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Papers by J. Malone

Research paper thumbnail of Seasonal dynamics of Fasciola hepatica burdens in grazing timahdit sheep in Morocco

International Journal for Parasitology, 1991

Seasonal transmission of Fasciola hepatica was observed in sentinel sheep and the dynamics of the... more Seasonal transmission of Fasciola hepatica was observed in sentinel sheep and the dynamics of the snail intermediate host, Lymnaea truncatula, was followed over a 3-year study period in the Middle-Atlas mountains in Morocco. High fluke burdens were recorded in both lambs and ewes in the fall and winter, suggesting that transmission occurred in late spring. Fluke burdens ranged from one to 302 in ewes and from one to 345 in lambs. Infections with 200 or more flukes were always fatal. A unique feature of this study was the annual cyclical fluctuation of the fluke burdens. Burdens reached maximum levels during the winter and then declined to low numbers by late spring and summer. This suggested self-regulation which may be dependent on breed resistance or may be related to forage factors, including lack of forage (nutritional stress). Snail populations were cyclical and correlated with fluke transmission as observed in the sentinel sheep. The weather was observed to affect the snail populations which in turn limited fluke transmission.

Research paper thumbnail of Climate-based risk models for Fasciola hepatica in Colombia

Research paper thumbnail of Application of geographic information systems and remote sensing to schistosomiasis control in China

Research paper thumbnail of Löffler syndrome on a Louisiana pig farm

Respiratory Medicine Case Reports, 2016

Research paper thumbnail of Löffler syndrome on a Louisiana pig farm

Respiratory Medicine Case Reports, 2016

Research paper thumbnail of Ecological niche modeling for visceral leishmaniasis in the state of Bahia, Brazil, using genetic algorithm for rule-set prediction and growing degree day-water …

Research paper thumbnail of Ecological niche modeling for visceral leishmaniasis in the state of Bahia, Brazil, using genetic algorithm for rule-set prediction and growing degree day-water budget analysis

Geospatial health, 2006

Two predictive models were developed within a geographic information system using Genetic Algorit... more Two predictive models were developed within a geographic information system using Genetic Algorithm Rule-Set Prediction (GARP) and the growing degree day (GDD)-water budget (WB) concept to predict the distribution and potential risk of visceral leishmaniasis (VL) in the State of Bahia, Brazil. The objective was to define the environmental suitability of the disease as well as to obtain a deeper understanding of the eco-epidemiology of VL by associating environmental and climatic variables with disease prevalence. Both the GARP model and the GDDWB model, using different analysis approaches and with the same human prevalence database, predicted similar distribution and abundance patterns for the Lutzomyia longipalpis-Leishmania chagasi system in Bahia. High and moderate prevalence sites for VL were significantly related to areas of high and moderate risk prediction by: (i) the area predicted by the GARP model, depending on the number of pixels that overlapped among eleven annual model...

Research paper thumbnail of Brugia pahangi in golden hamsters

Transactions of the Royal Society of Tropical Medicine and Hygiene, 1974

Research paper thumbnail of Towards establishment of GeoHealth, an open-data portal for health mapping and modelling based on Earth observations by remote sensing

Research paper thumbnail of Application of geographic information systems and remote sensing to schistosomiasis control in China

Acta Tropica, Apr 27, 2001

Progress in China on developing prediction models using remote sensing, geographic information sy... more Progress in China on developing prediction models using remote sensing, geographic information systems and climate data with historical infection prevalence and malacology databases is reviewed. Special reference is made to the effects of the Yangtze river Three Gorges dam project on environmental changes that may impact changes in the spatial and temporal distribution and abundance of Schistosoma japonicum in China, and the future success of disease control programs.

