Two Cases of Cleft Lip and Other Congenital Anomalies in Wild Chimpanzees Living in Kibale National Park, Uganda.

DESIGN: Observations of wild chimpanzees ( Pan troglodytes schweinfurthii) were conducted in Kibale National Park, Uganda, at the sites of Sebitoli and Ngogo. RESULTS: We report the first two cases of cleft lip in wild chimpanzees. Additionally, some other chimpanzees in the Sebitoli community show facial dysplasia and congenital anomalies, such as patches of depigmented hairs and limb defects. CONCLUSIONS: Cleft lip has been documented in several species of nonhuman primates, but much remains unknown about the occurrence of cleft lip and cleft palate in great apes, probably because such malformations are rare, wild apes are difficult to monitor and observe, and severe cases associated with cleft palates render suckling impossible and lead to early death of infants. The genetic basis of such defects in great apes warrants investigation, as does the possibility that environmental toxins contribute to their etiology in Kibale in ways that could affect humans as well.

Wild chimpanzees on the edge: nocturnal activities in croplands.

In a rapidly changing landscape highly impacted by anthropogenic activities, the great apes are facing new challenges to coexist with humans. For chimpanzee communities inhabiting encroached territories, not bordered by rival conspecifics but by human agricultural fields, such boundaries are risky areas. To investigate the hypothesis that they use specific strategies for incursions out of the forest into maize fields to prevent the risk of detection by humans guarding their field, we carried out video recordings of chimpanzees at the edge of the forest bordered by a maize plantation in Kibale National Park, Uganda. Contrary to our expectations, large parties are engaged in crop-raids, including vulnerable individuals such as females with clinging infants. More surprisingly chimpanzees were crop-raiding during the night. They also stayed longer in the maize field and presented few signs of vigilance and anxiety during these nocturnal crop-raids. While nocturnal activities of chimpanzees have been reported during full moon periods, this is the first record of frequent and repeated nocturnal activities after twilight, in darkness. Habitat destruction may have promoted behavioural adjustments such as nocturnal exploitation of open croplands.

Facial dysplasia in wild chimpanzees.

At least 10% of the Sebitoli chimpanzee community of the Kibale National Park (Uganda) present a characteristic facial phenotype with flattened nose, reduced nostrils, and concave mid-face. Affected individuals do not present skin lesions, and also young infants are affected. We suggest, therefore, a congenital origin of this defect.

Investigations on anopheline mosquitoes close to the nest sites of chimpanzees subject to malaria infection in Ugandan highlands.

BACKGROUND: Malaria parasites (Plasmodium sp.), including new species, have recently been discovered as low grade mixed infections in three wild chimpanzees (Pan troglodytes schweinfurthii) sampled randomly in Kibale National Park, Uganda. This suggested a high prevalence of malaria infection in this community. The clinical course of malaria in chimpanzees and the species of the vectors that transmit their parasites are not known. The fact that these apes display a specific behaviour in which they consume plant parts of low nutritional value but that contain compounds with anti-malarial properties suggests that the apes health might be affected by the parasite. The avoidance of the night-biting anopheline mosquitoes is another potential behavioural adaptation that would lead to a decrease in the number of infectious bites and consequently malaria. METHODS: Mosquitoes were collected over two years using suction-light traps and yeast-generated CO(2) traps at the nesting and the feeding sites of two chimpanzee communities in Kibale National Park. The species of the female Anopheles caught were then determined and the presence of Plasmodium was sought in these insects by PCR amplification. RESULTS: The mosquito catches yielded a total of 309 female Anopheles specimens, the only known vectors of malaria parasites of mammalians. These specimens belonged to 10 species, of which Anopheles implexus, Anopheles vinckei and Anopheles demeilloni dominated. Sensitive DNA amplification techniques failed to detect any Plasmodium-positive Anopheles specimens. Humidity and trap height influenced the Anopheles capture success, and there was a negative correlation between nest numbers and mosquito abundance. The anopheline mosquitoes were also less diverse and numerous in sites where chimpanzees were nesting as compared to those where they were feeding. CONCLUSIONS: These observations suggest that the sites where chimpanzees build their nests every night might be selected, at least in part, in order to minimize contact with anopheline mosquitoes, which might lead to a reduced risk in acquiring malaria infections.

[Great apes: who are they? Are they able to self-medicate?]. / Les grands singes: qui sont-ils? Sont-ils capables d'automédication?

Six great ape species (chimpanzees, bonobos, Western gorillas, Eastern gorillas, Sumatran orangutans and Bornean orangutans) live in tropical forests of Africa and South-East Asia. Their habitat, severely threatened by deforestation, contains a vast chemical and biological diversity. During the last decade, we have isolated and identified novel pharmacologically active compounds from plants used by wild chimpanzees in Kibale National Park, Uganda. Our continuous observations over the last 12 years confirm that chimpanzees, when sick, may ingest plant material that are not generally eaten, supporting the existence of self-medication among great apes. Knowledge of great-ape diseases, and the medicinal resources of tropical forests, may be improved by preserving and studying our closest relatives in their natural habitat.

On the diversity of malaria parasites in African apes and the origin of Plasmodium falciparum from Bonobos.

The origin of Plasmodium falciparum, the etiological agent of the most dangerous forms of human malaria, remains controversial. Although investigations of homologous parasites in African Apes are crucial to resolve this issue, studies have been restricted to a chimpanzee parasite related to P. falciparum, P. reichenowi, for which a single isolate was available until very recently. Using PCR amplification, we detected Plasmodium parasites in blood samples from 18 of 91 individuals of the genus Pan, including six chimpanzees (three Pan troglodytes troglodytes, three Pan t. schweinfurthii) and twelve bonobos (Pan paniscus). We obtained sequences of the parasites' mitochondrial genomes and/or from two nuclear genes from 14 samples. In addition to P. reichenowi, three other hitherto unknown lineages were found in the chimpanzees. One is related to P. vivax and two to P. falciparum that are likely to belong to distinct species. In the bonobos we found P. falciparum parasites whose mitochondrial genomes indicated that they were distinct from those present in humans, and another parasite lineage related to P. malariae. Phylogenetic analyses based on this diverse set of Plasmodium parasites in African Apes shed new light on the evolutionary history of P. falciparum. The data suggested that P. falciparum did not originate from P. reichenowi of chimpanzees (Pan troglodytes), but rather evolved in bonobos (Pan paniscus), from which it subsequently colonized humans by a host-switch. Finally, our data and that of others indicated that chimpanzees and bonobos maintain malaria parasites, to which humans are susceptible, a factor of some relevance to the renewed efforts to eradicate malaria.