Survey on 'lumpy jaw' on deer farms in western Canada: Prevalence and distribution, and identification of associated factors

AIM: To investigate the prevalence and geographical distribution of 'lumpy jaw' (LJ) in a population of white-tailed deer (WTD; Odocoileus virginianus) and mule deer ( MD; Odocoileus hemionus) farms from the western Canadian provinces of Saskatchewan and Alberta, and to identify factors associated with its occurrence. METHODS: A cross-sectional study, in which the target population was all farmers of WTD and MD registered in Saskatchewan and Alberta, was conducted between July 2004 and January 2005. A questionnaire was mailed to all farmers requesting information about the presence of LJ and othernecrobacillosisrelated syndromes (footrot and fawn death syndrome), and various farm characteristics, during 2002, 2003 and 2004. Herd and within-herd incidences of disease were estimated. Global and local spatial analyses were performed to identify possible clusters of occurrence of LJ in the region. Logistic regression analysis was used to identify factors associated with the occurrence of LJ. RESULTS: A total of 139/268 (52%) deer farmers responded to the survey. Over the entire study period, 108/139 (78%) of farmers reported having cases of LJ in their herds, and in any given year the incidence amongst herds was about 40%. The presence of footrot was not associated with the presence of LJ. The proportion of fawns dying suddenly in 2004 was higher on farms affected by LJ than in those considered LJ-free (median of 11.1% and 0%, respectively; p < 0.001). Two areas in Saskatchewan were identified as having a higher herd prevalence of LJ (clusters) than all other areas. Density of animals, moving and handling animals, lack of basic hygiene measures, and bottle-feeding of fawns increased the odds of a herd being affected by LJ. CONCLUSIONS AND CLINICAL RELEVANCE: LJ should be considered a common disease in farmed deer in western Canada. The observed relationship between the occurrence of LJ and acute mortality of fawns emphasises the potential of this infection to result in significant economic loss. Intensive management of deer, characterised by high densities and frequent moving and handling of animals, may contribute significantly to the occurrence of LJ. Observed geographical clusters may reflect areas where management of deer was more intensive or the trading of deer more common.