François Roger: "It is vital to include human sciences in the fight against foot-and-mouth in the South"

The disease has been around for a long time. What impact is it having today?

François Roger: The disease is well known in the veterinary world, and is continuing to grow in importance in economic terms. In particular, once detected somewhere, it limits trade opportunities. It is under control in the North, but any outbreak would have far-reaching economic consequences. According to estimates, the one in the United Kingdom some ten years ago cost the country around 20 billion euros in direct or indirect losses. Australia, for its part, has long been free of the disease, but it exports so many animals that any outbreak of the disease would cost its economy 3% of its GDP over a year.
In sub-Saharan Africa and Southeast Asia, the disease is widespread, according to the data passed on to the countries concerned by the OIE. Indeed, at the moment, it is easier to list the countries free of the disease than the opposite. In Africa, this applies to roughly ten countries out of fifty-two: Morocco, Algeria, Tunisia, Mozambique, Zambia, Madagascar, Gabon, and Senegal, with a few other countries for which data are not available. In Asia, the disease is found in thirteen countries, with just five disease-free: Indonesia, Philippines, Tajikistan, Syria, and Jordan. International trade plays a less significant role in these countries, at least apparently. The role of trade in motivating people to fight the disease is thus not sufficiently important to generate significant progress in terms of control. Despite this, the economic damage is significant. A study in Cambodia estimated the total cost of a foot-and-mouth epidemic at the start of the rainy season, for a family with two water buffaloes, at 34 US dollars, notably due to the loss of the draught they provide. The average monthly income per household in rural areas of Cambodia is around 40 US dollars, while control (vaccine) costs for such families would be around 6 dollars a year. Another survey of 36 small farms in Vietnam after the appearance of a foot-and-mouth focus in 2006 showed that the financial loss per farm varied between 84 and 930 US dollars. Taking account of and limiting these risks would in many cases allow a shift from a highly precarious subsistence economy to a much more sustainable economy. This would preserve what is often these farmers' only mobile form of capital.

How do things stand as regards control of the disease in the South?

F. R.: In the South, there are constraints on disease control that hardly exist, if at all, in the North. The main obstacles are the cost of surveillance and vaccination, the involvement of wildlife, particularly in southern Africa, and animal farmers' perception of the disease. Unlike rinderpest, which wiped out whole herds, foot-and-mouth is more contagious, but much less visible, insofar as large numbers of animals fall sick but relatively few die. For animal farmers, the disease is not a problem, at first glance, in relation to other, more visible ones, such as haemorrhagic septicaemia. Farmers do not necessarily realize that their animals are producing less and that there will be an economic impact in the long term. Fighting the disease is therefore not a priority for them, whereas it may be on a national level, and for some firms, for commercial reasons.
Despite this, in both Africa and Southeast Asia, it should be entirely possible to control the disease, although it would call for substantial resources. Public and private veterinary services need to be expanded, and further studies are required, particularly of the epidemiology of the disease or aspects relating to vaccines and vaccination strategies. While the basic tools are available, it is still difficult to apply them: should we vaccinate or not? When should we vaccinate? Which animals? Should cattle farms be protected from buffaloes? How can we work with farmers? How can different approaches be validated? If we are to come up with answers to these questions, it is vital to take account of social and human aspects, including economics, epidemiology and ecology.

What approach is CIRAD taking as regards foot-and-mouth control?

F.R.: In fact, we are working on several parallel approaches. In southern Africa, we are concentrating on wild reservoirs. The aim is to assess the efficacy of building barriers to separate infected animals, healthy animals, wildlife and domestic animals (1). In Asia, where there are fewer large mamals, the aim is to improve risk detection and awareness among farmers.
There is a significant interaction between our work in Asia and that in Africa. We feel it is very important to transfer to Africa the methods we use in Asia, particularly participatory methods. For instance, the tools we use include semi-directive interviews, two-by-two disease comparisons, and matrix scoring, which serves to rank diseases. We systematically use three different data sources. It is this triangulation principle that ensures quality results. Conversely, the study conducted in Africa to analyse the risk of transmission from reservoirs could also be carried out in Asia for domestic buffaloes. In terms of epidemiological approaches, we are also working on statistical methods - so-called capture-recapture methods - to assess the extent of the disease in Cambodia more accurately (2). It would also be worth applying these methods in Africa. We also recently helped train Thai veterinary surgeons in the spatial epidemiology of foot-and-mouth. Assessments concerning the risk of disease introduction (3) on the one hand, and of vaccination (4) on the other, are under way in southern Africa. Lastly, we are also thinking about launching economic assessments of foot-and-mouth surveillance systems, which could be conducted in close collaboration with the OIE.
However, we will not be working directly on the pathogen: this is being done in liaison with laboratories in the South, and we could eventually work with reference laboratories in the North such as ANSES in France and the IAH in the UK. We will be looking more to provide clues that will enable a better understanding of the situation in the field, better modelling, and better communication with both farmers and decision-makers. All this will be done with the help of the human and social sciences.

Interview by Elsa Bru

(1) De Garine-Wichatitsky M., Pfukenyi D., Zisadza P., Body G., Makwangudze J., Caron A., 2010. Seroprevalence of Foot-and-Mouth disease at the wildlife/livestock interface in the South-east Lowveld of Zimbabwe: influence of home range overlap. FMD International Symposium and Workshop, 12-14 April, Melbourne, Australia.

(2) Vergne T., Grosbois V., Durand B., Goutard F., Bellet C., Holl D., Roger F., Dufour B. A capture-recapture analysis for assessing the epidemiological situation of foot-and-mouth disease in Svay Rieng province, Cambodia. Prev. Vet. Med. In Press.

(3) Jori F., Etter E., Gummow B., Vosloo W., 2010. A stochastic probability model to quantify the risk of transmission of foot and mouth disease virus at the wildlife/livestock interface of Kruger national park, South Africa. Foot and Mouth Disease International Symposium, 12-14 April 2010, Melbourne, Australia.

(4) Caron A., Heath L., Pfukenyi D., de Garine-Wichatitsky M., Jori F., 2010. FMD vaccination trial and viral circulation at the wildlife/livestock interface in the South-East Lowveld of Zimbabwe. FMD International Symposium and Workshop, 12-14th of April, Melbourne, Australia.