The Influence of Climate Change on Insect. Director Australian Animal Health Laboratory, Geelong

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1 The Influence of Climate Change on Insect Borne Diseases (1) Professor Martyn Jeggo Professor Martyn Jeggo Director Australian Animal Health Laboratory, Geelong

2 The problem the risk of infectious disease to humans and animals continues to grow alarmingly both globally and in Australia 75% of new diseases in human come from animals What is causing this and what can we do about?

3 The complex dynamics of disease emergence PATHOGEN INFLUENCES Quasispecies variation Genetic recombination Host/ vector adaptation Tissue tropism Virulence determinants Latency/persistence HOST INFLUENCES Reservoir host spillover Intermediary hosts Vector competence Susceptible host range Pathogenesis Immune response PATHOGEN HOST DISEASE ENVIRONMENT ANTHROPOGENIC INFLUENCES Globalisation Ub Urbanisation Land use change Behavioral/cultural change Regional/global conflict GEOPHYSICAL INFLUENCES Climate change Climate variability Extreme weather events

4 And the role of an insect? Direct contact, aerosol, through eating First Infected Host transmission of pathogen Second Host Via an insect insect borne infectious diseases, eg. malaria, dengue fever, bluetongue, rift valley fever

5 So what can we do? Understand the determinants of insect competence Understand viruses and insect at population level Understand the impacts of climate change Develop (novel) interventions

6 And some complications! Insect numbers fluctuate throughout the year and in response to climate change (e.g. more when it rains) Some hosts show disease whilst others may be symptomless Insects can travel significant distances whilst carrying a virus Insects often have a broad host range for feeding Viruses continual change (mutate) and this includes their ability to use different e insects for transmission ss Viruses can evolve (mutate) in the insect as well as the host Viruses can overwinter (hide) in the insect All the above makes risk management of these diseases extremely difficult (when the disease will occur, to what extent and even what to do when they do occur!

7 And what has happened in this wet year? Significant outbreaks of encephalitis related symptoms in horses in Victoria, South Australia, NSW, Queensland and latterly, Western Australia Evidence of a number of insect borne virus infections

8 Cases in Victoria Mid May

9 And what has happened in this wet year? Number of these viruses also affect man (and other species) Growing evidence of virus evolution in the case of Kunjin virus Kunjin virus is an Australian strain of the West Nile Flavivirus Another strain of West Nile virus has caused severe disease in USA in birds, horses and humans

10 West Nile in the USA West Nile

11 And so the risk in this case Started in New York and spread throughout USA in four years Vaccines are available both for uses in horses and in man Our crows not able to support Kunjin virus (AAHL 2009) Kunjin virus has clearly evolved It is STILL unlike the USA West Nile Will it evolve further? Do we understand why it is evolving? What are the risks we are facing? What can we do? Thank you and over to John!

12 The Influence of Climate Change on Insect Borne Diseases (1) Professor Martyn Jeggo Director, Australian Animal Health Laboratory, Geelong The Problem the risk of infectious disease to humans and animals continues to grow alarmingly both globally and in Australia 75% of new diseases in human come from animals What is causing this and what can we do about it? Those factors that lead to new and emerging diseases are complex and involve changes to the host, to the agent causing the disease (pathogens such as viruses, bacteria, parasites), and the environment. In terms of the environment this involves many interconnecting factors but climate has a significant influence The Role for Insects Insects act as vectors by transmitting the pathogen between different hosts (animals, birds, humans). There are many serious diseases that are transmitted by insects e.g. dengue, malaria, bluetongue, rift valley fever. What can we do in managing these insect borne diseases? Understand the determinants of insect competence Understand viruses and insect at population level Understand the impacts of climate change Develop (novel) interventions And some complications Insect numbers fluctuate throughout the year and in response to climate change (e.g. more when it rains) Some hosts show disease whilst others may be symptomless Insects can travel significant distances whilst carrying a virus Insects often have a broad host range for feeding Viruses continual change (mutate) and this includes their ability to use different insects for transmission Viruses can evolve (mutate) in the insect as well as the host Viruses can overwinter (hide) in the insect All the above makes risk management of these diseases extremely difficult (determining when the disease will occur, to what extent and even what to do when they do occur!) And so what has happened in this very wet year? Significant outbreaks of encephalitis related symptoms in horses in Victoria, South Australia, NSW, Queensland and latterly, Western Australia Many of these have been shown to be insect borne virus infections

13 Significant outbreaks of Kunjin virus in horses (an Australian insect borne virus infection that is related to the serious disease of West Nile) Whilst originating in Africa, West Nile now a very serious disease in the USA Initially started in New York affecting crows, and subsequently horses and humans Spread throughout USA in four years Vaccines are through available both for uses in horses and in man Our crows not able to support Kunjin virus (AAHL 2009) Kunjin virus has clearly evolved this year! It is STILL unlike the USA West Nile Will it evolve further? Do we understand why it is evolving? What are the risks we are facing? What can we do? Over to Professor John Mackenzie.