Three monumental challenges to our health
An alliance of top researchers is trying to keep New Zealand ahead of complex health challenges from overuse of antibiotics, threats to freshwater quality and emerging infectious diseases.
New Zealand faces a growing number of challenges to our population’s health, such as antimicrobial resistance, declining freshwater quality and emerging infectious diseases. Each of them is pressing, complex and potentially monumental in their impact.
Take for example, infectious diseases. Sixty percent of those known in humans originate in domestic or wild animals, as do 75 percent of emerging ones. Unknown infections appear at regular intervals. Known infections such as Ebola re-emerge in explosive outbreaks. This pattern of emergence and re-emergence is what infections have always done. What has changed is human behaviour and our interaction with the environment. Factors such as increased urbanisation, overcrowded living conditions, increased global migration and the over-use of antibiotics have created environments that promote the transmission of infections.
The idea that the health of humans and animals and the viability of ecosystems are inextricably linked is the basis of a concept known as One Health. In 2013, the One Health Aotearoa (OHA) alliance was established to bring together New Zealand’s top researchers from diverse disciplines.
Founding partners were New Zealand’s oldest medical school (the University of Otago), New Zealand’s only veterinary school (Massey University), and the New Zealand Crown Research Institute of Environmental Science and Research (ESR), which is the main provider of infectious disease services to the Ministry of Health. One Health Aotearoa now involves researchers from other New Zealand universities, crown research institutions, government agencies, district health boards, and community groups. Increasing efforts are also being made to work with regional partners in the Pacific and Australia.
For many reasons, New Zealand is an ideal place to undertake One Health research. Its isolated island ecosystem makes it vulnerable to introduced pests and pathogens. Our economy is reliant on agriculture. Recent primary sector intensification has increased health risks. We have a small, well-connected scientific community with links to communities, government and industry, and the interconnectivity between humans, animals and the environment is integral to the Māori worldview.
Since its establishment, the One Health Aotearoa alliance has identified three areas of research priority:
Fresh water quality
Emerging infectious diseases.
Underpinning all its activities is a commitment to acknowledge three key areas: Mātauranga Māori (Māori knowledge developed from experiences, history, worldview, culture, and aspirations), climate change, and the importance of effective policy change.
New Zealand historically has low rates of antibiotic resistance, but this is changing. So One Health Aotearoa is studying reasons for the increase and sources of resistant strains and how they spread. Researchers have found New Zealand has high rates of antibiotic use in humans compared with other countries such as Europe, Australia, Canada and the United States, and is working to reverse this trend by better understanding behaviours and environmental factors that promote antibiotic resistance .
In comparison to our human usage, New Zealand has low rates of antibiotic use in animals. Our veterinary profession has set an aspirational goal to reduce further the use of antibiotics in animals, and phase out reliance on antimicrobials for the maintenance of animal health and welfare by 2030.
Fresh water quality in New Zealand is declining. This trend relates to our agricultural intensification, which is among the highest globally. While the average global ratio of livestock to humans is about 2:1, in New Zealand it is about 25:1. Agricultural intensification increases water contamination. This in turns increases our already high rate of gut diseases originating in animals, such as Salmonella or leptospirosis.
The importance of a One Health approach in maintaining fresh water quality was demonstrated in 2016 with the outbreak of gastroenteritis in Havelock North. The incident, one of the world’s largest reported waterborne outbreaks, was traced to sheep faeces contaminating bores supplying drinking water.
Contaminated water can also affect humans through irrigation of food crops, recreational activities, shellfish, and drinking water. Greater understanding of specific risks for transmission of potential pathogens between animals, humans, and waterways is urgently needed. To this end, One Health Aotearoa is currently looking at better predictors of water quality and improved diagnostic tests for water-borne pathogens with a view to ensuring a safe and sustainable supply of fresh water for New Zealand.
New and recurring infectious diseases are a constant threat to the health of New Zealanders, and our livestock. Recent examples include leptospirosis (a bacteria that affects humans and animals); murine typhus (spread by infected fleas); mycoplasma bovis (a devastating infection in cows); and salmonella typhimurium DT160 (a serious gut disease spread by wild birds). Each of these diseases came to New Zealand via different pathways and species. To understand these myriad and complex infectious threats, One Health Aotearoa is bringing together researchers from diverse backgrounds in human, animal and ecosystem health in order to jointly tackle the prevention and control of these diseases.
The incidence of Staphylococcus aureus infections in New Zealand is among the highest reported in the developed world, with the highest incidence among Māori and Pacific Peoples. The incidence of serious infectious diseases has also increased markedly in New Zealand over recent decades, as ethnic and social inequalities have also risen. A major challenge for One Health Aotearoa will be to understand and provide guidance on how to address the social, cultural, and environmental determinants of these high rates of infectious diseases.
Concerns about the potential to introduce mosquito-borne and other diseases not currently established in New Zealand are real. Rates of international travel by New Zealand residents are among the highest globally, and net gain migration remains high. Consequently, New Zealand remains vulnerable to pandemics and other global emerging disease threats. Understanding external drivers of imported infectious diseases is essential for informing biosecurity measures and pandemic preparedness, and will be a future focus for the alliance.
All the health challenges One Health Aotearoa is addressing are complex and have evolved over time. As such, the OHA alliance hopes to continue to grow in number and breadth of membership so it can help provide New Zealand and the world with answers to some of the most concerning questions the future might pose.
Professor David Murdoch is the co-director of One Health Aotearoa. He is the Dean of the University of Otago’s Christchurch health campus and a world-renowned infectious disease expert. He is the co-leader of Christchurch-based research team The Infection Group, a senior associate in the Department of International Health at Johns Hopkins School of Public Health, and clinical microbiologist at Canterbury Health Laboratories.
One Health Aotearoa is holding its annual symposium on Tuesday 10 and Wednesday 11 December 2019 at the University of Otago, Wellington.
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