Research paper thumbnail of Environmental and socio-economic risk modelling for Chagas disease in Bolivia

Geospatial health, 2012

Accurately defining disease distributions and calculating disease risk is an important step in th... more Accurately defining disease distributions and calculating disease risk is an important step in the control and prevention of diseases. Geographical information systems (GIS) and remote sensing technologies, with maximum entropy (Maxent) ecological niche modelling computer software, were used to create predictive risk maps for Chagas disease in Bolivia. Prevalence rates were calculated from 2007 to 2009 household infection survey data for Bolivia, while environmental data were compiled from the Worldclim database and MODIS satellite imagery. Socio-economic data were obtained from the Bolivian National Institute of Statistics. Disease models identified altitudes at 500-3,500 m above the mean sea level (MSL), low annual precipitation (45-250 mm), and higher diurnal range of temperature (10-19 °C; peak 16 °C) as compatible with the biological requirements of the insect vectors. Socio-economic analyses demonstrated the importance of improved housing materials and water source. Home adobe...

Research paper thumbnail of Effect of soil surface salt on the density and distribution of the snail Bithynia siamensis goniomphalos in northeast Thailand

Research paper thumbnail of Mapping and modelling neglected tropical diseases and poverty in Latin America and the Caribbean

Geospatial health, 2012

The prospects and opportunities for application of risk mapping and modelling of the neglected tr... more The prospects and opportunities for application of risk mapping and modelling of the neglected tropical diseases (NTDs) in Latin America are examined with the aim to broaden the interest in geospatial research there. Special reference is made to the potential use of geospatial tools in health planning and implementation of national disease control programmes.

Research paper thumbnail of Schistosomiasis Information Systems and Control of Snail-borne Diseases

Research paper thumbnail of An essential need: creating opportunities for veterinary students and graduates to gain an appreciation of responsibilities and opportunities in global veterinary issues

Globalisation trends and bioterrorism issues have led to new concerns relating to public health, ... more Globalisation trends and bioterrorism issues have led to new concerns relating to public health, animal health, international trade and food security. There is an imperative to internationalise and strengthen global public health capacity by renewed emphasis on veterinary public health in veterinary education and increasing opportunities for elective experiential learning in public practice programmes for veterinary students. Recent experience with a US-Brazil Higher Education Consortia Program is used as an example of potential ways in which veterinary students can gain an appreciation for global veterinary issues.

Conference Presentations by J. Malone

Research paper thumbnail of Spatio-temporal modeling the ASF epidemic in the territory of the Russian Federation in 2007 – 2012

African swine fever (ASF) is the viral disease of domestic and wild pigs that can lead up to 100%... more African swine fever (ASF) is the viral disease of domestic and wild pigs that can lead up to 100% mortality among affected animals and it causes huge economic impact. After its introduction into the Russian Federation in 2007 the disease spread widely and formed two spatio-temporal clusters. The model is developed to describe the epidemic on the basis of probabilistic approach, which includes: 1) Maximum Entropy suitability analysis of the territory by the aggregation of geographical and socio-economic factors and 2) statistical analysis of distances and time intervals between the ASF cases reported in 2007 – 2012.
Modeling was based on the data on ASF outbreaks in domestic pigs from the largest cluster. MaxEnt software was used for suitability analysis that allows to reveal the associative relations between localization of ASF cases and risk factors, such as swine population density, human population density, settlements density, roads density. Statistical analysis and distributions fitting were performed by means of @Risk software package.
Statistical analysis of distances distribution shows the mean distance between two subsequent ASF outbreaks is 156 km (95% CI: 0 – 467). The average time interval between subsequent outbreaks is 8 days (0 – 23). These parameters allow to create an exponential probability surface around an ASF outbreak location, which reflects the risk of the next case emergence within the MaxEnt suitability surface.
The main conclusions are as follows: a) the leading factor of ASF virus spread is transportation of contaminated animal products from the focus of infection; b) the established size of risk zone of 20 km around the focus of infection is insufficient for effective control of the disease.

