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Foot and mouth disease (FMD) is a highly contagious viral disease that affects all Artiodactyla. Seven immunologically distinct serotypes of FMD virus (FMDV) exist. In Chad, although FMD is included in the list of diseases monitored by the Chadian Animal Disease Surveillance Network (REPIMAT), the epidemiological situation remains unclear. A serological survey was conducted in the cattle population in eight of the nine administrative regions of the country (those regions with the highest cattle densities), to evaluate the prevalence and serotypes of circulating FMDV.A total of 796 sera from randomly selected cattle were analysed at the World Organisation for Animal Health/Food and Agriculture Organization of the United Nations FMD Reference Laboratory at the Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna(IZSLER), in Brescia (Italy). An enzyme-linked immunosorbent assay (ELISA), called 3ABC ELISA, was used to detect antibodies against non-structural proteins (NSPs), as well as a series of six competitive ELISAs to detect and serotype antibodies against the structural proteins of FMDV serotypes O, A, SAT 1, SAT 2, Asia 1 and C. Based on the detection of anti-NSP antibodies, the animal-level seroprevalence was 35.6%(95% confidence interval [CI]: 32.2-38.9) and the herd-level seroprevalence was 62.3% (95%CI: 53.0-71.5). FMD was present in all livestock administrative divisions surveyed, with a higher prevalence in southern regions, which are characterised by higher rainfall and humidity and more important transboundary animal movements. Cattle aged more than four years had a higher seroprevalence, which may be due to repeated exposure. Semi-sedentary farming and transhumance were also risk factors. Antibodies against serotypes A, O, SAT 1 and SAT 2 were detected.

In sub-Saharan Africa, most epidemiological surveillance networks for animal diseases were temporarily funded by foreign aid. It should be possible for national public funds to ensure the sustainability of such decision support tools. Taking the epidemiological surveillance network for animal diseases in Chad (REPIMAT) as an example, this study aims to estimate the network's cost by identifying the various costs and expenditures for each level of intervention. The network cost was estimated on the basis of an analysis of the operational organisation of REPIMAT, additional data collected in surveys and interviews with network field workers and a market price listing for Chad. These costs were then compared with those of other epidemiological surveillance networks in West Africa. The study results indicate that REPIMAT costs account for 3% of the State budget allocated to the Ministry of Livestock. In Chad in general, as in other West African countries, fixed costs outweigh variable costs at every level of intervention. The cost of surveillance principally depends on what is needed for surveillance at the local level (monitoring stations) and at the intermediate level (official livestock sectors and regional livestock delegations) and on the cost of the necessary equipment. In African countries, the cost of surveillance per square kilometre depends on livestock density.

One of the objectives of the Pan African Programme for the Control of Epizootics (PACE) was to set up epidemiological surveillance networks in African countries. A survey based on a written questionnaire was conducted to review the technical and institutional organisation of epidemiological surveillance networks in nine French-speaking countries, including five in West Africa (Senegal, Burkina Faso, Cote d'lvoire, Togo and Guinea) and four in Central Africa (Cameroon, Central African Republic, Democratic Republic of Congo and Chad). The survey results showed that there are more similarities than differences among epidemiological surveillance networks. In general, they were found to be technically and institutionally well established. However, the two weaknesses of the majority of networks are the inadequate diagnostic capacity of laboratories and the insufficient operationality of steering committees. Epidemiological surveillance should exclusively be the domain of Veterinary Services and it is crucial for ensuring that any change in the health status of an animal population is detected rapidly. However, the networks' continuing survival after external financing ceases is generally not guaranteed because, in many cases, governments fail to fund them adequately.

An epidemiosurveillance network for diseases of animals was introduced in Chad to ensure early reporting to animal husbandry organisations should the incidence of an existing disease increase, or should an exotic disease reappear. The network also serves for the collection of information on the principal diseases of livestock. A list of eight priority diseases was drawn up with specific surveillance objectives for each disease. Information (from surveys and sampling) from all new outbreaks of the diseases under surveillance is gathered by participants in the field (officials in public service and private veterinarians) and sent to the diagnostic laboratory, which examines the findings before disseminating them to the field. The first year of operation in the field has made it possible to evaluate the feasibility of the method and to collect fundamental epidemiological information on the diseases under surveillance. The advantage of the network is the provision of a means of communication between the field and the laboratory. The network enables collection of information in a standard form, the training of field agents and the organisation of the structure of the laboratory. Persistent problems are the motivation of some participants in the field and difficulties in communication which have to be overcome in order to obtain reliable data rapidly.