagostomiasis to explain the thin condition or diarrhea. All five of these chimpanzees had moderate to numerous parasitic nodules. In general, nodules were more numerous in older chimpanzees. Three of four chimpanzees with the highest average Oesophagostomum egg counts in feces collected during the year prior to their death had numerous parasitic nodules at necropsy. In contrast, the four chimpanzees with the lowest egg counts had only moderate numbers of nodules. No association (P = 0.74) was noted between frequency of diarrhea in the year prior to death and the number of nodules noted at necropsy. Nodules were also present in all baboons examined documenting pathology associated with Oesophagostomum infection in wild baboons. In contrast, no lesions were noted in colobus or cercopithecid monkeys, although it is uncertain if they are infected as no fecal studies have been completed in these species to date at Gombe. Sequence of DNA isolated from nodules in chimpanzees matched (99%) Oesophagostomum stephanostomum. Further research is needed to identify the types of Oesophagostomum causing lesions in baboons and to determine if baboons suffer from these infections. Am. J. Primatol. 80:e22572, 2018. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Cross-species infection among humans, chimpanzees (Pan troglodytes) and baboons (Papio spp.) is potentially a significant public health issue in Africa, and of concern in the conservation of P. troglodytes. However, to date, no statistical comparisons have been made between the prevalence, richness and composition of parasite communities in sympatric populations of baboons and P. troglodytes. We compared parasite communities in sympatric P. troglodytes and Papio papio living in a wilderness site, in the Republic of Senegal, West Africa. We asked whether, in the absence of humans, there are significant differences between these hosts in their interactions with gastrointestinal parasites. We tested whether host, location, or time of collection accounted for variation in prevalence, richness and community composition, and compared prevalence across six studies. We concluded that, despite being closely related, there are significant differences between these two hosts with respect to their parasite communities. At our study site, prevalence of Balantidium, Trichuris and Watsonius was higher in P. papio. Papio papio harboured more parasites per host, and we found evidence of a positive association between Trichuris and Balantidium in P. troglodytes but not P. papio.

A combination of deep-sequencing and bioinformatics analysis enabled identification of twenty-two microRNA candidates of potential nematode origin in plasma from Loa loa-infected baboons and a further ten from the plasma of an Onchocerca ochengi-infected cow. The obtained data were compared to results from previous work on miRNA candidates from Dirofilaria immitis and O. volvulus found in host circulating blood, to examine the species specificity of the released miRNA. None of the miRNA candidates was found to be present in all four host-parasite scenarios and most of them were specific to only one of them. Eight candidate miRNAs were found to be identical in the full sequence in at least two different infections, while nine candidate miRNAs were found to be similar but not identical in at least four filarial species., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: Whipworms (Trichuris sp.) are a globally distributed genus of parasitic helminths that infect a diversity of mammalian hosts. Molecular methods have successfully resolved porcine whipworm, Trichuris suis, from primate whipworm, T. trichiura. However, it remains unclear whether T. trichiura is a multi-host parasite capable of infecting a wide taxonomic breadth of primate hosts or a complex of host specific parasites that infect one or two closely related hosts., Methods and Findings: We examined the phylogenetic structure of whipworms in a multi-species community of non-human primates and humans in Western Uganda, using both traditional microscopy and molecular methods. A newly developed nested polymerase chain reaction (PCR) method applied to non-invasively collected fecal samples detected Trichuris with 100% sensitivity and 97% specificity relative to microscopy. Infection rates varied significantly among host species, from 13.3% in chimpanzees (Pan troglodytes) to 88.9% in olive baboons (Papio anubis). Phylogenetic analyses based on nucleotide sequences of the Trichuris internal transcribed spacer regions 1 and 2 of ribosomal DNA revealed three co-circulating Trichuris groups. Notably, one group was detected only in humans, while another infected all screened host species, indicating that whipworms from this group are transmitted among wild primates and humans., Conclusions and Significance: Our results suggest that the host range of Trichuris varies by taxonomic group, with some groups showing host specificity, and others showing host generality. In particular, one Trichuris taxon should be considered a multi-host pathogen that is capable of infecting wild primates and humans. This challenges past assumptions about the host specificity of this and similar helminth parasites and raises concerns about animal and human health.

