Journal Article

Mycobacterium ulcerans low infectious dose and mechanical transmission support insect bites and puncturing injuries in the spread of Buruli ulcer

Howden, Brian, Axford, Jason K., Stinear, Timothy P., Zeng, Weiguang, Mangas, Kirstie M., Wallace, John R., Marcsisin, Renee, Johnson, Paul D. R., Porter, Jessica L., Pidot, Sacha J., Omansen, Till F.

2017

Overview

Addressing the transmission enigma of the neglected disease Buruli ulcer (BU) is a World Health Organization priority. In Australia, we have observed an association between mosquitoes harboring the causative agent, Mycobacterium ulcerans, and BU. Here we tested a contaminated skin model of BU transmission by dipping the tails from healthy mice in cultures of the causative agent, Mycobacterium ulcerans. Tails were exposed to mosquito (Aedes notoscriptus and Aedes aegypti) blood feeding or punctured with sterile needles. Two of 12 of mice with M. ulcerans contaminated tails exposed to feeding A. notoscriptus mosquitoes developed BU. There were no mice exposed to A. aegypti that developed BU. Eighty-eight percent of mice (21/24) subjected to contaminated tail needle puncture developed BU. Mouse tails coated only in bacteria did not develop disease. A median incubation time of 12 weeks, consistent with data from human infections, was noted. We then specifically tested the M. ulcerans infectious dose-50 (ID50) in this contaminated skin surface infection model with needle puncture and observed an ID50 of 2.6 colony-forming units. We have uncovered a biologically plausible mechanical transmission mode of BU via natural or anthropogenic skin punctures.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Aedes / Aedes aegypti / Aedes notoscriptus / Animal models / Animals / Anthropogenic factors / Aquatic insects / Australia / Biology and Life Sciences / Bites / Buruli ulcer / Buruli Ulcer - transmission / Care and treatment / Contamination / Disease transmission / Epidemiology / Exposure / Female / Gene expression / Hypodermic needles / Immunology / Infections / Infectious diseases / Injuries / Insect bites / Insect Bites and Stings - complications / Insects / Leprosy / Mechanical transmissions / Medicine and Health Sciences / Mice, Inbred BALB C / Mosquitoes / Mycobacteria / Mycobacterium ulcerans / Mycobacterium ulcerans - growth & development / Needles / Needlestick Injuries - complications / People and Places / Piercing / Public health / Puncture / Research and Analysis Methods / Skin / Studies / Tails / Tropical diseases / Ulcers