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1.
Artigo em Inglês | MEDLINE | ID: mdl-33530386

RESUMO

Aims: This study examines the dynamics of malaria as influenced by meteorological factors in French Guiana from 2005 to 2019. It explores spatial hotspots of malaria transmission and aims to determine the factors associated with variation of hotspots with time. Methods: Data for individual malaria cases came from the surveillance system of the Delocalized Centers for Prevention and Care (CDPS) (n = 17) from 2005-2019. Meteorological data was acquired from the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) database. The Box-Jenkins autoregressive integrated moving average (ARIMA) model tested stationarity of the time series, and the impact of meteorological indices (issued from principal component analysis-PCA) on malaria incidence was determined with a general additive model. Hotspot characterization was performed using spatial scan statistics. Results: The current sample includes 7050 eligible Plasmodium vivax (n = 4111) and Plasmodium falciparum (n = 2939) cases from health centers across French Guiana. The first and second PCA-derived meteorological components (maximum/minimum temperature/minimum humidity and maximum humidity, respectively) were significantly negatively correlated with total malaria incidence with a lag of one week and 10 days, respectively. Overall malaria incidence decreased across the time series until 2017 when incidence began to trend upwards. Hotspot characterization revealed a few health centers that exhibited spatial stability across the entire time series: Saint Georges de l'Oyapock and Antecume Pata for P. falciparum, and Saint Georges de l'Oyapock, Antecume Pata, Régina and Camopi for P. vivax. Conclusions: This study highlighted changing malaria incidence in French Guiana and the influences of meteorological factors on transmission. Many health centers showed spatial stability in transmission, albeit not temporal. Knowledge of the areas of high transmission as well as how and why transmission has changed over time can inform strategies to reduce the transmission of malaria in French Guiana. Hotspots should be further investigated to understand other influences on local transmission, which will help to facilitate elimination.


Assuntos
Malária Falciparum , Malária Vivax , Guiana Francesa/epidemiologia , Humanos , Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Plasmodium falciparum , Plasmodium vivax
2.
Drug Discov Ther ; 14(6): 330-335, 2021 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-33390562

RESUMO

Traditionally attributed only to Plasmodium falciparum, Plasmodium vivax has recently been reported to cause a significant burden of complicated malaria cases. The present study aimed to delineate the clinical spectrum and identify predictors for severe disease. This was a prospective observational cohort study conducted at a tertiary care hospital in North India. Patients with acute febrile illness (AFI) aged at least 14 years were included if they were diagnosed with vivax malaria based on rapid kits or peripheral smears. Clinical data and investigations during hospital stay was recorded. 439 cases of acute febrile illness were screened, of whom 50 (11%) were diagnosed with malaria including eight P. falciparum infections. Forty-two vivax malaria cases, 22 (52%) of whom were severe, were followed till discharge or death. The median age of the cohort was 24.5 years (Q1-Q3, 19-36 years), including a total of 29 males (69%). Severe malaria was more frequently associated with historical complaints of oliguria or dyspnea, and examination findings of pallor, splenomegaly or altered sensorium. The following five factors were identified to predict severe disease: prolonged illness over 7 days, symptoms of oliguria or dyspnea, examination findings of pallor or crepitations on auscultation. Malaria accounts for 1 in 10 cases of AFI at our North Indian tertiary care center and approximately half of them present with severe disease. Prolonged duration of disease prior to presentation is a modifiable predictor for severe disease and should be targeted for reducing morbidity.


Assuntos
Febre/parasitologia , Hospitalização/estatística & dados numéricos , Malária Vivax/epidemiologia , Plasmodium vivax/patogenicidade , Adulto , Dispneia/epidemiologia , Dispneia/etiologia , Feminino , Humanos , Índia , Tempo de Internação , Masculino , Oligúria/epidemiologia , Oligúria/etiologia , Estudos Prospectivos , Índice de Gravidade de Doença , Centros de Atenção Terciária , Adulto Jovem
3.
PLoS One ; 15(12): e0244479, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33370376

