本文就疟原虫抗药性测定方法近几年的研究进展及其在测定中的影响因素加以综述。对抗药性测定方法,如传统的微量测试法和同位素测定法,以及近几年发展起来的利用HRP Ⅱ和LDH酶联免疫法、利用SYBR Green I等标记的荧光法和流式细胞仪法...本文就疟原虫抗药性测定方法近几年的研究进展及其在测定中的影响因素加以综述。对抗药性测定方法,如传统的微量测试法和同位素测定法,以及近几年发展起来的利用HRP Ⅱ和LDH酶联免疫法、利用SYBR Green I等标记的荧光法和流式细胞仪法进行了介绍。文内还分析了血清、红细胞压积和原虫起始密度、原虫时期和状态等因素对测定值的影响。展开更多
Xenorhabdus nematophila, a Gram-negative proteobacterium belonging to the family Enterobacteriaceae and associated symbiotically with soil entomopathogenic nematodes, Steinernema carpocapsae, is pathogenic to a wide r...Xenorhabdus nematophila, a Gram-negative proteobacterium belonging to the family Enterobacteriaceae and associated symbiotically with soil entomopathogenic nematodes, Steinernema carpocapsae, is pathogenic to a wide range of insects. A protein complex with insecticidal activity was isolated from the cells ofX. nematophila HB310 strain using methods of salting out and native polyacrylamide gel electrophoresis （PAGE）. Seven polypeptides ranging 50~250 kDa were well separated from the protein complex （named Xnpt） by sodium dodecyl sulfate （SDS）-PAGE, five of which are identified as XptA2, xptC 1, XptB 1, GroEL and hypothetical protein by matrix-assisted laser desorption- time-of-flight mass spectrometry （MALDI-TOFMS）. Xnpt showed high oral virulence to larvae of diamondback moth （DBM）, Plutella xylostella L. （Lepidoptera, Plutellidae） as its median lethal concentration （LC50） against second and third instar larvae were 331.45 ng/mL and 553.59 ng/mL at 72 h, respectively. The histological analysis of Xnptfed DBM larvae showed extensive histopathological effects on the midgut. Biochemical analysis indicated that Xnpt markedly inhibited the activities of three important enzymes in the midgut. Overall, our data showed that the protein complex isolated from X. nematophila HB310 induced the antifeedant and death of insects by destroying midgut tissues and inhibiting midgut proteases activities.展开更多
Background:Despite major reductions in malaria burden across Myanmar,clusters of the disease continue to persist in specific subregions.This study aimed to assess the predictors of test positivity among people living ...Background:Despite major reductions in malaria burden across Myanmar,clusters of the disease continue to persist in specific subregions.This study aimed to assess the predictors of test positivity among people living in Paletwa Township of Chin State,an area of persistently high malaria burden.Methods:Four villages with the highest malaria incidence from Paletwa Town ship were purposively selected.The characteristics of 1045 subjects seeking malaria diagnosis from the four assigned village health volunteers from January to December,2018 were retrospectively analyzed.Their household conditions and surroundings were also recorded using a checklist.Descriptive statistics and logistic regression models were applied to investigate potential associations between individual and household characteristics and malaria diagnosis.Results:In 2017,the Paletwa township presented 20.9%positivity and an annual parasite index of 46.9 cases per 1000 people.Plasmodium falciparum was the predominant species and accounted for more than 80.0%of all infections.Among 1045 people presenting at a clinic with malaria symptoms,31.1% were diagnosed with malaria.Predictors for test positivity included living in a hut[adjusted odds ratios(aOR):2.3,95%confidence intervals(CI ):1.2-4.6],owning farm animals(aOR:1.7,95% CI:1.1-3.6),using non-septic type of toilets(aOR:1.9,95%CI:1.1-8.4),presenting with fever(aOR:1.9,95%CI:1.1-3.0),having a malaria episode within the last year(aOR:2.9,95%CI:1.45.8),traveling outside the village in the previous 14 days (aOR:4.5,95%CI:1.5-13.4),and not using bed nets(aOR:3.4,95%CI:2.3-5.1).There were no statistically significant differences by age or gender in this present analysis.Conclusions:The results from this study,including a high proportion of P.falciparum infections,little difference in age,sex,or occupation,suggest that malaria is a major burden for these study villages.Targeted health education campaigns should be introduced to strengthen synchronous diagnosis-seeking behaviors,tighten treatment adheren ce,receiving a diagnosis after traveling to endemic regi ons,and using bed nets properly.We suggest in creased surveillance,early diagnosis,and treatment efforts to control the disease and then to consider the local elimination.展开更多