Research paper thumbnail of The use of spatial statistics tools and the maximum entropy method for study and forecasting of infectious animal diseases spread

The applied usage of GIS in epidemiology means the mapping of information on the epidemic situa-t... more The applied usage of GIS in epidemiology means the mapping of information on the epidemic situa-tion in a particular territory against a set of topical layers (i.e. animal and human population, transportation network, water bodies, vegetation etc.). The availability of geospatial information helps solve one of the principal problems in epidemiology: it allows discovering the causes that contribute to the occurrence and spread of emerging infections in a population, since such causes may be closely connected with both environmental and socio-economic factors of certain localization. Here we consider the application of some spatial analysis functions of ArcMap (Esri, USA) by the example of diseases under study in the Federal Centre of Animal Health.
The basic instruments of geostatistical analysis that are used in the practice of epidemiological analysis are the calculation of Mean Centre allowing to estimate the tendency of disease-front advance in time; and Standard Deviational Ellipse that allows to define the main direction of the disease spread.
The simplest GIS tool that allows estimating the tendency towards the cases clustering is the Nearest Neighbor Index. Other program instruments that are also frequently used are Moran’s I Statistic and Getis-Ord Statistic, based on which it is possible to visualize the existing cases’ clusters. Multi-Distance Cluster Analysis: Ripley K Function is another useful tool for the estimation of case clustering at different distances from the mean center.
To define the correlation of disease cases with geographical and socio-economic factors in the study area, a methodology of Associative Analysis is applied. This methodology means the application of a regression model that correlates the Spatial Density of cases’ distribution within the territory with the values of the selected geospatial and socio-economic variables. Based on the obtained regression equation, a risk map can be created that illustrates the probability of emergence of the disease within the study area.
One of the novel methods that are used to detect the habitat of a certain host/causative agent/parasite species is the Maximum Entropy Modeling. MaxEnt software (Princeton University, USA) allows to carry out a complex analysis of habitat factors and to create a probability map which illustrates suitable conditions for the habitation of a particular species. We suggest using MaxEnt software for the analysis of possible emergence of disease cases in the territory of study due to an aggregate of geographical and socio-economic factors. This method was used for analyzing of African swine fever cases distribution in the territory of Russian Federation.

Research paper thumbnail of Seasonal dynamics of Fasciola hepatica burdens in grazing timahdit sheep in Morocco

International Journal for Parasitology, 1991

Seasonal transmission of Fasciola hepatica was observed in sentinel sheep and the dynamics of the... more Seasonal transmission of Fasciola hepatica was observed in sentinel sheep and the dynamics of the snail intermediate host, Lymnaea truncatula, was followed over a 3-year study period in the Middle-Atlas mountains in Morocco. High fluke burdens were recorded in both lambs and ewes in the fall and winter, suggesting that transmission occurred in late spring. Fluke burdens ranged from one to 302 in ewes and from one to 345 in lambs. Infections with 200 or more flukes were always fatal. A unique feature of this study was the annual cyclical fluctuation of the fluke burdens. Burdens reached maximum levels during the winter and then declined to low numbers by late spring and summer. This suggested self-regulation which may be dependent on breed resistance or may be related to forage factors, including lack of forage (nutritional stress). Snail populations were cyclical and correlated with fluke transmission as observed in the sentinel sheep. The weather was observed to affect the snail populations which in turn limited fluke transmission.

Research paper thumbnail of Climate-based risk models for Fasciola hepatica in Colombia

Research paper thumbnail of Application of geographic information systems and remote sensing to schistosomiasis control in China

Research paper thumbnail of Löffler syndrome on a Louisiana pig farm

Respiratory Medicine Case Reports, 2016

Research paper thumbnail of Löffler syndrome on a Louisiana pig farm

Respiratory Medicine Case Reports, 2016

Research paper thumbnail of Ecological niche modeling for visceral leishmaniasis in the state of Bahia, Brazil, using genetic algorithm for rule-set prediction and growing degree day-water …

Research paper thumbnail of Ecological niche modeling for visceral leishmaniasis in the state of Bahia, Brazil, using genetic algorithm for rule-set prediction and growing degree day-water budget analysis