RESUMO

Malaria is a vector-borne disease transmitted by Anopheline mosquitoes. In Korea, Plasmodium vivax malaria is an endemic disease and the main vector is Anopheles sinensis. Plasmodium vivax malaria is common in the northwestern part of South Korea, including in the city of Goyang in regions near the demilitarized zone. This study aimed to identify the best time-series model for predicting mosquito average abundance in Goyang, Korea. Mosquito data were obtained from the Mosquito Surveillance Program of the Goyang Ilsanseogu Public Health Center for the period 2008-2012. Black light traps were set up periodically in a park, a senior community center, and a village community center, public health center, drainage pumping station, cactus research center, restaurant near forest, in which many activities occur at night. In total, 9,512 female mosquitoes were collected at 12 permanent trapping sites during the mosquito season in the study period. Weekly An. sinensis average abundance was positively correlated with minimum grass temperature (r = 0.694, p < 0.001), precipitation (r = 0.326, p = 0.001). The results showed that seasonal autoregressive integrated moving average (SARIMA) (1,0,0)(0,0,1)21 with minimum grass temperature variable at time lag0 weeks and the precipitation variable at time lag1 weeks provided that best model of mosquito average abundance. The multivariate model accounted for about 54.1% of the mosquito average abundance variation. Time-series analysis of mosquito average abundance and climate factors provided basic information for predicting the occurrence of malaria mosquitoes.


Assuntos
Anopheles/parasitologia , Monitorização de Parâmetros Ecológicos/estatística & dados numéricos , Doenças Endêmicas/prevenção & controle , Malária Vivax/prevenção & controle , Mosquitos Vetores/parasitologia , Animais , Estudos Transversais , Feminino , Humanos , Malária Vivax/epidemiologia , Malária Vivax/parasitologia , Malária Vivax/transmissão , Controle de Mosquitos , Análise Multivariada , Plasmodium vivax/isolamento & purificação , República da Coreia/epidemiologia , Medição de Risco/métodos , Estações do Ano
4.
PLoS Negl Trop Dis ; 14(9): e0008697, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32925910

RESUMO

The proportion of Plasmodium vivax malaria among all malarias is increasing worldwide. Treatment with 8-aminoquinolines remain the only radical cure. However, 8-aminoquinolines can cause severe hemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficient patients. The population of the multi-ethnic Chittagong Hill Tracts (CHT) carry the highest malaria burden within Bangladesh. As in many countries the national treatment guidelines recommend 8-aminoquinoline based radical cure without routine G6PD deficiency (G6PDd) testing to guide treatment. Aim of this study was to determine the need for routine testing within a multi-ethnic population by assessing the prevalence of G6PDd among the local population. Participants from 11 ethnicities were randomly selected and malaria status was assessed by microscopy, rapid diagnostic test (RDT) and polymerase chain reaction (PCR). G6PD status was determined by spectrophotometry and G6PD genotyping. The adjusted male median (AMM) was defined as 100% G6PD activity, participants were categorized as G6PD deficient (<30% activity), G6PD intermediate (30% to 70% activity) or G6PD normal (>70% activity). Median G6PD activities between ethnicities were compared and the association between G6PD activity and malaria status was assessed. 1002 participants were enrolled and tested for malaria. G6PD activity was measured by spectrophotometry in 999 participants and host G6PD genotyping undertaken in 323 participants. Seven participants (0.7%) had peripheral parasitaemia detected by microscopy or RDT and 42 by PCR (4.2%). Among 106 participants (32.8%) with confirmed genotype, 99 (93.4%) had the Mahidol variant. The AMM was 7.03U/gHb with 90 (9.0%) G6PD deficient participants and 133 (13.3%) with intermediate G6PD activity. Median G6PD activity differed significantly between ethnicities (p<0.001), proportions of G6PD deficient individuals ranged from 2% to 26% but did not differ between participants with and without malaria. The high G6PDd prevalence and significant variation between ethnicities suggest routine G6PDd testing to guide 8-aminoquinoline based radical in the CHT and comparable settings.


Assuntos
Grupos Étnicos/genética , Deficiência de Glucosefosfato Desidrogenase/epidemiologia , Deficiência de Glucosefosfato Desidrogenase/genética , Glucosefosfato Desidrogenase/genética , Glucosefosfato Desidrogenase/metabolismo , Adulto , Aminoquinolinas/efeitos adversos , Aminoquinolinas/uso terapêutico , Bangladesh/epidemiologia , Testes Diagnósticos de Rotina , Feminino , Deficiência de Glucosefosfato Desidrogenase/complicações , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Humanos , Malária Vivax/complicações , Malária Vivax/tratamento farmacológico , Malária Vivax/epidemiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Prevalência , Adulto Jovem
5.
PLoS Med ; 17(8): e1003177, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32817632

