NRU :: Browsing by Author "Chapman, Colin A."

Browsing by Author "Chapman, Colin A."

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Agricultural expansion as risk to endangered wildlife: Pesticide exposure in wild chimpanzees and baboons displaying facial dysplasia
(Science of the Total Environment, 2017) Krief, Sabrina; Berny, Philippe; Gumisiriza, Francis; Gross, Régine; Demeneix, Barbara; Baptiste Fini, Jean; Chapman, Colin A.; Chapman, Lauren J.; Seguya, Andrew; Wasswa, John
Prenatal exposure to environmental endocrine disruptors can affect development and induce irreversible abnormalities in both humans and wildlife. The northern part of Kibale National Park, a mid-altitude rainforest in western Uganda, is largely surrounded by industrial tea plantations and wildlife using this area (Sebitoli) must cope with proximity to human populations and their activities. The chimpanzees and baboons in this area raid crops (primarily maize) in neighboring gardens. Sixteen young individuals of the 66 chimpanzeesmonitored (25%) exhibit abnormalities including reduced nostrils, cleft lip, limb deformities, reproductive problems and hypopigmentation. Each pathology could have a congenital component, potentially exacerbated by environmental factors. In addition, at least six of 35 photographed baboons from a Sebitoli troop (17%) have similar severe nasal deformities. Our inquiries in villages and tea factories near Sebitoli revealed use of eight pesticides (glyphosate, cypermethrin, profenofos, mancozeb, metalaxyl, dimethoate, chlorpyrifos and 2,4-D amine). Chemical analysis of samples collected from 2014 to 2016 showed that mean levels of pesticides in fresh maize stems and seeds, soils, and river sediments in the vicinity of the chimpanzee territory exceed recommended limits. Notably, excess levels were found for total DDT and its metabolite pp′-DDE and for chlorpyrifos in fresh maize seeds and in fish from Sebitoli. Imidacloprid was detected in coated maize seeds planted at the edge the forest and in fish samples from the Sebitoli area, while no pesticides were detected in fish from central park areas. Since some of these pesticides are thyroid hormone disruptors, we postulate that excessive pesticide use in the Sebitoli area may contribute to facial dysplasia in chimpanzees and baboons through this endocrine pathway. Chimpanzees are considered as endangered by IUCN and besides their intrinsic value and status as closely related to humans, they have major economic value in Uganda via ecotourism. Identifying and limiting potential threats to their survival such be a conservation priority.
Antibiotic-Resistant Escherichia coli and Class 1 Integrons in Humans, Domestic Animals, and Wild Primates in Rural Uganda
(Applied and environmental microbiology, 2018) Weiss, Debora; Wallace, Ryan M.; Rwego, Innocent B.; Gillespie, Thomas R.; Chapman, Colin A.; Singer, Randall S.; Goldberg, Tony L.
Antibiotic resistance is a global concern, although it has been studied most extensively in developed countries. We studied Escherichia coli and class 1 integrons in western Uganda by analyzing 1,685 isolates from people, domestic animals, and wild nonhuman primates near two national parks. Overall, 499 isolates (29.6%) were resistant to at least one of 11 antibiotics tested. The frequency of resistance reached 20.3% of isolates for trimethoprim-sulfamethoxazole but was nearly zero for the less commonly available antibiotics ciprofloxacin (0.4%), gentamicin (0.2%), and ceftiofur (0.1%). The frequency of resistance was 57.4% in isolates from people, 19.5% in isolates from domestic animals, and 16.3% in isolates from wild nonhuman primates. Isolates of livestock and primate origin displayed multidrug resistance patterns identical to those of human-origin isolates. The percentage of resistant isolates in people was higher near Kibale National Park (64.3%) than near Bwindi Impenetrable National Park (34.6%), perhaps reflecting local socioeconomic or ecological conditions. Across antibiotics, resistance correlated negatively with the local price of the antibiotic, with the most expensive antibiotics (nalidixic acid and ciprofloxacin) showing near-zero resistance. Among phenotypically resistant isolates, 33.2% harbored class 1 integrons containing 11 common resistance genes arranged into nine distinct gene cassettes, five of which were present in isolates from multiple host species. Overall, these results show that phenotypic resistance and class 1 integrons are distributed broadly among E. coli isolates from different host species in this region, where local socioeconomic and ecological conditions may facilitate widespread diffusion of bacteria or resistance-conferring genetic elements.
Changes in Elephant Abundance Affect Forest Composition or Regeneration?
(Biotropica, 2014) Omeja, Patrick A.; Jacob, Aerin L.; Lwanga, Jeremiah S.; Tumwesigye, Charles; Chapman, Colin A.
