John Mackenzie is a Professor of Tropical Infectious Diseases and part-time Faculty Member at Curtin University, Western Australia, and is an Honorary Professor at the University of Queensland and Honorary Senior Principal Fellow at the Burnet Institute, Melbourne. He was formerly Professor of Microbiology and Tropical Infectious Diseases at the University of Queensland. He received his PhD in 1969 from the Australian National University where he worked with Professor Frank Fenner and Dr Robert Webster. He was then a faculty member at the University of Western Australia for 22 years, working principally on influenza and mosquito-borne viral diseases. He was elected Secretary-General of the International Union of Microbiological Societies (IUMS) from 1999-2005, Fellow of the American Academy of Microbiology, and is a Past President of the Australian Society for Microbiology and the Asia-Pacific Society for Medical Virology. In 2002, he was appointed as Officer in the Order of Australia for services to public health research and to education, and in 2005, he was the inaugural recipient of the Academy of Science Malaysia's Mahathir Science Award for Excellence in Tropical Research. He serves on a number of international committees with the United Nations, World Health Organization (WHO) and other Non-Government Organizations. He is a member of the steering committee of the Global Outbreak Alert and Response Network (GOARN), a member of the Technical Advisory Group of the WHO Asia-Pacific Strategy for Emerging Diseases, and a consultant to the new International Health Regulations (2005). Over the past year he has served as Chair of the IHR Emergency Committee for Influenza H1N1. His recent research interests have been in mosquito-borne virus diseases and emerging zoonotic viruses, and he has published over 300 major papers and research chapters on these and other research topics concerned with human and animal viral diseases.
Societal drivers of disease emergence - the consequences of human actions and activities
It is becoming increasingly clear that there is a strong human dimension to emerging and re-emerging diseases, and that most outbreaks or epidemics of emergent diseases are due in large part to human activities and/or human actions. Thus a better understanding of the underlying causes or mechanisms that predispose to disease emergence is crucial for improving our ability to predict future disease outbreaks, and also to prevent or mitigate their emergence. In this context, it is important to recall that emerging viral diseases are defined as either novel diseases not previously recognised or known viral diseases which are increasing ,or which threaten to increase, in incidence or geographic range. The major human activities and actions which predispose to disease emergence are those which bring humans closer to the source of virus, or which increase the environmental opportunities for transmission. These include changes in human demographics and urbanisation, changes in land use and agricultural practices, increases in globalisation of food supplies and trade, and the phenomenal increase in international travel and tourism. Added to these activities, genetic variation and mutations can change the transmissibility and/or the virulence of viruses. Thus changes in human demographics , such as increased urbanisation as a consequence of a movement from rural to urban areas leading to the development of shanty towns, often without water or sewage resources, or increased population growth leading to over-crowding, poverty and migration, are examples of the activities which predispose to viral disease transmission and spread. Similarly, changes in agricultural practices including intensive agriculture, deforestation, and increased irrigation also provide a potential for transmission as we struggle to feed an ever increasing world population. Indeed the globalisation of food supplies may also lead to virus transmission causing food poisoning. Travel and tourism provide an excellent avenue for the rapid spread of viral diseases, bringing exotic viruses from distant continents, and spreading viral diseases across national borders. Globalisation of trade may also spread mosquito vectors between continents, leading to the possibility of local transmission of exotic diseases. For all of these, societal pressures for improved quality and quantity of safe food and water supplies, for exotic and distant places to go for business or holidays, and for the potential of an improved future with respect to jobs and education in increasingly large urban centres, all serve to increase the potential for the spread and transmission of known and novel viral disease threats. Unfortunately, there are also examples were a breakdown of societal values can occur with increased transmission of some vaccine-preventable viral diseases, as exemplified by a reduction in public health programs leading to reduced levels of immunisation, resulting in the re-emergence of viral diseases such as measles and rubella. In addition, a reduction in public health measures may also lead to inadequate vector control and thus increased incidence of mosquito-borne disease. Finally, the economic consequences of emerging disease outbreaks can be significant, as seen from the emergence of SARS coronavirus in 2003 in China, and the spread of West Nile virus to North America in 1999.