Barbara Moloney | NSW Office of Environment and Heritage (original) (raw)
Papers by Barbara Moloney
Australian Veterinary Journal, 2011
To use modelling and epidemiological analyses to assess the effectiveness of control strategies e... more To use modelling and epidemiological analyses to assess the effectiveness of control strategies employed during the equine influenza outbreak and determine if early vaccination might have had a beneficial effect. Transmission of infection was modelled using stochastic, spatial simulation, based on data from 16 regions in New South Wales and Queensland over the first month of the outbreak. The model accurately represented the spread of infection in both space and time and showed that vaccination strategies would have reduced new infections by ∼60% and reduced the size of the infected area by 8-9%, compared to the non-vaccination baseline. When used in conjunction with biosecurity measures and movement controls, early vaccination could play an important role in the containment and eradication of equine influenza.
PLoS neglected tropical diseases, 2016
The ecology and distribution of B. anthracis in Australia is not well understood, despite the con... more The ecology and distribution of B. anthracis in Australia is not well understood, despite the continued occurrence of anthrax outbreaks in the eastern states of the country. Efforts to estimate the spatial extent of the risk of disease have been limited to a qualitative definition of an anthrax belt extending from southeast Queensland through the centre of New South Wales and into northern Victoria. This definition of the anthrax belt does not consider the role of environmental conditions in the distribution of B. anthracis. Here, we used the genetic algorithm for rule-set prediction model system (GARP), historical anthrax outbreaks and environmental data to model the ecological niche of B. anthracis and predict its potential geographic distribution in Australia. Our models reveal the niche of B. anthracis in Australia is characterized by a narrow range of ecological conditions concentrated in two disjunct corridors. The most dominant corridor, used to redefine a new anthrax belt, p...
Australian veterinary journal, 2014
To determine the presence and estimate the prevalence of Brucella suis, Leptospira interrogans se... more To determine the presence and estimate the prevalence of Brucella suis, Leptospira interrogans serovar Pomona (hereafter L. pomona) and Leptospira borgpetersenii serovar Hardjo (hereafter L. hardjo) in feral pigs culled in New South Wales (NSW), Australia. During 2012 and 2013, 239 serum samples were collected from feral pigs killed as pests or game in NSW. All sera were subjected to the rose-bengal test for B. suis, with positives subjected to the complement fixation test (CFT). Attempts were made to detect B. suis by culture and PCR on CFT-positive samples. All sera were tested separately for the presence of L. pomona and L. hardjo antibodies using the microscopic agglutination test. Of 238 samples tested, 7 were positive (4 with CFT titres ≥ 32) for B. suis antibodies (3% seroprevalence). However, B. suis was not cultured or detected by PCR. Of 239 sera tested for L. pomona antibodies, 126 samples were positive (53%) and 9 (4%) were positive for L. hardjo. The findings are the fi...
PLoS ONE, 2013
Hendra virus is a highly pathogenic novel paramyxovirus causing sporadic fatal infection in horse... more Hendra virus is a highly pathogenic novel paramyxovirus causing sporadic fatal infection in horses and humans in Australia. Species of fruit-bats (genus Pteropus), commonly known as flying-foxes, are the natural host of the virus. We undertook a survey of horse owners in the states of Queensland and New South Wales, Australia to assess the level of adoption of recommended risk management strategies and to identify impediments to adoption. Survey questionnaires were completed by 1431 respondents from the target states, and from a spectrum of industry sectors. Hendra virus knowledge varied with sector, but was generally limited, with only 13% of respondents rating their level of knowledge as high or very high. The majority of respondents (63%) had seen their state's Hendra virus information for horse owners, and a similar proportion found the information useful. Fifty-six percent of respondents thought it moderately, very or extremely likely that a Hendra virus case could occur in their area, yet only 37% said they would consider Hendra virus if their horse was sick. Only 13% of respondents stabled their horses overnight, although another 24% said it would be easy or very easy to do so, but hadn't done so. Only 13% and 15% of respondents respectively had horse feed bins and water points under solid cover. Responses varied significantly with state, likely reflecting different Hendra virus history. The survey identified inconsistent awareness and/or adoption of available knowledge, confusion in relation to Hendra virus risk perception, with both over-and under-estimation of true risk, and lag in the uptake of recommended risk minimisation strategies, even when these were readily implementable. However, we also identified frustration and potential alienation by horse owners who found the recommended strategies impractical, onerous and prohibitively expensive. The insights gained from this survey have broader application to other complex risk-management scenarios.