RESUMO

BACKGROUND: The World Health Organization has yet to endorse deployment of topical repellents for malaria prevention as part of public health campaigns. We aimed to quantify the effectiveness of repellent distributed by the village health volunteer (VHV) network in the Greater Mekong Subregion (GMS) in reducing malaria in order to advance regional malaria elimination. METHODS AND FINDINGS: Between April 2015 and June 2016, a 15-month stepped-wedge cluster randomised trial was conducted in 116 villages in Myanmar (stepped monthly in blocks) to test the effectiveness of 12% N,N-diethylbenzamide w/w cream distributed by VHVs, on Plasmodium spp. infection. The median age of participants was 18 years, approximately half were female, and the majority were either village residents (46%) or forest dwellers (40%). No adverse events were reported during the study. Generalised linear mixed modelling estimated the effect of repellent on infection detected by rapid diagnostic test (RDT) (primary outcome) and polymerase chain reaction (PCR) (secondary outcome). Overall Plasmodium infection detected by RDT was low (0.16%; 50/32,194), but infection detected by PCR was higher (3%; 419/13,157). There was no significant protection against RDT-detectable infection (adjusted odds ratio [AOR] = 0.25, 95% CI 0.004-15.2, p = 0.512). In Plasmodium-species-specific analyses, repellent protected against PCR-detectable P. falciparum (adjusted relative risk ratio [ARRR] = 0.67, 95% CI 0.47-0.95, p = 0.026), but not P. vivax infection (ARRR = 1.41, 95% CI 0.80-2.47, p = 0.233). Repellent effects were similar when delayed effects were modelled, across risk groups, and regardless of village-level and temporal heterogeneity in malaria prevalence. The incremental cost-effectiveness ratio was US$256 per PCR-detectable infection averted. Study limitations were a lower than expected Plasmodium spp. infection rate and potential geographic dilution of the intervention. CONCLUSIONS: In this study, we observed apparent protection against new infections associated with the large-scale distribution of repellent by VHVs. Incorporation of repellent into national strategies, particularly in areas where bed nets are less effective, may contribute to the interruption of malaria transmission. Further studies are warranted across different transmission settings and populations, from the GMS and beyond, to inform WHO public health policy on the deployment of topical repellents for malaria prevention. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry (ACTRN12616001434482).


Assuntos
Serviços de Saúde Comunitária/métodos , Repelentes de Insetos/administração & dosagem , Malária Falciparum/epidemiologia , Malária Falciparum/prevenção & controle , Malária Vivax/epidemiologia , Malária Vivax/prevenção & controle , Voluntários , Administração Tópica , Adolescente , Adulto , Criança , Análise por Conglomerados , Serviços de Saúde Comunitária/economia , Análise Custo-Benefício/métodos , Feminino , Humanos , Repelentes de Insetos/economia , Malária Falciparum/economia , Malária Vivax/economia , Masculino , Mianmar/epidemiologia , Gravidez , Resultado do Tratamento , Adulto Jovem
6.
PLoS Negl Trop Dis ; 14(8): e0008506, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32745103

RESUMO

Plasmodium vivax has become the predominant malaria parasite and a major challenge for malaria elimination in the Greater Mekong Subregion (GMS). Yet, our knowledge about the evolution of P. vivax populations in the GMS is fragmental. We performed whole genome sequencing on 23 P. vivax samples from the China-Myanmar border (CMB) and used 21 high-coverage samples to compare to over 200 samples from the rest of the GMS. Using genome-wide single nucleotide polymorphisms (SNPs), we analyzed population differentiation, genetic structure, migration and potential selection using an array of methods. The CMB parasites displayed a higher proportion of monoclonal infections, and 52% shared over 90% of their genomes in identity-by-descent segments with at least one other sample from the CMB, suggesting preferential expansion of certain parasite strains in this region, likely resulting from the P. vivax outbreaks occurring during this study period. Principal component, admixture, fixation index and phylogenetic analyses all identified that parasites from the CMB were genetically distinct from parasites from eastern parts of the GMS (Cambodia, Laos, Vietnam, and Thailand), whereas the eastern GMS parasite populations were largely undifferentiated. Such a genetic differentiation pattern of the P. vivax populations from the GMS parasite was largely explainable through geographic distance. Using the genome-wide SNPs, we narrowed down to a set of 36 SNPs for differentiating parasites from different areas of the GMS. Genome-wide scans to determine selection in the genome with two statistical methods identified genes potentially under drug selection, including genes associated with antifolate resistance and genes linked to chloroquine resistance in Plasmodium falciparum.


