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Arboviral diseases in Southern Africa - identification of the vectors and development of a climate-driven risk assessment model

Objective

The main objectives are as follows:
* To devise methods based on DNA sequences that identify with certainty between the various sibling species of Culicoides imicola, a species complex that comprises the major Old-World vector of African horse sickness virus (AHSV), bluetongue virus (BTV) and other arboviruses of veterinary significance.
* To measure in detail the vector competence of the major sibling species of the C.imicola complex (and other Culicoides species considered to be potential vectors of the arboviruses under study in southern Africa) in order to determine their relative importance in virus transmission.
* To elucidate the distribution, in time and space, of the vectorially-important members of the C.imicola complex (and other Culicoides considered to be important potential vectors) in southern Africa, and to identify the climatic or environmental factors that determine their distribution.
* To use the data acquired in the first 3 objectives to develop a climate-driven model that identifies those areas of southern Africa that are at risk to AHS, BT and other Culicoides-transmitted arboviral diseases. The model will also be able to determine those areas where there is little or no risk from these diseases (i.e. virus-free areas).
Expected Outcome

This project will lead to a clearer understanding of the epidemiology of AHSV, BTV and other important arboviruses in southern Africa by identifying the major vectors and by providing detailed information on their distribution, abundance, seasonal incidence and vector capacity. Furthermore climate-driven models based upon these data and upon local weather data will be constructed that generate predictive maps of AHSV and BTV transmission risk in southern Africa leading to the identification of areas that can be reliably designated as virus-free. This will lead to increased opportunities for international trade and equine sporting activities.
The key activities envisaged are divided into 7 work packages and are:
* Development of molecular techniques to distinguish among the species comprising the C.imicola complex.
* Measurement of the ability of members of the C.imicola complex (and other Culicoides species considered to be potential vectors) to transmit AHSV and BTV.
* Laboratory studies on how climate affects the mortality of vectors and development rates of AHSV and BTV in vectors.
* Study of the distribution, seasonal incidence and mortality of vectors in southern Africa, and the effects of climate on these parameters.
* Identification of the main Culicoides vectors of AHSV, BTV and other arboviruses in a region of southern Africa where vectors other than C.imicola ss are suspected.
* Identification of remotely-sensed images that are correlated with climatic variables relevant to the distribution and abundance of Culicoides vectors in southern Africa.
* Using GIS, to produce a climate-driven model that generates risk maps for AHS and BT for southern Africa.

Coordinator

INSTITUTE FOR ANIMAL HEALTH
Address
Ash Road, Nr Woking
GU24 0NF Woking
United Kingdom

Participants (3)

AGRICULTURAL RESEARCH COUNCIL
South Africa
Address
X055,old Soutpan Road, Private Bag X5
0110 Pretoria
Biomedical Research and Training Institute
Zimbabwe
Address
17,Beveridge Road 17
30 Harare
Università degli Studi di Pavia
Italy
Address
Piazza Botta 9
27100 Pavia