Australian Veterinary Journal, 2011
Australian Veterinary Journal, 2013
To provide an overview and descriptive analysis of the 2011 arboviral disease epidemic in horses ... more To provide an overview and descriptive analysis of the 2011 arboviral disease epidemic in horses that involved three important Australian mosquito-borne viruses: Murray Valley encephalitis virus, West Nile virus (Kunjin strain) and Ross River virus. Data from states affected between January and June 2011 were collated and comprised reports of horses showing signs of neuromuscular disease and the associated laboratory findings. A summary of the data is presented, together with a spatiotemporal analysis of cases and preliminary assessment of rainfall patterns and case distribution. A total of 982 cases of equine arboviral disease were reported across Australia between January and June 2011. The majority of cases were reported from south-east Australia and included horses that developed neurological signs consistent with encephalitis. It was the largest epidemic of equine arboviral disease in Australia's history. Two likely causes for this unprecedented epidemic were the unusual weather events that preceded the epidemic and the emergence of a new strain of Kunjin virus. The epidemic highlights to horse owners and policy makers the potential for future outbreaks of arboviral diseases and the need for vigilance. It also highlights the complex interactions among hosts, vectors and climatic conditions that are required for such an outbreak to occur.
Australian Veterinary Journal, 2011
To use modelling and epidemiological analyses to assess the effectiveness of control strategies e... more To use modelling and epidemiological analyses to assess the effectiveness of control strategies employed during the equine influenza outbreak and determine if early vaccination might have had a beneficial effect. Transmission of infection was modelled using stochastic, spatial simulation, based on data from 16 regions in New South Wales and Queensland over the first month of the outbreak. The model accurately represented the spread of infection in both space and time and showed that vaccination strategies would have reduced new infections by ∼60% and reduced the size of the infected area by 8-9%, compared to the non-vaccination baseline. When used in conjunction with biosecurity measures and movement controls, early vaccination could play an important role in the containment and eradication of equine influenza.
Australian Veterinary Journal, 2011
This overview of the equine influenza (EI) epidemic as it occurred in two Australian states, New ... more This overview of the equine influenza (EI) epidemic as it occurred in two Australian states, New South Wales and Queensland, in 2007 describes the functions and activities of the epidemiology teams that were engaged during the outbreak and also identifies key features of the epidemiology of EI during the outbreak.
PLoS ONE, 2012
The influences of relative humidity and ambient temperature on the transmission of influenza A vi... more The influences of relative humidity and ambient temperature on the transmission of influenza A viruses have recently been established under controlled laboratory conditions. The interplay of meteorological factors during an actual influenza epidemic is less clear, and research into the contribution of wind to epidemic spread is scarce. By applying geostatistics and survival analysis to data from a large outbreak of equine influenza (A/H3N8), we quantified the association between hazard of infection and air temperature, relative humidity, rainfall, and wind velocity, whilst controlling for premises-level covariates. The pattern of disease spread in space and time was described using extraction mapping and instantaneous hazard curves. Meteorological conditions at each premises location were estimated by kriging daily meteorological data and analysed as time-lagged time-varying predictors using generalised Cox regression. Meteorological covariates time-lagged by three days were strongly associated with hazard of influenza infection, corresponding closely with the incubation period of equine influenza. Hazard of equine influenza infection was higher when relative humidity was <60% and lowest on days when daily maximum air temperature was 20-25°C. Wind speeds >30 km hour(-1) from the direction of nearby infected premises were associated with increased hazard of infection. Through combining detailed influenza outbreak and meteorological data, we provide empirical evidence for the underlying environmental mechanisms that influenced the local spread of an outbreak of influenza A. Our analysis supports, and extends, the findings of studies into influenza A transmission conducted under laboratory conditions. The relationships described are of direct importance for managing disease risk during influenza outbreaks in horses, and more generally, advance our understanding of the transmission of influenza A viruses under field conditions.
