For India to achieve elimination by 2030,the challenges posed by Plasmodium(P.)vivax cannot be overlooked owing to its burden and unique biology.In 2023,in India,about 224000 malaria cases were reported,and a signific...For India to achieve elimination by 2030,the challenges posed by Plasmodium(P.)vivax cannot be overlooked owing to its burden and unique biology.In 2023,in India,about 224000 malaria cases were reported,and a significant proportion(40%)were P.vivax cases.In P.vivax infection,the persistence of dormant liver stage of parasite,i.e.,hypnozoites,leading to relapses weeks or months later poses challenge in its elimination.展开更多
The World Health Organization South-East Asia Regional Office estimates a significantly higher burden-around 15 million cases and 20000 deaths per year.India alone accounts for approximately 77%of the total malaria ca...The World Health Organization South-East Asia Regional Office estimates a significantly higher burden-around 15 million cases and 20000 deaths per year.India alone accounts for approximately 77%of the total malaria cases reported in this region[1,2].Among the five Plasmodium species infecting humans,Plasmodium(P.)vivax is the most prevalent species in India.Its asexual blood stages-ring forms,trophozoites,schizonts-and gametocytes are routinely identified in peripheral blood smears.However,the observation of exflagellated microgametes in human blood is exceedingly rare and typically occurs under certain in vitro conditions[3].展开更多
Objective:To compare the applicability of the SYBK Grcen-Ⅰ assay with the standard schizont maturalion assay,for determination of sensitivity of Plasmodium vivax(P.vivax) to chloroquine and a new antifolale WR 99210....Objective:To compare the applicability of the SYBK Grcen-Ⅰ assay with the standard schizont maturalion assay,for determination of sensitivity of Plasmodium vivax(P.vivax) to chloroquine and a new antifolale WR 99210.Methods:The study was conducted at Mae Tao Clinic for migrant workers,Tak Province during April 2009 to July 2010.A total of 64 blood samples(1 mL blood collected into sodium heparinized plastic tube) were collected from patients with monoinfection with P.vivax malaria prior to treatment with standard regimen of a 3-day chloroquine. In vitro sensitivity of P.vivax isolates was evaluated by schizont maturation inhibition and SYBR Green-Ⅰ assays.Results:A total of 30 out of 64 blood samples collected from patients with P.vivax malaria were successfully analyzed using both the microscopic schizont maturation inhibition and SYBR Green-I assays.The failure rates of the schizont maturation inhibition assay(50%) and the SYBR Green-I assay(54%) were similar(P=0.51).The median IC_(10)s,IC_(50)s and IC_(90)s of both chloroquine and WR99210 were not significantly different from the clinical isolates of P.vivax tested.Based on the cut-off of 100 nM,the prevalences of chloroquine resistance determined by schizont maturation inhibition and SYBR Green-I assays were 19 and 11 isolates,respectively.The strength of agreement between the two methods was very poor for both chloroquine and WR992I0.Conclusions:On the basis of this condition and its superior sensitivity,the microscopic method appears better than the SYUK Green-I Green assay for assessing in vitro sensitivity of fresh P.vivax isolates to antimalarial drugs.展开更多
Complicated malaria is usually due to Plasmodium falciparum.Nevertheless,Plasmodium vivax is infrequently related with life-threatening complications.Few cases have been reported of severe Plasmodium vivax infection,a...Complicated malaria is usually due to Plasmodium falciparum.Nevertheless,Plasmodium vivax is infrequently related with life-threatening complications.Few cases have been reported of severe Plasmodium vivax infection,and most of them from Southeast Asia and India.We report the first case of cerebral malaria due to Plasmodium vivax in Latin America,complicated with sagittal sinus thrombosis and confirmed by a molecular method.展开更多
Most common cause of thalamic bleed is hypertension;other causes are arteriovenous malformation,aneurysm,bleeding thathesis,drugs,amyloid angiopathy,tumor etc.We present a case of Plasmodium vivax(P.vivax) malaria wit...Most common cause of thalamic bleed is hypertension;other causes are arteriovenous malformation,aneurysm,bleeding thathesis,drugs,amyloid angiopathy,tumor etc.We present a case of Plasmodium vivax(P.vivax) malaria with unusual site of bleeding i.e.left thalamus of brain.To the best of our knowledge,this is the first reported case of thalamic bleed caused by vivax malaria in absence of severe thrombocytopenia/disseminated intravascular coagulation (DIC).展开更多