No vaccines are available for human use for any parasitic infections, including the helminthic disease schistosomiasis. Sm-p80, the large subunit of Schistosoma mansoni calpain, is a leading antigen candidate for a schistosomiasis vaccine. Prophylactic and antifecundity efficacies of Sm-p80 have been tested using a variety of vaccine approaches in both rodent and nonhuman primate models. However, the therapeutic efficacy of a Sm-p80-based vaccine had not been determined. In this study, we evaluated the therapeutic efficacy of Sm-p80 by using 2 different strategies and 3 Sm-p80-based vaccine formulations in baboons. Vaccine formulations were able to decrease established adult worms by 10%-36%, reduce retention of eggs in tissues by 10%-57%, and decrease egg excretion in feces by 13%-33%, compared with control formulations. Marked differences were observed in B and T cell immune correlates between vaccinated and control animals. This is the first report of killing of established adult schistosome worms by a vaccine. In addition to distinct prophylactic efficacy of Sm-p80, this study adds to the evidence that Sm-p80 is a potentially important antigen with both substantial prophylactic and therapeutic efficacies. These data reinforce that Sm-p80 should be moved forward along the path toward human clinical trials., (© The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: The whipworm Trichuris trichiura has been estimated to infect 604 - 795 million people worldwide. The current control strategy against trichuriasis using the benzimidazoles (BZs) albendazole (400 mg) or mebendazole (500 mg) as single-dose treatment is not satisfactory. The occurrence of single nucleotide polymorphisms (SNPs) in codons 167, 198 or 200 of the beta-tubulin gene has been reported to convey BZ-resistance in intestinal nematodes of veterinary importance. It was hypothesised that the low susceptibility of T. trichiura to BZ could be due to a natural occurrence of such SNPs. The aim of this study was to investigate whether these SNPs were present in the beta-tubulin gene of Trichuris spp. from humans and baboons. As a secondary objective, the degree of identity between T. trichiura from humans and Trichuris spp. from baboons was evaluated based on the beta-tubulin gene and the internal transcribed spacer 2 region (ITS2)., Methods: Nucleotide sequences of the beta-tubulin gene were generated by PCR using degenerate primers, specific primers and DNA from worms and eggs of T. trichiura and worms of Trichuris spp. from baboons. The ITS2 region was amplified using adult Trichuris spp. from baboons. PCR products were sequenced and analysed. The beta-tubulin fragments were studied for SNPs in codons 167, 198 or 200 and the ITS2 amplicons were compared with GenBank records of T. trichiura., Results: No SNPs in codons 167, 198 or 200 were identified in any of the analysed Trichuris spp. from humans and baboons. Based on the ITS2 region, the similarity between Trichuris spp. from baboons and GenBank records of T. trichiura was found to be 98 - 99%., Conclusions: Single nucleotide polymorphisms in codon 167, 198 and 200, known to confer BZ-resistance in other nematodes, were absent in the studied material. This study does not provide data that could explain previous reports of poor BZ treatment efficacy in terms of polymorphism in these codons of beta-tubulin. Based on a fragment of the beta-tubulin gene and the ITS2 region sequenced, it was found that T. trichiura from humans and Trichuris spp. isolated from baboons are closely related and may be the same species.

Background: Zoonoses pose a risk to public health., Objective: To carry out the investigation of the prevalence of gastrointestinal parasites of baboons, Papio anubis, frequenting the Wikki base Camp in Yankari National Park, Nigeria., Method: Formol-ether concentration technique was used to isolate parasite eggs and cysts from faecal samples., Results: Parasites recovered were Ascaris lumbricoides, Ancylostoma duodenale, Strongyloides stercoralis, Fasciola sp, Schistosoma mansoni, Hymenolepis nana, and Trichostrongylus sp, and cysts of protozoan parasites Entomoeba histolytica, E. coli, and Iodamoeba butschii., Conclusion: Most of the parasites identified are known to have high pathologic involvement in humans, implicating the baboons as potential source and reservoirs for human zoonotic parasitic infections although further molecular work would be necessary to ascertain if these gastrointestinal parasites are the same strains that infect humans.

Fecal samples from 55 free-ranging olive baboons (Papio anubis) in Mole National Park, Ghana, were collected 22 June-7 July 2008 and analyzed for gastrointestinal parasites. This is the first survey of baboon gastrointestinal parasites in Ghana and provides baseline data for this area. Ninety-three percent of samples were infected, leaving 7% with no parasites observed. Of those infected, there was a 76% prevalence of strongyles, 53% Strongyloides spp., 11% Abbreviata caucasica , 62% prevalence of Balantidium coli (trophozoites and cysts identified), 4% Entomeba hystolytica/dispar, and 47% unidentified protozoan parasites. Of the strongyle infections, 9% were identified as Oesophagostamum sp. One sample contained an unidentified spirurid nematode that resembled Gongylonema sp. Mole has a mixed forest-savanna habitat, and baboons frequently range into human areas, which makes them subject to parasites from each habitat and multiple sources of exposure. We found a high prevalence of nematode parasites, consistent with a wet or cooler forest environment, or high rates of fecal contamination. The presence of Strongyloides sp., E. hystolitica/dispar, and B. coli suggest potential public health risk from baboons, but molecular identification of these parasites, and documentation of their presence in local human populations, would be necessary to confirm zoonotic transmission.

We conducted cross-sectional surveys of parasites infecting a large free-living colony of baboons at the Southwest National Primate Research Center in San Antonio in October 2003 and April 2004, immediately before, and 6 mo after, treatment with ivermectin. Trichuris sp. was the predominant species present, infecting 79 and 69% of individual animals in the 2 surveys, with fecal egg counts (FEC) of up to 60,200 eggs per g (epg) (mean = 1,235 in October 2003 and 1,256 in April 2004). Prevalence remained fairly stable across age groups, and intensity was highest in animals <1 or >15 yr old, in contrast to patterns observed in humans, where school-age children show the heaviest infections. Strongyloides sp. was also identified, but the species identity remains uncertain. Small subunit ribosomal DNA sequences differed from published sequences of Strongyloides fuelleborni at multiple sites, but resided in a monophyletic group with other Strongyloides species with 92% bootstrap support. This may reflect a recent acquisition from a local host, or that the published sequence of S. fuelleborni is incorrect. Widespread infections with 2 nematode genera in a free-ranging baboon colony that are an important source of morbidity in human populations provide a useful model system for work on the epidemiology, control, pathology, and genetics of these parasites in a host species that is physiologically, immunologically, and genetically similar to humans.

