Insects are a major cause of mortality and reduced productivity in domestic livestock. The insects cause this damage directly by feeding on or parasitising livestock, or indirectly, by transmitting livestock diseases. NRI has worked on a wide range of insect pests including vectors, such as tsetse flies which transmit African trypanosomiasis, ectoparasites such as screwworm flies which attack livestock in the tropical regions of Africa, Asia and the Americas, and nuisance pests such as stable flies.

 

NRI's work is mainly focused on the development of cost-effective and environmentally-benign methods for controlling pests affecting the animals of poorer livestock owners in developing countries. Research is highly multidisciplinary, drawing on a wide range of expertise in the Institute, including: · Research on insect behaviour and ecology in laboratory and field; · Chemical ecology of insect vectors; · Molecular characterisation of insect vectors and their hosts; · Use of GIS to study disease epidemiology, cattle management practices and vector distributions , for example; · Assessment of environmental impact of animal diseases and their control; · Socioeconomic research to assess demand and ensure research outputs are practicable, appropriate and cost-effective.

Key Research Areas

Odour-baited traps and targets for veterinary pests.
Chemists and entomologists collaborated with Zimbabwean scientists to identify the odours used by tsetse to locate their hosts. These chemicals are now routinely used to bait traps and insecticide-treated targets to control tsetse. Similar attractants research has been conducted on other veterinary pests including stable flies, screwworm and blowflies.

 

Livestock-management practices, disease and vector control.
Social scientists, GIS specialists, molecular biologists and entomologists have been looking at how herding and grazing practices affect contact between livestock and insect vectors. Such contact affects the probability of an animal contracting disease. However, by treating the livestock with insecticide, fly-livestock contact can also provide an opportunity for controlling the pest. Knowledge of how livestock management affects contact provides a rational basis for designing strategies to control vector-borne diseases.

 

Implications for human health.
Work on tsetse-borne trypanosomiasis and cattle in Tanzania and Zimbabwe has led to exploration of the feasibility of using insecticide-treated cattle to control malaria in those areas where malarial mosquitoes feed on livestock and humans.

 

Vector control operations.
NRI has been closely involved in the implementation of large-scale tsetse control operations in Botswana, Zimbabwe, and Somalia. These operations have included aerial spraying, odour-baited targets and the use of insecticide-treated cattle. Environmental scientists, geographers and social scientists from NRI have also been involved in assessing the epidemiological, environmental and socio-economic impacts of these, and other national and regional vector control operations.

Staff

Dr Stephen Torr
Dr Gay Gibson
Prof. John Morton

Projects

Epidemiology & Cntl of Orbiviral Diseases with Ref. to Bluetongue/African Horse Sickness (DEFRA/BBSRC)

Tsetse Muse: interactive programme to assess the impact of control operations on tsetse populations (DFID LPP)

General model for predicting the effect of insecticide-treated cattle on tsetse populations (DFID LPP)

Recommendations for Integrated Control of Malaria and Livestock Diseases in Ethiopia (DFID AHP)

Message in a bottle: disseminating tsetse control technologies (DFID AHP)

Cattle management practices: implications for tsetse control (DFID LPP).

Livestock/wildlife interactions in areas of tsetse fly elimination and prevalence (DFID AHP).

Improving the control of tsetse: The use of DNA profiling to establish feeding response to cattle (DFID AHP)

Support to Botswana Tsetse Control Division (FAO)

Publications

Torr, S.J., Mangwiro, T.N.C. and Hall, D.R. (2006). The effects of host physiology on the attraction of tsetse (Diptera: Glossinidae) and Stomoxys (Diptera: Muscidae) to cattle. Bulletin of Entomological Research, 96: 71-84.

Torr, S.J., Hargrove, J.W. and Vale, G.A. (2005). Towards a rational policy for dealing with tsetse. Trends in Parasitology, 21(11): 537-541.

Vale, G.A. and Torr, S.J. (2005). User-friendly models of the costs and efficacy of tsetse control: application to sterilizing and insecticidal techniques. Medical and Veterinary Entomology, 19:293-305.

Habtewold, T., Prior, A., Torr, S.J. and Gibson, G. (2004). Could insecticide-treated cattle reduce Afrotropical malaria transmission? Effects of deltamethrin-treated Zebu on Anopheles arabiensis behaviour and survival in Ethiopia. Medical and Veterinary Entomology, 18:408-417.

Zollner, G.E., Torr, S.J., Ammann, C. and Meixner, F.X. (2004). Dispersion of carbon dioxide plumes in African woodland: implications for host-finding by tsetse flies. Physiological Entomology, 29:381-394.

Eisler, M.C., Torr, S.J., Coleman, P.G., Machila, N. and Morton, J.F. (2003). Integrated control of vector-borne diseases of livestock - pyrethroids: panacea or poison? Trends in Parasitology, 19: 341-345.

Hargrove, J.W., Torr, S.J. and Kindness, H.M. (2003). Insecticide-treated cattle against tsetse (Diptera: Glossinidae): what governs success? Bulletin of Entomological Research, 93: 203-217.

Schofield, S. and Torr, S.J. (2002). A comparison of the feeding behaviour of tsetse and stable flies Medical and Veterinary Entomology, 16:177-185.

Prior, A. and Torr, S.J. (2002). Host selection by Anopheles arabiensis and An. quadriannulatus feeding on cattle in Zimbabwe. Medical and Veterinary Entomology, 16:207-213.

Torr, S.J., Wilson, P.J., Schofield, S., Mangwiro, T.N.C., Akber, S. and White, B.N. (2001). Application of DNA markers to identify the individual-specific hosts of tsetse feeding on cattle. Medical and Veterinary Entomology, 15, 78-86.

Grant, I.F. (2001) Insecticides for tsetse and trypanosomiasis control: is the environmental risk acceptable? Trends in Parasitology 17: 10-14.

Torr, S.J. & Mangwiro, T.N.C. (2000). Interactions between cattle and biting flies: effects on the feeding rate of tsetse. Medical and Veterinary Entomology, 14, 400-409.

Gibson, G. and Torr, S (1999) Visual and olfactory responses of haematophagous Diptera to host stimuli. Medical & Veterinary Entomology, 13, 1-22.