Background Plasmodium vivax is the predominant malaria species in many Southeast Asian countries.Eliminating all human malaria species by 2030 requires greater focus on P.vivax,with targeted measures to address its un...Background Plasmodium vivax is the predominant malaria species in many Southeast Asian countries.Eliminating all human malaria species by 2030 requires greater focus on P.vivax,with targeted measures to address its unique challenges.This study evaluated slide positivity rates,temporal trends,and risk factors associated with febrile P.vivax infections in a malaria-endemic district along the Thailand-Myanmar border.Methods This study employed a community-based longitudinal surveillance design over six years(January 2018-December 2023).Data were collected through routine passive case detection at field malaria clinics using extended,standardized case record forms.Malaria diagnosis was conducted via microscopy examination.Descriptive statistics and logistic regression models were used for data analysis.Results Among 13,347 febrile malaria-suspected patients,the cumulative slide positivity rate for P.vivax was 11.0%.Although no distinct seasonal peaks were observed,P.vivax cases generally increased in April and again in November and December.Multivariable logistic regression analysis identified several significant risk factors for febrile P.vivax infection,including school-aged children(5-14 years)(aOR:1.56,95%CI:1.24-1.97),working-age adults(15-34 years)(aOR:1.43,95%CI:1.02-2.00),males(aOR:1.19,95%CI:1.06-1.35),Myanmar nationals(aOR:2.37,95%CI:2.01-2.80),and other non-Thai nationals,such as individuals from Laos and Cambodia(aOR:5.50,95%CI:3.36-8.90).A history of malaria(aOR:1.59,95%CI:1.38-1.83),recent travel within two weeks(aOR:2.38,95%CI:1.94-2.92),and engagement in livestock-related occupations(aOR:2.49,95%CI:1.14-5.35)were also associated with higher odds of infection.In contrast,being unemployed(aOR:0.55,95%CI:0.36-0.81),working in occupations such as maid,driver,or teacher(aOR:0.78,95%CI:0.66-0.93),and consistent use of bed nets(aOR:0.39,95%CI:0.30-0.51)significantly reduced infection risk.Conclusions This study identified a relatively high slide positivity rate of febrile P.vivax infection in a malaria-endemic district in western Thailand along the Myanmar border.Strengthening malaria surveillance,targeting high-risk populations,ensuring treatment adherence,and promoting early care-seeking behavior are crucial for reducing P.vivax transmission and advancing malaria elimination efforts.展开更多
Background Understanding Plasmodium sexual differentiation is crucial for blocking transmission.This study identified risk factors for gametocyte carriage and gametocytemia in P.vivax and P.falciparum to inform malari...Background Understanding Plasmodium sexual differentiation is crucial for blocking transmission.This study identified risk factors for gametocyte carriage and gametocytemia in P.vivax and P.falciparum to inform malaria elimination strategies at the China-Myanmar border.Methods Gametocytes and asexual parasites were microscopically detected on thick smears collected from 2011 to 2020 in Laiza Township,Kachin State,Myanmar.Mono-/polyclonality were detected by genotyping at Pvmsp3α/βfor P.vivax,and Pfmsp1/2 for P.falciparum.Kulldorff’s retrospective time scan statistics tested for likely clusters of gametocyte-positive cases over time.Chi-square or Fisher’s exact tests compared proportions of gametocyte-positive cases in categorical variables.Generalized linear models assessed risk factors(year,season,demographics,clinical/parasitological features)for gametocyte carriage(logistic regression for a binomial outcome)and gametocytemia(Gaussian regression for continuous outcome),respectively.Results During 2011-2020,8240 patients had P.vivax infections,with 7249 testing positive for gametocytes.Among 510 P.falciparum cases,56 tested positive for gametocytes.A significant cluster of P.vivax gametocyte carriage occurred from May 2015 to August 2017(P=0.001).For P.vivax,dry season,previous malaria history,fever,and parasite density were associated with gametocyte carriage.Gametocyte density increased with asexual parasite density(P<0.001)but was lower during the rainy season and in those with a history of malaria infection(P<0.001).Over time,gametocytes carriage proportion increased while density decreased(P<0.001).For P.falciparum,younger age and previous malaria history were associated with gametocyte carriage,and density was higher in the dry season(P=0.0115).Polyclonal P.vivax infections had higher gametocyte densities than monoclonal infections(P<0.0001)and P.falciparum gametocyte density tended to increase with multiplicity of infection.Conclusions Younger age,prior malaria infection,travel,and polyclonal infections correlate with higher P.vivax gametocyte prevalence.Gametocyte carriage peakes during the dry season,highlighting the need for seasonal strategies to support malaria elimination.These findings enhance understanding of risk factors for the transmissible stage of the two main human Plasmodium species in the Greater Mekong Subregion border areas.展开更多