Although there has been extensive debate about whether Trichuris suis and Trichuris trichiura are separate species, only one species of the whipworm T. trichiura has been considered to infect humans and non-human primates. In order to investigate potential cross infection of Trichuris sp. between baboons and humans in the Cape Peninsula, South Africa, we sequenced the ITS1-5.8S-ITS2 region of adult Trichuris sp. worms isolated from five baboons from three different troops, namely the Cape Peninsula troop, Groot Olifantsbos troop and Da Gama Park troop. This region was also sequenced from T. trichiura isolated from a human patient from central Africa (Cameroon) for comparison. By combining this dataset with Genbank records for Trichuris isolated from other humans, non-human primates and pigs from several different countries in Europe, Asia, and Africa, we confirmed the identification of two distinct Trichuris genotypes that infect primates. Trichuris sp. isolated from the Peninsula baboons fell into two distinct clades that were found to also infect human patients from Cameroon, Uganda and Jamaica (named the CP-GOB clade) and China, Thailand, the Czech Republic, and Uganda (named the DG clade), respectively. The divergence of these Trichuris clades is ancient and precedes the diversification of T. suis which clustered closely to the CP-GOB clade. The identification of two distinct Trichuris genotypes infecting both humans and non-human primates is important for the ongoing treatment of Trichuris which is estimated to infect 600 million people worldwide. Currently baboons in the Cape Peninsula, which visit urban areas, provide a constant risk of infection to local communities. A reduction in spatial overlap between humans and baboons is thus an important measure to reduce both cross-transmission and zoonoses of helminthes in Southern Africa.

Cyclospora papionis, Cryptosporidium hominis, and Enterocytozoon bieneusi were detected in 42 (17.9%), 6 (2.6%), and 29 (12.3%) of 235 newly captured baboons in Kenya, respectively. Most C. hominis subtypes and E. bieneusi genotypes found have been detected in humans in the area, suggesting that cross-species transmission of cryptosporidiosis and microsporidiosis is possible.

Several species of African trypanosomes cause fatal disease in livestock, but most cannot infect humans due to innate trypanosome lytic factors (TLFs). Human TLFs are pore forming high-density lipoprotein (HDL) particles that contain apolipoprotein L-I (apoL-I) the trypanolytic component, and haptoglobin-related protein (Hpr), which binds free hemoglobin (Hb) in blood and facilitates the uptake of TLF via a trypanosome haptoglobin-hemoglobin receptor. The human-infective Trypanosoma brucei rhodesiense escapes lysis by TLF by expression of serum resistance-associated (SRA) protein, which binds and neutralizes apoL-I. Unlike humans, baboons are not susceptible to infection by T. b. rhodesiense due to previously unidentified serum factors. Here, we show that baboons have a TLF complex that contains orthologs of Hpr and apoL-I and that full-length baboon apoL-I confers trypanolytic activity to mice and when expressed together with baboon Hpr and human apoA-I, provides protection against both animal infective and the human-infective T. brucei rhodesiense in vivo. We further define two critical lysines near the C terminus of baboon apoL-1 that are necessary and sufficient to prevent binding to SRA and thereby confer resistance to human-infective trypanosomes. These findings form the basis for the creation of TLF transgenic livestock that would be resistant to animal and human-infective trypanosomes, which would result in the reduction of disease and the zoonotic transmission of human infective trypanosomes.

Background: Three species of non-human primates comprising African green monkeys (AGMs), (Cercopithecus aethiops, n = 89), Syke's monkeys (Cercopithecus mitis, n = 60) and olive baboons (Papio cynocephalus anubis, n = 30), were screened for Entopolypoides macaci., Methods: Observation of blood smears prepared from these animals revealed E. macaci infection rate of 42.7% in AGMs, 35% in Syke's monkeys and 33.3% in baboons., Results: Gender infection rate was 38.2% in females and 29% in males. Statistically, there was no significant difference in infection rates between the monkey species and sexes (P > 0.05). Subsequent indirect immuno fluorescent antibody test supported the morphological appearance of E. macaci observed by microscopy. Sera from infected animals reacted positively (1:625) with E. macaci antigen, but not to Babesia bigemina or B. bovis antigen at 1:125 titer., Conclusion: This study has revealed high prevalence of E. macaci infection in all three widely distributed Kenyan non-human primates. With the continued use of these animals as models for human parasitic diseases, the presence of this highly enzootic parasite should be noted.

The glycoproteins secreted by Schistosoma mansoni cercariae and eggs play a key role in parasite transmission to and from the mammalian host. We used secreted preparations from these two life cycle stages to characterize the reactivity of sera from baboons exposed to normal and/or attenuated cercariae, in comparison with somatic antigen preparations and defined glycan epitopes. Periodate treatment of native antigens revealed that responses to the two secreted preparations were overwhelmingly directed against glycans rather than peptides. Considerable immunological cross-reactivity between glycans in the two preparations was inferred from a comparison of sera from infected-only and vaccinated-only animals, predominantly exposed to egg and cercarial secretions, respectively. In contrast, when somatic antigen preparations derived from adult worms or eggs were used to probe sera, a stronger antipeptide response was seen that accounted for up to 66% of maximum reactivity. Probing of sera with defined glycan structures confirmed the time course of responses and the presence of cross-reactive epitopes. In spite of the intense antiglycan response elicited in mice by administration of live eggs, no protection against a cercarial challenge was observed. Our data further support the hypothesis that antiglycan responses are a smokescreen with negligible protective potential.

Adult Oesophagostomum bifurcum (Nematoda: Strongylida) from human and non-human primates from Ghana were compared in order to investigate the extent of morphological variability within the species. Using analysis of variance and principal component analysis, significant differences in morphological characters (such as parasite length, width, length of the oesophagus and length of spicules) were demonstrated between O. bifurcum worms from humans, the Mona, Patas or Green monkey and/or Olive baboons. These findings suggest that O. bifurcum from different species of primate host represent distinct population variants, also supported by recent epidemiological and genetic studies of O. bifurcum from such hosts.