Objective:To investigate the genetic polymorphism of Plasmodium vivax(P.vivax) PvCSP and PvMSP1 genes from field isolates at four endemic regions(North,East,West and South) of Thailand.Methods:The 152 P.vivax injected...Objective:To investigate the genetic polymorphism of Plasmodium vivax(P.vivax) PvCSP and PvMSP1 genes from field isolates at four endemic regions(North,East,West and South) of Thailand.Methods:The 152 P.vivax injected cases from dried blood spots were DMA extracted and confirmed by species-specific primer sets using multiplex PCR method.PvMSPI fragments F2 and F3:PvCSP were gcnotvped using RFLP-PCR method.Resuits:Totally amplified DNA which was multiple genotypes for PvMSP1 F2 and PvMSP1 F3 were 12.50%and 8.55%.respectively while PvCSP was 3.95%.The overall frequency of multiple genotypes was 25%.There were 12 allele tvpes of PvMSP1 F2 using AluI enzyme digestion and 8 size variations were found in P\MSP1 F3.The isolates from western region was highly genetic diverse when compare among all isolates.The predominant variant type of PvCSP gene was \ K2I0 type.Conclusions:The niulliple genotypes are common found in Thailand and it might hide the real genotype.PvCSP does not have extensive genetic diversity in this study.However.PvMSPI marker due to multiple genotypes is difficult In be analyzed.The multiple genotypes findings might stem from population migration and vector species findings.展开更多
Objective:To determine the range and incidence of complications associated with Plasmodium vivax[P.vivax) malaria.Methods:A retrospective analysis was performed of all patients of P.vivax malaria admitted in kasturba ...Objective:To determine the range and incidence of complications associated with Plasmodium vivax[P.vivax) malaria.Methods:A retrospective analysis was performed of all patients of P.vivax malaria admitted in kasturba Medical College.Manipal between January and December,2010.Patients with mixed malarial infection were excluded by appropriate tests. Clinical presentation and laboratory parameters were studied.Results:Medical records of 213 individuals who satisfied the inclusion criteria were reviewed.Anaemia was seen in 65 (30.5%),leucopenia in 38(17.8%]and thrombocytopenia in 184(86.4%l patients.Aspartate and alanine aminotransferases were elevated in 86(40.4%).and 89(41.9%) patients respectively. Hypoalbuminemia was observed in 157(73.6%) cases.Elevated serum creatinine was noted in in 59(27.5%) patients.Creatine kinase was elevated in 30 nut of 59 patients(50.8%).Overall.107 (50.2%) patients fulfilled WHO criteria for sever=e malaria.None of the patients succumbed to the disease.Conclusion:P.vivax malaria is a potentially severe disease,and the term ’ benign" tertian malaria is a misnomer.Despite significant morbidity,with timely and appropriate treatment P.rirax malaria has an excellent outcome.展开更多
Objective:To identify cases of severe Plasmodium vivax(P.vivax) mono-infections among adults.Methods:In this retrospective study,30 adult patients admitted to medical wards of a tertiary hospital in a malaria endemic ...Objective:To identify cases of severe Plasmodium vivax(P.vivax) mono-infections among adults.Methods:In this retrospective study,30 adult patients admitted to medical wards of a tertiary hospital in a malaria endemic urban area from March 2010 to April 2010 were included. The diagnosis of P.vivax malaria was established by peripheral blood film(PBF) examination, and severe malaria was categorized as per World Health Organization guidelines.Results: Complications observed were thrombocytopenia in 28(93.3%),hepatic dysfunction and jaundice in 13(433%),renal dysfunction in 8(26.7%),severe anaemia in 3(10.0%),cerebral malaria in 2 (6.7%),and acute respiratory distress syndrome(ARDS) in 1(3.3%) of 30 patients.Conclusions:P. vivax malaria with severe complications is common in the investigated area,and an intensive and large-scale study of the disease is necessary.展开更多
Objective:To determine the distribution of Duffy blood group genotypes in Balouch population as a major ethnic group that living in a sub-tropical area in south East of Iran.Methods:In this study,the Duffy blood group...Objective:To determine the distribution of Duffy blood group genotypes in Balouch population as a major ethnic group that living in a sub-tropical area in south East of Iran.Methods:In this study,the Duffy blood group FY phenolypes were determined using indireet anti-globulin technique and also genotype by PCR-RFLP in 160 vivax malaria patients and 160 control individuals.Results:The results showed that the most common Duffy geitolype was FYA/FYB(46.6%)followed by FYA/FYA(15.3%),FYA/FYO(14.4%),FYB/FYO(11.9%,),FYB/FYB(10%)and FYO/FYO(1.9%).In case individuals,frequency of FY A.FYB and FYO alleles were 0.471,0.431and 0.097,respectively compaired to 0.444,0.353 and 0.203,respectively in control(non-infected)group.Conclusions:This data provide evidence that individuals with the FYA/FYB genotype have higher susceptibility to malaria and there are significant associations between Duffy blood group variants and susceptibility or resistance to vivax malaria.展开更多
In tropical countries like India,malaria has been one of the most common parasitic illnesses leading to frequent hospitalization and causing major economic burden among the masses. Although Plasmodium vivax infection ...In tropical countries like India,malaria has been one of the most common parasitic illnesses leading to frequent hospitalization and causing major economic burden among the masses. Although Plasmodium vivax infection is considered to be benign,in contrast to Plasmodium, falciparum infection which is notorious for its severe splenic complications can occur frequently. Splenomegaly tends not to receive special attention,as it is not usually accompanied by any symptoms and can be gradually resolved via standard antimalarial therapy.Splenic infarction, although rarely attributable to malaria in an endemic region with high parasitemia,can be a rare presentation of this disease entity.展开更多
