Objective: To present a case history and review serological results of human hydatid disease in Australia from 2005 to 2016, when echinococcosis is no longer a communicable notifiable disease.
Setting and data sample: Sullivan Nicolaides Pathology (SNP) is a medical testing laboratory providing diagnostic private pathology in Queensland, northern New South Wales and Darwin. SNP is also a key referral lab for specialized diagnosis of uncommon infectious diseases, such as echinococcosis, from other medical testing laboratories. As a result, the facility has access to a large data sample of individuals throughout Australia.
Diagnosis algorithm: Serological diagnosis of echinococcosis is determined using hydatid haemagglutination assay (IHA). Since 2011, all positive samples from the initial IHA screen are reflexed for confirmation with western blot (Euroimmun Euroline WB-IgG).
Results: Over the 12 year time frame, 4644 patients were screened for Echinococcus infection, of whom 389 were IHA positive (8.3%). A majority of the patient sample data originated from Queensland (41.75%) and NSW (34.1%), which is to be expected considering the majority of SNP’s clients are based in these two states. Nevertheless, the sample dataincluded patients from all 8 states and territories of Australia. The median age of IHA positive patients was 47.8 years (range, 11 - 92 years). Reported titers ranged from 32 to > 2048. There was a relatively even ratio of women (43.2%) and men (56.8%) infected. Since 2011 following implementation of a two-tier testing algorithm, of the 155 IHA positive patients, 35 were confirmed with immunoblot for the highly specific Echinococcus granulosus P7 antigen (22.6%).
Conclusion: Echinococcosis is an uncommon disease in Australia with low rates of western blot confirmed positives (1.32%). However, due to the fact that infection can remain quiescent for many years with symptoms only occurring in the advanced stages of disease, it is possible that hydatid disease is under-reported.