Supervisory team
LSHTM
- Lead: Dr Mojca Kristan (Mojca.Kristan@lshtm.ac.uk, Faculty of Infectious and Tropical Diseases)
- Dr Susana Campino (Susana.Campino@lshtm.ac.uk)
- Dr Jody Phelan (Jody.Phelan@lshtm.ac.uk)
Nagasaki University
Project
Tick-borne diseases have become increasingly important, leading to a significant public health burden worldwide. This is due to the expansion of tick populations, the surge of incidence of tick-borne diseases as well as a series of novel pathogens discovered in the last few decades.
Studies have reported that ticks transferred by movements of humans and animals elevated the risks of the pathogens spreading beyond country borders. Japan is an island nation, visited by millions of migratory birds from a number of neighbouring countries, which have been implicated in the spread of ticks as well as tick-borne pathogens. Tick species such as Haemaphysalis longicornis, Ixodes persulcatus, Ixodes turdus and other Ixodes spp are some of the main vectors of major tick-borne diseases in Japan and are introduced into the country by birds. Thus, conducting a population genetics analysis of various tick species in Japan, with a particular focus on tick species collected from avian hosts, will help to elucidate the origins of ticks, assess population variance, and investigate the pathogens transmitted by these arachnids.
Two of the major tick-borne diseases in Japan are Japanese spotted fever (JSF) and severe fever with thrombocytopenia syndrome (SFTS), causing around 300-400 cases and around 100 cases, respectively. The JSF has been reported since 1984, but the SFTS is a relatively newly emerged disease. The SFTS was first reported in 2011 in Wuhan, China and the first domestic case in Japan was confirmed in 2013 in the western part of the country (Yamaguchi Prefecture). The disease is now further expanding its range and was detected near Tokyo or Chiba Prefecture in 2021.
This joint PhD project aims to expand a fundamental understanding on the ecology of ticks and tick-borne diseases in Japan and eventually to contribute valuable insights for disease surveillance, prevention and control in Japan and elsewhere.
The specific objectives of this project will be to:
1) carry out a review of the most important ticks and tick-borne diseases in Japan, with a focus on important vectors of human diseases often associated with migratory birds.
2) study spatial and temporal variation in tick populations of the tick species of interest (identified under objective 1) in rural vs urbanizing environments in the Kyushu area including Nagasaki prefecture, and the occurrence of tick-borne pathogens in tick populations in different environments.
3) perform molecular analysis to characterise population genetic diversity and origin of the selected tick species and improve the current understanding on genetic flow between different tick populations.
4) detect pathogens in tick samples to understand pathogen prevalence in tick populations and study their genetic diversity.
The student will have access to nearly 12,000 tick samples collected at 74 sites in Nagasaki in 2021, and will also perform additional sampling in the same sites during their PhD. A subset of collected ticks will be tested for pathogens.
References:
Cairns V, Wallenhorst C, Rietbrock S, et al. Incidence of Lyme disease in the UK: a population-based cohort study. BMJ Open 2019;9:e025916.
Yamaji K, Aonuma H, Kanuka H. Distribution of tick-borne diseases in Japan: Past patterns and implications for the future. J Infect Chemother. 2018;24(7):499-504.
Hasle G. Transport of ixodid ticks and tick-borne pathogens by migratory birds. Front Cell Infect Microbiol. 2013;3:48.
Buczek A, Buczek W. Importation of Ticks on Companion Animals and the Risk of Spread of Tick-Borne Diseases to Non-Endemic Regions in Europe. Animals (Basel). 2020;11(1):6
Ishiguro F, Takada N, Masuzawa T, Fukui T. Prevalence of Lyme disease Borrelia spp. in ticks from migratory birds on the Japanese mainland. Appl Environ Microbiol. 2000 Mar;66(3):982-6.
The role of LSHTM and NU in this collaborative project
LSHTM team will provide support for molecular work and bioinformatics, mainly in relation to population genetics of ticks and pathogen detection, including laboratory work and interpretation of the results.
Nagasaki team will support the student to perform tick sampling field work using various sampling methods. Also, the student will be supported to develop skills to identify Japanese ticks based on morphological keys and DNA barcoding methods. The ecological results will be analysed using bioinformatics software libraries mainly in Python and R, with guidance from Nagasaki and LSHTM teams.
Particular prior educational requirements for a student undertaking this project
This project preferably requires the following education and experience:
- educational background in medical entomology
- fieldwork experience, including tick collection
- entomological skills such as the use of morphological identification keys
- basic experience in molecular work (DNA extraction, PCR, etc)
Skills we expect a student to develop/acquire whilst pursuing this project
The successful candidate will be expected to develop skills to perform the fieldwork to collect ticks, handle the samples safely and properly, and carry out morphological identification under the dissecting microscope. The student also will be expected to acquire skills to perform molecular work and bioinformatic analysis to perform population genetic research and to inform surveillance of ticks and tick-borne diseases.