PLOS One, 2012
The influences of relative humidity and ambient temperature on the transmission of influenza A vi... more The influences of relative humidity and ambient temperature on the transmission of influenza A viruses have recently been established under controlled laboratory conditions. The interplay of meteorological factors during an actual influenza epidemic is less clear, and research into the contribution of wind to epidemic spread is scarce. By applying geostatistics and survival analysis to data from a large outbreak of equine influenza (A/H3N8), we quantified the association between hazard of infection and air temperature, relative humidity, rainfall, and wind velocity, whilst controlling for premises-level covariates. The pattern of disease spread in space and time was described using extraction mapping and instantaneous hazard curves. Meteorological conditions at each premises location were estimated by kriging daily meteorological data and analysed as time-lagged time-varying predictors using generalised Cox regression. Meteorological covariates time-lagged by three days were strongly associated with hazard of influenza infection, corresponding closely with the incubation period of equine influenza. Hazard of equine influenza infection was higher when relative humidity was ,60% and lowest on days when daily maximum air temperature was 20-25uC. Wind speeds .30 km hour 21 from the direction of nearby infected premises were associated with increased hazard of infection. Through combining detailed influenza outbreak and meteorological data, we provide empirical evidence for the underlying environmental mechanisms that influenced the local spread of an outbreak of influenza A. Our analysis supports, and extends, the findings of studies into influenza A transmission conducted under laboratory conditions. The relationships described are of direct importance for managing disease risk during influenza outbreaks in horses, and more generally, advance our understanding of the transmission of influenza A viruses under field conditions.
Preventive Veterinary Medicine, 2011
In August 2007, Australia which had previously been free of equine influenza, experienced a large... more In August 2007, Australia which had previously been free of equine influenza, experienced a large outbreak that lasted approximately 4 months before it was eradicated. The outbreak required a significant national response by government and the horse industries. The main components of the response were movement controls, biosecurity measures, risk-based zoning and, subsequently, vaccination to contain the outbreak. Although not initially used, vaccination became a key element in the eradication program, with approximately 140000 horses vaccinated. Vaccination is recognised as a valuable tool for managing EI in endemically infected countries but there is little experience using it in situations where the objective is disease eradication. Vaccination was undoubtedly an important factor in 2007 as it enabled movements of some horses and associated industry activities to recommence. However, its contribution to containment and eradication is less clear. A premises-level equine influenza model, based on an epidemiological analysis of the 2007 outbreak, was developed to evaluate effectiveness of the mitigation strategies used and to investigate whether vaccination, if applied earlier, would have had an effect on the course of the outbreak. The results indicate that early use of strategic vaccination could have significantly reduced the size of the outbreak. The four vaccination strategies evaluated had, by 1 month into the control program, reduced the number of new infections on average by 60% and the size of the infected area by 8-9%. If resources are limited, a 1 km suppressive ring vaccination around infected premises gave the best results, but with greater vaccination capacity, a 3 km ring vaccination was the most effective strategy. The findings suggest that as well as reducing clinical and economic impacts, vaccination when used with biosecurity measures and movement controls could play an important role in the containment and eradication of equine influenza.
Australian Veterinary Journal, 2008
Objective To determine the prevalence of infection of cattle with the sheep strain of Mycobacter... more Objective To determine the prevalence of infection of cattle with the sheep strain of Mycobacterium avium subsp paratuberculosis at least two years after exposure at < 6 months old.Design Prospective survey One thousand seven hundred and seventy-four cattle from 12 properties (Farms A to L) were sampled by ELISA and faecal culture to detect evidence of infection with M a paratuberculosis. All properties had a known history of Johne's disease (JD) in sheep, and sampled cattle were likely to be susceptible to JD at the time they were first exposed, being at an age of 6 months or less. In addition, opportunistic investigations were undertaken of ELISA reactor cattle discovered during testing for the Australian Johne's Disease Market Assurance Program for Cattle (Farms M and N).Results All animals in the survey gave negative results on serology while one animal from a herd of 349 gave a positive faecal culture result. Follow-up faecal culture, post-mortem and histopathology on the latter animal were negative, suggesting that it was a passive faecal shedder or carrier.Two occurrences of OJD transmission to cattle were detected during the opportunistic investigations.Conclusion These observations confirm existing beliefs about the risk of transmission of OJD to cattle, that the risk of transmission is low. However transmission occurs sporadically. An estimated upper limit of prevalence of S strain M a paratuberculosis infection in susceptible exposed cattle in the OJD high prevalence area of New South Wales is 0.8%, assuming a common prevalence within herds.