This study examined the endoparasite load of a group of olive baboons (Papio cynocephalus anubis) that share their habitat with a population of mountain gorillas (Gorilla gorilla berengei) in Bwindi Impenetrable National Park, Uganda. During a 2-week period in June 2002, shared habitat was substantiated by noting the ranging patterns of both species and recording observations and trail remains with a global positioning system (GPS). Parasite load was determined by collecting fecal samples preserved in 10% formalin and analyzed by sedimentation techniques and immunofluorescent antibodies (IFA). Bwindi baboons were infected with Cryptosporidium, Giardia, Eimeria, Ascaris spp., Strongyloides spp., Trichuris spp., Hymenolepis spp., and Ternidens diminuta. Of these, the Bwindi mountain gorillas had previously been found to carry Cryptosporidium, Giardia, Strongyloides spp., and Trichuris spp., but not Eimeria, Ascaris, Hymenolepis, or T. diminuta. This study is the first to record Giardia in olive baboons and demonstrates that at least three parasite species in Bwindi baboons have yet to be found in Bwindi gorillas. Early monitoring is essential to the health and well being of both of these sympatric primate species, especially as they continue to interact more often and over a larger area.

A total of 59 faecal samples from ranging Papio anubis (baboons) and another 41 from Cercopithecus aethiops (vervet) from the Rift Valley areas of Ethiopia were microscopically examined to determine the prevalence and species of major gastro-intestinal parasites of zoonotic importance. Faecal smears were prepared from fresh faecal samples, stained using modified Ziehl-Neelsen method and microscopically examined. About 3 gm of the dropping was also preserved separately in clean and properly labelled containers containing 10% formalin. The specimens were microscopically examined after formalin-ether concentration for ova, larvae, cysts and oocyst of intestinal parasites. The results of microscopic examination of faecal samples of baboons demonstrated the presence of Trichuris sp. (27.1%), Strongyloides sp. (37.3%), Trichostrongylus sp. (8.5%), Oesophagostomum sp. (10.2%), Schistosoma mansoni (20.3%), Entamoeba coli (83.1%), Entamoeba histolytica/dispar (16.9%), Blastocystis hominis (3.3%), Cyclospora sp. (13.3%) and Cryptosporidium sp. (11.9%). Likewise, the results of microscopic examination of faecal samples of vervets demonstrated the presence of Trichuris sp. (36.6%), Oesophagostomum sp. (4.9%), E. coli (61.0%), E. histolytica/dispar (24.4%), B. hominis (34.2%), Cyclospora sp. (22.0%) and Cryptosporidium sp. (29.3%). The presence of parasitic protozoa and helminths in baboons and vervets in the study areas is a high risk to human welfare because these non-human primates use the same water sources as humans and range freely in human habitats. An implication of such parasitic infection for the control programme is discussed.

Six mandrills were immunized with 150 Loa loa infective stage larvae (L3) irradiated with 40 Krad, and challenged with 100 L3, 60 days after initial vaccination. The parasitological outcome of this immunization was compared to results from six mandrills infected with normal L3. No clear association was seen between vaccination and microfilaremia until day 245 when a significant drop in the level of microfilaria occurred in vaccinated compared to infected animals (5 vs 10 mf/ml; p = 0.012). A one-year follow-up of the humoral immune response showed a strong adult, microfilariae (Mf) and L3 specific IgG response, with distinct profiles for each extract. In immunized animal a significant decrease in antibody level was systematically observed between days 90-145 for the anti-L3 and anti-adult IgG. However, in the same group anti-Mf antibody levels that peaked around 160-175 days post-challenge, were inversely correlated with the decrease in Mf density between day 200 and day 386. These results suggest that immunization with irradiated L3 using these specific conditions may affect the appearance of Mf.

Approximately 90% of freshly imported macaques and other Old World Monkeys are known to be infected with respiratory mites. The lung associated pigments are integral components of pulmonary acariasis in Old World Monkeys; at least three distinctive pigmental bodies are identified in association with lung mite infection. Two major components of pigments are recently identified as silica by using elemental analysis using a high voltage electron microscope and an energy-dispersive X-ray analysis technique. Since a limited number of infected monkey lung tissues and associated pigments can be examined by this tedious procedure, it was important for us to examine much greater number of specimens to verify our initial observation. Ten microincineration technique described provided a unique and practical way to identify the mineral elements in as many 27 histologic sections within a short span of time. Silica and silicates are heat resistant whereas majority of organic materials including lung mite parasites disintegrated under the extreme temperature. Mineral elements were exclusively located within the polarizable white ash. More than 90% of total pigmental bodies identified were found to be related to siliceous materials in 20 incinerated infected monkey lung tissues whereas five noninfected lungs similarly examined did not reveal any pigmental bodies. Other than a small of fine granular mucin substances which were PAS positive, the majority of lung mite associated pigments such as large granules of hemosiderin, needle-like crystals and other fine granules engulfed by macrophages were identified to be siliceous materials as they have persisted even after microincineration. Mite parasites and other organic materials were completely disintegrated. Similar pigmental bodies examined by microscope X-ray analysis were positive for silicate. This finding suggests that lung mite infection in Old Monkeys apparently predisposed silicosis. Therefore, until the link between lung mite infection and silicosis is clarified, experimental inhalation toxicologic findings in mite-infected Old World monkeys should be interpreted cautiously.

Blood samples were collected from 121 individuals of three species of wild-caught nonhuman primates from Kenya, including African green monkeys (Cercopithecus aethiops), Syke's monkeys (C. mitis), and olive baboons (Papio cynocephalus anubis), and were examined for circulating Trypanosoma brucei and for T. brucei antigen and anti-trypanosome antibody. Indirect antibody enzyme-linked immunosorbent assay detected titers of anti-T. brucei antibodies in 13 of the primates sampled, and field-oriented latex agglutination test detected invariant T. brucei antigens in 10 (8.3%) of the primates. However, no trypanosomes were visible in blood smears, on wet blood films, or by buffy coat technique, nor were they demonstrable in a subset of C. aethiops individuals that were studied using mouse subinoculation.