Assuntos
Malária Vivax/epidemiologia , Malária Vivax/parasitologia , Plasmodium vivax/genética , Polimorfismo de Nucleotídeo Único , Antimaláricos/farmacologia , China , Surtos de Doenças , Resistência a Medicamentos/genética , Antagonistas do Ácido Fólico/farmacologia , Genômica , Humanos , Mianmar , Filogenia , Plasmodium vivax/efeitos dos fármacos
7.
Am J Trop Med Hyg ; 103(4): 1540-1548, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32748781

RESUMO

Malaria in Vietnam has become focal to a few provinces, including Phu Yen. This study aimed to assess correlations between intervention (population proportion protected by insecticide-treated nets and indoor residual spraying) and climatic variables with malaria incidence in Phu Yen Province. The Vietnam National Institute of Malariology, Parasitology, and Entomology provided incidence data for Plasmodium falciparum and Plasmodium vivax for 104 communes of Phu Yen Province from January 2005 to December 2016. A multivariable, zero-inflated Poisson regression model was developed with a conditional autoregressive prior structure to identify the underlying spatial structure of the data and quantify associations with covariates. There were a total of 2,778 P. falciparum and 1,770 P. vivax cases during the study period. Plasmodium falciparum and P. vivax incidence increased by 5.4% (95% credible interval [CrI] 5.1%, 5.7%) and 3.2% (95% CrI 2.9%, 3.5%) for a 10-mm increase in precipitation without lag, respectively. Plasmodium falciparum and P. vivax incidence decreased by 7.7% (95% CrI 5.6%, 9.7%) and 10.5% (95% CrI 8.3%, 12.6%) for a 1°C increase in minimum temperature without lag, respectively. There was a > 95% probability of a higher than provincial average trend of P. falciparum and P. vivax in Song Cau and Song Hoa districts. There was a > 95% probability of a lower than provincial average trend in Tuy Dong Xuan and Hoa districts for both species. Targeted distribution of resources, including intensified interventions, in this part of the province will be required for local malaria elimination.


Assuntos
Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Plasmodium falciparum/fisiologia , Plasmodium vivax/fisiologia , Monitoramento Epidemiológico , Geografia , Humanos , Incidência , Malária Falciparum/parasitologia , Malária Vivax/parasitologia , Risco , Análise Espaço-Temporal , Temperatura , Vietnã/epidemiologia
8.
BMC Infect Dis ; 20(1): 573, 2020 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-32758164

RESUMO

BACKGROUND: Malaria during pregnancy leads to serious adverse effects on mothers and the fetus. Approximately 25 million pregnant women in sub-Saharan Africa live at risk of malaria. This study would help to achieve Sustainable Development Goals (SDGs) by improving programs that deal with the prevention of malaria. Therefore, this study aimed to assess the prevalence and associated factors of malaria among pregnant women. METHODS: A community-based cross-sectional study was conducted from July to August 2018 in Sherkole district, West Ethiopia. A multi-stage sampling technique was used to select 504 pregnant women. The interviewer-administered semi-structured questionnaire was used for data collection. Malaria was also diagnosed using a rapid diagnostic test. The data was entered using EPI info version 7.2.2.2 and transferred to SPSS version 20 for analysis. Descriptive statistics were done using frequency and percentages. Both bivariable and multivariable logistic regression models were employed. Variables having p-value < 0.2 were included in the final multivariable model. Variables having p-values < 0.05 from the multivariable model were considered to be significantly associated with the dependent variable. The adjusted odds ratio with its 95% confidence interval (CI) was used as a measure of association. RESULTS: Of the total 498 pregnant women who participated in this study, 51(10.2, 95% CI: 7.72-13.24) were found to have malaria. Of these, 46 (90.2%) and 5 (9.8%) were caused by Plasmodium falciparum and Plasmodium vivax, respectively. Decreasing Age (Adjusted Odds Ratio (AOR) 0.78; 95% CI 0.67-0.911), not using insecticide-treated bed net (ITN) (AOR 12.5; 95% CI 4.86-32.21), lack of consultation and health education about malaria prevention (AOR 7.18; 95% CI 2.74-18.81), being on second-trimester pregnancy (AOR 7.58; 95% CI 2.84-20.2), gravidae II (AOR 5.99; 95% CI 1.68-21.44) were found to be significantly associated with malaria during pregnancy. CONCLUSION: Malaria is still a public health problem among pregnant women in the Sherkole district. Age, ITN use, gravidity, gestational age, and health education had a significant association with malaria. Screening pregnant women for asymptomatic malaria infection and educating and consulting on the appropriate malaria preventive methods shall be provided.


