Project Description
Parasitic worm infections (helminthiases) of humans greatly impact low to medium income countries such as Thailand, by undermining health and agricultural productivity. Particularly across Southeast Asia, the expansion of urban areas and the movement of people from countries with less developed public health programs, have increased disease transmission. This project will investigate environmental influences on helminth disease transmission. Many emerging helminthiases are linked to the environment through increased contact between humans and animals, the intensification and integration of food production systems, and the expansion of migration [1]. Therefore, effective control and treatment of many helminth diseases would benefit from better integration of clinical, veterinary and agricultural components embedded in an environmentally-driven research strategy.
Thailand is classified as an ‘Upper Middle Income’ Country. However due the nature of helminth diseases endemic sites are significantly impacted by border countries including Cambodia, Laos and Myanmar, all of which are classified as ‘Least Developed’ Countries. Our research team has recently established baseline human infection rates in three Thailand border regions, using highly sensitive molecular diagnostics. In the past the under-estimation of helminth infections in communities such as Thailand (see below) and our previous work in the Philippines [2], provides incomplete information for the development of government policy.
The proposed project will use our recently published human prevalence data [3] to focus on specific locations and parasite species in endemic regions of Northern Thailand, so that environmental components of disease transmission can be identified. Under-regulated national borders in Southeast Asia represent potential regions for enhanced parasitic helminth transmission and present barriers to helminthiasis disease control. Three Thailand border regions close to Myanmar, Laos and Cambodia were surveyed for clinical parasitic helminth disease.
These areas will be potential sites for your project.
In our previous study in-field microscopy was performed on stools and sub-samples transported to Bangkok and Mahidol University for molecular analysis comprising three multiplex qPCR assays. The overall helminth infection prevalence was 17.99% as assessed by Kato-Katz and 24.51% by qPCR. The combined prevalence of the two methods was 28.57%; the most predominant species detected were Opisthorchis viverrini (18.34%), hookworm (6.88%; Ancylostoma spp. and Necator americanus), Ascaris lumbricoides (2.29%) and Trichuris trichiura (1.76%). These data demonstrate the value of molecular diagnostics for determining more precise prevalence levels of helminthiases in Southeast Asia.
Availability of such accurate prevalence information will help guide future public health initiatives and highlights the need for more rigorous surveillance and timely intervention in these regions. This data will also guide the design of your project.
One class of parasites, soil transmitted helminths (STH), requires significant environmental contamination for effective disease transmission. Approximately 1.5 billion or ¼ of the world’s population are infected by STH, including the main species of Ascaris, Trichuris and hookworm. Parasite eggs found in the soil or unwashed vegetables are the primary source of infection. Similarly, food borne diseases, including the cancer-causing Opisthorchis, are contracted by consuming uncooked fish, and are linked to water sources, and the interaction between snail and fish hosts.
Essential & desirable candidate skills
The student should have a good appreciation of the biology and epidemiology of helminth parasites of human and animals in tropical regions of the world. Molecular biology skills in DNA extraction and qPCR will be important. Field collections in Thailand will require extended travel, and the student should have good organisational and interpersonal skills required when working in a field team.
Essential: BSc in either biochemistry, ecology, parasitology or similar fields. Interest in zoonotic parasitic diseases. Experience working independently and/or in groups.
Desirable: MSc in ecology or parasitology. Skills in molecular biology and PCR based assays. GIS and field techniques would also be beneficial. Experience in overseas field work (particularly Asia).
Supervisors
Geoffrey GobertPrimary Supervisor: | Profile: Geoffrey Gobert Email: g.gobert@qub.ac.uk Institution: Queen's University, Belfast Department/School: School of Biological Sciences |
Sandra TelferSecondary Supervisor: | Profile: Sandra Telfer Email: s.telfer@abdn.ac.uk Institution: University of Aberdeen Department/School: School of Biological Sciences |
Mark EmmersonAdditional Supervisor: | Profile: Mark Emmerson Email: m.emmerson@qub.ac.uk Institution: Queen's University, Belfast Department/School: School of Biological Sciences |
References
[1] Gordon CA, McManus DP, Jones MK, Gray DJ, Gobert GN: The Increase of Exotic Zoonotic Helminth Infections: The Impact of Urbanization, Climate Change and Globalization. Adv Parasitol 2016, 91:311-397.
