Nodular worms (Oesophagostomum spp.) are common intestinal parasites found in cattle, pig, and primates including humans. In human, they are responsible for serious clinical disease called oesophagostomosis resulting from the formation of granulomas, caseous lesions or abscesses in intestinal walls. In wild great apes, the fecal prevalence of this parasite is high, but little information is available concerning the clinical signs and lesions associated. In the present study, we describe six cases of multinodular oesophagostomosis in free-ranging and ex-captive chimpanzees and captive gorillas caused by Oesophagostomum stephanostomum. While severe clinical signs associated with this infection were observed in great apes raised in sanctuaries, nodules found in wild chimpanzees do not seem to affect their health status. One hypothesis to explain this difference would be that in wild chimpanzees, access to natural environment and behavior such as rough leaves swallowing combined with ingestion of plants having pharmacological properties would prevent severe infection and decrease potential symptoms.

No abstract

Returning confiscated animals to their native habitats is desirable when it makes a positive contribution to the conservation of the species. Release of captive individuals is complex and controversial, however, particularly when risks are potentially high, as in the case of orphaned apes. We describe the decision-making process that led to the successive release of 20 wild-born orphan chimpanzees ( Pan troglodytes troglodytes ) into the Conkouati Reserve in the Republic of Congo. Recommendations of the Reintroduction Specialist Group of the World Conservation Union's Species Survival Commission were followed closely. The conservation status, ecology, and behavior of wild chimpanzees; the biological, social, economic and political context of the release site; and the health and genetic status of the candidates for release were all taken into account in the planning and execution of the project. Rigorous post-release monitoring of behavior and health allowed documentation of the outcome. The project was of benefit to the chimpanzees that were released but also brought broad benefits to the site through effective protection from poaching and deforestation, and direct and indirect benefits to local people. The genetic and behavioral diversity of chimpanzees require a variety of conservation strategies to reduce threats and maintain as many viable wild populations as possible. Marco de Trabajo de Conservación Biológica para la Liberación de Chimpancés Huérfanos Silvestres Nacidos en la Reserva Conkouati, CongoResumen: El retorno de animales confiscados a sus hábitats nativos es deseable cuando ocasiona una contribución positiva para la conservación de la especie. Sin embargo, la liberación de individuos cautivos es compleja y controversial, particularmente cuando los riesgos son potencialmente altos, como es el caso de los monos huérfanos. Describimos el proceso de toma de decisiones que condujo a la liberación de exitosa de 20 chimpancés silvestres huérfanos ( Pan troglodytes troglodytes ) dentro de la Reserva Conkouati de la República de Congo. Las recomendaciones del Grupo de especialistas en reintroducción de la UICN-SSC fueron seguidas de cerca. El estatus de conservación, ecología y conducta de los chimpancés silvestres; el contexto biológico, social, económico y político del sitio de liberación y la salud y estatus genético de los candidatos a ser liberados fueron también tomados en consideración en la planeación y ejecución del proyecto. El monitoreo riguroso post-liberación de la conducta y salud permitió la documentación de los resultados. El proyecto fue § § Current address: Le benéfico para los chimpancés liberados pero también trajo beneficios amplios al sitio mediante la protección efectiva de la caza fortuita y la deforestación y beneficios directos e indirectos para la población humana local. La diversidad genética y conductual de los chimpancés requiere de una variedad de estrategias de conservación para reducir las amenazas y mantener cuantas poblaciones silvestres viables sean posibles.

Coprophagy occurred during major periods of feeding on fruits of Dialium spp. (Caesalpiniaceae) in a group of orphaned chimpanzees released in Conkouati Douli National Park, Republic of Congo. Since stress, boredom or food scarcity could not explain coprophagy according to our daily behavioral and veterinary control observations, we suggest that Dialium seeds were the item of interest in the feces. Two types of Dialium seeds were commonly found in the feces after chimpanzees swallowed the mesocarp and whole seeds together. These seeds were either whole and hard or whole/broken and soft imbibed. A mechanical and/or chemical effect of the gut passage may enable the chimpanzees to chew and ingest the seeds, thus providing nutritional intake.

Logging and poaching have dramatically reduced chimpanzee density and distribution in the Republic of Congo. Most chimpanzee translocations attempted in the past failed because a number of biological and non-biological factors can influence success. Biological considerations include knowledge of behaviour, disease, habitat requirements and genetics. We critically review genetic considerations in pre-and post-release phases of translocations and apply them to a welfare-based chimpanzee release project in the Republic of Congo which aimed to re-establish orphan chimpanzees in the wild with a native chimpanzee population. We analyze genetic diversity and relatedness in released animals and devise a genotyping strategy for monitoring of released individuals and their future offspring. Fifty-nine confiscated chimpanzees from different areas of the Republic of Congo were typed for 20 microsatellites using plucked hair as the DNA source. Genetic diversity was high, with an average expected heterozygosity of 81%, and three to 18 alleles per locus. Between 1996 and 1998, 19 individuals were released, and genetic analysis showed that these are unrelated (mean r ± jack-knifed SD = -0.014 ± 0.001). Using F ST and population admixture analysis, we identified population structure in wild chimpanzees. For long-term genetic monitoring of released and native chimpanzees, we identified a set of six informative markers, which are easy to score using basic techniques.