Assuntos
Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Plasmodium falciparum/imunologia , Plasmodium vivax/imunologia , Complicações Parasitárias na Gravidez/epidemiologia , Adolescente , Adulto , Antígenos de Protozoários/sangue , Infecções Assintomáticas , Estudos Transversais , Testes Diagnósticos de Rotina/métodos , Etiópia/epidemiologia , Feminino , Seguimentos , Humanos , Mosquiteiros Tratados com Inseticida , Modelos Logísticos , Malária Falciparum/prevenção & controle , Malária Vivax/prevenção & controle , Razão de Chances , Gravidez , Complicações Parasitárias na Gravidez/prevenção & controle , Prevalência , Fatores de Risco , Inquéritos e Questionários , Adulto Jovem
9.
PLoS Negl Trop Dis ; 14(7): e0008471, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32639964

RESUMO

In Brazil, Plasmodium vivax infection accounts for around 80% of malaria cases. This infection has a substantial impact on the productivity of the local population as the course of the disease is usually prolonged and the development of acquired immunity in endemic areas takes several years. The recent emergence of drug-resistant strains has intensified research on alternative control methods such as vaccines. There is currently no effective available vaccine against malaria; however, numerous candidates have been studied in the past several years. One of the leading candidates is apical membrane antigen 1 (AMA1). This protein is involved in the invasion of Apicomplexa parasites into host cells, participating in the formation of a moving junction. Understanding how the genetic diversity of an antigen influences the immune response is highly important for vaccine development. In this study, we analyzed the diversity of AMA1 from Brazilian P. vivax isolates and 19 haplotypes of P. vivax were found. Among those sequences, 33 nonsynonymous PvAMA1 amino acid sites were identified, whereas 20 of these sites were determined to be located in predicted B-cell epitopes. Nonsynonymous mutations were evaluated for their influence on the immune recognition of these antigens. Two distinct haplotypes, 5 and 16, were expressed and evaluated for reactivity in individuals from northern Brazil. Both PvAMA1 variants were reactive. Moreover, the IgG antibody response to these two PvAMA1 variants was analyzed in an exposed but noninfected population from a P. vivax endemic area. Interestingly, over 40% of this population had antibodies recognizing both variants. These results have implications for the design of a vaccine based on a polymorphic antigen.


Assuntos
Antígenos de Protozoários/genética , Malária Vivax/imunologia , Malária Vivax/parasitologia , Proteínas de Membrana/genética , Plasmodium vivax/genética , Proteínas de Protozoários/genética , Dicroísmo Circular , DNA de Protozoário/genética , Epitopos de Linfócito B , Haplótipos , Humanos , Malária Vivax/epidemiologia , Mutação , Plasmodium vivax/imunologia , Conformação Proteica , Proteínas Recombinantes
10.
Am J Trop Med Hyg ; 103(3): 1107-1110, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32618263

RESUMO

Asymptomatic and/or low-density malaria infection has been acknowledged as an obstacle to achieving a malaria-free country. This study aimed to determine the prevalence of asymptomatic and/or low-density malaria infection in previously reported malarious localities using nested PCR in four states, namely, Johor, Pahang, Kelantan, and Selangor, between June 2019 and January 2020. Blood samples (n = 585) were collected and were extracted using a QIAamp blood kit. The DNA was concentrated and subjected to nested PCR. Thin and thick blood smears were examined as well. Of the 585 samples collected, 19 were positive: 10 for Plasmodium knowlesi, eight for Plasmodium vivax, and one for Plasmodium ovale. Asymptomatic and/or low-density malaria infection is a threat to malaria elimination initiatives. Eliminating countries should develop guidance policy on the importance of low-density malaria infection which includes detection and treatment policy.