A cloned DNA fragment specific for Plasmodium vivax was cleaved from theplasmid pVA1 and ligated into phage M13mp18.The nucleotides of the insert were se-quenced by the dideoxy-chain termination procedure.The fragment...A cloned DNA fragment specific for Plasmodium vivax was cleaved from theplasmid pVA1 and ligated into phage M13mp18.The nucleotides of the insert were se-quenced by the dideoxy-chain termination procedure.The fragment was composed of 261base pairs and 3 Hinf Ⅰ sites but no tandem repeat sequences.Computer retrieval andanalysis show that the nucleotide sequence of the cloned DNA fragment is unique,forthere has not been any significant homologue with that of other Plasmodium genes pub-lished as yet.展开更多
India bears the largest Plasmodium (P.) vivax (Pv) malaria burden and contributes 48%of Pv cases globally[1]. The efforts of government and private bodies to control malaria have successfully reduced the number of Pla...India bears the largest Plasmodium (P.) vivax (Pv) malaria burden and contributes 48%of Pv cases globally[1]. The efforts of government and private bodies to control malaria have successfully reduced the number of Plasmodium falciparum (Pf) malaria cases in several countries, including India.展开更多
Objective:To do mapping and modeling of conformational B cell epitope regions of highly conserved and protective regions of three merozoitecandidate vaccine proteins of Plasmodium vivax(P.vivax),ie.merozoite purface p...Objective:To do mapping and modeling of conformational B cell epitope regions of highly conserved and protective regions of three merozoitecandidate vaccine proteins of Plasmodium vivax(P.vivax),ie.merozoite purface protein-1(PvMSP-1),apical membrane antigen-1 domainⅡ(PvAMA1-DⅡ)and regionⅡof the Duffy binding protein(PvDBPⅡ).and to analyze the immunogenie properties of these predicted epitopes.Methods:3-D structures of amino acid haplotypes from Sri Lanka(available in GeneBank)of PvMSP-1_(19)(n=27),PvAMA1-DⅡ(n=21)and PvDBPⅡ(n=33)were modeled.SEPPA,selected as the best online server was used for conformational epitope predictions,while prediction and moodeling of protein structuve and properties related to immunogenicity was carried out with Geno3D server.SCRATCH Protein Server,NetSurfP Server and standaloneroftware,Genious 5.4.4.Results:SEPPA revealed that regions of predicted conformational epitopes formed 4 clusters in PvMSP-I_(19),and 3 clusters each in PvAMA1-DⅡand PvDBPⅡ,all of which displayed a high degree of hydrophilicity,contained solveut exposed residues,displayed high probability of antigenicity and showed positive antigenic propensity values,that indicated high degree of immunogenicity.Conclusions:Findings of this study revealed and confirmed that different parts of the sequences of each of the conserved regions of the three selected potential vaccine candidate antigens of P.vivax are important with regard to conformational epitope prediction that warrants further laboratory experimental invertigations in in vivo animal models.展开更多
Hemophagocytic lymphohistiocytosis syndrome (HPS) is a potentially fatal hyperinflammatory response characterized by a generalized histiocytic proliferation with marked hemophagocytosis in bone marrow [1]. Hemophagocy...Hemophagocytic lymphohistiocytosis syndrome (HPS) is a potentially fatal hyperinflammatory response characterized by a generalized histiocytic proliferation with marked hemophagocytosis in bone marrow [1]. Hemophagocytic syndrome has been associated with genetic mutations, autoimmune diseases, hematological malignancies or infections [2,3]. According to the data from Centre for Disease Control and prevention (CDC) Plasmodium falciparum has been associated with HPS but not the Plasmodium vivax [4-7]. We report a case of hemophagocytic syndrome as a complication of Plasmodium vivax malaria which is a rare presentation according to the data. This patient presented with high grade fever with chills (P. vivax positive), fever however did not respond to anti-malarials. The patient continued to have high grade fever with altered sensorium and deranged liver function with pancytopenia. Since she fulfilled the criteria of (HPS), patient was put on injectable steroids and responded dramatically. Hemophagocytic syndrome is a potentially fatal syndrome and therefore high index suspicion and early treatment is the key to reduce the mortatlity.展开更多
Trypanosomosis remains a major challenge to livestock production in much of tropical Sub-Saharan Africa, while diagnosis and treatment still depend on inefficient parasitological techniques. Endemic infections depend ...Trypanosomosis remains a major challenge to livestock production in much of tropical Sub-Saharan Africa, while diagnosis and treatment still depend on inefficient parasitological techniques. Endemic infections depend on animal reservoirs with subclinical parasitemia. We report molecular diagnosis of subclinical Trypanosoma vivax (T. vivax) infection using polymerase chain reaction (PCR) for the first time in Nigerian goats and associate parasite presence with gross physiological traits and serum metabolites in extensively managed Nigerian goats. PCR was used to amplify a 400 bp DNA fragment of the parasite genome in 205 