A study was undertaken to search for DNA recombinant Schistosoma mansoni proteins responsible for eliciting an antibody response from the host at a very early phase after infection. A S. mansoni adult worm cDNA expression library was screened using pooled sera from baboons with four weeks of infection. Based on their specific reactivity with the S. mansoni infected sera and no reactivity when tested against the pre-infection sera from the same baboons, four clones were selected for further studies. Sequence analysis revealed that they were homologous to the S. mansoni heat shock protein 70 (hsp70). The insert sizes of the four selected clones varied from 1150 to 2006 bp. The preliminary characterization for antibody reactivity against a panel of baboon sera showed that the longest clone was the most reactive, eight out of eight acute and three out of four chronic sera reacting positively to this clone. The shortest clone was the least reactive. Our results suggest that the S. mansoni hsp70 elicits an early and strong antibody response in baboons and that antibodies to this protein can be detected in chronically infected animals. Therefore S. mansoni hsp70 may be a valid target for immunodiagnosis. However further studies are needed to identify the portion of the hsp70 that best fits the requirements for a valuable diagnostic antigen.

From March 1999 through August 2000, 511 stool samples collected from 11 different primate species in 10 geographically distinct locations in Kenya, East Africa, were screened for the presence of Cyclospora spp. oocysts. Positive samples (43/102, 42%) were identified in vervet monkeys (Cercopithecus aethiops) in 4 of 4 locations; 19/206 (9%) in yellow and olive baboons (Papio cynocephalus, P. anubis, respectively) in 5 of 5 locations; and 19/76 (25%) in black and white colobus monkeys (Colobus angolensis, C. guereza, respectively) from 2 of 3 locations. DNA sequences obtained from 18 S rRNA coding regions from respective subsets of these positive samples were typed as Cyclospora cercopitheci (samples from Cercopithecus aethiops). Cyclospora papionis (samples from Papio cynocephalus and P. anubis), and Cyclospora colobi (samples from Colobus angolensis and C. guereza). Cyclospora oocysts were not detected in samples collected from patas, highland sykes, lowland sykes, blue sykes, DeBrazza, or red-tailed monkeys. A coded map showing the geographic location of the collected samples is given. Stool samples from 1 troop of vervet monkeys were collected over a 12-mo period. Positive samples ranged between 21 and 63%. These results suggest that there is no strongly marked seasonality evident in Cyclospora infection in monkeys as has been noted in human infection. This is further confirmed by the recovery of positive samples collected from vervet monkeys, baboons, and colobus monkeys at all times of the year during this survey. This absence of seasonality in infection is especially notable because of the extreme weather patterns typical of Kenya, where marked rainy and dry seasons occur. A second noteworthy observation is that the striking host specificity of the Cyclospora species initially described was confirmed in this survey. Baboons were only infected with C. papionis, vervet monkeys with C. cercopitheci, and colobus monkeys with C. colobi, despite geographic overlaps of both the monkey and parasite species and wide geographic distribution of each parasite and monkey host.

Epidemiological studies were conducted in the Lake Langano area in the Rift Valley of Ethiopia to determine the occurrence of schistosomiasis and assess factors involved in its transmission. Microscopic examination of faecal specimens from free ranging Papio anubis (anubis baboon) troops from Bishan Gari and Burka Dita forest reserves revealed Schistosoma mansoni eggs with a prevalence of 12.1% (11/91) and 26.2%(34/130), respectively. The eggs were viable as confirmed by miracidial hatching and infectivity tests. Out of the total 12 communities (three schools, five villages and one herdsmen community) surveyed for schistosomiasis around Lake Langano, individuals excreting S. mansoni eggs were found in nine communities with prevalence of infection ranging from 1.4 to 43%. The intensity of infection ranged from 24 EPG (eggs per gram of faeces) to 243 EPG. Excretion of viable eggs by the baboons indicate that they play a role in maintenance of S. mansoni infection in the locality. The detection of S. mansoni eggs in young children, collection of cercarial-infected Biomphalaria pfeifferi in water bodies, and establishment of S. mansoni infection in lab-bred mice have confirmed establishment of transmission foci in Kime area, south-east of Lake Langano. However, the lake itself does not seem to support transmission of schistosomiasis since no snails were found along the shore of the Lake. Further investigations are indicated to fully elucidate the role baboons play in the epidemiology of schistosomiasis in the Rift Valley of Ethiopia. The risk of introduction of water-based development projects in these new endemic foci in relation to S. mansoni infection in the baboons is discussed.

Trypanosoma cruzi (Schyzotrypanum, Chagas, 1909), and Chagas disease are endemic in captive-reared baboons at the Southwest Foundation for Biomedical Research, San Antonio, Texas. We obtained PCR amplification products from DNA extracted from sucking lice collected from the hair and skin of T. cruzi-infected baboons, with specific nested sets of primers for the protozoan kinetoplast DNA, and nuclear DNA. These products were hybridized to their complementary internal sequences. Selected sequences were cloned and sequencing established the presence of T. cruzi nuclear DNA, and minicircle kDNA. Competitive PCR with a kDNA set of primers determined the quantity of approximately 23.9 +/- 18.2 T. cruzi per louse. This finding suggests that the louse may be a vector incidentally contributing to the dissemination of T. cruzi infection in the baboon colony.

A 26-lb wild-caught adult female baboon was obtained from a commercial vendor. Routine tests for parasites, pathogenic bacteria, and tuberculosis were negative throughout the 10-week quarantine. However, routine radiographs performed at the end of the quarantine period detected multiple small radioopaque nodules evenly dispersed throughout the liver. A hepatic biopsy was obtained during routine ovariectomy of the baboon, and a diagnosis of granulomatous hepatitis made. Approximately 1 year after her arrival, the baboon was euthanized for reasons unrelated to the hepatitis. The liver contained multiple (40 to 50) white foci that were 1 to 3 mm in diameter; these foci were visible on the surface as well as throughout the parenchyma. There was multifocal, moderate capsular fibrosis, with adhesions between the hepatic lobes and between the diaphragm and liver. Histologic examination revealed multiple degenerate Hepatocystis sp. merocysts. H. kochi and H. simiae are malarial-type nonpathogenic protozoa endemic to Old World nonhuman primates, including baboons. Infected animals are asymptomatic and do not experience hemolysis. Transmission requires an insect vector, therefore infection with Hepatocystis sp. has minimal implications for colony health. There is no known danger of transmission to humans.

