Epidemiologic features of an intracranial abscessation/suppurative meningoencephalitis complex in white-tailed deer

Case records of 683 white-tailed deer (Odocoileus virginianus) submitted to the Southeastern Cooperative Wildlife Disease Study (Georgia, USA) for diagnostic purposes from 1971 to 1989 were reviewed for the occurrence of pyogenic infections of the central nervous system, specifically intracranial abscessation or suppurative meningoencephalitis. These conditions, either alone or in combination, were diagnosed in 24 of 683 (4%) deer. Thirteen genera of bacteria were isolated; the most frequent species was Actinomyces pyogenes. The disease was strongly sex biased (P less than 0.01); 88% of the cases occurred in males. Cases were more prevalent (P less than 0.05) in older bucks; the median age of infected bucks was 3.2 yr, and 71% of these were greater than or equal to 2.5-yr-old. Intracranial abscessation/suppurative meningoencephalitis cases accounted for 20% of the diagnoses among 56 bucks greater than or equal to 3-yr-old. Cases were seasonal, occurring only from October to April. Characteristic necrosis, erosion, and pitting of skull bones were common, and this bone damage may be useful in determining cause of death when only skeletal remains are found. Males, especially older bucks, apparently are predisposed to intracranial abscessation/suppurative meningoencephalitis because of the cycle of antler development and behavioral traits associated with reproduction. The strong bias toward prime age bucks suggests that these infections could specifically hinder management strategies designed to produce populations with older buck age structures.