goats across three geographical zones of the country. Results showed a high subclinical infection rate (SCIR) of 71.7% in the total goats examined. Overall SCIRs of 71%, 75.9% and 55.6% were recorded in West African Dwarf, Red Sokoto and Sahel goats respectively, while geographical SCIRs were 71.2% (Southwest), 75% (Northwest) and 70% (Northeast). T. vivax presence had significant (P 0.05) effect on respiratory rate and is associated with higher creatinine levels in sera. Logistic regression analyses with Hosmer-Lemeshow goodness-of-fit showed that respiratory rate is the most important predictive trait for the presence of T. vivax infection (P 0.05). Goats appear to be a viable reservoir for T. vivax infection of other livestock. Molecular diagnosis of subclinical trypanosomosis using PCR could be useful for large scale epidemiological studies, early diagnosis of subclinical infection and treatment of the disease in extensively managed tropical goats.展开更多
Despite the vigorous research and development, as of 2017, there is currently no widely available antimalarial vaccine. An effective, commercially available vaccine would be a huge game changer;however, it seems like ...Despite the vigorous research and development, as of 2017, there is currently no widely available antimalarial vaccine. An effective, commercially available vaccine would be a huge game changer;however, it seems like there is still a long way to go until that target is reached. Therefore, the purpose of this study was to use molecular docking technique to identify new inhibitors for a novel antimalarial target with the overall aim of finding hit compounds which could be further optimized to become potential drug candidates. The docking protocol AutoDockVina was used alongside the molecular visualisation software UCSF Chimera to dock 100 naphthoquinones (labelled TM1-100) and 66 aryl diketones (labelled TM101-166) with the chosen target, Plasmodium vivax N-myristoyltransferase (PvNMT). Each docking session yielded the best 9 binding modes between the ligand and target. The hydrogen bond interactions of all binding modes were analysed, and the top six target molecules (TM) were short listed as the possible hit compounds (TM40, TM65, TM66, TM81, TM94 and TM165). These compounds displayed more than six hydrogen bonds under 3 angstroms over the 9 binding modes. Using Lipinski’s rule of 5, the potential hit compounds were further analysed to determine the drug-likeness and all were found to obey the parameters. Following the same method used to dock the ligands, twelve FDA approved antimalarial drugs were also docked with PvNMT for comparison purposes. Apart from proguanil, the other eleven antimalarial drugs displayed fewer hydrogen bonds under 3 angstroms over the 9 binding modes compared to all six of the potential hit compounds. This study discovered six compounds which displayed stronger interactions with the target protein compared to majority of the FDA approved drugs. The results of this investigation gave us new molecules that could be further investigated for the designing of novel drug-like compounds for the treatment of Malaria.展开更多
Background:In most of the Americas,the recommended treatment to prevent relapse of Plasmodium vivax malaria is primaquine at a total dose of 3.5 mg per kilogram of body weight,despite evidence of only moderate efficac...Background:In most of the Americas,the recommended treatment to prevent relapse of Plasmodium vivax malaria is primaquine at a total dose of 3.5 mg per kilogram of body weight,despite evidence of only moderate efficacy.Methods:In this trial conducted in Brazil,we evaluated three primaquine regimens to prevent relapse of P.vivax malaria in children at least 5 years of age and in adults with microscopy-confirmed P.vivax monoinfection.All the patients received directly observed chloroquine for 3 days(total dose,25 mg per kilogram).Group 1 received a total primaquine dose of 3.5 mg per kilogram(0.5 mg per kilogram per day)over 7 days with unobserved administration;group 2 received the same regimen as group 1 but with observed administration;and group 3 received a total primaquine dose of 7.0 mg per kilogram over 14 days(also 0.5 mg per kilogram per day)with observed administration.We monitored the patients for 168 days.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 The final challenge for malaria elimination in many countries is to interrupt the circulation of Plasmodium vivax.Given the unique biology of this parasite,innovative approaches are imperative,with a focus ...Background The final challenge for malaria elimination in many countries is to interrupt the circulation of Plasmodium vivax.Given the unique biology of this parasite,innovative approaches are imperative,with a focus on identifying asymptomatic carriers of dormant parasite forms.This article delineates the recent epidemiological patterns of P.vivax malaria within a highly mobile and hard-to-reach population in the Guiana Shield.It further proposes an assessment of the potential reservoir of asymptomatic carriers.Methods This analysis was based on data from:(i)two cross-sectional surveys carried out at the French-Surinamese border in 2015 and 2019,including adults returning from gold mining sites located in French Guiana(FG),[questionnaires and blood samples,tested