Savanna chimpanzee (Pan troglodytes) crop feeding at Dindefelo, Senegal: challenges and implications for conservation

Chimpanzees (Pan troglodytes) are categorized as Endangered by the International Union for Conservation of Nature, and habitat loss due to conversion of land for agriculture is one of the major threats to wild populations of this species. This challenging scenario can lead to negative human-chimpanzee interactions, including crop feeding. Chimpanzees consume crops across their geographical range, although little is known about this behavior in savanna habitats. Here we provide new evidence of crop feeding by savanna chimpanzees. We conducted our observations at Dindefelo, a community nature reserve in southeastern Senegal. The chimpanzees were observed to feed on mango (Mangifera indica) and also on baobab (Adansonia digitata), a wild species considered a crop by local people when found in and around villages. Although local people use the fruits of these species for food and income, they tolerated crop-feeding events until recently. In 2023, a case of harassment of a crop-feeding chimpanzee in a mango orchard was witnessed, and four days later a chimpanzee corpse was found at the same place. We conclude that habitat conversion into agricultural fields, uncontrolled bush fires and extraction of wild fruits are the important factors influencing crop-feeding events at Dindefelo. Our findings highlight the need to better understand human-chimpanzee interactions in the anthropogenic landscape of Dindefelo to help mitigate negative attitudes and behaviors towards chimpanzees.

Population Diversity of Antibiotic Resistant Enterobacterales in Samples From Wildlife Origin in Senegal: Identification of a Multidrug Resistance Transposon Carrying blaCTX–M–15 in Escherichia coli

Introduction

The role of wildlife in the transmission of antimicrobial resistant (AMR) is suspected but scarcely reported in current studies. Therefore, we studied the dynamics and prevalence of antibiotic-resistant Enterobacterales in antibiotic-limited areas of Senegal.

Materials and Methods

We collected fecal samples from monkeys and apes (N = 226) and non-fecal environmental samples (N = 113) from Senegal in 2015 and 2019. We grew the samples on selective media, subsequently isolated AMR Enterobacterales, and then sequenced their genomes.

Results

We isolated 72 different Enterobacterales among which we obtained a resistance rate of 65% for colistin (N = 47/72) and 29% for third generation-cephalosporin (C3G) (29%, N = 21/72). Interestingly, almost 46% of our isolates, among Enterobacter sp., Citrobacter cronae and Klebsiella aerogenes, belong to 34 new STs. Moreover, the genes bla_CTX–M–15, bla_TEM1B, sul2, dfrA14, qnrs, aph(3′′), aph(6), tetA, and tetR harbored within a transposon on the IncY plasmid of ST224 Escherichia coli were transferred and inserted into a ST10 E. coli phage coding region.

Conclusion

Wildlife constitutes a rich, unexplored reservoir of natural microbial diversity, AMR genes and international resistant clones pathogenic in humans. The presence of a transposon that carries AMR genes is intriguing since no antibiotics are used in the non-human primates we studied.

Bacterial Infections in Humans and Nonhuman Primates from Africa: Expanding the Knowledge

The close phylogenetic relationship between humans and other primates creates exceptionally high potential for pathogen exchange. The surveillance of pathogens in primates plays an important role in anticipating possible outbreaks. In this study, we conducted a molecular investigation of pathogenic bacteria in feces from African nonhuman primates (NHPs). We also investigated the pathogens shared by the human population and gorillas living in the same territory in the Republic of Congo. In total, 93% of NHPs (n=176) and 95% (n=38) of humans were found to carry at least one bacterium. Non-pallidum Treponema spp. (including T. succinifaciens, T. berlinense, and several potential new species) were recovered from stools of 70% of great apes, 88% of monkeys, and 79% of humans. Non-tuberculosis Mycobacterium spp. were also common in almost all NHP species as well as in humans. In addition, Acinetobacter spp., members of the primate gut microbiota, were mainly prevalent in human and gorilla. Pathogenic Leptospira spp. were highly present in humans (82%) and gorillas (66%) stool samples in Congo, but were absent in the other NHPs, therefore suggesting a possible gorillas-humans exchange. Particular attention will be necessary for enteropathogenic bacteria detected in humans such as Helicobacter pylori, Salmonella spp. (including S. typhi/paratyphi), Staphyloccocus aureus, and Tropheryma whipplei, some of which were also present in gorillas in the same territory (S. aureus and T. whipplei). This study enhances our knowledge of pathogenic bacteria that threaten African NHPs and humans by using a non-invasive sampling technique. Contact between humans and NHPs results in an exchange of pathogens. Ongoing surveillance, prevention, and treatment strategies alone will limit the spread of these infectious agents.

Adenovirus Infections in African Humans and Wild Non-Human Primates: Great Diversity and Cross-Species Transmission

Non-human primates (NHPs) are known hosts for adenoviruses (AdVs), so there is the possibility of the zoonotic or cross-species transmission of AdVs. As with humans, AdV infections in animals can cause diseases that range from asymptomatic to fatal. The aim of this study was to investigate the occurrence and diversity of AdVs in: (i) fecal samples of apes and monkeys from different African countries (Republic of Congo, Senegal, Djibouti and Algeria), (ii) stool of humans living near gorillas in the Republic of Congo, in order to explore the potential zoonotic risks. Samples were screened by real-time and standard PCRs, followed by the sequencing of the partial DNA polymerase gene in order to identify the AdV species. The prevalence was 3.3 folds higher in NHPs than in humans. More than 1/3 (35.8%) of the NHPs and 1/10 (10.5%) of the humans excreted AdVs in their feces. The positive rate was high in great apes (46%), with a maximum of 54.2% in chimpanzees (Pan troglodytes) and 35.9% in gorillas (Gorilla gorilla), followed by monkeys (25.6%), with 27.5% in Barbary macaques (Macaca sylvanus) and 23.1% in baboons (seven Papio papio and six Papio hamadryas). No green monkeys (Chlorocebus sabaeus) were found to be positive for AdVs. The AdVs detected in NHPs were members of Human mastadenovirus E (HAdV-E), HAdV-C or HAdV-B, and those in the humans belonged to HAdV-C or HAdV-D. HAdV-C members were detected in both gorillas and humans, with evidence of zoonotic transmission since phylogenetic analysis revealed that gorilla AdVs belonging to HAdV-C were genetically identical to strains detected in humans who had been living around gorillas, and, inversely, a HAdV-C member HAdV type was detected in gorillas. This confirms the gorilla-to-human transmission of adenovirus. which has been reported previously. In addition, HAdV-E members, the most often detected here, are widely distributed among NHP species regardless of their origin, i.e., HAdV-E members seem to lack host specificity. Virus isolation was successful from a human sample and the strain of the Mbo024 genome, of 35 kb, that was identified as belonging to HAdV-D, exhibited close identity to HAdV-D members for all genes. This study provides information on the AdVs that infect African NHPs and the human populations living nearby, with an evident zoonotic transmission. It is likely that AdVs crossed the species barrier between different NHP species (especially HAdV-E members), between NHPs and humans (especially HAdV-C), but also between humans, NHPs and other animal species.