A survey of gastrointestinal parasites of nonhuman primates in Gombe National Park, Tanzania, was conducted during July and August 1989. Fresh fecal samples collected from 35 baboons (Papio cynocephalus anubis) and 20 chimpanzees (Pan troglodytes) were analyzed for intestinal parasites. Parasite identifications were based upon the size and appearance of eggs and larvae on both direct and fecal flotation examinations. Seven species of helminths and three species of protozoa were noted in the chimpanzees, and seven species of helminths, two species of trematodes, and one species of protozoa were noted in baboons. An unidentified parasite, with a thick egg shell similar to that of ascarids, was noted in both the chimpanzee and baboon population. Unfortunately a definitive identification of this parasite could not be made based upon egg size and morphology alone and insufficient numbers of larva were present to aid identification. One previously unreported parasite, Schistosoma mansoni, was identified in the baboon population. This is the first report of a schistosome in Gombe's nonhuman primate population.

Mandrills (Mandrillus sphinx) experimentally infected with human Loa loa usually remain microfilaremic for a long period of time. Nevertheless some control their microfilaremia while still harboring adults worms, and therefore become occult-infected. A nested polymerase chain reaction (PCR) assay, targeted on the repeat 3 region of the gene coding for the L. loa 15-kD protein (15r3-PCR), has been evaluated in mandrills infected with third-stage larvae (L3) of L. loa. The results of this assay were negative during the prepatency period (4 months after inoculation), but became positive when microfilariae appeared in the blood, and remained positive in all mandrills, even in those that became amicrofilaremic. These results show that the positivity of the 15r3-PCR assay is linked to the appearance of microfilariae in peripheral blood and demonstrated that L. loa-specific DNA can be detected in blood from occult-infected mandrills.

Over the past three decades, intensive studies of murine schistosomiasis have provided important clues to the understanding of the human disease, but growing evidence suggests that these results derived from highly inbred strains of mice might not have direct applicability to the human infection. Recent data based on the baboon indicate that infection in this non-human primate might mirror the human situation. In this review, Mramba Nyindo and Idle Farah demonstrate that baboons provide an excellent non-human primate model that produces pathology and disease closely resembling that observed in humans, and address how studies in baboons can provide insights into mechanisms regulating schistosomiasis mansoni pathology and immunity. They also address, in a general way, issues related to the use of non-human primates in biomedical research.

In recent years, human cyclosporiasis has emerged as an important infection, with large outbreaks in the United States and Canada. Understanding the biology and epidemiology of Cyclospora has been difficult and slow and has been complicated by not knowing the pathogen s origins, animal reservoirs (if any), and relationship to other coccidian parasites. This report provides morphologic and molecular characterization of three parasites isolated from primates and names each isolate: Cyclospora cercopitheci sp.n. for a species recovered from green monkeys, C. colobi sp.n. for a parasite from colobus monkeys, and C. papionis sp.n. for a species infecting baboons. These species, plus C. cayetanensis, which infects humans, increase to four the recognized species of Cyclospora infecting primates. These four species group homogeneously as a single branch intermediate between avian and mammalian Eimeria. Results of our analysis contribute toward clarification of the taxonomic position of Cyclospora and its relationship to other coccidian parasites.

Blood smear evaluation of two baboons (Papio cynocephalus) experiencing acute hemolytic crises following experimental stem cell transplantation revealed numerous intraerythrocytic organisms typical of the genus Babesia. Both animals had received whole-blood transfusions from two baboon donors, one of which was subsequently found to display rare trophozoites of Entopolypoides macaci. An investigation was then undertaken to determine the prevalence of hematozoa in baboons held in our primate colony and to determine the relationship, if any, between the involved species. Analysis of thick and thin blood films from 65 healthy baboons (23 originating from our breeding facility, 26 originating from an out-of-state breeding facility, and 16 imported from Africa) for hematozoa revealed rare E. macaci parasites in 31%, with respective prevalences of 39, 35, and 12%. Phylogenetic analysis of nuclear small-subunit rRNA gene sequences amplified from peripheral blood of a baboon chronically infected with E. macaci demonstrated this parasite to be most closely related to Babesia microti (97.9% sequence similarity); sera from infected animals did not react in indirect fluorescent-antibody tests with Babesia microti antigen, however, suggesting that they represent different species. These results support an emerging view that the genus Entopolypoides Mayer 1933 is synonymous with that of the genus Babesia Starcovici 1893 and that the morphological variation noted among intracellular forms is a function of alteration in host immune status. The presence of an underrecognized, but highly enzootic, Babesia sp. in baboons may result in substantial, unanticipated impact on research programs. The similarity of this parasite to the known human pathogen B. microti may also pose risks to humans undergoing xenotransplantation, mandating effective screening of donor animals.

