Spatial Analysis Of The An. Punctulatus Group Of Malaria Vectors In Australia And Papua New Guinea.
Funder
National Health and Medical Research Council
Funding Amount
$66,430.00
Summary
Malaria has been eradicated from Australia but the country remains receptive to its reintroduction as the mosquitoes which transmit the disease are still present in the tropical north of the country. These are the Anopheles punctulatus group which are the major malaria vectors in the south west Pacific region. The Australian Army Malaria Institute conducted Operation Anopheles to collect these mosquitoes in northern Australia and Papua New Guinea by detailed surveys with the aid of helicopters a ....Malaria has been eradicated from Australia but the country remains receptive to its reintroduction as the mosquitoes which transmit the disease are still present in the tropical north of the country. These are the Anopheles punctulatus group which are the major malaria vectors in the south west Pacific region. The Australian Army Malaria Institute conducted Operation Anopheles to collect these mosquitoes in northern Australia and Papua New Guinea by detailed surveys with the aid of helicopters and 4-wheel-drive vehicles. These surveys, which were made for a month each year between 1984-1998, represent the most detailed dataset of mosquito locality records that have ever been produced. This project will utilise the computing power of modern Geographical Information Systems (GIS) software and computer induction techniques to spatially map the range of the different mosquitoes collected during Operation Anopheles to highlight environmental characteristics which limit their distribution and to permit control activities to accurately target the species which actually transmit malaria.Read moreRead less
Japanese Encephalitis Virus In Northern Australia And Papua New Guinea:its Ecology And Risk To Australia.
Funder
National Health and Medical Research Council
Funding Amount
$292,045.00
Summary
Japanese encephalitis (JE) virus is a mosquito-transmitted virus of Asia. Infection causes clinical disease in about 1 in 50 people infected, and of these, about 25% will die from a fatal encephalitis (inflammation of the brain), and a further 50% will have lifelong severe disabilities. There are over 50,000 cases annually in Asia, with about 12,000 fatalities. However, many more cases may go unrecognised. The virus normally circulates between mosquitoes and water birds and between mosquitoes an ....Japanese encephalitis (JE) virus is a mosquito-transmitted virus of Asia. Infection causes clinical disease in about 1 in 50 people infected, and of these, about 25% will die from a fatal encephalitis (inflammation of the brain), and a further 50% will have lifelong severe disabilities. There are over 50,000 cases annually in Asia, with about 12,000 fatalities. However, many more cases may go unrecognised. The virus normally circulates between mosquitoes and water birds and between mosquitoes and pigs. The World Health Organization has recognised JE as one of the most important mosquito-borne viruses because of its propensity to spread and to colonise new areas. The virus first appeared in the Torres Strait of northern Australia in 1995, causing three clinical cases of whom 2 died. This was unexpected as the nearest known focus of virus activity was in Bali, over 3000km away. The virus returned again in 1998, with a further case in the Torres Strait and the first case to occur on mainland Australia in Cape York. Both of these patients recovered. We have shown that the virus is established in Papua New Guinea (PNG), where it is spreading rapidly, and our results suggest that PNG was the source of the virus causing the outbreaks in 1995 and 1998. This project is aimed at finding out more about JE virus in PNG, particularly as it relates to spread into northern Australia. The project also seeks to investigate the potential mosquito and animal hosts in Australia that might be involved if the virus becomes established in our wildlife in Cape York. Australia is already known to have suitable mosquito vector species and suitable animal hosts in water birds and feral pigs, but the ecology is not yet understood. Thus the overall aim is to provide information on which a sound risk assessment can be based.Read moreRead less
Dengue is the leading mosquito-borne virus causing morbidity and mortality in the tropics. North Queens land has a history of dengue outbreaks, with 5 outbreaks in the last 3 years. Queensland Health has developed a Dengue Fever Management Plan for north Queensland that has had considerable success in preventing small outbreaks of dengue from developing into large epidemics. The cornerstone of this plan is the application of residual insecticide inside premises near dengue cases to kill the mosq ....Dengue is the leading mosquito-borne virus causing morbidity and mortality in the tropics. North Queens land has a history of dengue outbreaks, with 5 outbreaks in the last 3 years. Queensland Health has developed a Dengue Fever Management Plan for north Queensland that has had considerable success in preventing small outbreaks of dengue from developing into large epidemics. The cornerstone of this plan is the application of residual insecticide inside premises near dengue cases to kill the mosquito vector, Aedes aegypti, before it can spread the virus. While this method is effective, it is labor intensive, requires the cooperation of homeowners who may find it intrusive and exposes nontarget insects and animals to insecticide. We propose to develop a lure and kill strategy to improve the efficacy of vector control while minimising the exposure of nontarget animals. Several chemicals have been identified as highly attractive to dengue mosquitoes. Among these are extracts from water infusions of grass that are highly attractive to egg-laying mosquitoes and emanations from human skin that attract host-seeking mosquitoes. We will develop traps incorporating a. mosquito attractants and b. a killing agent to selectively control Ae. aegypti mosquitoes. These will be collectively called lethal traps. This project will employ the following approach towards the development of a lure and kill strtaegy for dengue control a. determine which compounds are most attractive to north Queensland Ae. aegypti in a laboratory wind tunnel; b. confirm the attraction of these compounds using sticky traps in the field; c. conduct field trials of candidate lethal traps to determine the spacing and density of traps needed to control mosquitoes d. conduct a large field trial to examine the efficacy of the optimised lure and kill strategy. We will also conduct ecological studies on aging and the flight range of Ae. aegypti to enhance the development of the strategy.Read moreRead less
Development Of Early Warning Systems For Dengue Fever Based On Socio-ecological Factors
Funder
National Health and Medical Research Council
Funding Amount
$327,402.00
Summary
Global climate change has potentially serious effects on the transmission of dengue. An early warning system (EWS) based on socio-ecological factors will be developed to examine where and when outbreaks of dengue are likely to occur and how the future dengue control strategies and prevention efforts need to be applied and strengthened in Australia. This project will provide a platform for future research on developing and implementing an EWS for dengue in the Asia-Pacific region.
