| dc.description.abstract | Infectious diseases are a major and growing issue in global health and wildlife conservation. Preventative measures can be instrumental in limiting the burden of diseases on human and animal populations, for which knowledge of disease transmission routes is key. However, transmission cycles can be complex. For instance, there are different transmission pathways, including direct (eg. skin-skin contact, sexual transmission) and indirect (eg. via vectors, water, food) pathways, and some diseases can have multiple transmission pathways. Furthermore, some diseases can infect a broad range of hosts and are not limited to a single species. Therefore, we still do not fully understand the transmission of many present-day diseases. Molecular techniques, which generally refer to DNA-based methods such as polymerase chain reaction (PCR), are increasingly used in microbiology research to help fill gaps in our knowledge of disease transmission in wildlife populations as they offer several advantages compared to non-molecular methods, such as high accuracy, greater discriminatory power, and fast turnaround. As there is a wide array of molecular techniques available with varying benefits and limitations, I reviewed the literature to consolidate information on which molecular techniques are used and how they are applied to reconstruct indirect transmission routes and their benefits. This information will potentially be useful when designing future transmission research. Overall, the main advantages when investigating any transmission type included the accuracy, sensitivity, and specificity of molecular techniques, the ability to detect genetic differences in pathogens through molecular typing, and the range of sample types these techniques can be used with, such as faeces, blood, soil, and water. There are also particular ways in which molecular techniques can be applied to suit the focus of the research. For example, when investigating vector-based transmission, testing for pathogen presence in a specific body part, such as the salivary glands, of a potential vector and testing a potential vector’s ability to acquire and transmit pathogens to a naive host. Leprosy is an infectious disease where our knowledge of transmission is still extremely limited. Wild western chimpanzees, Pan troglodytes verus, in Cantanhez National Park (CNP) in Guinea-Bissau were confirmed as a new animal host of leprosy in 2018, but the source of these infections is currently unknown. Humans and chimpanzees coexist and share space and resources in CNP. Although the transmission of Mycobacterium leprae (aetiological agent of leprosy) from humans to chimpanzees is one possible pathway, considering low levels of present-day direct interaction, alternate transmission routes must be considered. Chimpanzees are omnivorous and most communities across Africa hunt and feed on a diverse range of animal species. One pathway for potential leprosy transmission to chimpanzees is through the consumption of infected prey. Guinea baboons, Papio papio, in CNP have also been confirmed to have leprosy, suggesting the presence of sympatric unidentified hosts of leprosy. However, there is no data on chimpanzee prey species and meat consumption at CNP. Therefore, I used DNA metabarcoding to detect mammalian prey species consumed by western chimpanzees from an infected community in CNP to identify putative sources of leprosy. There were 21 detections of mammalian prey DNA attributed to 14 individual chimpanzees: five females and nine males. Three species were detected, including red colobus, Piliocolobus badius, red river hog, Potamochoerus porcus, and Demidoff’s galago, Galagoides demidoff. DNA metabarcoding is the first technique to detect chimpanzee meat consumption in this community and identify prey species, emphasising the usefulness of molecular techniques and non-invasive data collection on wild unhabituated animals, and shedding new light on their feeding ecology to inform possible disease transmission networks. | en_GB |