Geospatial health, 2006

Two predictive models were developed within a geographic information system using Genetic Algorit... more Two predictive models were developed within a geographic information system using Genetic Algorithm Rule-Set Prediction (GARP) and the growing degree day (GDD)-water budget (WB) concept to predict the distribution and potential risk of visceral leishmaniasis (VL) in the State of Bahia, Brazil. The objective was to define the environmental suitability of the disease as well as to obtain a deeper understanding of the eco-epidemiology of VL by associating environmental and climatic variables with disease prevalence. Both the GARP model and the GDDWB model, using different analysis approaches and with the same human prevalence database, predicted similar distribution and abundance patterns for the Lutzomyia longipalpis-Leishmania chagasi system in Bahia. High and moderate prevalence sites for VL were significantly related to areas of high and moderate risk prediction by: (i) the area predicted by the GARP model, depending on the number of pixels that overlapped among eleven annual model...

Research paper thumbnail of Brugia pahangi in golden hamsters

Transactions of the Royal Society of Tropical Medicine and Hygiene, 1974

Research paper thumbnail of Towards establishment of GeoHealth, an open-data portal for health mapping and modelling based on Earth observations by remote sensing

Research paper thumbnail of Application of geographic information systems and remote sensing to schistosomiasis control in China

Acta Tropica, Apr 27, 2001

Progress in China on developing prediction models using remote sensing, geographic information sy... more Progress in China on developing prediction models using remote sensing, geographic information systems and climate data with historical infection prevalence and malacology databases is reviewed. Special reference is made to the effects of the Yangtze river Three Gorges dam project on environmental changes that may impact changes in the spatial and temporal distribution and abundance of Schistosoma japonicum in China, and the future success of disease control programs.

Research paper thumbnail of Environmental and socio-economic risk modelling for Chagas disease in Bolivia

Geospatial health, 2012

Accurately defining disease distributions and calculating disease risk is an important step in th... more Accurately defining disease distributions and calculating disease risk is an important step in the control and prevention of diseases. Geographical information systems (GIS) and remote sensing technologies, with maximum entropy (Maxent) ecological niche modelling computer software, were used to create predictive risk maps for Chagas disease in Bolivia. Prevalence rates were calculated from 2007 to 2009 household infection survey data for Bolivia, while environmental data were compiled from the Worldclim database and MODIS satellite imagery. Socio-economic data were obtained from the Bolivian National Institute of Statistics. Disease models identified altitudes at 500-3,500 m above the mean sea level (MSL), low annual precipitation (45-250 mm), and higher diurnal range of temperature (10-19 °C; peak 16 °C) as compatible with the biological requirements of the insect vectors. Socio-economic analyses demonstrated the importance of improved housing materials and water source. Home adobe...

Research paper thumbnail of Effect of soil surface salt on the density and distribution of the snail Bithynia siamensis goniomphalos in northeast Thailand

Research paper thumbnail of Mapping and modelling neglected tropical diseases and poverty in Latin America and the Caribbean

Geospatial health, 2012

The prospects and opportunities for application of risk mapping and modelling of the neglected tr... more The prospects and opportunities for application of risk mapping and modelling of the neglected tropical diseases (NTDs) in Latin America are examined with the aim to broaden the interest in geospatial research there. Special reference is made to the potential use of geospatial tools in health planning and implementation of national disease control programmes.

Research paper thumbnail of Schistosomiasis Information Systems and Control of Snail-borne Diseases

Research paper thumbnail of An essential need: creating opportunities for veterinary students and graduates to gain an appreciation of responsibilities and opportunities in global veterinary issues

Globalisation trends and bioterrorism issues have led to new concerns relating to public health, ... more Globalisation trends and bioterrorism issues have led to new concerns relating to public health, animal health, international trade and food security. There is an imperative to internationalise and strengthen global public health capacity by renewed emphasis on veterinary public health in veterinary education and increasing opportunities for elective experiential learning in public practice programmes for veterinary students. Recent experience with a US-Brazil Higher Education Consortia Program is used as an example of potential ways in which veterinary students can gain an appreciation for global veterinary issues.