for polymerase chain reaction(PCR)and P.vivax serological exposure markers(SEM)of recent infection];(ii)epidemiological malaria surveillance system in Suriname,including cases imported from gold mining sites located in western FG between 2014 and 2020.Factors associated with P.vivax seropositivity were analysed by multiple logistic regression.The probability of carrying P.vivax parasites(blood-stage or hypnozoite)was estimated by a classification drawn from PCR results,SEM and reported recent history of illness.Results Surveillance data showed a decrease in malaria imported cases from French Guiana between beginning and end of the analysed period(236 in 2014 to 74 in 2020)and an increase in the proportion of cases associated with P.vivax(52.4%in 2014 to 100%in 2020).The PCR-prevalence of P.vivax in survey samples decreased from 11.4%in 2015 to 4.0%in 2019;P.vivax seropositivity decreased from 44.7%to 28.4%.P.vivax seropositivity was positively associated with male sex,age and number of years spent in gold mining,type of activity,and reported malaria history(episode within less than nine months OR=10.73,95%CI:5.87–19.6,or history of repeated older episodes OR=5.31,95%CI:3.13–9.01).Conclusions Our analysis shows an epidemiological evolution typical of a scenario of decreasing malaria circulation.Nevertheless,in 2020,gold miners in western FG still showed a moderate level of P.vivax circulation.Biological methods and epidemiological criteria can help to select potential parasite carriers,who could benefit from targeted drug administration.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For India to achieve elimination by 2030,the challenges posed by Plasmodium(P.)vivax cannot be overlooked owing to its burden and unique biology.In 2023,in India,about 224000 malaria cases were reported,and a significant proportion(40%)were P.vivax cases.In P.vivax infection,the persistence of dormant liver stage of parasite,i.e.,hypnozoites,leading to relapses weeks or months later poses challenge in its elimination.
文摘The World Health Organization South-East Asia Regional Office estimates a significantly higher burden-around 15 million cases and 20000 deaths per year.India alone accounts for approximately 77%of the total malaria cases reported in this region[1,2].Among the five Plasmodium species infecting humans,Plasmodium(P.)vivax is the most prevalent species in India.Its asexual blood stages-ring forms,trophozoites,schizonts-and gametocytes are routinely identified in peripheral blood smears.However,the observation of exflagellated microgametes in human blood is exceedingly rare and typically occurs under certain in vitro conditions[3].
基金Supported by the Commission on Higher EducationMinistry of Education of Thailand and Thailand National Research University(NRU)
文摘Objective:To compare the applicability of the SYBK Grcen-Ⅰ assay with the standard schizont maturalion assay,for determination of sensitivity of Plasmodium vivax(P.vivax) to chloroquine and a new antifolale WR 99210.Methods:The study was conducted at Mae Tao Clinic for migrant workers,Tak Province during April 2009 to July 2010.A total of 64 blood samples(1 mL blood collected into sodium heparinized plastic tube) were collected from patients with monoinfection with P.vivax malaria prior to treatment with standard regimen of a 3-day chloroquine. In vitro sensitivity of P.vivax isolates was evaluated by schizont maturation inhibition and SYBR Green-Ⅰ assays.Results:A total of 30 out of 64 blood samples collected from patients with P.vivax malaria were successfully analyzed using both the microscopic schizont maturation inhibition and SYBR Green-I assays.The failure rates of the schizont maturation inhibition assay(50%) and the SYBR Green-I assay(54%) were similar(P=0.51).The median IC_(10)s,IC_(50)s and IC_(90)s of both chloroquine and WR99210 were not significantly different from the clinical isolates of P.vivax tested.Based on the cut-off of 100 nM,the prevalences of chloroquine resistance determined by schizont maturation inhibition and SYBR Green-I assays were 19 and 11 isolates,respectively.The strength of agreement between the two methods was very poor for both chloroquine and WR992I0.Conclusions:On the basis of this condition and its superior sensitivity,the microscopic method appears better than the SYUK Green-I Green assay for assessing in vitro sensitivity of fresh P.vivax isolates to antimalarial drugs.
文摘Complicated malaria is usually due to Plasmodium falciparum.Nevertheless,Plasmodium vivax is infrequently related with life-threatening complications.Few cases have been reported of severe Plasmodium vivax infection,and most of them from Southeast Asia and India.We report the first case of cerebral malaria due to Plasmodium vivax in Latin America,complicated with sagittal sinus thrombosis and confirmed by a molecular method.
文摘Most common cause of thalamic bleed is hypertension;other causes are arteriovenous malformation,aneurysm,bleeding thathesis,drugs,amyloid angiopathy,tumor etc.We present a case of Plasmodium vivax(P.vivax) malaria with unusual site of bleeding i.e.left thalamus of brain.To the best of our knowledge,this is the first reported case of thalamic bleed caused by vivax malaria in absence of severe thrombocytopenia/disseminated intravascular coagulation (DIC).