Cyclospora organisms are intestinal pathogens of humans that are increasingly recognized in many parts of the world; yet, the reservoirs and host range remain poorly defined. Analysis of 18S ribosomal DNA (rDNA) suggests that the human-associated Cyclospora species (Cyc-hu) is most closely related to the Eimeria species, which are host species-specific. Recently, oocysts identical to those of Cyc-hu were detected in baboon fecal specimens from Tanzania. The 18S rDNA from 3 of these baboon-associated oocyst specimens was amplified and sequenced. Phylogenetic analysis indicated that these baboon-associated Cyclospora-like organisms (Cyc-bab) are nearly identical to each other and are distinct from Cyc-hu (1.6%-1.7% dissimilar); however, these Cyc-bab organisms are the closest known relatives of Cyc-hu. Together, these primate-associated cyclosporans constitute a coherent clade within the diverse group of Eimeria species. These findings raise important questions about the evolutionary relationships of the eimeriids and Cyc-hu host range and should lead to improved polymerase chain reaction-based diagnostics.

A study was undertaken to categorise some gastro-intestinal (GIT) parasites commonly observed in Kenyan non-human primates (NHPs) on the basis of their health implications for humans. Six species of locally available non-human primates, namely olive baboons (Papio cyanocephalus anubis), Vervet monkey (Cercopithecus aethiops), Sykes monkey (Cercopithecus mitis), Black and white colobus (Colobus abyssinicus), Debrazzas monkey (Cercopithecus neglectus) and Grey and Black mangabeys (Cercocebus torquatus and Cercocebus albigena) which were imported from Zaire (Democratic Republic of Congo) were sampled. Simple laboratory methods involving microscopic examination of stained faecal smears were used. Wet faecal smears stained with iodine and unstained controls were used for conventional parasites while acid fast staining was employed to detect Cryptosporidium oocysts. Both helminths and protozoan parasites were detected in varying rates in all primate species. Trichuris sp. was the most frequent helminth followed by Strongyloides fulleborni, Strongyles sp. and Schistosoma mansoni in that order. Entamoeba coli was the most common protozoan followed, respectively, by Balantidiun coli and Entamoeba histolytica. All primate species examined were infected with all the parasites listed except the black and white colobus. Cryptosporidium was found in both clinically normal and diarrhoeic baboons and vervets. Most taxa of parasites observed could prejudice human welfare directly through infection and causation of illness and indirectly through increased cost of livestock production and decreased availability of animal proteins. The potential of some of the agents to cause opportunistic infections in immuno-compromised persons was suggested as a likely threat to man's well-being. This would warrant such person's exemption from high risk operations at primate and other animal facilities in developing countries. Further, specific studies are needed to provide data on the epidemiology, socio-economic impact and pathogenicity of the primate parasites to other species of animals and man.

The objective of this study was to investigate the gastro-intestinal (GIT) parasites commonly occurring in captive and wild-trapped (WT) non-human primates (baboons, vervets and Sykes) in Kenya and compare their prevalence. Three hundred and fifteen faecal samples were subjected to a battery of diagnostic tests, namely, direct smear, modified formal ether sedimentation, Kato thick smear, Harada-Mori techniques for parasite detection and culture to facilitate nematode larvae identification. Of these, 203 (64.4%) harboured helminths and 54 (17.1%) had protozoa. The helminth parasites comprised Strongyloides fulleborni 141 (44.8%), Trichuris trichuira 200 (63.5,%), Oesophagostomum sp. 48 (15.2%), Trichostrongylus sp. 73 (23.2%), Enterobius vermicularis 44 (14.0%), Schistosoma mansoni 4/92 (4.3%) and Streptopharagus sp. 68 (21.6%). Protozoan parasites consisted of Entamoeba coli 204 (64.8%), Balantidium coli 127 (40.3%) and Entamoeba histolytica 78 (24.8%). Both WT and colony-borne (CB) primates had similar species of parasites, but higher prevalences of protozoan infection were observed in CB baboons while helminth infections were relatively more common in WT primates. Some of the parasites observed in this study are reported to be zoonotic in various parasitological literatures. Chemoprophylaxis and other managerial practices were believed to be responsible for the lower worm prevalence in CB primates. Similar intervention against protozoa and other agents will not only improve primate health, but also increase safety to animal handlers and colony workers.

A case of disseminated coccidioidomycosis caused by a dimorphic fungus Coccidioides immitis in a mandrill baboon (Mandrillus sphinx) was diagnosed following radiography, ultrasound-guided aspiration of thoracic lesions, and aspiration cytology of skeletal lesions of the left sixth rib. The diagnosis was confirmed by fungal culture and serum quantitative immunodiffusion for antibodies against C. immitis.

A total of 114 nonhuman primates comprising 51 vervet monkeys (Cercopithecus aethiops) and 63 olive baboons (Papio anubis) were examined for Cryptosporidium oocysts using the modified Kinyoun's acid-fast staining technique. About 51.7% (59/114) of all the specimens examined, representing 78.4% (40/51) of the vervet monkeys and 30.1% (19/63) of the olive baboons were positive. Bright red, refractile Cryptosporidium oocysts were observed in the stained faecal smears against a blue background. Up to 4/6 (66.7%) of the diarrhoeic vervets and 2/3 (66.7%) baboons, respectively, were positive while the rest were negative. To the best of our knowledge, this report is the first on cryptosporidiosis in old world nonhuman primates in Kenya and probably the first report of the infection in olive baboons. Given the high frequency of oocysts in diarrhoeal specimens, the parasite may have been associated with clinical diarrhoea in the sampled animals. Cryptosporidium, which has been reported in humans in Kenya, is also suspected to occur in livestock. Its isolation from clinically ill, normal colony-borne and newly caught feral nonhuman primates has significant implications for both public health and animal agriculture in Kenya.

