Exposure Risk for Infection and Lack of Human-to-Human Transmission of Mycobacterium ulcerans Disease, Australia

Daniel O. and Eugene A.

Authors: O’Brien, Daniel P.; Wynne, James W.; Buultjens, Andrew H.; Michalski, Wojtek P.; Stinear, Timothy R.; Friedman, N. Deborah; Hughes, Andrew; Athan, Eugene

Source: EMERGING INFECTIOUS DISEASES, 23 (5):837-840, MAY 2017

Brief summary of the paper: We conducted epidemiologic and genetic analyses of family clusters of Mycobacterium ulcerans (Buruli ulcer) disease in southeastern Australia. We found that the incidence of M. ulcerans disease in family members was increased. However, the risk for exposure appeared short-term and not related to human-human transmission.

Mycobacterium ulcerans is a slow-growing organism that causes necrotizing infections of skin and soft tissue, often requiring reconstructive surgery and resulting in long-term disability. Prevailing opinion is that humans are infected from the environment; insects, such as mosquitoes, and water-residing biting arthropods, have been proposed as vectors for transmission. In Victoria, Australia, there is evidence that native opossums might be involved in transmission. However, despite extensive research, the environmental reservoir of the organism and mode of transmission remain unknown.

We postulated that examination of M. ulcerans disease (Buruli ulcer) family clusters might provide useful new information about disease epidemiology. Theoretically, genetically related first-degree relatives have similar susceptibility to disease, and families share the same environment and therefore a similar exposure risk.

Thus, we examined the epidemiology of M. ulcerans disease in family clusters managed in a large prospective observational cohort from the Bellarine Peninsula in southeastern Australia. We used data collected from all confirmed M. ulcerans cases managed during January 1, 1998–April 12, 2016, at Barwon Health, a tertiary referral hospital in Geelong, Australia.