Assuntos
Infecções Assintomáticas/epidemiologia , Malária Vivax/epidemiologia , Malária/epidemiologia , Plasmodium/isolamento & purificação , Adolescente , Adulto , Feminino , Humanos , Malária/parasitologia , Malária Vivax/parasitologia , Malásia/epidemiologia , Masculino , Pessoa de Meia-Idade , Plasmodium/genética , Plasmodium knowlesi/genética , Plasmodium knowlesi/isolamento & purificação , Plasmodium ovale/genética , Plasmodium ovale/isolamento & purificação , Plasmodium vivax/genética , Plasmodium vivax/isolamento & purificação , Reação em Cadeia da Polimerase , Prevalência , Adulto Jovem
11.
Infect Dis Poverty ; 9(1): 95, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32678025

RESUMO

BACKGROUND: Disease surveillance systems are essential for effective disease intervention and control by monitoring disease prevalence as time series. To evaluate the severity of an epidemic, statistical methods are widely used to forecast the trend, seasonality, and the possible number of infections of a disease. However, most statistical methods are limited in revealing the underlying dynamics of disease transmission, which may be affected by various impact factors, such as environmental, meteorological, and physiological factors. In this study, we focus on investigating malaria transmission dynamics based on time series data. METHODS: A data-driven nonlinear stochastic model is proposed to infer and predict the dynamics of malaria transmission based on the time series of prevalence data. Specifically, the dynamics of malaria transmission is modeled based on the notion of vectorial capacity (VCAP) and entomological inoculation rate (EIR). A particle Markov chain Monte Carlo (PMCMC) method is employed to estimate the model parameters. Accordingly, a one-step-ahead prediction method is proposed to project the number of future malaria infections. Finally, two case studies are carried out on the inference and prediction of Plasmodium vivax transmission in Tengchong and Longling, Yunnan province, China. RESULTS: The results show that the trained data-driven stochastic model can well fit the historical time series of P. vivax prevalence data in both counties from 2007 to 2010. Moreover, with well-trained model parameters, the proposed one-step-ahead prediction method can achieve better performances than that of the seasonal autoregressive integrated moving average model with respect to predicting the number of future malaria infections. CONCLUSIONS: By involving dynamically changing impact factors, the proposed data-driven model together with the PMCMC method can successfully (i) depict the dynamics of malaria transmission, and (ii) achieve accurate one-step-ahead prediction about malaria infections. Such a data-driven method has the potential to investigate malaria transmission dynamics in other malaria-endemic countries/regions.


Assuntos
Malária Vivax/transmissão , Plasmodium vivax/fisiologia , China/epidemiologia , Humanos , Malária Vivax/epidemiologia , Modelos Teóricos , Estações do Ano
12.
PLoS One ; 15(6): e0235119, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32574179

RESUMO

BACKGROUND: Colombia has officially adopted the parasite density levels of severe malaria established by the WHO (>50,000 parasites/µl). These values have been inferred from areas of high transmission in Africa and are not consistent with the dynamics of low and unstable transmission in Colombia. The objective of this study was therefore to determine the parasite density values observed in patients with severe malaria and their distribution in the different ecoepidemiological regions of Colombia. METHODS: A retrospective and descriptive study of confirmed cases of severe malaria was conducted in endemic areas of malaria in Colombia over the period 2014-2017. Data were collected from secondary sources of the Subnational Programs of Malaria Prevention and Control. Person, place, and time variables were selected. The official definition of severe malaria was adopted, and compliance with these criteria was determined. Univariate and bivariate analyses were conducted with absolute and relative frequency measures, and the relevant statistical tests were applied. RESULTS: The overall parasite density values in Colombia showed a geometric mean of 5,919 parasites/µl (95% CI: 5,608-6,248). By parasite species, the values were 6,151 (95% CI: 5,631-6,718) for Plasmodium falciparum and 5,815 (95% CI: 5,428-6,230) for Plasmodium vivax. The highest parasite density values were recorded in the Amazon ecoepidemiological region (8,177; 95% CI: 6,015-11,116), and the lowest values were recorded in the Andean region (5,026; 95% CI: 2,409-10,480). CONCLUSIONS: In endemic areas of low and unstable malaria transmission in the Colombian territory, the parasite density levels observed in populations with severe malaria are lower than the officially established values. The parasite density criterion is not really a relevant criterion for the definition of severe cases in Colombia and it certainly not be used to make a clinical decision about the severity of the disease.