[2] Gordon CA, McManus DP, Acosta LP, Olveda RM, Williams GM, Ross AG, Gray DJ, Gobert GN: Multiplex real-time PCR monitoring of intestinal helminths in humans reveals widespread polyparasitism in Northern Samar, the Philippines. Int J Parasitol 2015, 45(7):477-483.
[3] Adisakwattana P, Yoonuan T, Phuphisut O, Poodeepiyasawat A, Homsuwan N, Gordon CA, McManus DP, Atkinson LE, Mousley A, Gobert GN: Clinical helminthiases in Thailand border regions show elevated prevalence levels using qPCR diagnostics combined with traditional microscopic methods. Parasit Vectors 2020, 13(1):416.
Research Methods
The student will gains skills in epidemiological methods, questionnaires, geographical parameters of field sites and collation of ecological factors, all within the framework of identifying helminth parasite transmission risk factors. Modelling of data with molecular diagnosis of disease prevalence will be important. The development of new diagnostic assays and the identification of new molecular biomarkers will be goals of the project.
The student will spend considerable time in Thailand, collecting soil, vegetable and aquatic samples for diagnostics using traditional microscopy and more recently developed molecular analysis. Environmental foci of disease will be stratified using spatial modelling (GIS geographical information system) to demonstrating the importance of food and geography, in helminth disease transmission. Earth observation data will be used to build GIS layers of climatic and other relevant environmental factors, and enable intervention strategies to be assessed against likely future changes. Identification of environmental components of disease transmission will lead to predictive models for better informed government control policies.
Expected Training Provision
Training in methods to be used in field site collections in Thailand will be performed by collaborator Dr Adisakwattana of the Faculty of Tropical Medicine, Mahidol University Bangkok. You will join his experienced field team for a regional collection of materials. Molecular methods will be taught back in Belfast at QUB. GIS training will be provided by second supervisor Dr Sandra Telfer in Uni. Of Aberdeen.
Impact
Parasitic worm infections (helminthiases) of humans greatly impact low to medium income countries such as Thailand, by undermining health and agricultural productivity. Availability of such accurate prevalence information will help guide future public health initiatives and highlights the need for more rigorous surveillance and timely intervention in these regions.
The identification of new transmission factors and new methods to detecting active infections of parasites, particularly with helminths is important since many species cause significant environmental contamination. Since helminth eggs passed from animals contaminate the soils and natural water bodies, DNA represent the molecular overlap between ecological and veterinary approaches. As such parasite monitoring using DNA can provide more comprehensive information to guide the control of clinically important helminthiases.
Proposed Supervision
Dr Gobert will oversee the project and will organise the training of the student. Dr Telfer will provide expertise in modelling and geographical modelling of diagnostics obtained from molecular methods. Field site collections in Thailand will be performed by collaborator Dr Adisakwattana of the Faculty of Tropical Medicine, Mahidol University Bangkok.
Proposed Timetable
The student will initially start at QUB helping to establishing and refine SOPs (standard operating procedures) for the project and becoming familiar with the background topics. At the end of year 1 and potentially for a second visit in year 2 the student will visit 1-2 of the field sites in regional border areas of Thailand. Samples will be collected, ecological parameters recorded and initial molecular isolations undertaken in Bangkok. Work in the UK (QUB) will include molecular diagnostics use DNA markers. Modelling of data will be undertaken with collaboration from University of Aberdeen.
QUADRAT Themes
- biodiversity
Partners
Not applicable at this time.
