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Shlomit Paz - One of the best experts on this subject based on the ideXlab platform.
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Environmental predictors of West Nile Fever risk in Europe.
International journal of health geographics, 2014Co-Authors: Annelise Tran, Bertrand Sudre, Shlomit Paz, Massimiliano Rossi, Annie Desbrosse, Véronique Chevalier, Jan C. SemenzaAbstract:Background West Nile virus (WNV) is a mosquito-borne pathogen of global public health importance. Transmission of WNV is determined by abiotic and biotic factors. The objective of this study was to examine environmental variables as predictors of WNV risk in Europe and neighboring countries, considering the anomalies of remotely sensed water and vegetation indices and of temperature at the locations of West Nile Fever (WNF) outbreaks reported in humans between 2002 and 2013.
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Environmental predictors of West Nile Fever risk
2014Co-Authors: Annelise Tran, Bertrand Sudre, Shlomit Paz, Massimiliano Rossi, Annie Desbrosse, Véronique Chevalier, Jan C. SemenzaAbstract:Background: West Nile virus (WNV) is a mosquito-borne pathogen of global public health importance. Transmission of WNV is determined by abiotic and biotic factors. The objective of this study was to examine environmental variables as predictors of WNV risk in Europe and neighboring countries, considering the anomalies of remotely sensed water and vegetation indices and of temperature at the locations of West Nile Fever (WNF) outbreaks reported in humans between 2002 and 2013. Methods: The status of infection by WNV in relationship to environmental and climatic risk factors was analyzed at the district level using logistic regression models. Temperature, remotely sensed Normalized Difference Vegetation Index (NDVI) and Modified Normalized Difference Water Index (MNDWI) anomalies, as well as population, birds’ migratory routes, and presence of wetlands were considered as explanatory variables. Results: The anomalies of temperature in July, of MNDWI in early June, the presence of wetlands, the location under migratory routes, and the occurrence of a WNF outbreak the previous year were identified as risk factors. The best statistical model according to the Akaike Information Criterion was used to map WNF risk areas in 2012 and 2013. Model validations showed a good level of prediction: area under Receiver Operator Characteristic curve=0.854 (95% Confidence Interval 0.850-0.856) for internal validation and 0.819 (95% Confidence Interval 0.814-0.823) (2012) and 0.853 (95% Confidence Interval 0.850-0.855) (2013) for external validations, respectively. Conclusions: WNF incidence is increasing in Europe and WNV is expanding into new areas where it had never been observed before. Our model can be used to direct surveillance activities and public health interventions for the upcoming WNF season.
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Environmental Drivers of West Nile Fever Epidemiology in Europe and Western Asia—A Review
International journal of environmental research and public health, 2013Co-Authors: Shlomit Paz, Jan C. SemenzaAbstract:Abiotic and biotic conditions are both important determinants of West Nile Fever (WNF) epidemiology. Ambient temperature plays an important role in the growth rates of vector populations, the interval between blood meals, viral replication rates and transmission of West Nile Virus (WNV). The contribution of precipitation is more complex and less well understood. In this paper we discuss impacts of climatic parameters (temperature, relative humidity, precipitation) and other environmental drivers (such as bird migration, land use) on WNV transmission in Europe. WNV recently became established in southeastern Europe, with a large outbreak in the summer of 2010 and recurrent outbreaks in 2011 and 2012. Abundant competent mosquito vectors, bridge vectors, infected (viremic) migrating and local (amplifying) birds are all important characteristics of WNV transmission. In addition, certain key climatic factors, such as increased ambient temperatures, and by extension climate change, may also favor WNF transmission, and they should be taken into account when evaluating the risk of disease spread in the coming years. Monitoring epidemic precursors of WNF, such as significant temperature deviations in high risk areas, could be used to trigger vector control programs and public education campaigns.