文摘本文就疟原虫抗药性测定方法近几年的研究进展及其在测定中的影响因素加以综述。对抗药性测定方法,如传统的微量测试法和同位素测定法,以及近几年发展起来的利用HRP Ⅱ和LDH酶联免疫法、利用SYBR Green I等标记的荧光法和流式细胞仪法进行了介绍。文内还分析了血清、红细胞压积和原虫起始密度、原虫时期和状态等因素对测定值的影响。
基金Acknowledgments This work was supported by the National Nature Science Foundation of China （NSFC, No. 30400296）, Natural Science Foundation of Hebei Province, China （C2006000443, C2008000277, C2010000706）
文摘Xenorhabdus nematophila, a Gram-negative proteobacterium belonging to the family Enterobacteriaceae and associated symbiotically with soil entomopathogenic nematodes, Steinernema carpocapsae, is pathogenic to a wide range of insects. A protein complex with insecticidal activity was isolated from the cells ofX. nematophila HB310 strain using methods of salting out and native polyacrylamide gel electrophoresis （PAGE）. Seven polypeptides ranging 50~250 kDa were well separated from the protein complex （named Xnpt） by sodium dodecyl sulfate （SDS）-PAGE, five of which are identified as XptA2, xptC 1, XptB 1, GroEL and hypothetical protein by matrix-assisted laser desorption- time-of-flight mass spectrometry （MALDI-TOFMS）. Xnpt showed high oral virulence to larvae of diamondback moth （DBM）, Plutella xylostella L. （Lepidoptera, Plutellidae） as its median lethal concentration （LC50） against second and third instar larvae were 331.45 ng/mL and 553.59 ng/mL at 72 h, respectively. The histological analysis of Xnptfed DBM larvae showed extensive histopathological effects on the midgut. Biochemical analysis indicated that Xnpt markedly inhibited the activities of three important enzymes in the midgut. Overall, our data showed that the protein complex isolated from X. nematophila HB310 induced the antifeedant and death of insects by destroying midgut tissues and inhibiting midgut proteases activities.
基金This research was financially supported a grant(U19AI089672)from the Nation al Institute of Allergy and Infectious Diseases,National In stitutes of Health,USA.
文摘Background:Despite major reductions in malaria burden across Myanmar,clusters of the disease continue to persist in specific subregions.This study aimed to assess the predictors of test positivity among people living in Paletwa Township of Chin State,an area of persistently high malaria burden.Methods:Four villages with the highest malaria incidence from Paletwa Town ship were purposively selected.The characteristics of 1045 subjects seeking malaria diagnosis from the four assigned village health volunteers from January to December,2018 were retrospectively analyzed.Their household conditions and surroundings were also recorded using a checklist.Descriptive statistics and logistic regression models were applied to investigate potential associations between individual and household characteristics and malaria diagnosis.Results:In 2017,the Paletwa township presented 20.9%positivity and an annual parasite index of 46.9 cases per 1000 people.Plasmodium falciparum was the predominant species and accounted for more than 80.0%of all infections.Among 1045 people presenting at a clinic with malaria symptoms,31.1% were diagnosed with malaria.Predictors for test positivity included living in a hut[adjusted odds ratios(aOR):2.3,95%confidence intervals(CI ):1.2-4.6],owning farm animals(aOR:1.7,95% CI:1.1-3.6),using non-septic type of toilets(aOR:1.9,95%CI:1.1-8.4),presenting with fever(aOR:1.9,95%CI:1.1-3.0),having a malaria episode within the last year(aOR:2.9,95%CI:1.45.8),traveling outside the village in the previous 14 days (aOR:4.5,95%CI:1.5-13.4),and not using bed nets(aOR:3.4,95%CI:2.3-5.1).There were no statistically significant differences by age or gender in this present analysis.Conclusions:The results from this study,including a high proportion of P.falciparum infections,little difference in age,sex,or occupation,suggest that malaria is a major burden for these study villages.Targeted health education campaigns should be introduced to strengthen synchronous diagnosis-seeking behaviors,tighten treatment adheren ce,receiving a diagnosis after traveling to endemic regi ons,and using bed nets properly.We suggest in creased surveillance,early diagnosis,and treatment efforts to control the disease and then to consider the local elimination.