Australian Veterinary Journal, 2011
To use modelling and epidemiological analyses to assess the effectiveness of control strategies e... more To use modelling and epidemiological analyses to assess the effectiveness of control strategies employed during the equine influenza outbreak and determine if early vaccination might have had a beneficial effect. Transmission of infection was modelled using stochastic, spatial simulation, based on data from 16 regions in New South Wales and Queensland over the first month of the outbreak. The model accurately represented the spread of infection in both space and time and showed that vaccination strategies would have reduced new infections by ∼60% and reduced the size of the infected area by 8-9%, compared to the non-vaccination baseline. When used in conjunction with biosecurity measures and movement controls, early vaccination could play an important role in the containment and eradication of equine influenza.
PLoS neglected tropical diseases, 2016
The ecology and distribution of B. anthracis in Australia is not well understood, despite the con... more The ecology and distribution of B. anthracis in Australia is not well understood, despite the continued occurrence of anthrax outbreaks in the eastern states of the country. Efforts to estimate the spatial extent of the risk of disease have been limited to a qualitative definition of an anthrax belt extending from southeast Queensland through the centre of New South Wales and into northern Victoria. This definition of the anthrax belt does not consider the role of environmental conditions in the distribution of B. anthracis. Here, we used the genetic algorithm for rule-set prediction model system (GARP), historical anthrax outbreaks and environmental data to model the ecological niche of B. anthracis and predict its potential geographic distribution in Australia. Our models reveal the niche of B. anthracis in Australia is characterized by a narrow range of ecological conditions concentrated in two disjunct corridors. The most dominant corridor, used to redefine a new anthrax belt, p...
Australian veterinary journal, 2014
To determine the presence and estimate the prevalence of Brucella suis, Leptospira interrogans se... more To determine the presence and estimate the prevalence of Brucella suis, Leptospira interrogans serovar Pomona (hereafter L. pomona) and Leptospira borgpetersenii serovar Hardjo (hereafter L. hardjo) in feral pigs culled in New South Wales (NSW), Australia. During 2012 and 2013, 239 serum samples were collected from feral pigs killed as pests or game in NSW. All sera were subjected to the rose-bengal test for B. suis, with positives subjected to the complement fixation test (CFT). Attempts were made to detect B. suis by culture and PCR on CFT-positive samples. All sera were tested separately for the presence of L. pomona and L. hardjo antibodies using the microscopic agglutination test. Of 238 samples tested, 7 were positive (4 with CFT titres ≥ 32) for B. suis antibodies (3% seroprevalence). However, B. suis was not cultured or detected by PCR. Of 239 sera tested for L. pomona antibodies, 126 samples were positive (53%) and 9 (4%) were positive for L. hardjo. The findings are the fi...
PLoS ONE, 2013
Hendra virus is a highly pathogenic novel paramyxovirus causing sporadic fatal infection in horse... more Hendra virus is a highly pathogenic novel paramyxovirus causing sporadic fatal infection in horses and humans in Australia. Species of fruit-bats (genus Pteropus), commonly known as flying-foxes, are the natural host of the virus. We undertook a survey of horse owners in the states of Queensland and New South Wales, Australia to assess the level of adoption of recommended risk management strategies and to identify impediments to adoption. Survey questionnaires were completed by 1431 respondents from the target states, and from a spectrum of industry sectors. Hendra virus knowledge varied with sector, but was generally limited, with only 13% of respondents rating their level of knowledge as high or very high. The majority of respondents (63%) had seen their state's Hendra virus information for horse owners, and a similar proportion found the information useful. Fifty-six percent of respondents thought it moderately, very or extremely likely that a Hendra virus case could occur in their area, yet only 37% said they would consider Hendra virus if their horse was sick. Only 13% of respondents stabled their horses overnight, although another 24% said it would be easy or very easy to do so, but hadn't done so. Only 13% and 15% of respondents respectively had horse feed bins and water points under solid cover. Responses varied significantly with state, likely reflecting different Hendra virus history. The survey identified inconsistent awareness and/or adoption of available knowledge, confusion in relation to Hendra virus risk perception, with both over-and under-estimation of true risk, and lag in the uptake of recommended risk minimisation strategies, even when these were readily implementable. However, we also identified frustration and potential alienation by horse owners who found the recommended strategies impractical, onerous and prohibitively expensive. The insights gained from this survey have broader application to other complex risk-management scenarios.