While overall numbers of African elephant have declined dramatically in recent times, some populations are now confined to protected areas and are locally overabundant—an undesirable situation for both biodiversity conservation and elephants. In forested protected areas, options to manage elephants are limited because it is difficult to safely approach animals, yet it is vital that these populations are managed because browsing by elephants can dramatically alter forest ecosystems. Using data collected over 50 yr in Kibale National Park, Uganda, we examine the prediction that increasing elephant numbers and associated changes in their foraging behavior have caused a shift in tree community composition. Although the relative abundance of elephants increased significantly between 1996 and 2010, the population structure of their preferred tree food species did not change, nor did tree community composition change in favor of species able to re-sprout after elephant damage. Furthermore, over the last 50 yr Kibale elephants have not become more selective foragers, as would be expected if more nutritious tree species were declining. However, elephants are more abundant in disturbed areas dominated by shrubs and grasses and appear to have arrested forest succession in these areas. At their current abundance, elephants have not selectively altered the composition of intact old growth forest, but they do inhibit the regeneration of disturbed areas.
Coinfection of Ugandan Red Colobus (Procolobus [Piliocolobus] rufomitratus tephrosceles) with Novel, Divergent Delta-, Lenti-, and Spumaretroviruses
(Journal of virology, 2009) Goldberg, Tony L.; Sintasath, David M.; Chapman, Colin A.; Cameron, Kenneth M.; Karesh, William B.; Tang, Shaohua; Wolfe, Nathan D.; Rwego, Innocent B.; Ting, Nelson; Switzer, William M.
Nonhuman primates host a plethora of potentially zoonotic microbes, with simian retroviruses receiving heightened attention due to their roles in the origins of human immunodeficiency viruses type 1 (HIV-1) and HIV-2. However, incomplete taxonomic and geographic sampling of potential hosts, especially the African colobines, has left the full range of primate retrovirus diversity unexplored. Blood samples collected from 31 wild-living red colobus monkeys (Procolobus [Piliocolobus] rufomitratus tephrosceles) from Kibale National Park, Uganda, were tested for antibodies to simian immunodeficiency virus (SIV), simian T-cell lymphotrophic virus (STLV), and simian foamy virus (SFV) and for nucleic acids of these same viruses using genus-specific PCRs. Of 31 red colobus tested, 22.6% were seroreactive to SIV, 6.4% were seroreactive to STLV, and 97% were seroreactive to SFV. Phylogenetic analyses of SIV polymerase (pol), STLV tax and long terminal repeat (LTR), and SFV pol and LTR sequences revealed unique SIV and SFV strains and a novel STLV lineage, each divergent from corresponding retroviral lineages previously described in Western red colobus (Procolobus badius badius) or black-and-white colobus (Colobus guereza). Phylogenetic analyses of host mitochondrial DNA sequences revealed that red colobus populations in East and West Africa diverged from one another approximately 4.25 million years ago. These results indicate that geographic subdivisions within the red colobus taxonomic complex exert a strong influence on etroviral phylogeny and that studying retroviral diversity in closely related primate taxa should be particularly informative for understanding host-virus coevolution.
Floristic heterogeneity between forested sites in Kibale National Park, Uganda: insights into the fine-scale determinants of density in a large-bodied frugivorous primate
(Journal of animal ecology, 2009) Potts, Kevin B.; Chapman, Colin A.; Lwanga, Jeremiah S.
