Communicable Disease Control in New South Wales and globally

Abstract

Effective communicable disease control calls for a wide range of core public health competencies. In fulfilling the requirements of the Masters of Philosophy in Applied Epidemiology (MAE), I conducted projects in my placement at Health Protection New South Wales (NSW) between March 2014 and October 2015 which highlight some of these competencies.

In May 2014, the Communicable Diseases Branch was notified of hepatitis E virus (HEV) infection in two men who had not recently travelled overseas, but had both shared a meal with seven other work colleagues at a single Sydney restaurant. We conducted an investigation to assess the source and extent of the outbreak. We found a further 15 HEV cases linked to the restaurant. Pork pate was consumed by all 17 diners. Pork livers used to make pate were traced back to a single Australian farm. This is the first reported outbreak of locally-acquired HEV in Australia and has important clinical and public health implications. We recommend that clinicians consider locally-acquired HEV infection in patients with unexplained acute hepatitis regardless of travel history and that the public cook pork products thoroughly.

An outbreak was also the basis for my epidemiological project which involved a case-control study assessing risk factors for acquisition of a novel strain of Methicillin-resistant Staphylococcal aureus (MRSA) in a local health district (LHD) in NSW. Despite this new strain replacing endemic MRSA strains in nine hospitals in the LHD, we found no significant differences in clinical infection, admission to an intensive care unit or mortality when compared to people infected with endemic strains. Whole genome sequencing was used to describe transmission pathways. This modality may play a role in better characterising MRSA outbreaks in future.

In November 2014, I volunteered to assist in the Ebola virus disease (EVD) epidemic that affected three countries in West Africa. I worked in Monrovia, Liberia as a clinician at a Medecins sans Frontieres Ebola transit centre. At this centre, we admitted and tested patients with signs and symptoms of EVD. I analysed clinical and demographic data of patients who presented to the centre in our first month of opening and found that almost half did not have a measured temperature greater than 37.5oC. This has important implications for screening procedures in EVD-affected countries and elsewhere.

Acute Rheumatic Fever (ARF) and its sequelae, Rheumatic Heart Disease (RHD) are conditions thought to be rare in NSW. With an aim of improving cardiac outcomes in Aboriginal and Torres Strait Islander people, NSW Health committed to establishing a register-based control program for these diseases. In establishing this program, my work included quantifying the burden of disease, engaging with stakeholders and designing a system for notification and registration of cases. Both conditions were made notifiable in NSW in October 2015.

This thesis documents the investigation of Australia’s first reported locally-acquired hepatitis E outbreak, the assessment of a novel strain of MRSA, the establishment of a system for notification of two important public health conditions in Australia and the public health response to a global health emergency. Findings from these projects will contribute to the body of knowledge and provide important information to guide public health policy and stimulate ongoing research.