Assuntos
Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium vivax/crescimento & desenvolvimento , Densidade Demográfica , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Colômbia/epidemiologia , Doenças Endêmicas/prevenção & controle , Feminino , Geografia , Humanos , Lactente , Malária Falciparum/parasitologia , Malária Falciparum/transmissão , Malária Vivax/parasitologia , Malária Vivax/transmissão , Masculino , Pessoa de Meia-Idade , Plasmodium falciparum/fisiologia , Plasmodium vivax/fisiologia , Prevalência , Estudos Retrospectivos , Índice de Gravidade de Doença , Adulto Jovem
14.
BMC Infect Dis ; 20(1): 363, 2020 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-32448216

RESUMO

BACKGROUND: Plasmodium vivax rarely develops severe complications when compared to severe falciparum malaria. However, severe vivax malaria also needs urgent, intensive care and treatment as severe falciparum malaria. This systematic review aimed to explore pooled prevalence of severe vivax malaria and to identify factors related to poor outcome of patients who developed severe manifestation. METHODS: The systematic review conducted by two reviewers independently through searching of research publications related to severe P. vivax malaria in three databases including MEDLINE, Web of Science (ISI), and Scopus until October, 22 2019. The pooled prevalence of severe vivax malaria was achieved using STATA and RevMan 5 Software. Factors related to poor outcome of patients with severe vivax malaria were analyzed using SPSS 11.5 Software. RESULTS: Among 2615 research publications retrieved from three databases, 49 articles reporting on 42,325 severity cases were selected for calculating pooled prevalence. Seventy-six patients from case reports, case series, letter to editors, and research communications were collected to identify factors related to poor outcome of patients with severe vivax malaria. The results showed that severe anemia, jaundice, respiratory distress, impaired consciousness, and renal failure were the most common major manifestations of severe malaria guided by the World Health Organization (WHO) criterion. The meta-analysis indicated that severe malaria was less frequent in patient with P. vivax compared to those with P. falciparum (P -value < 0.00001, OR = 0.38, 95% CI = 0.25-0.56, I2 = 87%). In addition, thrombocytopenia, anemia, hepatitis, and severe thrombocytopenia were the most common minor complications. Analysis of cases indicated that convulsion, respiratory distress, renal failure, jaundice, anuria/oliguria, and complication during treatment impacted on longer hospital stays compared to other severe complications (P-value < 0.05). Respiratory distress was frequently found after first treatment with anti-malarial drugs (P-value = 0.002). Renal failure was frequently found before treatment with anti-malarial drugs (P-value = 0.016). Mean days of fever and higher pulse rates at presentation were predictors of poor outcome among patients with severe vivax malaria (P-value < 0.05). CONCLUSIONS: Severe anemia was the most common major manifestation of P. vivax malaria guided by the WHO criterion. Severe anemia was found less frequently in patients with P. vivax than those with P. falciparum. Renal failure, jaundice, anuria/oliguria, and complication during treatment along with, mean days of fever and higher pulse rates at presentation might be predictors of poor outcome of patients with severe vivax malaria.


Assuntos
Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Plasmodium falciparum , Plasmodium vivax , Índice de Gravidade de Doença , Adulto , Anemia/etiologia , Antimaláricos/uso terapêutico , Anuria/etiologia , Feminino , Febre , Frequência Cardíaca , Humanos , Icterícia/etiologia , Malária Falciparum/complicações , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Malária Vivax/complicações , Malária Vivax/tratamento farmacológico , Malária Vivax/parasitologia , Masculino , Oligúria/etiologia , Prevalência , Insuficiência Renal/etiologia , Fatores de Risco , Trombocitopenia/etiologia , Resultado do Tratamento , Organização Mundial da Saúde , Adulto Jovem
15.
BMC Infect Dis ; 20(1): 373, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-32456698

