Diarrhoea remains a major, yet often overlooked, health problem in Papua New Guinea (PNG). It is a common causes of hospitalisation of children, and in the top 10 causes of childhood (<5 years) death. This presentation highlights successes and challenges in our efforts to improve knowledge of diarrhoeal pathogens circulating in PNG over the past ~15 years. In that time the first reported cholera outbreak in PNG has come and gone (2009 – 2011), resulting in >15,000 cases and 500 deaths. We demonstrated that the outbreak was caused by an incursion of a single strain of Vibrio cholerae O1 closely related to stains from the Indonesian archipelago. Typhoid fever has been endemic in PNG for over 50 years. It is also the result of a single incursion of the aetiological agent, Salmonella enterica serovar Typhi, which has undergone relatively little evolutionary change in that time. Fortuitously, this includes the absence of antibiotic resistance in the majority of isolates. A third important bacterial pathogen of importance in PNG is Shigella spp. Our surveillance revealed Shigella to be the leading cause of diarrhoea in Eastern Highlands Province. Here the molecular phylogeny tells a different story, with multiple incursions of S. flexneri, and at least one incursion of S. sonnei. Both species of Shigella were commonly resistant to first-line antibiotics such as ampicillin, chloramphenicol, tetracycline and co-trimoxazole.
There is ongoing work seeking to investigate S. Typhi environmental persistence, addressing our lack of knowledge of gastrointestinal parasites, and to better understand the burden of disease of important gastrointestinal pathogens.