Effects of Anthropogenic Disturbance on Zoonotic Pathogen Transmission in People, Wild Primates and Domesticated Animals in the Greater Gombe Ecosystem, Tanzania Open Access

Parsons, Michele Marie (2015)

Permanent URL: https://etd.library.emory.edu/concern/etds/v118rf289?locale=en


Disease ecology involves understanding the mechanisms driving the complex interactions occurring between pathogens, their hosts, and the shared environment. The primary aim of this dissertation was to test theoretical principles of ecology and epidemiology that underlie zoonotic disease emergence in a complex natural system. Broadly, this research focused on examining how land use changes and multi-host interactions affect pathogen exchange from humans to non-human primates (NHPs), specifically chimpanzees (Pan troglodytes schweinfurthii) and baboons (Papio anubis) in habitats experiencing varying degree of anthropogenic disturbance from humans and domesticated animals in and around Gombe National Park, Tanzania. Using low-cost GPS data-loggers to establish the extent of domesticated animal overlap with NHP habitat, I found little evidence of domesticated animal mobility into the park, but rather identified potential hotspots for pathogen spillover where wild chimpanzees are known to raid agricultural crops that have high visitation rates by domesticated animals and village residents. My research uncovered a complex cycle of Cryptosporidium occurring in Gombe with humans, baboons and a subset of chimpanzees infected with C. hominis subtype IfA12G2; another subset of chimpanzees infected with C. suis; and all positive domesticated animals infected with C. xiaoi. The dominance of C. hominis subtype IfA12G2 among humans and NHPs suggests regular cross-species transmission. The finding of C. suis, a pig subtype, in chimpanzees is novel. Bacterial studies determined that humans are the likely source for antimicrobial resistance genes that spread to NHPs, regardless of human density. I found that NHPs have resistant pathogenic strains of Salmonella and Shigella that are similar in genotype and resistance pattern to strains locally circulating in humans. As NHPs are not routinely administered antimicrobials, this suggests spillover of resistance genes and associated pathogens from humans to NHPs. Salmonella from domesticated animals represented a different genotype cluster and were not as drug resistant. My research deepens our understanding of the ecology and epidemiology of zoonotic enteric pathogen transmission at the human-animal-wildlife interface in western Tanzania. Our results highlight the importance of considering the spread of infectious diseases in wildlife conservation.

Table of Contents

CHAPTER 1 pg. 1

Introduction: The application of disease ecology theory and field research to further our understanding of the risk for emerging zoonoses among wild primates at the human-animal interface

1.1 Principles of disease ecology and its role in zoonotic disease emergence pg. 2

1.2 Applying theory to empirical field work - my dissertation research pg. 13

1.3 Figures pg. 19

1.4 Tables pg. 19

1.5 References pg. 20

CHAPTER 2 pg. 27

Global Positioning System Data-Loggers: A Tool to Quantify Fine-Scale Movement of Domestic Animals to Evaluate Potential for Zoonotic Transmission to an Endangered Wildlife Population

2.1 Summary pg. 27

2.2 Introduction pg. 28

2.3 Materials and Methods pg. 30

2.4 Results pg. 34

2.5 Discussion pg. 37

2.6 Figures pg. 41

2.7 Tables pg. 44

2.8 References pg. 44

CHAPTER 3 pg. 48

Epidemiology and Molecular Characterization of Cryptosporidium spp. in Humans, Wild Primates, and Domesticated Animals in the Greater Gombe Ecosystem, Tanzania

3.1 Summary pg. 48

3.2 Introduction pg. 49

3.3 Materials and Methods pg. 52

3.4 Results pg. 56

3.5 Discussion pg. 58

3.6 Tables pg. 64

3.7 References pg. 67

CHAPTER 4 pg. 73

Detection of antimicrobial resistance genes from fecal specimens of humans, animals and wild primates of Gombe National Park: evidence of spillover on a local scale

4.1 Summary pg. 73

4.2 Introduction pg. 75

4.3 Materials and Methods pg. 78

4.4 Results pg. 82

4.5 Discussion pg. 85

4.6 Figures pg. 90

4.7 Tables pg. 91

4.8 References pg. 93

CHAPTER 5 pg. 97

Epidemiology and ecology of zoonotic enteric pathogens in Gombe National Park based upon phenotypic and genotypic characterization of bacterial strains from humans, domesticated animals and wild primates

5.1 Summary pg. 97

5.2 Introduction pg. 98

5.3 Materials and Methods pg. 101

5.4 Results pg. 106

5.5 Discussion pg. 112

5.6 Figures pg. 120

5.7 Tables pg. 123

5.8 References pg. 124

CHAPTER 6 pg. 130

Principle Findings, Limitations and Future Directions

6.1 Principle Findings pg. 132

6.2 Study Limitations pg. 136

6.3 Future Directions pg. 139

6.4 Figures pg. 143

6.5 References pg. 144

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