The ability of the host to modulate the granulomatous response around ova trapped in tissues determines the severity of disease to schistosome infections. Multiple factors may affect this modulation such as age, prior sensitization, history of treatment, and exposure. The present study examines the effect of different patterns of exposure on the sequential development and modulation of granuloma in juvenile Kenyan baboons (Papio cynocephalus anubis) after receiving either a single infection (SI) of 1500 Schistosoma mansoni cercariae or multiple infections (MI) of 150 cercariae, once a week for 10 weeks. Prior to sacrifice at 17 weeks postinfection (p.i.), liver biopsies were obtained at Weeks 0, 6, 9, and 13. SI animals experienced more prolonged dysentery and greater weight loss compared to MI animals. Peak hepatic granuloma size (mean 355 +/- 65.5 microns diameter), the maximum percentage of eosinophils in the granuloma (61%), and severity of disease occurred at 6 weeks in SI animals. Peak granuloma size and pathology did not appear until Week 9 in the MI animals (mean 317.7 +/- 67.3 microns diameter). Granuloma size, tissue eosinophilia, and gross pathology diminished by Week 13 p.i. and were virtually absent in both groups by Week 17. The decrease in granuloma size, pathology, and clinical illness resolved more rapidly in the MI baboons. Singly infected baboons were more susceptible to infection (83 +/- 12% of cercariae developed into adult worms) compared to MI baboons (67 +/- 7%, P < 0.01). Eggs recovered from tissues at necropsy were primarily confined to the large intestine (85% of total egg recovered), followed by liver (10%) and small intestine (5%). Significantly more eggs were recovered from MI compared to SI animals, indicating a higher fecundity of female worms in the MI baboons. These date demonstrate that granulomatous responses develop more slowly and modulate more rapidly with repeated infection compared to a single heavy infection and suggest the type of exposure may affect the pathologic response to infection.

Free ranging hamadryas baboons (Papio hamadryas) in four localities in the west and north of Saudi Arabia were examined for natural infection with Schistosoma mansoni. Faecal examination revealed infection with S. mansoni on four occasions within one year (at a prevalence rate of 2.5-4.0%) in only one locality, the Al-Baha area. The eggs were viable, as shown by miracidial hatching tests, and were recorded at a density of 140-280 eggs/g of faeces (7000-14,000 eggs/day). Post-mortem examination of 13-24 baboons from each locality revealed infection with S. mansoni (adult worms and eggs in tissue) in only one locality, the Al-Baha area, at a prevalence rate of 4.16%. Viable eggs were found in the faeces and tissue of the infected baboons. The low prevalence rate of S. mansoni in hamadryas baboons in Saudi Arabia is in accordance with the low prevalence rate of S. mansoni in humans in the area. This natural baboon isolate was highly infective to snail intermediate hosts and mammalian hosts under experimental conditions. The epidemiological significance of the role of P. hamadryas (considering their large overall population of 250,000) as maintenance hosts of S. mansoni in Saudi Arabia is discussed.

Light and scanning electron microscopic study of intestines of 5 baboons (Papio anubis) in a state of acute schistosomiasis mansoni after exposure to 800 cercariae was made. In addition to overt granulomatous inflammation in the mucosa of the colon and ileum, more subtle microscopic lesions consisting of smooth muscle hypertrophy and villous atrophy were present. The intensity and distribution of these lesions were less marked in 5 baboons previously vaccinated with 40,000 30-krad-attenuated cercariae and presenting a 39% mean protection level measured as a percent reduction in adult worms recovered from mesenteric vasculature at perfusion. No similar lesions were observed in 2 normal uninfected and nonvaccinated baboons. These results are comparable to what has been reported in mice infected by Schistosoma mansoni. The data indicate that villous atrophy, hypertrophy of muscularis mucosa, nd goblet cell hyperplasia are important pathological changes to be included in the evaluation of the efficacy of schistosomiasis vaccines in the baboon model, together with the routine adult worm recovery from mesenteric blood vessels and the overt liver and bowel pathology.

A cross-sectional parasitological study of a population of wild olive baboons (Papio cynocephalus anubis), consisting of 5 troops, was conducted in Gombe Stream National Park. Baboons were individually recognizable. Information on age, sex, troop membership, reproductive status, social rank and life-history of each individual baboon could be related to parasite infection. Seven helminth taxa and 2 protozoan taxa were found. All baboons were parasitized by at least 1 taxon. Distributions of helminths were aggregated among hosts. There were significant differences among troops in the prevalence of all but 2 of the recorded helminths. Age had a significant impact on the prevalence and intensity of Strongyloides sp. No significant effect of sex on the prevalence of infection could be detected. There was some indication that female reproductive status was related to Trichuris egg output. In contrast to a previous study, no significant correlations between parasite infection and social rank could be found. Troop membership constituted the predominant factor contributing to heterogeneity of prevalence of infection. This suggests that spatial location and/or genetics may be important in determining levels of parasite infection.

Six hundred and thirty-three faecal samples were randomly collected and examined for ova and cysts of intestinal parasites from five groups of hamadryas baboons of different population densities, with different human contact and in different ecological conditions (Al-Baha, Turabah and Al-Taif in south-western and Al-Rihat and Al-Akhal in north-western Saudi Arabia). Nine parasites were recorded (Giardia lamblia, Entamoeba histolytica, Escherichia coli, Balantidium coli, Enterobius sp., Trichuris sp., Hookworm, Hymenolepis nana and Schistosoma mansoni) in 274 samples (43.28%). The prevalence of parasites was high (36.0-58.5%) in areas of mild, cool climatic conditions, where baboons were at high density and had maximum human contact. However, in an area (Al-Akhal) of hot, dry climatic conditions, low baboon density and minimum human contact, the parasites' prevalence was very low (9.5%). The concentration of parasites (ova or cysts per g of faeces) was medium. Post-mortem examination of 24, 20, 19 and 13 baboons from Al-Baha, Al-Taif, Turabah and Al-Rihat revealed most of the parasites recorded in random faecal samples at prevalence rates of 37.5, 30.0, 36.0 and 23.0% respectively. The overall prevalence rate was 32.9%. Most of the parasites recorded in baboons were also recorded in humans in the areas of study.