Factors regulating the density of consumer populations include both top-down (predation effects and disease) and bottom-up (resource availability and quality) components. Although the relative influence of each component is widely debated (e.g. Polis & Strong 1996; Schmitz, Hambäck & Beckerman 2000; Terborgh et al. 2001), it is likely that top-down and bottom-up processes play synergistic roles in limiting consumers (Krebs et al. 1995). Disentangling the relative effects of predators vs. resources ultimately requires either eliminating or controlling for one of these variables, thereby assessing the impact of the other (Moen & Oksanen 1998). Similarly, bottom-up and top-down regulatory factors may exert both spatial and temporal influences on consumers, and a complete understanding of how the environment limits populations requires examination of both factors. For example, Brown, Mehlman & Stevens (1995) found that the spatial distribution of abundance within North American bird species was well explained by concomitant spatial environmental variability that was relatively fixed over time. However, Ives & Klopfer (1997), building on Brown et al.’s (1995) work, suggested that similar spatial patterning could be created from temporal environmental variation without a fixed spatial component. Tropical forests are ideal sites in which to simultaneously incorporate both spatial and temporal components in understanding the determinants of density in vertebrates, particularly frugivorous species, as such ecosystems generally exhibit considerable spatiotemporal variability in fruiting phenology (van Schaik, Terborgh & Wright 1993; Condit et al. 2002; Cannon et al. 2007). Furthermore, the great apes (family Hominidae), the vast majority of which inhabit tropical forests (Campbell et al. 2007), represent a model taxon in which to address the role of bottom-up processes in regulating vertebrate frugivores. With some exceptions, most great apes are not subject to notable mortality risk from natural predators (Miller & Treves 2007), thus removing (or at least diminishing) the effect of top-down processes. We assessed which fine-scale ecological characteristics are potentially limiting the density of chimpanzees (Pan troglodytes Blumenbach, 1799) by comparing the spatiotemporal availability of resources between the home ranges of two communities of known size inhabiting Kibale National Park (KNP), Uganda. Chimpanzees are large-bodied, wide-ranging frugivorous apes with home ranges of c. 8–40 km2. The two communities included in this study are separated by only 12 km (or approximately one to three home ranges), and that at Ngogo (hereafter referred to as the ‘high-chimpanzee-density’ site) is the largest and most densely populated chimpanzee community currently known, with over 155 members (5·1 individuals km−2; Mitani & Watts 2005; Potts 2008), compared to c. 50 chimpanzees (1·5 individuals km−2) at Kanyawara (hereafter referred to as the ‘low-chimpanzee-density’ site; Muller & Wrangham 2004). Detailed long-term observations from this population suggest that other extrinsic variables (both top-down and bottom-up factors) not explicitly dealt with here, including disease, inter-specific niche overlap, predation, and/or non-fruit resource availability have played relatively limited roles in influencing spatial variations in chimpanzee density in KNP (Potts 2008). This population therefore presents an ideal model for isolating the effects of fruit resource availability in both space and time on the population ecology of large-bodied tropical frugivores.
Forest Fragmentation as Cause of Bacterial Transmission among Nonhuman Primates, Humans, and Livestock, Uganda
(Emerging infectious diseases, 2008) Goldberg, Tony L.; Gillespie, Thomas R.; Rwego, Innocent B.; Estoff, Elizabeth L.; Chapman, Colin A.
We conducted a prospective study of bacterial transmission among humans, nonhuman primates (primates hereafter), and livestock in western Uganda. Humans living near forest fragments harbored Escherichia coli bacteria that were ≈75% more similar to bacteria from primates in those fragments than to bacteria from primates in nearby undisturbed forests. Genetic similarity between human/livestock and primate bacteria increased ≈3-fold as anthropogenic disturbance within forest fragments increased from moderate to high. Bacteria harbored by humans and livestock were approximately twice as similar to those of red-tailed guenons, which habitually enter human settlements to raid crops, than to bacteria of other primate species. Tending livestock, experiencing gastrointestinal symptoms, and residing near a disturbed forest fragment increased genetic similarity between a participant’s bacteria and those of nearby primates. Forest fragmentation, anthropogenic disturbance within fragments, primate ecology, and human behavior all influence bidirectional, interspecific bacterial transmission. Targeted interventions on any of these levels should reduce disease transmission and emergence.
Intensive Tree Planting Facilitates Tropical Forest Biodiversity and Biomass accumulation in Kibale National Park, Uganda
(Forest Ecology and Management, 2011) Omeja, Patrick A.; Chapman, Colin A.; Obua, Joseph; Lwanga, Jeremiah S.; Jacob, Aerin L.; Wanyama, Frederick; Mugenyi, Richard
The extensive area of degraded tropical land and the calls to conserve forest biodiversity and sequester carbon to offset climate change demonstrate the need to restore forest in the tropics. Deforested land is sometimes replanted with fast-growing trees; however, the consequences of intensive replanting on biomass accumulation or plant and animal diversity are poorly understood. The purpose of this study was to determine how intensive replanting affected tropical forest regeneration and biomass accumulation over ten years. We studied reforested sites in Kibale National Park, Uganda, that were degraded in the 1970s and replanted with five native tree species in 1995. We identified and measured the size of planted versus naturally regenerating trees, and felled and weighed matched trees outside the park to calculate region-specific allometric equations for above-ground tree biomass. The role of shrubs and grasses in facilitating or hindering the establishment of trees was evaluated by correlating observed estimates of percent cover to tree biomass. We found 39 tree species naturally regenerating in the restored area in addition to the five originally planted species. Biomass was much higher for planted (15,675kg/ha) than naturally regenerated trees (4560kg/ha), but naturally regenerating tree regrowth was an important element of the landscape. The establishment of tree seedlings initially appeared to be facilitated by shrubs, primarily Acanthus pubescens and the invasive Lantana camara; however, both are expected to hinder tree recruitment in the long-term. Large and small-seeded tree species were found in the replanted area, indicating that bird and mammal dispersers contributed to natural forest restoration. These results demonstrate that intensive replanting can accelerate the natural accumulation of biomass and biodiversity and facilitate the restoration of tropical forest communities. However, the long-term financial costs and ecological benefits of planting and maintaining reforested areas need to be weighed against other potential restoration strategies.