基金provided by Mahidol University.This study is financially supported by the National Institute of Allergy and Infectious Diseases(NIAID),National Institutes of Health(NIH),USA(U19AI089672,U19AI181583,and TW011509)support from Mahidol University。
文摘Background Plasmodium vivax is the predominant malaria species in many Southeast Asian countries.Eliminating all human malaria species by 2030 requires greater focus on P.vivax,with targeted measures to address its unique challenges.This study evaluated slide positivity rates,temporal trends,and risk factors associated with febrile P.vivax infections in a malaria-endemic district along the Thailand-Myanmar border.Methods This study employed a community-based longitudinal surveillance design over six years(January 2018-December 2023).Data were collected through routine passive case detection at field malaria clinics using extended,standardized case record forms.Malaria diagnosis was conducted via microscopy examination.Descriptive statistics and logistic regression models were used for data analysis.Results Among 13,347 febrile malaria-suspected patients,the cumulative slide positivity rate for P.vivax was 11.0%.Although no distinct seasonal peaks were observed,P.vivax cases generally increased in April and again in November and December.Multivariable logistic regression analysis identified several significant risk factors for febrile P.vivax infection,including school-aged children(5-14 years)(aOR:1.56,95%CI:1.24-1.97),working-age adults(15-34 years)(aOR:1.43,95%CI:1.02-2.00),males(aOR:1.19,95%CI:1.06-1.35),Myanmar nationals(aOR:2.37,95%CI:2.01-2.80),and other non-Thai nationals,such as individuals from Laos and Cambodia(aOR:5.50,95%CI:3.36-8.90).A history of malaria(aOR:1.59,95%CI:1.38-1.83),recent travel within two weeks(aOR:2.38,95%CI:1.94-2.92),and engagement in livestock-related occupations(aOR:2.49,95%CI:1.14-5.35)were also associated with higher odds of infection.In contrast,being unemployed(aOR:0.55,95%CI:0.36-0.81),working in occupations such as maid,driver,or teacher(aOR:0.78,95%CI:0.66-0.93),and consistent use of bed nets(aOR:0.39,95%CI:0.30-0.51)significantly reduced infection risk.Conclusions This study identified a relatively high slide positivity rate of febrile P.vivax infection in a malaria-endemic district in western Thailand along the Myanmar border.Strengthening malaria surveillance,targeting high-risk populations,ensuring treatment adherence,and promoting early care-seeking behavior are crucial for reducing P.vivax transmission and advancing malaria elimination efforts.
基金supported by a grant(U19AI089672)from the National Institute of Allergy and Infectious Diseases,National Institutes of Health,USA.
文摘Background Understanding Plasmodium sexual differentiation is crucial for blocking transmission.This study identified risk factors for gametocyte carriage and gametocytemia in P.vivax and P.falciparum to inform malaria elimination strategies at the China-Myanmar border.Methods Gametocytes and asexual parasites were microscopically detected on thick smears collected from 2011 to 2020 in Laiza Township,Kachin State,Myanmar.Mono-/polyclonality were detected by genotyping at Pvmsp3α/βfor P.vivax,and Pfmsp1/2 for P.falciparum.Kulldorff’s retrospective time scan statistics tested for likely clusters of gametocyte-positive cases over time.Chi-square or Fisher’s exact tests compared proportions of gametocyte-positive cases in categorical variables.Generalized linear models assessed risk factors(year,season,demographics,clinical/parasitological features)for gametocyte carriage(logistic regression for a binomial outcome)and gametocytemia(Gaussian regression for continuous outcome),respectively.Results During 2011-2020,8240 patients had P.vivax infections,with 7249 testing positive for gametocytes.Among 510 P.falciparum cases,56 tested positive for gametocytes.A significant cluster of P.vivax gametocyte carriage occurred from May 2015 to August 2017(P=0.001).For P.vivax,dry season,previous malaria history,fever,and parasite density were associated with gametocyte carriage.Gametocyte density increased with asexual parasite density(P<0.001)but was lower during the rainy season and in those with a history of malaria infection(P<0.001).Over time,gametocytes carriage proportion increased while density decreased(P<0.001).For P.falciparum,younger age and previous malaria history were associated with gametocyte carriage,and density was higher in the dry season(P=0.0115).Polyclonal P.vivax infections had higher gametocyte densities than monoclonal infections(P<0.0001)and P.falciparum gametocyte density tended to increase with multiplicity of infection.Conclusions Younger age,prior malaria infection,travel,and polyclonal infections correlate with higher P.vivax gametocyte prevalence.Gametocyte carriage peakes during the dry season,highlighting the need for seasonal strategies to support malaria elimination.These findings enhance understanding of risk factors for the transmissible stage of the two main human Plasmodium species in the Greater Mekong Subregion border areas.
