Tracking tsetse and trypanosomes: analysis of the transmission of trypanosomes between tsetse and their wild and domestic hosts
Lead Research Organisation:
University of Liverpool
Department Name: Health Sciences
Abstract
Tracking tsetse and trypanosomes: analysis of the transmission of trypanosomes between tsetse and their wild and domestic hosts
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/N503563/1 | 01/10/2015 | 30/09/2019 | |||
| 1854885 | Studentship | BB/N503563/1 | 01/10/2015 | 30/09/2019 | Rachel Hopper |
| Description | Rhodesian human African trypanosomiasis (r-HAT) and Animal African trypanosomiasis (AAT) are diseases caused by Trypanosoma spp. transmitted by tsetse (Glossina). In East and Southern Africa, the risk of r-HAT and AAT is greater in the vicinity of conservation areas where wild reservoir hosts and tsetse are abundant. The over-arching aim of this study was to analyse fine-scale variations in the abundance and distribution of tsetse at the interface of conservation and farming areas in northern Tanzania. Towards this aim, research was undertaken at the edges of the Serengeti and Saadani national parks to address four specific questions. First, what is the impact of natural environmental variables on the fine-scale (<1 km) distribution and abundance of tsetse? Second, is the treatment of cattle with insecticides by livestock keepers having an impact on tsetse populations? Third, can satellite imagery be used to predict the fine-scale distribution and abundance of tsetse across different agro-ecological zones? Finally, does the molecular genetics of tsetse populations reflect the prior impact of natural and anthropogenic factors on population dynamics. Analyses of catches of Glossina pallidipes and Landsat imagery showed that the abundance of tsetse in conservation areas was correlated positively with normalised difference vegetation index (NDVI), tree cover, soil moisture (Band 7), land surface temperature (LST) and proximity to rivers. In nearby farming areas, the correlations were less marked or not significant, indicating that other factors were controlling tsetse populations. Questionnaire surveys of livestock keepers showed that in Serengeti district, ~70% of cattle owners reported treating their animals with pyrethroids at monthly intervals. Chemical analyses of hair from cattle using gas-chromatography with mass spectrometry, high-performance liquid chromatography and an insecticide quantification kit showed that ~30% of herds contained animals which had been recently treated with cypermethrin or alphacypermethrin. Previous literature suggests that treatment of cattle with pyrethroids at these levels will reduce the density of tsetse. Models based on satellite data, developed with data from Serengeti National Park, were successfully used to predict the relative abundance of tsetse in Saadani but were less useful in farming areas where abundance of tsetse was much less than predicted. The low numbers observed may be related to widespread treatment of cattle with insecticide in the farming areas of Tanga region surrounding Saadani. Analyses of the genetics of G. pallidipes populations in Serengeti and Saadani found no evidence for the impact of tsetse control operations. At Saadani, two cryptic and sympatric species of G. pallidipes were detected. The discovery of cryptic species may explain intraspecific variation in the behavioural responses of G. pallidipes and also makes the use of sterile insect technique a more difficult prospect. |
| Exploitation Route | The findings presented in this thesis provide the first exciting indications that livestock keepers in Tanzania, at district, regional and national levels, have been successfully controlling trypanosomiasis, both directly and indirectly through vector control facilitated by national policies to promote use of pyrethroids. Further work is required to confirm the extent and impact of these farmer-led interventions, and the development of a cost effective, simple and rapid system to quantify pyrethroid will play an important part in this. Lessons learned about how farmers can be enabled to control tsetse in Tanzania will provide important lessons for all countries affected by African trypanosomiasis. |
| Sectors | Environment,Government, Democracy and Justice |
| Description | Sharing of results during Tanzanian National Stakeholders meeting at the end of associated ZELS project |
| Geographic Reach | National |
| Policy Influence Type | Contribution to a national consultation/review |
| Description | Bluedot Festival |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | LSTM had a stand at the festival where we could interact with members of the public of all ages. I had a tsetse trap with me and an information board and was able to talk about my research. Many people had never heard of sleeping sickness so this increased knowledge of the disease. |
| Year(s) Of Engagement Activity | 2018 |
| URL | https://www.lstmed.ac.uk/news-events/news/lstm-at-the-bluedot |
| Description | Rotary club talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I spoke to the local rotary club in Tanga, Tanzania about my research. This sparked questions and discussions and they offered valuable local insights and contacts with local cattle owners. |
| Year(s) Of Engagement Activity | 2017 |
| Description | School careers visit |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | Returned to my old school to discuss different career options. I discussed my route into PhD and what research I am doing now. The children and their parents were interested to hear about a biology route which led to a career they not had thought about, and interested to hear about my research. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Talk at ECTMIH 2019 in Liverpool |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | I gave a talk on the development of the Insecticide Quantification Kit for use on cattle hair samples. After the talk I spoke with people who highlighted the potential commercial applications for this kit. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Talk at GEOMED conference in 2019 at the University of Glasgow |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Other audiences |
| Results and Impact | Approximately 50 people attended my talk about the use of remote sensing and geostatistical modelling to predict the abundance of tsetse. This prompted questions from the audience about how they could apply something similar to their work and it was suggested to be a good example of a model which can be finely adjusted following additional sampling. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Talk for Tanzanian Undergraduate students |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Undergraduate students |
| Results and Impact | Visit of University of Dar es Salaam students to VVBDRI (Tanzania) where I spoke to four groups (total approx. 80 students) about my research. They were visiting to learn about tsetse control methods and research. |
| Year(s) Of Engagement Activity | 2017 |