Australian Veterinary Journal, 2011
Australian Veterinary Journal, 2013
To provide an overview and descriptive analysis of the 2011 arboviral disease epidemic in horses ... more To provide an overview and descriptive analysis of the 2011 arboviral disease epidemic in horses that involved three important Australian mosquito-borne viruses: Murray Valley encephalitis virus, West Nile virus (Kunjin strain) and Ross River virus. Data from states affected between January and June 2011 were collated and comprised reports of horses showing signs of neuromuscular disease and the associated laboratory findings. A summary of the data is presented, together with a spatiotemporal analysis of cases and preliminary assessment of rainfall patterns and case distribution. A total of 982 cases of equine arboviral disease were reported across Australia between January and June 2011. The majority of cases were reported from south-east Australia and included horses that developed neurological signs consistent with encephalitis. It was the largest epidemic of equine arboviral disease in Australia's history. Two likely causes for this unprecedented epidemic were the unusual weather events that preceded the epidemic and the emergence of a new strain of Kunjin virus. The epidemic highlights to horse owners and policy makers the potential for future outbreaks of arboviral diseases and the need for vigilance. It also highlights the complex interactions among hosts, vectors and climatic conditions that are required for such an outbreak to occur.
Australian Veterinary Journal, 2011
To use modelling and epidemiological analyses to assess the effectiveness of control strategies e... more To use modelling and epidemiological analyses to assess the effectiveness of control strategies employed during the equine influenza outbreak and determine if early vaccination might have had a beneficial effect. Transmission of infection was modelled using stochastic, spatial simulation, based on data from 16 regions in New South Wales and Queensland over the first month of the outbreak. The model accurately represented the spread of infection in both space and time and showed that vaccination strategies would have reduced new infections by ∼60% and reduced the size of the infected area by 8-9%, compared to the non-vaccination baseline. When used in conjunction with biosecurity measures and movement controls, early vaccination could play an important role in the containment and eradication of equine influenza.
Australian Veterinary Journal, 2011
This overview of the equine influenza (EI) epidemic as it occurred in two Australian states, New ... more This overview of the equine influenza (EI) epidemic as it occurred in two Australian states, New South Wales and Queensland, in 2007 describes the functions and activities of the epidemiology teams that were engaged during the outbreak and also identifies key features of the epidemiology of EI during the outbreak.
PLoS ONE, 2012
The influences of relative humidity and ambient temperature on the transmission of influenza A vi... more The influences of relative humidity and ambient temperature on the transmission of influenza A viruses have recently been established under controlled laboratory conditions. The interplay of meteorological factors during an actual influenza epidemic is less clear, and research into the contribution of wind to epidemic spread is scarce. By applying geostatistics and survival analysis to data from a large outbreak of equine influenza (A/H3N8), we quantified the association between hazard of infection and air temperature, relative humidity, rainfall, and wind velocity, whilst controlling for premises-level covariates. The pattern of disease spread in space and time was described using extraction mapping and instantaneous hazard curves. Meteorological conditions at each premises location were estimated by kriging daily meteorological data and analysed as time-lagged time-varying predictors using generalised Cox regression. Meteorological covariates time-lagged by three days were strongly associated with hazard of influenza infection, corresponding closely with the incubation period of equine influenza. Hazard of equine influenza infection was higher when relative humidity was &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;60% and lowest on days when daily maximum air temperature was 20-25°C. Wind speeds &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;30 km hour(-1) from the direction of nearby infected premises were associated with increased hazard of infection. Through combining detailed influenza outbreak and meteorological data, we provide empirical evidence for the underlying environmental mechanisms that influenced the local spread of an outbreak of influenza A. Our analysis supports, and extends, the findings of studies into influenza A transmission conducted under laboratory conditions. The relationships described are of direct importance for managing disease risk during influenza outbreaks in horses, and more generally, advance our understanding of the transmission of influenza A viruses under field conditions.