Population Dynamics And Evolution Of Mosquitoes That Transmit Malaria
Funder
National Health and Medical Research Council
Funding Amount
$381,807.00
Summary
Population dynamics and evolutionary process are fundamental to mosquito-borne infectious diseases as evolutionary forces steer both mosquito and malaria parasite to evolve around obstacles in their natural development. Environmental and ecological factors also influence the relationship between mosquito, parasite and humans. Therefore control of mosquito borne disease depends on an innate understanding of the genetics, behavior and environment. Thus studies on mosquito population dynamics inclu ....Population dynamics and evolutionary process are fundamental to mosquito-borne infectious diseases as evolutionary forces steer both mosquito and malaria parasite to evolve around obstacles in their natural development. Environmental and ecological factors also influence the relationship between mosquito, parasite and humans. Therefore control of mosquito borne disease depends on an innate understanding of the genetics, behavior and environment. Thus studies on mosquito population dynamics including population densities, migration, population subdivisions and competition for resources will allow an understanding of these relationships. Island populations of malaria transmitting mosquitoes contain less genetic complexity (genetic variation in mosquito subpopulations) than mainland populations. Thus mosquito island populations may not contain the genetic capability of evolving around detrimental selection pressures such as the use of insecticides or predators. Armed with accurate knowledge of genetic complexity, biology and behavior of mosquito disease vector species, control measures can be accurately focused at specific populations (high disease transmission mosquito populations). This project we will identify specific populations of mosquitoes using their DNA to reveal genetic markers for specific behavior traits. Due to the smaller amount of genetic variations that island mosquito populations contain, and our aquired knowledge of their behavior and biology. We will design focused mosquito control strategies with knowledge that the mosquitoes will have a smaller chance of evolving around these control measures.Read moreRead less
Japanese Encephalitis Virus In Australasia: Molecular Studies Of Isolates And Consequences Of Immunisation.
Funder
National Health and Medical Research Council
Funding Amount
$212,036.00
Summary
Japanese encephalitis (JE) virus is a mosquito-transmitted virus of Asia. Infection causes clinical disease in about 1 in 50 people infected, and of these, about 25% will die from a fatal encephalitis (inflammation of the brain), and a further 50% will have lifelong severe disabilities. There are over 50,000 cases annually in Asia, with about 12,000 fatalities.The virus normally circulates between mosquitoes and water birds and between mosquitoes and pigs. The World Health Organization has recog ....Japanese encephalitis (JE) virus is a mosquito-transmitted virus of Asia. Infection causes clinical disease in about 1 in 50 people infected, and of these, about 25% will die from a fatal encephalitis (inflammation of the brain), and a further 50% will have lifelong severe disabilities. There are over 50,000 cases annually in Asia, with about 12,000 fatalities.The virus normally circulates between mosquitoes and water birds and between mosquitoes and pigs. The World Health Organization has recognised JE as one of the most important mosquito-borne viruses because of its propensity to spread and to colonise new areas. The virus first appeared in northern Australia in the Torres Strait in 1995, causing three clinical cases of whom 2 died, and returned again in 1998, with a further case in the Torres Strait and the first case to occur on mainland Australia in Cape York. Both of these patients recovered. The virus returned again to the Torres Strait in 2000, but so far without causing human disease. We have shown that the virus is established in Papua New Guinea (PNG), where it is spreading rapidly, and our results suggest that PNG was the source of the virus causing the outbreaks in 1995 and 1998. It is believed that JE virus will almost certainly become established in Australia within the next few years. The aims of this project are to explore the consequences of JE becoming established and specifically: (a) the use of inactivated JE vaccine to protect at-risk populations and whether the vaccine will provide sufficient protection or whether it will lead to enhanced infection with indigenous flaviviruses such as Murray Valley encephalitis virus; and (b) the possibility of emergence of genetic variants with increased transmissibility, virulence, and altered neutralisation epitopes.Read moreRead less
Novel Use Of Fungal Entomopathogens For Sustainable Control Of Mosquito-borne Viruses
Funder
National Health and Medical Research Council
Funding Amount
$605,993.00
Summary
