The prevalence of human melioidosis in Northern Queensland.

Sera from 9,047 individuals from Northern Queensland were examined for the presence of hemagglutinating antibodies to Pseudomonas pseudomallei, the causative agent of melioidosis, and 512 (5.7%) were found to have titers of 1:40 or greater. The distribution of positive reactors in various groups was uneven, and significantly higher prevalences of positive antibody titers were found in the sera from Aborigines (7.9-10.6%), Torres Strait Islanders (7.8%), Vietnamese refugees (29%) and from persons with certain medical conditions including chronic alcoholism (15%), chronic infections (14.8%), diabetes mellitus (8.6%) and liver disease (12.9%). There were significantly fewer positive reactors (1.4%) amongst the armed forces stationed in Northern Queensland. At present, the boundaries of the major endemic region of Australia extend north from Rockhampton along the coast to Darwin and inland, west from Rockhampton to Tennant Creek in central Australia. Townsville was found to have the highest prevalence (5.2%) of positive reactors of all urban populations of Northern Queensland. The extent of the disease is such that it can no longer be considered a rare infection in Northern Queensland.