CONICET | Buscador de Institutos y Recursos Humanos

Purpose:Foot-mouth-disease (FMD) caused by the FMD virus is the one of the most important livestock disease globally both due to direct losses from production declines, mortality of neonates and welfare but also because of the severe restrictions on trade that disease free countries impose. One of the justifications for imposing such severe restrictions are concerns over individual animals becoming persistently infected which is also called the ?carrier state?. The carrier state in foot-and-mouth disease has been a useful construct for experimental studies although they have generally failed to provide evidence of transmission from cattle, but there are very few studies that have attempted to look at the factors associated with persistence in naturally infected endemic populations with multiple serotype exposures.Methods:Using historic data from 1,077 animals from an age stratified, clustered random sample of herds in the Adamawa Region of Cameroon in 2000, using a multi-level logistic regression model, we have estimated the association between the age of an animal, the months since the last reported outbreak of FMD in the herd it came from, the number of different previous serotype exposures and the probability of recovering viable virus from a probang sample.Results:The proposed model suggests that there is an exponential decline in the probability of recovery of viable virus with both age and months since last outbreak, however, the probability of recovering virus increased with the number of serotype exposures.Conclusions:These results suggest a need to redefine the ?carrier? state for the natural ecological setting.Relevance:This has direct relevance both to researchers planning FMD field studies and state veterinarians planning surveillance activities wanting to target animals to recover virus for typing.