Development of a method for optimal detection of emerging disease incursions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand
Emerging and re-emerging infectious diseases (ERID) are capable of generating sizable economic
loss, and causing loss of life and social instability. To prevent and mitigate the negative impacts of
ERID, it is imperative to have a sensitive surveillance system for early disease detection.
Furthermore, from the economic perspective, resources are always scarce and have opportunity cost,
so investment in surveillance programs has to demonstrate that it can maximize the utility of available
resources. The thesis was focused on development and application of a software toolbox, Human and
Animal Disease Response Program (HandiResponse), designed for (i) visualizing the disease risk
landscape and representing spatial variation in the expected occurrence of a zoonotic disease both
quantitatively and visually; (ii) evaluating economic benefit and costs of a single surveillance activity
or a multi-component portfolio; (iii) identifying optimal use of resources for surveillance. It
comprises four modules: (i) risk map development – HandiMap; (ii) surveillance portfolio
development – HandiSurv; (iii) economic impact assessment – HandiEcon and (iv) surveillance
optimization – OptiSurv.
The modules developed were tested on a number of data sets from various countries. The experience
demonstrated that using satellite-derived data in combination with national statistical data to produce
a disease risk map improved spatial prediction of avian influenza H5N1 outbreaks in southern
Vietnam. Development of a risk map from satellite data for Crimean Congo Haemorrhagic Fever for
Mongolia guided a field surveillance program which provided the first evidence that this disease is
present in both animals and people in Mongolia. Finally an invented disease affecting pigs and people
was used to investigate the likely consequences of an incursion of such a novel disease into Australia,
involving both domestic and feral pigs and transferring to people. Risk-based and classical disease
surveillance options were then tested for disease detection, and modelling work confirmed that a
portfolio consisting of different options was the most technically and economically appropriate.
HandiResponse is a practical tool that could promote the implementation of risk-based surveillance
approaches, and improve both technical and economic efficiency of surveillance programs for
infectious diseases, particularly those affecting both people and animals.