基金supported by "Strategic Scholarships Fellowships Fromtier Research Network"from the Commission Higher Education(Thailand) (Grant No.CHE-PhD-SW-INV-20060169)also parially supported by the China Medical Board,Faculty of Public Health,Mahidol University,Bangkok,Thailand
文摘Objective:To investigate the genetic polymorphism of Plasmodium vivax(P.vivax) PvCSP and PvMSP1 genes from field isolates at four endemic regions(North,East,West and South) of Thailand.Methods:The 152 P.vivax injected cases from dried blood spots were DMA extracted and confirmed by species-specific primer sets using multiplex PCR method.PvMSPI fragments F2 and F3:PvCSP were gcnotvped using RFLP-PCR method.Resuits:Totally amplified DNA which was multiple genotypes for PvMSP1 F2 and PvMSP1 F3 were 12.50%and 8.55%.respectively while PvCSP was 3.95%.The overall frequency of multiple genotypes was 25%.There were 12 allele tvpes of PvMSP1 F2 using AluI enzyme digestion and 8 size variations were found in P\MSP1 F3.The isolates from western region was highly genetic diverse when compare among all isolates.The predominant variant type of PvCSP gene was \ K2I0 type.Conclusions:The niulliple genotypes are common found in Thailand and it might hide the real genotype.PvCSP does not have extensive genetic diversity in this study.However.PvMSPI marker due to multiple genotypes is difficult In be analyzed.The multiple genotypes findings might stem from population migration and vector species findings.
文摘Objective:To determine the range and incidence of complications associated with Plasmodium vivax[P.vivax) malaria.Methods:A retrospective analysis was performed of all patients of P.vivax malaria admitted in kasturba Medical College.Manipal between January and December,2010.Patients with mixed malarial infection were excluded by appropriate tests. Clinical presentation and laboratory parameters were studied.Results:Medical records of 213 individuals who satisfied the inclusion criteria were reviewed.Anaemia was seen in 65 (30.5%),leucopenia in 38(17.8%]and thrombocytopenia in 184(86.4%l patients.Aspartate and alanine aminotransferases were elevated in 86(40.4%).and 89(41.9%) patients respectively. Hypoalbuminemia was observed in 157(73.6%) cases.Elevated serum creatinine was noted in in 59(27.5%) patients.Creatine kinase was elevated in 30 nut of 59 patients(50.8%).Overall.107 (50.2%) patients fulfilled WHO criteria for sever=e malaria.None of the patients succumbed to the disease.Conclusion:P.vivax malaria is a potentially severe disease,and the term ’ benign" tertian malaria is a misnomer.Despite significant morbidity,with timely and appropriate treatment P.rirax malaria has an excellent outcome.
文摘Objective:To identify cases of severe Plasmodium vivax(P.vivax) mono-infections among adults.Methods:In this retrospective study,30 adult patients admitted to medical wards of a tertiary hospital in a malaria endemic urban area from March 2010 to April 2010 were included. The diagnosis of P.vivax malaria was established by peripheral blood film(PBF) examination, and severe malaria was categorized as per World Health Organization guidelines.Results: Complications observed were thrombocytopenia in 28(93.3%),hepatic dysfunction and jaundice in 13(433%),renal dysfunction in 8(26.7%),severe anaemia in 3(10.0%),cerebral malaria in 2 (6.7%),and acute respiratory distress syndrome(ARDS) in 1(3.3%) of 30 patients.Conclusions:P. vivax malaria with severe complications is common in the investigated area,and an intensive and large-scale study of the disease is necessary.
文摘Objective:To determine the distribution of Duffy blood group genotypes in Balouch population as a major ethnic group that living in a sub-tropical area in south East of Iran.Methods:In this study,the Duffy blood group FY phenolypes were determined using indireet anti-globulin technique and also genotype by PCR-RFLP in 160 vivax malaria patients and 160 control individuals.Results:The results showed that the most common Duffy geitolype was FYA/FYB(46.6%)followed by FYA/FYA(15.3%),FYA/FYO(14.4%),FYB/FYO(11.9%,),FYB/FYB(10%)and FYO/FYO(1.9%).In case individuals,frequency of FY A.FYB and FYO alleles were 0.471,0.431and 0.097,respectively compaired to 0.444,0.353 and 0.203,respectively in control(non-infected)group.Conclusions:This data provide evidence that individuals with the FYA/FYB genotype have higher susceptibility to malaria and there are significant associations between Duffy blood group variants and susceptibility or resistance to vivax malaria.
文摘In tropical countries like India,malaria has been one of the most common parasitic illnesses leading to frequent hospitalization and causing major economic burden among the masses. Although Plasmodium vivax infection is considered to be benign,in contrast to Plasmodium, falciparum infection which is notorious for its severe splenic complications can occur frequently. Splenomegaly tends not to receive special attention,as it is not usually accompanied by any symptoms and can be gradually resolved via standard antimalarial therapy.Splenic infarction, although rarely attributable to malaria in an endemic region with high parasitemia,can be a rare presentation of this disease entity.