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environmental drivers of West Nile Fever epidemiology in europe and Western asia a review
International Journal of Environmental Research and Public Health, 2013Co-Authors: Shlomit Paz, Jan C. SemenzaAbstract:Abiotic and biotic conditions are both important determinants of West Nile Fever (WNF) epidemiology. Ambient temperature plays an important role in the growth rates of vector populations, the interval between blood meals, viral replication rates and transmission of West Nile Virus (WNV). The contribution of precipitation is more complex and less well understood. In this paper we discuss impacts of climatic parameters (temperature, relative humidity, precipitation) and other environmental drivers (such as bird migration, land use) on WNV transmission in Europe. WNV recently became established in southeastern Europe, with a large outbreak in the summer of 2010 and recurrent outbreaks in 2011 and 2012. Abundant competent mosquito vectors, bridge vectors, infected (viremic) migrating and local (amplifying) birds are all important characteristics of WNV transmission. In addition, certain key climatic factors, such as increased ambient temperatures, and by extension climate change, may also favor WNF transmission, and they should be taken into account when evaluating the risk of disease spread in the coming years. Monitoring epidemic precursors of WNF, such as significant temperature deviations in high risk areas, could be used to trigger vector control programs and public education campaigns.
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Permissive summer temperatures of the 2010 European West Nile Fever upsurge.
PloS one, 2013Co-Authors: Shlomit Paz, Dan Malkinson, Manfred S. Green, Gil Tsioni, Anna Papa, Kostas Danis, Anca Sirbu, Cornelia Ceianu, Krisztalovics Katalin, Emőke FerencziAbstract:Background In the summer of 2010, Europe experienced outbreaks of West Nile Fever (WNF) in humans, which was preceded by hot spells. The objective of this study was to identify potential drivers of these outbreaks, such as spring and summer temperatures, relative humidity (RH), and precipitation. Methods Pearson and lag correlations, binary and multinomial logistic regressions were used to assess the relationship between the climatic parameters and these outbreaks. Results For human morbidity, significant (
Renaud Lancelot - One of the best experts on this subject based on the ideXlab platform.
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Mapping the serological prevalence rate of West Nile Fever in equids, Tunisia
Transboundary and emerging diseases, 2015Co-Authors: Ramzi Bargaoui, Sylvie Lecollinet, Renaud LancelotAbstract:West Nile Fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in equid sera. However, clinical cases were never reported in equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis.
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Mapping the Serological Prevalence Rate of West Nile Fever in Equids, Tunisia
Transboundary and emerging diseases, 2013Co-Authors: Ramzi Bargaoui, Sylvie Lecollinet, Renaud LancelotAbstract:West Nile Fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in equid sera. However, clinical cases were never reported in equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis. (Resume d'auteur)
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Serological assessment of West Nile Fever virus activity in the pastoral system of Ferlo, Senegal
Annals of the New York Academy of Sciences, 2006Co-Authors: Véronique Chevalier, Renaud Lancelot, Amadou Diaite, Bernard Mondet, Sall, Xavier De LamballerieAbstract:The Ferlo area (north-central Senegal) is characterized by a system of temporary ponds favorable to arboviruses among which West Nile Fever (WNF) was already identified. During the rainy season in 2003, a serological study was undertaken on horses to assess the activity of the WNF virus (WNFV) in Barkedji (Ferlo). The observed serological preva- lence rate was 78.3% for neutralizing antibodies, with a 95% confidence interval (CI) of (64.0, 92.7). This prevalence rate significantly increased with age (P = 10 −5 ). This study confirmed that WNF was endemic in the Ferlo. The transmission risks depended on the introduction of the WNFV in the ecosystem—probably with migrating birds, on its amplification in hosts and on the vector-population dynamic. Further studies are needed to investigate how the cycle is initiated in Barkedji at the beginning of the rainy season and the impact of climatic variations on the risk of trans- mission of WNF. A surveillance system should be implemented: (a )t o assess the clinical impact of the WNF on human and equine populations, (b) to provide an early detection of virulent strains, and (c) to assess the risk of WNF transmission to disease-free ecosystems via migrating birds.
Jan C. Semenza - One of the best experts on this subject based on the ideXlab platform.
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Environmental predictors of West Nile Fever risk in Europe.
International journal of health geographics, 2014Co-Authors: Annelise Tran, Bertrand Sudre, Shlomit Paz, Massimiliano Rossi, Annie Desbrosse, Véronique Chevalier, Jan C. SemenzaAbstract:Background West Nile virus (WNV) is a mosquito-borne pathogen of global public health importance. Transmission of WNV is determined by abiotic and biotic factors. The objective of this study was to examine environmental variables as predictors of WNV risk in Europe and neighboring countries, considering the anomalies of remotely sensed water and vegetation indices and of temperature at the locations of West Nile Fever (WNF) outbreaks reported in humans between 2002 and 2013.
