ECONOMIC IMPACT OF USING AN ANTIVIRAL IN THE CONTROL OF A FOOT-AND-MOUTH DISEASE EPIZOOTIC IN SOUTHERN BELGIUM

Foot-and-mouth disease virus (FMDV) is a highly contagious pathogen of cloven-hoofed
mammals and one of the biggest concerns for veterinary authorities. The control measures to
be applied in case of an outbreak vary in function of the disease-free or disease-enzootic
status. Vaccination depends on the prior identification of the involved viral serotype and
subtype, it confers an immunity limited to 6 months and it requires between 4 to 7 days to
trigger the immune response (i.e. immunity-gap). The use of anti-FMD drugs has been
discussed as an alternative or supplementary method to be used in previously FMD-free
countries/zones. Such an antiviral treatment could protect against the viral dissemination to
fill the gap between vaccination and the rise of a protective immunity. Apart from broad
spectrum antiviral agents, such as ribavirin, specific anti-FMDV molecules have been
identified in vitro, but none of them has been used in clinical studies involving ruminants or
pigs. Next to the anti-FMDV activity, the absence of toxicity and the withdrawal period
influencing the food safety, the cost of the treatment would be another important parameter
influencing the potential use of an antiviral agent in the control of a FMD outbreak.
The aim of this study was to assess the economic impact of using an antiviral in the control
of a FMD epizootic in southern Belgium (Walloon Region). This work was based on the
results of previous investigations concerning the epidemiological and economic data of a
FMD outbreak in Southern Belgium. In the considered scenario, the epizootic was caused by
the introduction of an infected cow (during the incubation time) in a beef cattle farm during
winter. During the two weeks between the brood cow introduction and the official declaration
of the outbreak, animal movements occurred between other beef cattle farms. The economic
effects of the epidemic were evaluated taking into account the air-borne transmission of
FMDV, the occurrence of animal movements (two scenarios were considered, with a
minimum of 2 and a maximum of 17 movements), the presence of bovine and small ruminant
farms, as well as pig farms in the protection and surveillance zones around the initial and
secondary outbreaks. The wild fauna was not involved in the epidemic.
In order to integrate in the above scenario the application of an antiviral agent in the control
of the disease, it was assumed that the efficacy of the anti-FMDV drug was proven by
reducing viral excretion in infected animals as well as by preventing the infection in animals
at risk.
Two hypothetical prices were used to introduce in the model the costs related to the
administration of the antiviral drug (5€ and 10€ per dose). Furthermore, different strategies of
control could be envisaged, such as the administration of the drug to both domestic
ruminants and pigs, or depending on the epidemiological role of these species in the FMD
transmission and their density in the territory, the administration of the drug to only one of
them. Other scenarios could be characterized by the use of the antiviral in the control of the
epizootic within the protection and surveillance zones or in only one of them. The costs
associated with the use of antivirals in the different proposed scenarios are compared to the
costs and socio-economic losses associated with the FMD outbreak and the implementation
of control measures.