文摘A cloned DNA fragment specific for Plasmodium vivax was cleaved from theplasmid pVA1 and ligated into phage M13mp18.The nucleotides of the insert were se-quenced by the dideoxy-chain termination procedure.The fragment was composed of 261base pairs and 3 Hinf Ⅰ sites but no tandem repeat sequences.Computer retrieval andanalysis show that the nucleotide sequence of the cloned DNA fragment is unique,forthere has not been any significant homologue with that of other Plasmodium genes pub-lished as yet.
文摘India bears the largest Plasmodium (P.) vivax (Pv) malaria burden and contributes 48%of Pv cases globally[1]. The efforts of government and private bodies to control malaria have successfully reduced the number of Plasmodium falciparum (Pf) malaria cases in several countries, including India.
文摘Objective:To do mapping and modeling of conformational B cell epitope regions of highly conserved and protective regions of three merozoitecandidate vaccine proteins of Plasmodium vivax(P.vivax),ie.merozoite purface protein-1(PvMSP-1),apical membrane antigen-1 domainⅡ(PvAMA1-DⅡ)and regionⅡof the Duffy binding protein(PvDBPⅡ).and to analyze the immunogenie properties of these predicted epitopes.Methods:3-D structures of amino acid haplotypes from Sri Lanka(available in GeneBank)of PvMSP-1_(19)(n=27),PvAMA1-DⅡ(n=21)and PvDBPⅡ(n=33)were modeled.SEPPA,selected as the best online server was used for conformational epitope predictions,while prediction and moodeling of protein structuve and properties related to immunogenicity was carried out with Geno3D server.SCRATCH Protein Server,NetSurfP Server and standaloneroftware,Genious 5.4.4.Results:SEPPA revealed that regions of predicted conformational epitopes formed 4 clusters in PvMSP-I_(19),and 3 clusters each in PvAMA1-DⅡand PvDBPⅡ,all of which displayed a high degree of hydrophilicity,contained solveut exposed residues,displayed high probability of antigenicity and showed positive antigenic propensity values,that indicated high degree of immunogenicity.Conclusions:Findings of this study revealed and confirmed that different parts of the sequences of each of the conserved regions of the three selected potential vaccine candidate antigens of P.vivax are important with regard to conformational epitope prediction that warrants further laboratory experimental invertigations in in vivo animal models.
文摘Hemophagocytic lymphohistiocytosis syndrome (HPS) is a potentially fatal hyperinflammatory response characterized by a generalized histiocytic proliferation with marked hemophagocytosis in bone marrow [1]. Hemophagocytic syndrome has been associated with genetic mutations, autoimmune diseases, hematological malignancies or infections [2,3]. According to the data from Centre for Disease Control and prevention (CDC) Plasmodium falciparum has been associated with HPS but not the Plasmodium vivax [4-7]. We report a case of hemophagocytic syndrome as a complication of Plasmodium vivax malaria which is a rare presentation according to the data. This patient presented with high grade fever with chills (P. vivax positive), fever however did not respond to anti-malarials. The patient continued to have high grade fever with altered sensorium and deranged liver function with pancytopenia. Since she fulfilled the criteria of (HPS), patient was put on injectable steroids and responded dramatically. Hemophagocytic syndrome is a potentially fatal syndrome and therefore high index suspicion and early treatment is the key to reduce the mortatlity.
文摘Trypanosomosis remains a major challenge to livestock production in much of tropical Sub-Saharan Africa, while diagnosis and treatment still depend on inefficient parasitological techniques. Endemic infections depend on animal reservoirs with subclinical parasitemia. We report molecular diagnosis of subclinical Trypanosoma vivax (T. vivax) infection using polymerase chain reaction (PCR) for the first time in Nigerian goats and associate parasite presence with gross physiological traits and serum metabolites in extensively managed Nigerian goats. PCR was used to amplify a 400 bp DNA fragment of the parasite genome in 205 goats across three geographical zones of the country. Results showed a high subclinical infection rate (SCIR) of 71.7% in the total goats examined. Overall SCIRs of 71%, 75.9% and 55.6% were recorded in West African Dwarf, Red Sokoto and Sahel goats respectively, while geographical SCIRs were 71.2% (Southwest), 75% (Northwest) and 70% (Northeast). T. vivax presence had significant (P 0.05) effect on respiratory rate and is associated with higher creatinine levels in sera. Logistic regression analyses with Hosmer-Lemeshow goodness-of-fit showed that respiratory rate is the most important predictive trait for the presence of T. vivax infection (P 0.05). Goats appear to be a viable reservoir for T. vivax infection of other livestock. Molecular diagnosis of subclinical trypanosomosis using PCR could be useful for large scale epidemiological studies, early diagnosis of subclinical infection and treatment of the disease in extensively managed tropical goats.