Mosquito-born viruses such as Dengue, Ross River and Barmah Forest are increasing in regional significance. At a broader scale, an estimated 2.5 billion people live in areas at risk of epidemic Dengue transmission. Chemical insecticides are the mainstay of current mosquito control throughout many parts of the world. However, problems of insecticide resistance, environmental contamination and risks to human health, mean that chemical pesticides have not provided a universal solution, either as ou ....Mosquito-born viruses such as Dengue, Ross River and Barmah Forest are increasing in regional significance. At a broader scale, an estimated 2.5 billion people live in areas at risk of epidemic Dengue transmission. Chemical insecticides are the mainstay of current mosquito control throughout many parts of the world. However, problems of insecticide resistance, environmental contamination and risks to human health, mean that chemical pesticides have not provided a universal solution, either as outdoor sprays, residual house sprays or as insecticide treated nets. This creates a pressing need for practical alternatives. Building on approaches and technologies developed for control of locusts in Australia and Africa, we have recently discovered that the ability of mosquitoes to transmit malaria can be substantially reduced with insect fungal pathogens used as biological pesticides. We found that exposure to biopesticide-treated surfaces reduced the number of mosquitoes able to transmit malaria 80-fold. Other supporting data from semi-field trials confirm the feasibility of infecting mosquitoes under real field conditions. Together, these results represent a significant advance in the development of a cheap and sustainable biological alternative to chemical insecticides for disease control. We now wish to extend this research to explore the potential for use of fungal pathogens in control of mosquito-borne viruses. Preliminary studies already confirm that we can infect the key mosquito species responsible for transmitting Dengue. The aim of the current project is to conduct a more comprehensive evaluation of a wider range of fungal isolates to identify strains with the greatest potential to stop transmission of mosquito-borne viruses. The longer term goal is to translate this research into a practical product. Such a product would offer a cheap, environmentally friendly disease control measure, with reduced potential for resistance evolution.Read moreRead less
The Interactions Of Dengue Virus RNA Dependent RNA Polymerase (NS5) With Other Viral And Host Factors.
Funder
National Health and Medical Research Council
Funding Amount
$170,165.00
Summary
Dengue fever is a mosquito-borne disease that is prevalent in tropical countries. It is estimated that 40% of the global population is at risk of dengue infection. Classical dengue fever is not life threatening. However, the more serious disease, dengue haemorrhagic fever-shock syndrome requires intensive medical attention to prevent fatality. A significant number of deaths are recorded each year especially in the underdeveloped countries. Dengue is periodically also a problem in northern Austra ....Dengue fever is a mosquito-borne disease that is prevalent in tropical countries. It is estimated that 40% of the global population is at risk of dengue infection. Classical dengue fever is not life threatening. However, the more serious disease, dengue haemorrhagic fever-shock syndrome requires intensive medical attention to prevent fatality. A significant number of deaths are recorded each year especially in the underdeveloped countries. Dengue is periodically also a problem in northern Australia. There is no cure for dengue fever. The present research aims to use a knowledge-based approach to develop novel antiviral strategies based on preventing the critical protein interactions required for the normal virus life cycle. Two of the most important proteins involved in dengue virus replication are called the NS3 and NS5 proteins. The protein-protein interaction (contact) that occurs between NS5 and NS3 is crucial for the replication of the virus. Little is known about this interaction at present, and the studies we propose will directly address this issue. We have previously shown that a 37 amino acid in the middle of NS5 contains a nuclear localisation signal that can target the normally cytoplasmic protein to the nucleus of the infected cell. What the function of this protein is in the nucleus is not known. We will use a technique called the yeast two-hybrid test to address the question of dengue virus protein interactions in the common bakers yeast. This method is very sensitive and powerful and will provide important insights that will contribute to the development of a rapid high-throughput test to screen the extensive extract collection from Australia's marine biodiversity, held by the Australian Institute of Marine Sciences, to discover suitable inhibitors of NS3-NS5 interaction.Read moreRead less