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Environmental predictors of West Nile Fever risk
2014Co-Authors: Annelise Tran, Bertrand Sudre, Shlomit Paz, Massimiliano Rossi, Annie Desbrosse, Véronique Chevalier, Jan C. SemenzaAbstract:Background: West Nile virus (WNV) is a mosquito-borne pathogen of global public health importance. Transmission of WNV is determined by abiotic and biotic factors. The objective of this study was to examine environmental variables as predictors of WNV risk in Europe and neighboring countries, considering the anomalies of remotely sensed water and vegetation indices and of temperature at the locations of West Nile Fever (WNF) outbreaks reported in humans between 2002 and 2013. Methods: The status of infection by WNV in relationship to environmental and climatic risk factors was analyzed at the district level using logistic regression models. Temperature, remotely sensed Normalized Difference Vegetation Index (NDVI) and Modified Normalized Difference Water Index (MNDWI) anomalies, as well as population, birds’ migratory routes, and presence of wetlands were considered as explanatory variables. Results: The anomalies of temperature in July, of MNDWI in early June, the presence of wetlands, the location under migratory routes, and the occurrence of a WNF outbreak the previous year were identified as risk factors. The best statistical model according to the Akaike Information Criterion was used to map WNF risk areas in 2012 and 2013. Model validations showed a good level of prediction: area under Receiver Operator Characteristic curve=0.854 (95% Confidence Interval 0.850-0.856) for internal validation and 0.819 (95% Confidence Interval 0.814-0.823) (2012) and 0.853 (95% Confidence Interval 0.850-0.855) (2013) for external validations, respectively. Conclusions: WNF incidence is increasing in Europe and WNV is expanding into new areas where it had never been observed before. Our model can be used to direct surveillance activities and public health interventions for the upcoming WNF season.
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Environmental Drivers of West Nile Fever Epidemiology in Europe and Western Asia—A Review
International journal of environmental research and public health, 2013Co-Authors: Shlomit Paz, Jan C. SemenzaAbstract:Abiotic and biotic conditions are both important determinants of West Nile Fever (WNF) epidemiology. Ambient temperature plays an important role in the growth rates of vector populations, the interval between blood meals, viral replication rates and transmission of West Nile Virus (WNV). The contribution of precipitation is more complex and less well understood. In this paper we discuss impacts of climatic parameters (temperature, relative humidity, precipitation) and other environmental drivers (such as bird migration, land use) on WNV transmission in Europe. WNV recently became established in southeastern Europe, with a large outbreak in the summer of 2010 and recurrent outbreaks in 2011 and 2012. Abundant competent mosquito vectors, bridge vectors, infected (viremic) migrating and local (amplifying) birds are all important characteristics of WNV transmission. In addition, certain key climatic factors, such as increased ambient temperatures, and by extension climate change, may also favor WNF transmission, and they should be taken into account when evaluating the risk of disease spread in the coming years. Monitoring epidemic precursors of WNF, such as significant temperature deviations in high risk areas, could be used to trigger vector control programs and public education campaigns.
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environmental drivers of West Nile Fever epidemiology in europe and Western asia a review
International Journal of Environmental Research and Public Health, 2013Co-Authors: Shlomit Paz, Jan C. SemenzaAbstract:Abiotic and biotic conditions are both important determinants of West Nile Fever (WNF) epidemiology. Ambient temperature plays an important role in the growth rates of vector populations, the interval between blood meals, viral replication rates and transmission of West Nile Virus (WNV). The contribution of precipitation is more complex and less well understood. In this paper we discuss impacts of climatic parameters (temperature, relative humidity, precipitation) and other environmental drivers (such as bird migration, land use) on WNV transmission in Europe. WNV recently became established in southeastern Europe, with a large outbreak in the summer of 2010 and recurrent outbreaks in 2011 and 2012. Abundant competent mosquito vectors, bridge vectors, infected (viremic) migrating and local (amplifying) birds are all important characteristics of WNV transmission. In addition, certain key climatic factors, such as increased ambient temperatures, and by extension climate change, may also favor WNF transmission, and they should be taken into account when evaluating the risk of disease spread in the coming years. Monitoring epidemic precursors of WNF, such as significant temperature deviations in high risk areas, could be used to trigger vector control programs and public education campaigns.
