Spectrum of illness among returned Australian travellers from Bali, Indonesia: a 5-year retrospective observational study

Background: Bali, Indonesia, presents significant infectious and non-infectious health risks for Australian travellers. Understanding this spectrum of illnesses has the potential to assist clinicians in evaluating unwell returning travellers and guide provision of pre-travel advice. Aim: To describe the spectrum of illnesses seen in returned travellers from Bali. Methods: Using a novel text mining approach, we performed a retrospective, observational study of all adult emergency department presentations to a metropolitan health service in Melbourne, from 2011 to 2015. Outcome measures included demographic, clinical and laboratory features of travel-related illnesses. Results: A total of 464 patients met inclusion criteria. Gastroenteritis (119/464, 26%), systemic febrile illness (88/464, 19%) and respiratory tract infection (51/464, 11%) were the most common diagnoses. Dengue was the most common laboratory-confirmed diagnosis (25/464, 5%). No cases of malaria were identified. Common non-infectious presentations included traumatic injury (47/464, 10%) and animal bites requiring rabies post-exposure prophylaxis (29/464, 6%). A total of 110 patients (24%) was admitted to the hospital; those presenting with systemic febrile illness were more likely to be admitted compared to those presenting with other illnesses (odds ratio 3.42, 95% confidence interval 2.02–5.75, P < 0.001). Conclusion: This is the first study to use a text mining approach to identify and describe emergency department presentations related to diseases acquired in Bali by Australian travellers. Although infections are important causes of illness, trauma and animal bites account for a significant number of hospital presentations. Our findings contribute to the knowledge on the health risks for travellers to Bali, and will assist clinicians in relevant pre- and post-travel evaluations.