Objective: To investigate and predict the effects of climate change on the potential distribution of the main vector and reservoir hosts of the disease in Yazd province in the future.Methods: Distribution data for vec...Objective: To investigate and predict the effects of climate change on the potential distribution of the main vector and reservoir hosts of the disease in Yazd province in the future.Methods: Distribution data for vector and reservoir hosts of zoonotic cutaneous leishmaniasis in Yazd province were obtained from earlier studies conducted in the area.MaxEnt ecological niche modeling was used to predict environmental suitability.BCC-CSM1-1(m) model and two climate change scenarios, RCP 4.5 and RCP 8.5 were used for horizons 2030 and 2050 climate projections.Future projections were based on data of a regional climate change model.Results: With both scenarios in 2030 and 2050, the results of jackknife test indicated that the mean temperature of wettest quarter and temperature annual range had the greatest effect on the model for the vector and the reservoir hosts, respectively.Conclusions: The climate conditions are the major determinants of zoonotic cutaneous leishmaniasis incidence rate in Yazd Province.These climate conditions provide favorable habitats for ease transmission of zoonotic cutaneous leishmaniasis in this endemic area.Habitats suitability for the vector and reservoir will be expanding in the coming years compared with the current conditions, such that, in horizon 2030 & 2050, the probability of the presence of the vector and reservoir within 38 580 and 37 949 km^2, respectively, from Yazd province is above 60%.Moreover, an increase is predicted in the presence of the vector in the western parts and the reservoir in the northern and central parts of the province in the future.Understanding the role of environmental and bioclimatic factors in zoonotic cutaneous leishmaniasis occurrence can provide a guide for policy-makers in the creation and implementation of more effective policies for prevention and control.展开更多
Ohjective:To assess molecular characterization,distribution,seasonal activities of sandfly species and Leishmania parasites infecting them for this zoonotic cutaneous leishmaniasis focus.Methods:The collections were c...Ohjective:To assess molecular characterization,distribution,seasonal activities of sandfly species and Leishmania parasites infecting them for this zoonotic cutaneous leishmaniasis focus.Methods:The collections were carried out in 2009-2011 using CDC traps,Sticky Papers and manual aspirator in and around the villages in Abarkouh district.Individual sandflies were characterized by PCR amplification and sequencing of fragments of their mitochondrial cytochrome b gene.Leishmania parasite infections within sandflies were performed by targeting Cyt b,ITS-rDNA,k-DNA and microsatellite genes.Results:The PCR assays detected only Leishmania major(L.major).All infections(30)were found in the abundant and widespread vector Phlebolomus papalasi(P.papatasi).Small numbers of other sandfly species were also screened for infections,but none was found.Sergentomyia sinloni and P.papalasi were the predominant members in all locations of this district and in all habitats throughout the trapping season.Only five other sandfly species were found,namely Phlebolomus ansari,Phlebotomus caucasicus,Phlebotomus sergenti,Sergentomyia dentata and Sergentomyia merviney.Conclusions:In the current survey,the only infections detected are of L.major in females of P.papatasi(30 out of190).The rates of infection of P.papalasi by L.major are not significantly different in compare with other locations in Iran with no diversity of parasite strains.Zoonotic cutaneous leishmaniasis may have emerged only recently in Abarkouh district,and the reason may well be the instability of the transmission cycles there.展开更多
Background:Visceral leishmaniasis,commonly known as kala-azar in India,is a global public health problem.In Southeast Asia,Bangladesh,Bhutan,India,Nepal,Sri Lanka and Thailand are endemic for visceral leishmaniasis.Th...Background:Visceral leishmaniasis,commonly known as kala-azar in India,is a global public health problem.In Southeast Asia,Bangladesh,Bhutan,India,Nepal,Sri Lanka and Thailand are endemic for visceral leishmaniasis.The role of sandflies as the vector of kala-azar was first confirmed in 1942 in India.Insecticide resistance in Phlebotomus argentipes Annandale and Brunetti,the vector of kala-azar in the Indian subcontinent,was first reported in 1987 in Bihar,India.This article provides a scoping review of the studies undertaken from 1959 to 2015 on insecticide resistance in P.argentipes and P.papatasi(Scopoli),the vectors of visceral and cutaneous leishmaniasis respectively,in Southeast Asia,mainly in Bangladesh,India,Nepal and Sri Lanka.Results:Studies undertaken in areas of Bihar and West Bengal in India where kala-azar is endemic have reported resistance of P.argentipes to DDT,while in non-endemic areas it has been reported to be susceptible.In areas of Nepal bordering India,there are indications of resistance to DDT;biochemical resistance has been reported in Sri Lanka.No laboratory studies have been undertaken in Bangladesh;however,the sandfly vector is reported to be still susceptible to pyrethroids in all kala-azar endemic areas in the aforementioned countries.Conclusions:Studies are needed to determine the resistance of sandfly vectors to all available classes of potential insecticides in kala-azar endemic areas.There is a need to assess the impact of indoor residual spraying with DDT and pyrethroids on the incidence of kala-azar in India where 54 districts remain endemic for the disease,strengthen entomological surveillance capacity,and develop and implement an insecticide management plan.Alpha-cypermethrin indoor residual spraying has been introduced in 33 kala-azar endemic districts in Bihar State of India in a pilot trial;the outcomes should be used to inform decisions on expanding coverage with alpha-cypermethrin in all remaining endemic districts to achieve the revised goal of elimination of visceral leishmaniasis by 2020.展开更多