Sylvie Lecollinet - One of the best experts on this subject based on the ideXlab platform.
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Improved reliability of serological tools for the diagnosis of West Nile Fever in horses within Europe
PLoS neglected tropical diseases, 2017Co-Authors: Cécile Beck, Stephan Zientara, Steeve Lowenski, Benoit Durand, Céline Bahuon, Sylvie LecollinetAbstract:West Nile Fever is a zoonotic disease caused by a mosquito-borne flavivirus, WNV. By its clinical sensitivity to the disease, the horse is a useful sentinel of infection. Because of the virus' low-level, short-term viraemia in horses, the primary tools used to diagnose WNV are serological tests. Inter-laboratory proficiency tests (ILPTs) were held in 2010 and 2013 to evaluate WNV serological diagnostic tools suited for the European network of National Reference Laboratories (NRLs) for equine diseases. These ILPTs were designed to evaluate the laboratories' and methods' performances in detecting WNV infection in horses through serology. The detection of WNV immunoglobulin G (IgG) antibodies by ELISA is widely used in Europe, with 17 NRLs in 2010 and 20 NRLs in 2013 using IgG WNV assays. Thanks to the development of new commercial IgM capture kits, WNV IgM capture ELISAs were rapidly implemented in NRLs between 2010 (4 NRLs) and 2013 (13 NRLs). The use of kits allowed the quick standardisation of WNV IgG and IgM detection assays in NRLs with more than 95% (20/21) and 100% (13/13) of satisfactory results respectively in 2013. Conversely, virus neutralisation tests (VNTs) were implemented in 33% (7/21) of NRLs in 2013 and their low sensitivity was evidenced in 29% (2/7) of NRLs during this ILPT. A comparison of serological diagnostic methods highlighted the higher sensitivity of IgG ELISAs compared to WNV VNTs. They also revealed that the low specificity of IgG ELISA kits meant that it could detect animals infected with other flaviviruses. In contrast VNT and IgM ELISA assays were highly specific and did not detect antibodies against related flaviviruses. These results argue in favour of the need for and development of new, specific serological diagnostic assays that could be easily transferred to partner laboratories.
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Mapping the serological prevalence rate of West Nile Fever in equids, Tunisia
Transboundary and emerging diseases, 2015Co-Authors: Ramzi Bargaoui, Sylvie Lecollinet, Renaud LancelotAbstract:West Nile Fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in equid sera. However, clinical cases were never reported in equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis.
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Mapping the Serological Prevalence Rate of West Nile Fever in Equids, Tunisia
Transboundary and emerging diseases, 2013Co-Authors: Ramzi Bargaoui, Sylvie Lecollinet, Renaud LancelotAbstract:West Nile Fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in equid sera. However, clinical cases were never reported in equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis. (Resume d'auteur)
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Clinical diagnosis of West Nile Fever in equids by classification and regression tree analysis and comparative study of clinical appearance in three European countries
2011Co-Authors: S.r. Porter, G. Van Galen, Agnès Leblond, P. Tritz, Sylvie Lecollinet, C. Cantile, O. Kutasi, Stephan Zientara, Sophie Pradier, N. SpeybroekAbstract:This retrospective study describes risk/protection factors for the development of clinical West Nile Fever (WNF) in equids, compares clinical presentation in three European countries, France, Italy and Hungary, and creates classification and regression trees (CART) to facilitate clinical diagnosis. The peak of WNF occurrence was observed in September whatever the country. A significant difference between Italy and France was observed in the delay between initial clinical signs and veterinary consultation. No clinical sign was significantly associated with WNF. Despite similar clinical presentations in the three countries, occurrence of hyperthermia was more frequently reported in France. Classification and regression tree demonstrated the major importance of geographical locality and month to reach a diagnosis and emphasized differences in predominant clinical signs depending on the period of detection of the suspected case (epizootic or not). However, definite diagnosis requires specific serological tests. Centralized reporting system and time-space risk mapping should be promoted in every country.