文摘Despite the vigorous research and development, as of 2017, there is currently no widely available antimalarial vaccine. An effective, commercially available vaccine would be a huge game changer;however, it seems like there is still a long way to go until that target is reached. Therefore, the purpose of this study was to use molecular docking technique to identify new inhibitors for a novel antimalarial target with the overall aim of finding hit compounds which could be further optimized to become potential drug candidates. The docking protocol AutoDockVina was used alongside the molecular visualisation software UCSF Chimera to dock 100 naphthoquinones (labelled TM1-100) and 66 aryl diketones (labelled TM101-166) with the chosen target, Plasmodium vivax N-myristoyltransferase (PvNMT). Each docking session yielded the best 9 binding modes between the ligand and target. The hydrogen bond interactions of all binding modes were analysed, and the top six target molecules (TM) were short listed as the possible hit compounds (TM40, TM65, TM66, TM81, TM94 and TM165). These compounds displayed more than six hydrogen bonds under 3 angstroms over the 9 binding modes. Using Lipinski’s rule of 5, the potential hit compounds were further analysed to determine the drug-likeness and all were found to obey the parameters. Following the same method used to dock the ligands, twelve FDA approved antimalarial drugs were also docked with PvNMT for comparison purposes. Apart from proguanil, the other eleven antimalarial drugs displayed fewer hydrogen bonds under 3 angstroms over the 9 binding modes compared to all six of the potential hit compounds. This study discovered six compounds which displayed stronger interactions with the target protein compared to majority of the FDA approved drugs. The results of this investigation gave us new molecules that could be further investigated for the designing of novel drug-like compounds for the treatment of Malaria.
文摘Background:In most of the Americas,the recommended treatment to prevent relapse of Plasmodium vivax malaria is primaquine at a total dose of 3.5 mg per kilogram of body weight,despite evidence of only moderate efficacy.Methods:In this trial conducted in Brazil,we evaluated three primaquine regimens to prevent relapse of P.vivax malaria in children at least 5 years of age and in adults with microscopy-confirmed P.vivax monoinfection.All the patients received directly observed chloroquine for 3 days(total dose,25 mg per kilogram).Group 1 received a total primaquine dose of 3.5 mg per kilogram(0.5 mg per kilogram per day)over 7 days with unobserved administration;group 2 received the same regimen as group 1 but with observed administration;and group 3 received a total primaquine dose of 7.0 mg per kilogram over 14 days(also 0.5 mg per kilogram per day)with observed administration.We monitored the patients for 168 days.
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funded by European Funds for Regional Development(Feder)the French Guiana regional health agency(ARS Guyane)the Ministry of Health of Suriname and the Global Fund.
文摘Background The final challenge for malaria elimination in many countries is to interrupt the circulation of Plasmodium vivax.Given the unique biology of this parasite,innovative approaches are imperative,with a focus on identifying asymptomatic carriers of dormant parasite forms.This article delineates the recent epidemiological patterns of P.vivax malaria within a highly mobile and hard-to-reach population in the Guiana Shield.It further proposes an assessment of the potential reservoir of asymptomatic carriers.Methods This analysis was based on data from:(i)two cross-sectional surveys carried out at the French-Surinamese border in 2015 and 2019,including adults returning from gold mining sites located in French Guiana(FG),[questionnaires and blood samples,tested for polymerase chain reaction(PCR)and P.vivax serological exposure markers(SEM)of recent infection];(ii)epidemiological malaria surveillance system in Suriname,including cases imported from gold mining sites located in western FG between 2014 and 2020.Factors associated with P.vivax seropositivity were analysed by multiple logistic regression.The probability of carrying P.vivax parasites(blood-stage or hypnozoite)was estimated by a classification drawn from PCR results,SEM and reported recent history of illness.Results Surveillance data showed a decrease in malaria imported cases from French Guiana between beginning and end of the analysed period(236 in 2014 to 74 in 2020)and an increase in the proportion of cases associated with P.vivax(52.4%in 2014 to 100%in 2020).The PCR-prevalence of P.vivax in survey samples decreased from 11.4%in 2015 to 4.0%in 2019;P.vivax seropositivity decreased from 44.7%to 28.4%.P.vivax seropositivity was positively associated with male sex,age and number of years spent in gold mining,type of activity,and reported malaria history(episode within less than nine months OR=10.73,95%CI:5.87–19.6,or history of repeated older episodes OR=5.31,95%CI:3.13–9.01).Conclusions Our analysis shows an epidemiological evolution typical of a scenario of decreasing malaria circulation.Nevertheless,in 2020,gold miners in western FG still showed a moderate level of P.vivax circulation.Biological methods and epidemiological criteria can help to select potential parasite carriers,who could benefit from targeted drug administration.
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.