基金financially supported by Research Deputy,Shahid Sadoughi University of Medical Sciences,Yazd,Iran,with project No.P/17/1/19412
文摘Objective: To investigate and predict the effects of climate change on the potential distribution of the main vector and reservoir hosts of the disease in Yazd province in the future.Methods: Distribution data for vector and reservoir hosts of zoonotic cutaneous leishmaniasis in Yazd province were obtained from earlier studies conducted in the area.MaxEnt ecological niche modeling was used to predict environmental suitability.BCC-CSM1-1(m) model and two climate change scenarios, RCP 4.5 and RCP 8.5 were used for horizons 2030 and 2050 climate projections.Future projections were based on data of a regional climate change model.Results: With both scenarios in 2030 and 2050, the results of jackknife test indicated that the mean temperature of wettest quarter and temperature annual range had the greatest effect on the model for the vector and the reservoir hosts, respectively.Conclusions: The climate conditions are the major determinants of zoonotic cutaneous leishmaniasis incidence rate in Yazd Province.These climate conditions provide favorable habitats for ease transmission of zoonotic cutaneous leishmaniasis in this endemic area.Habitats suitability for the vector and reservoir will be expanding in the coming years compared with the current conditions, such that, in horizon 2030 & 2050, the probability of the presence of the vector and reservoir within 38 580 and 37 949 km^2, respectively, from Yazd province is above 60%.Moreover, an increase is predicted in the presence of the vector in the western parts and the reservoir in the northern and central parts of the province in the future.Understanding the role of environmental and bioclimatic factors in zoonotic cutaneous leishmaniasis occurrence can provide a guide for policy-makers in the creation and implementation of more effective policies for prevention and control.
基金supported by the Pasteur Institute of Irangrant 501 awarded to Dr.Parviz Parvizi,Another part of this wok was funded by National Institute Of Health Research (NIHR) project No 63-9024
文摘Ohjective:To assess molecular characterization,distribution,seasonal activities of sandfly species and Leishmania parasites infecting them for this zoonotic cutaneous leishmaniasis focus.Methods:The collections were carried out in 2009-2011 using CDC traps,Sticky Papers and manual aspirator in and around the villages in Abarkouh district.Individual sandflies were characterized by PCR amplification and sequencing of fragments of their mitochondrial cytochrome b gene.Leishmania parasite infections within sandflies were performed by targeting Cyt b,ITS-rDNA,k-DNA and microsatellite genes.Results:The PCR assays detected only Leishmania major(L.major).All infections(30)were found in the abundant and widespread vector Phlebolomus papalasi(P.papatasi).Small numbers of other sandfly species were also screened for infections,but none was found.Sergentomyia sinloni and P.papalasi were the predominant members in all locations of this district and in all habitats throughout the trapping season.Only five other sandfly species were found,namely Phlebolomus ansari,Phlebotomus caucasicus,Phlebotomus sergenti,Sergentomyia dentata and Sergentomyia merviney.Conclusions:In the current survey,the only infections detected are of L.major in females of P.papatasi(30 out of190).The rates of infection of P.papalasi by L.major are not significantly different in compare with other locations in Iran with no diversity of parasite strains.Zoonotic cutaneous leishmaniasis may have emerged only recently in Abarkouh district,and the reason may well be the instability of the transmission cycles there.
文摘Background:Visceral leishmaniasis,commonly known as kala-azar in India,is a global public health problem.In Southeast Asia,Bangladesh,Bhutan,India,Nepal,Sri Lanka and Thailand are endemic for visceral leishmaniasis.The role of sandflies as the vector of kala-azar was first confirmed in 1942 in India.Insecticide resistance in Phlebotomus argentipes Annandale and Brunetti,the vector of kala-azar in the Indian subcontinent,was first reported in 1987 in Bihar,India.This article provides a scoping review of the studies undertaken from 1959 to 2015 on insecticide resistance in P.argentipes and P.papatasi(Scopoli),the vectors of visceral and cutaneous leishmaniasis respectively,in Southeast Asia,mainly in Bangladesh,India,Nepal and Sri Lanka.Results:Studies undertaken in areas of Bihar and West Bengal in India where kala-azar is endemic have reported resistance of P.argentipes to DDT,while in non-endemic areas it has been reported to be susceptible.In areas of Nepal bordering India,there are indications of resistance to DDT;biochemical resistance has been reported in Sri Lanka.No laboratory studies have been undertaken in Bangladesh;however,the sandfly vector is reported to be still susceptible to pyrethroids in all kala-azar endemic areas in the aforementioned countries.Conclusions:Studies are needed to determine the resistance of sandfly vectors to all available classes of potential insecticides in kala-azar endemic areas.There is a need to assess the impact of indoor residual spraying with DDT and pyrethroids on the incidence of kala-azar in India where 54 districts remain endemic for the disease,strengthen entomological surveillance capacity,and develop and implement an insecticide management plan.Alpha-cypermethrin indoor residual spraying has been introduced in 33 kala-azar endemic districts in Bihar State of India in a pilot trial;the outcomes should be used to inform decisions on expanding coverage with alpha-cypermethrin in all remaining endemic districts to achieve the revised goal of elimination of visceral leishmaniasis by 2020.