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Clinical diagnosis of West Nile Fever in equids by classification and regression tree (CART) analysis and comparative study of clinical appearance in three European countries
Transboundary and emerging diseases, 2011Co-Authors: S.r. Porter, G. Van Galen, Agnès Leblond, P. Tritz, Sylvie Lecollinet, C. Cantile, O. Kutasi, Stephan Zientara, Sophie Pradier, N. SpeybroekAbstract:This retrospective study describes risk/protection factors for the development of clinical West Nile Fever (WNF) in equids, compares clinical presentation in three European countries, France, Italy and Hungary, and creates classification and regression trees (CART) to facilitate clinical diagnosis. The peak of WNF occurrence was observed in September whatever the country. A significant difference between Italy and France was observed in the delay between initial clinical signs and veterinary consultation. No clinical sign was significantly associated with WNF. Despite similar clinical presentations in the three countries, occurrence of hyperthermia was more frequently reported in France. Classification and regression tree demonstrated the major importance of geographical locality and month to reach a diagnosis and emphasized differences in predominant clinical signs depending on the period of detection of the suspected case (epizootic or not). However, definite diagnosis requires specific serological tests. Centralized reporting system and time-space risk mapping should be promoted in every country.
Manfred S. Green - One of the best experts on this subject based on the ideXlab platform.
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Permissive summer temperatures of the 2010 European West Nile Fever upsurge.
PloS one, 2013Co-Authors: Shlomit Paz, Dan Malkinson, Manfred S. Green, Gil Tsioni, Anna Papa, Kostas Danis, Anca Sirbu, Cornelia Ceianu, Krisztalovics Katalin, Emőke FerencziAbstract:Background In the summer of 2010, Europe experienced outbreaks of West Nile Fever (WNF) in humans, which was preceded by hot spells. The objective of this study was to identify potential drivers of these outbreaks, such as spring and summer temperatures, relative humidity (RH), and precipitation. Methods Pearson and lag correlations, binary and multinomial logistic regressions were used to assess the relationship between the climatic parameters and these outbreaks. Results For human morbidity, significant (
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permissive summer temperatures of the 2010 european West Nile Fever upsurge
PLOS ONE, 2013Co-Authors: Shlomit Paz, Dan Malkinson, Manfred S. Green, Gil Tsioni, Anna Papa, Kostas Danis, Anca Sirbu, Cornelia Ceianu, Krisztalovics Katalin, Emőke FerencziAbstract:Background In the summer of 2010, Europe experienced outbreaks of West Nile Fever (WNF) in humans, which was preceded by hot spells. The objective of this study was to identify potential drivers of these outbreaks, such as spring and summer temperatures, relative humidity (RH), and precipitation. Methods Pearson and lag correlations, binary and multinomial logistic regressions were used to assess the relationship between the climatic parameters and these outbreaks. Results For human morbidity, significant (<0.05) positive correlations were observed between a number of WNF cases and temperature, with a geographic latitude gradient: northern (“colder”) countries displayed strong correlations with a lag of up to four weeks, in contrast to southern (“warmer”) countries, where the response was immediate. The correlations with RH were weaker, while the association with precipitation was not consistent. Horse morbidity started three weeks later than in humans where integrated surveillance was conducted, and no significant associations with temperature or RH were found for lags of 0 to 4 weeks. Conclusions Significant temperature deviations during summer months might be considered environmental precursors of WNF outbreaks in humans, particularly at more northern latitudes. These insights can guide vector abatement strategies by health practitioners in areas at risk for persistent transmission cycles.
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Prevalence of antibodies to West Nile Fever, sandfly Fever Sicilian, and sandfly Fever Naples viruses in healthy adults in Israel
Public health reviews, 1999Co-Authors: Dani Cohen, Yona Zaide, Erik Karasenty, Mikael Schwarz, James W. Leduc, Raphael Slepon, Thomas G. Ksiazek, Joshua Shemer, Manfred S. GreenAbstract:Background: The arbovirus infections West Nile Fever (WNF) and sandfly Fever (SFF) are both endemic in the Middle East. Despite the fact that the mosquito and sandfly vectors of these viruses are still found in Israel, SFF has not been reported since 1948, whereas outbreaks of WNF occur periodically. It is suspected that some of the cases of nonspecific febrile illnesses in Israel may in fact be either WNF or SFF.
