The Incidence of Scabies in Far North Queensland, Tropical Australia: Implications for Local Clinical Practice and Public Health Strategies

Abstract

The recognition and treatment of scabies has been incorporated into Australian guidelines for the prevention of acute rheumatic fever (ARF) and rheumatic heart disease (RHD). The incidence of both diagnosed ARF and RHD is increasing in Far North Queensland (FNQ) in northeast tropical Australia, but the local burden of scabies is incompletely defined. We reviewed the results of every skin scraping collected in FNQ's public health system between 2000 and 2023; 121/4345 (2.8%) scrapings were positive, including 19/1071 (1.8%) in the last 5 years of the study; the proportion of scrapings that were positive for scabies declined over the study period. Individuals who tested positive for scabies were no more likely to have had a prior diagnosis of ARF or RHD compared to the matched controls (1/101 (1%) versus 3/101 (3%), p = 1.0). During a median of 14.7 years of follow-up, individuals who tested positive for scabies were also no more likely to have a diagnosis of ARF or RHD than matched controls (2/100 (2%) versus 6/98 (6%); hazard ratio (95% confidence interval): 0.30 (0.06-1.50) p = 0.14). Microbiologically confirmed scabies is uncommon in FNQ and appears to make a limited contribution to the local incidence of ARF and RHD.