Research paper thumbnail of Spatio-temporal modeling the ASF epidemic in the territory of the Russian Federation in 2007 – 2012

African swine fever (ASF) is the viral disease of domestic and wild pigs that can lead up to 100%... more African swine fever (ASF) is the viral disease of domestic and wild pigs that can lead up to 100% mortality among affected animals and it causes huge economic impact. After its introduction into the Russian Federation in 2007 the disease spread widely and formed two spatio-temporal clusters. The model is developed to describe the epidemic on the basis of probabilistic approach, which includes: 1) Maximum Entropy suitability analysis of the territory by the aggregation of geographical and socio-economic factors and 2) statistical analysis of distances and time intervals between the ASF cases reported in 2007 – 2012.
Modeling was based on the data on ASF outbreaks in domestic pigs from the largest cluster. MaxEnt software was used for suitability analysis that allows to reveal the associative relations between localization of ASF cases and risk factors, such as swine population density, human population density, settlements density, roads density. Statistical analysis and distributions fitting were performed by means of @Risk software package.
Statistical analysis of distances distribution shows the mean distance between two subsequent ASF outbreaks is 156 km (95% CI: 0 – 467). The average time interval between subsequent outbreaks is 8 days (0 – 23). These parameters allow to create an exponential probability surface around an ASF outbreak location, which reflects the risk of the next case emergence within the MaxEnt suitability surface.
The main conclusions are as follows: a) the leading factor of ASF virus spread is transportation of contaminated animal products from the focus of infection; b) the established size of risk zone of 20 km around the focus of infection is insufficient for effective control of the disease.

Research paper thumbnail of The use of spatial statistics tools and the maximum entropy method for study and forecasting of infectious animal diseases spread

The applied usage of GIS in epidemiology means the mapping of information on the epidemic situa-t... more The applied usage of GIS in epidemiology means the mapping of information on the epidemic situa-tion in a particular territory against a set of topical layers (i.e. animal and human population, transportation network, water bodies, vegetation etc.). The availability of geospatial information helps solve one of the principal problems in epidemiology: it allows discovering the causes that contribute to the occurrence and spread of emerging infections in a population, since such causes may be closely connected with both environmental and socio-economic factors of certain localization. Here we consider the application of some spatial analysis functions of ArcMap (Esri, USA) by the example of diseases under study in the Federal Centre of Animal Health.
The basic instruments of geostatistical analysis that are used in the practice of epidemiological analysis are the calculation of Mean Centre allowing to estimate the tendency of disease-front advance in time; and Standard Deviational Ellipse that allows to define the main direction of the disease spread.
The simplest GIS tool that allows estimating the tendency towards the cases clustering is the Nearest Neighbor Index. Other program instruments that are also frequently used are Moran’s I Statistic and Getis-Ord Statistic, based on which it is possible to visualize the existing cases’ clusters. Multi-Distance Cluster Analysis: Ripley K Function is another useful tool for the estimation of case clustering at different distances from the mean center.
To define the correlation of disease cases with geographical and socio-economic factors in the study area, a methodology of Associative Analysis is applied. This methodology means the application of a regression model that correlates the Spatial Density of cases’ distribution within the territory with the values of the selected geospatial and socio-economic variables. Based on the obtained regression equation, a risk map can be created that illustrates the probability of emergence of the disease within the study area.
One of the novel methods that are used to detect the habitat of a certain host/causative agent/parasite species is the Maximum Entropy Modeling. MaxEnt software (Princeton University, USA) allows to carry out a complex analysis of habitat factors and to create a probability map which illustrates suitable conditions for the habitation of a particular species. We suggest using MaxEnt software for the analysis of possible emergence of disease cases in the territory of study due to an aggregate of geographical and socio-economic factors. This method was used for analyzing of African swine fever cases distribution in the territory of Russian Federation.