Kanyawara Virus: A Novel Rhabdovirus Infecting Newly Discovered Nycteribiid Bat Flies Infesting Previously Unknown Pteropodid Bats in Uganda
(Scientific Reports, 2017) Goldberg, Tony L.; Bennett, Andrew J.; Kityo, Robert; Kuhn, Jens H.; Chapman, Colin A.
Bats are natural reservoir hosts of highly virulent pathogens such as Marburg virus, Nipah virus, and SARS coronavirus. However, little is known about the role of bat ectoparasites in transmitting and maintaining such viruses. The intricate relationship between bats and their ectoparasites suggests that ectoparasites might serve as viral vectors, but evidence to date is scant. Bat flies, in particular, are highly specialized obligate hematophagous ectoparasites that incidentally bite humans. Using nextgeneration sequencing, we discovered a novel ledantevirus (mononegaviral family Rhabdoviridae, genus Ledantevirus) in nycteribiid bat flies infesting pteropodid bats in western Uganda. Mitochondrial DNA analyses revealed that both the bat flies and their bat hosts belong to putative new species. The coding-complete genome of the new virus, named Kanyawara virus (KYAV), is only distantly related to that of its closest known relative, Mount Elgon bat virus, and was found at high titers in bat flies but not in blood or on mucosal surfaces of host bats. Viral genome analysis indicates unusually low CpG dinucleotide depletion in KYAV compared to other ledanteviruses and rhabdovirus groups, with KYAV displaying values similar to rhabdoviruses of arthropods. Our findings highlight the possibility of a yetto- be-discovered diversity of potentially pathogenic viruses in bat ectoparasites.
Mangabey (Cercocebus albigena) Ranging Patterns in Relation to Fruit Availability and the Risk of Parasite Infection in Kibale National Park, Uganda
(American Journal of Primatology, 1997) Olupot, William; Chapman, Colin A.; Waser, Peter M.; Basuta, Gilbert Isabirye
Two opposing hypotheses concerning determinants of mangabey (Cercocebus albigena) ranging patterns have been advocated. One hypothesis suggests that ranging patterns of mangabeys are largely a response to fruit availability, while the other hypothesis advocates that concerns of fruit availability are supplemented or overridden by concerns of fecal contamination and that the risk of parasite infection, especially during dry weather, determines their pattern of range use. In this 9 month study of mangabeys in the Kanyawara study area of Kibale National Park, mangabeys moved longer distances during the wet season than during the dry season. There were no seasonal differences in group spread, number of 50 by 50 m quadrats used, or in quadrat overlap between sequential sample periods. Intensity of quadrat use was closely related to the number of fruiting trees/lianas in the quadrats, irrespective of season. These findings are consistent with the hypothesis that fruit availability is a main factor influencing mangabey ranging patterns. The results are not consistent with the hypothesis that mangabey ranging patterns largely reflect differential seasonal risk of parasite infection.
Patterns Of Gastrointestinal Bacterial Exchange Between Chimpanzees And Humans Involved In Research And Tourism In Western Uganda
(Biological Conservation, 2007) Goldberg, Tony L.; Gillespie, Thomas R.; Rwego, Innocent B.; Wheeler, Emily; Estoff, Elizabeth L.; Chapman, Colin A.
Ecological overlap may increase the risks of microbial exchange between humans and wild non-human primates. Escherichia coli bacteria were collected from chimpanzees and humans in Kibale National Park, western Uganda, in May and June 2004, in order to examine whether interaction between humans and apes in the wild might affect gastrointestinal bacterial communities in the two species. Chimpanzees harbored bacteria genetically more similar to those of humans employed in chimpanzee-directed research and tourism than to those of humans from a local village. Most humans (81.6%) and 4.4% of chimpanzees harbored at least one isolate resistant to locally available antibiotics. In isolates from both humans and chimpanzees, resistance was higher to five of these antibiotics than to Ceftiofur, an antibiotic not available in the region. These data indicate that humans and apes interacting in the wild can share genetically and phenotypically similar gastrointestinal bacteria, presumably originating from common environmental sources. Strategies to limit transmission of pathogens between humans and primates, whether that transmission is direct or indirect, would benefit both human health and primate conservation.

Browsing by Author "Chapman, Colin A."

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