PLOS One, 2012
The influences of relative humidity and ambient temperature on the transmission of influenza A vi... more The influences of relative humidity and ambient temperature on the transmission of influenza A viruses have recently been established under controlled laboratory conditions. The interplay of meteorological factors during an actual influenza epidemic is less clear, and research into the contribution of wind to epidemic spread is scarce. By applying geostatistics and survival analysis to data from a large outbreak of equine influenza (A/H3N8), we quantified the association between hazard of infection and air temperature, relative humidity, rainfall, and wind velocity, whilst controlling for premises-level covariates. The pattern of disease spread in space and time was described using extraction mapping and instantaneous hazard curves. Meteorological conditions at each premises location were estimated by kriging daily meteorological data and analysed as time-lagged time-varying predictors using generalised Cox regression. Meteorological covariates time-lagged by three days were strongly associated with hazard of influenza infection, corresponding closely with the incubation period of equine influenza. Hazard of equine influenza infection was higher when relative humidity was ,60% and lowest on days when daily maximum air temperature was 20-25uC. Wind speeds .30 km hour 21 from the direction of nearby infected premises were associated with increased hazard of infection. Through combining detailed influenza outbreak and meteorological data, we provide empirical evidence for the underlying environmental mechanisms that influenced the local spread of an outbreak of influenza A. Our analysis supports, and extends, the findings of studies into influenza A transmission conducted under laboratory conditions. The relationships described are of direct importance for managing disease risk during influenza outbreaks in horses, and more generally, advance our understanding of the transmission of influenza A viruses under field conditions.
Preventive Veterinary Medicine, 2011
In August 2007, Australia which had previously been free of equine influenza, experienced a large... more In August 2007, Australia which had previously been free of equine influenza, experienced a large outbreak that lasted approximately 4 months before it was eradicated. The outbreak required a significant national response by government and the horse industries. The main components of the response were movement controls, biosecurity measures, risk-based zoning and, subsequently, vaccination to contain the outbreak. Although not initially used, vaccination became a key element in the eradication program, with approximately 140000 horses vaccinated. Vaccination is recognised as a valuable tool for managing EI in endemically infected countries but there is little experience using it in situations where the objective is disease eradication. Vaccination was undoubtedly an important factor in 2007 as it enabled movements of some horses and associated industry activities to recommence. However, its contribution to containment and eradication is less clear. A premises-level equine influenza model, based on an epidemiological analysis of the 2007 outbreak, was developed to evaluate effectiveness of the mitigation strategies used and to investigate whether vaccination, if applied earlier, would have had an effect on the course of the outbreak. The results indicate that early use of strategic vaccination could have significantly reduced the size of the outbreak. The four vaccination strategies evaluated had, by 1 month into the control program, reduced the number of new infections on average by 60% and the size of the infected area by 8-9%. If resources are limited, a 1 km suppressive ring vaccination around infected premises gave the best results, but with greater vaccination capacity, a 3 km ring vaccination was the most effective strategy. The findings suggest that as well as reducing clinical and economic impacts, vaccination when used with biosecurity measures and movement controls could play an important role in the containment and eradication of equine influenza.
Australian Veterinary Journal, 2008
Objective To determine the prevalence of infection of cattle with the sheep strain of Mycobacter... more Objective To determine the prevalence of infection of cattle with the sheep strain of Mycobacterium avium subsp paratuberculosis at least two years after exposure at < 6 months old.Design Prospective survey One thousand seven hundred and seventy-four cattle from 12 properties (Farms A to L) were sampled by ELISA and faecal culture to detect evidence of infection with M a paratuberculosis. All properties had a known history of Johne's disease (JD) in sheep, and sampled cattle were likely to be susceptible to JD at the time they were first exposed, being at an age of 6 months or less. In addition, opportunistic investigations were undertaken of ELISA reactor cattle discovered during testing for the Australian Johne's Disease Market Assurance Program for Cattle (Farms M and N).Results All animals in the survey gave negative results on serology while one animal from a herd of 349 gave a positive faecal culture result. Follow-up faecal culture, post-mortem and histopathology on the latter animal were negative, suggesting that it was a passive faecal shedder or carrier.Two occurrences of OJD transmission to cattle were detected during the opportunistic investigations.Conclusion These observations confirm existing beliefs about the risk of transmission of OJD to cattle, that the risk of transmission is low. However transmission occurs sporadically. An estimated upper limit of prevalence of S strain M a paratuberculosis infection in susceptible exposed cattle in the OJD high prevalence area of New South Wales is 0.8%, assuming a common prevalence within herds.