Epidemiologic Features of an Intracranial Abscessation/Suppurative Meningoencephalitis Complex in White-Tailed Deer

Abstract

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.

EPIZOOTIOLOGY OF CRANIAL ABSCESS DISEASE IN WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) OF GEORGIA, USA

“…Beginning as a cranial abscess, these suppurative infections cause erosion and pitting of the cranium and necrosis of the tissue connecting the cranial bones (Davidson et al 1990). An unknown percentage of individuals with these purulent infections may recover, albeit with varying degrees of necrosis and erosion of the frontal bones and antler pedicel.…”

“…However, persistent infection results in erosion of the connecting tissue of the cranial bones allowing the abscess to enter the cranial chamber. Pressure on the brain from these intracranial abscess coupled with necrosis of brain tissue is fatal (Davidson et al 1990). Intracranial abscesses disproportionately affect adult ($3.5 yr old) male white-tailed deer, accounting for approximately 9% of natural mortality compared to ,1% of natural mortality in juvenile or female deer (Davidson et al 1990;Baumann et al 2001).…”

“…Pressure on the brain from these intracranial abscess coupled with necrosis of brain tissue is fatal (Davidson et al 1990). Intracranial abscesses disproportionately affect adult ($3.5 yr old) male white-tailed deer, accounting for approximately 9% of natural mortality compared to ,1% of natural mortality in juvenile or female deer (Davidson et al 1990;Baumann et al 2001). However, some geographically limited studies have reported up to 35% of natural mortality in adult males due to intracranial abscesses (Karns et al 2009).…”

“…Trueperella (Arcanobacterium) pyogenes (Yassin et al 2011), a resident bacterium on mucosal membranes and skin of healthy animals (Moore et al 2010), has been isolated from 65 of the 100 published cases of intracranial abscesses from white-tailed deer in which culture was attempted (Davidson et al 1990;Baumann et al 2001;Nettles et al 2002). Trueperella pyogenes may be the most widely distributed and most common opportunistic pathogen of mucosal surfaces in domestic animals (Jost and Billington 2005;Moore et al 2010) and is commonly found along the digestive tract, udders, urogenital region, and upper respiratory tracts of healthy animals (Natterman and Horsch 1977; Queen et al 1994;Narayanan et al 1998;Jost et al 2002).…”

“…Evidence suggests the population-level influences of cranial abscess may vary across physiographic regions and may be greater in management scenarios designed to increase the population density of mature males (Davidson et al 1990). If intracranial abscesses are an additive source of mortality, they could affect the success of some deer management efforts and may have broader impacts on deer population health than previously recognized.…”