Oral health in South East Queensland Koalas: Prevalence of periodontal disease and other pathologies

Abstract

The koala (Phascolarctos cinereus) is one of Australia's most highly specialised folivores with a diet exclusively of eucalyptus leaves to provide all nutritive needs. For this it is dependent on good dentition for optimal health and quality of life. The purpose of this study was to characterise and describe the level of oral health and disease in koalas and then create tools for ongoing analysis.The historical records over a 17-year period were noted for the koalas admitted to the Moggill Koala Hospital in South East Queensland. Further, in this study the conclusions were that oral health issues when they existed were only being identified as "low key" due to the lack of investigative tools being used during examinations. This provided the reasoning and impetus behind developing tools to determine the true extent of oral health conditions in the koala. A suitable assessment tool for diagnosing the oral health was designed based on the index scoring methodology and the layout of the Moggill Koala Hospital admission chart, a new oral health chart template was developed. The chart was based on examination of 30 "free-range koalas" and validation and quality assurance analysis of four examiners of varying qualifications. The chart was separated into three sections; containing general animal information such as sex, age, and current systemic health; the General Oral Cavity section and containing information on 12 koala-specific health questions and finally a section on the periodontal health. The charting data is multifunctional with analysis of individual koalas, (sex, group or age). The data from each section provided an index value that was compatible with values from other species clinical charting systems.Using the chart, populations of 200 "free-range" and 95 captive koalas (from three zoos) were examined. Three major indexes were developed during the chart development process and used the following equation; General Oral Cavity (GOCI) + Oral Health Index (OHI) = Final Oral Health Index (FOHI). Initially, the three major index values plus all additional information of each chart were analysed to show the current baseline values of oral health conditions in the koala. Any ii comparison based on singular or multiple animals would either show a decline, same rate or increase from the baseline. These baseline parameters could be compared against any other species that uses the same 0-3 index system.The proportion of koalas from the whole population with an orally related problem was 86%.The average FOHI for the koala as a species was 3.78 ± 3.19, median 3.00. This is the mild category and held 84.5% of all cases. The maximum scores for the groups showed Zoo 3 as having lower range (Zoo 1; 11.42 for a TWC 1 male, Zoo 2; 13.40, Zoo 3; 4.13 and "free-range"; 15.98). The third zoo was the only group to have also had significantly better oral health than "free-range" koalas.Captive koalas showed high scoring at young age (11.42), the "free-range" comparable age score was 3.84. At population level when controlli...

Periodontal disease in free‐ranging koalas (Phascolarctos cinereus) from the Mount Lofty Ranges, South Australia, and its association with koala retrovirus infection

“…FOHI were also mild to moderate with younger koalas having much lower index scores than older koalas. The pattern of poorer oral health observed in older koalas is similar to that seen in northern koalas and was similar to the rates recorded in other herbivores …”

“…The results of our study showed that PD is a significant oral disease in South Australian koalas, with 84% of the koalas having some form of PD, 77% having gingivitis, and 65% presenting with periodontitis. The prevalence of PD detected in South Australian koalas was similar to free‐ranging koalas from Queensland, where the prevalence of PD was estimated to be 74% . However, Queensland koalas had lower levels of gingivitis and periodontitis, with a prevalence of 50% and 28%, respectively .…”

“…The prevalence of PD detected in South Australian koalas was similar to free‐ranging koalas from Queensland, where the prevalence of PD was estimated to be 74% . However, Queensland koalas had lower levels of gingivitis and periodontitis, with a prevalence of 50% and 28%, respectively . The OHI levels based on calculus, inflammation, mobility, and bleeding all ranged from mild to severe.…”

“…The risk factors for PD in Queensland koalas were identified as age, presence of systemic disease and compaction of vegetation material around the teeth . In this study of South Australian koalas, the senior age group was found to have the highest prevalence of PD.…”

“…PD has been observed in 10.3% of captive wallabies and in a number of Australian marsupials, including koalas . In a study of wild Queensland koalas, 74% of koalas had PD, 50% had gingivitis and 28% had periodontitis . Increasing age and the presence of specific black‐pigmented bacteria were found to be risk factors for PD in Australian marsupials, while a specific study on Queensland koalas showed the extent, severity and prevalence of PD increased with age .…”