RESUMO

BACKGROUND: In 2017, inhabitants along the border between French Guiana and Brazil were affected by a malaria outbreak primarily due to Plasmodium vivax (Pv). While malaria cases have steadily declined between 2005 and 2016 in this Amazonian region, a resurgence was observed in 2017. METHODS: Two investigations were performed according to different spatial scales and information details: (1) a local study on the French Guiana border, which enabled a thorough investigation of malaria cases treated at a local village health center and the entomological circumstances in the most affected neighborhood, and (2) a regional and cross-border study, which enabled exploration of the regional spatiotemporal epidemic dynamic. Number and location of malaria cases were estimated using French and Brazilian surveillance systems. RESULTS: On the French Guianese side of the border in Saint-Georges de l'Oyapock, the attack rate was 5.5% (n = 4000), reaching 51.4% (n = 175) in one Indigenous neighborhood. Entomological findings suggest a peak of Anopheles darlingi density in August and September. Two female An. darlingi (n = 1104, 0.18%) were found to be Pv-positive during this peak. During the same period, aggregated data from passive surveillance conducted by Brazilian and French Guianese border health centers identified 1566 cases of Pv infection. Temporal distribution during the 2007-2018 period displayed seasonal patterns with a peak in November 2017. Four clusters were identified among epidemic profiles of cross-border area localities. All localities of the first two clusters were Brazilian. The localization of the first cluster suggests an onset of the outbreak in an Indigenous reservation, subsequently expanding to French Indigenous neighborhoods and non-Native communities. CONCLUSIONS: The current findings demonstrate a potential increase in malaria cases in an area with otherwise declining numbers. This is a transborder region where human mobility and remote populations challenge malaria control programs. This investigation illustrates the importance of international border surveillance and collaboration for malaria control, particularly in Indigenous villages and mobile populations.


Assuntos
Anopheles , Malária/epidemiologia , Adolescente , Animais , Brasil/epidemiologia , Surtos de Doenças , Feminino , Guiana Francesa/epidemiologia , Humanos , Incidência , Malária Vivax/epidemiologia , Masculino , Mosquitos Vetores , Plasmodium vivax , Características de Residência , Estações do Ano , Análise Espaço-Temporal , Adulto Jovem
16.
PLoS Negl Trop Dis ; 14(5): e0008295, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32379762

RESUMO

Genetic epidemiology can provide important insights into parasite transmission that can inform public health interventions. The current study compared long-term changes in the genetic diversity and structure of co-endemic Plasmodium falciparum and P. vivax populations. The study was conducted in Papua Indonesia, where high-grade chloroquine resistance in P. falciparum and P. vivax led to a universal policy of Artemisinin-based Combination Therapy (ACT) in 2006. Microsatellite typing and population genetic analyses were undertaken on available isolates collected between 2004 and 2017 from patients with uncomplicated malaria (n = 666 P. falciparum and n = 615 P. vivax). The proportion of polyclonal P. falciparum infections fell from 28% (38/135) before policy change (2004-2006) to 18% (22/125) at the end of the study (2015-2017); p<0.001. Over the same period, polyclonal P. vivax infections fell from 67% (80/119) to 35% (33/93); p<0.001. P. falciparum strains persisted for up to 9 years compared to 3 months for P. vivax, reflecting higher rates of outbreeding in the latter. Sub-structure was observed in the P. falciparum population, but not in P. vivax, confirming different patterns of outbreeding. The P. falciparum population exhibited 4 subpopulations that changed in frequency over time. Notably, a sharp rise was observed in the frequency of a minor subpopulation (K2) in the late post-ACT period, accounting for 100% of infections in late 2016-2017. The results confirm epidemiological evidence of reduced P. falciparum and P. vivax transmission over time. The smaller change in P. vivax population structure is consistent with greater outbreeding associated with relapsing infections and highlights the need for radical cure to reduce recurrent infections. The study emphasizes the challenge in disrupting P. vivax transmission and demonstrates the potential of molecular data to inform on the impact of public health interventions.


Assuntos
Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Monitoramento Epidemiológico , Lactonas/uso terapêutico , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Malária Vivax/tratamento farmacológico , Malária Vivax/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Quimioterapia Combinada/métodos , Feminino , Variação Genética , Técnicas de Genotipagem , Humanos , Indonésia , Masculino , Repetições de Microssatélites , Pessoa de Meia-Idade , Epidemiologia Molecular , Plasmodium falciparum/classificação , Plasmodium falciparum/genética , Plasmodium falciparum/isolamento & purificação , Plasmodium vivax/classificação , Plasmodium vivax/genética , Plasmodium vivax/isolamento & purificação , Adulto Jovem
17.
Nat Med ; 26(5): 741-749, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32405064

RESUMO

A major gap in the Plasmodium vivax elimination toolkit is the identification of individuals carrying clinically silent and undetectable liver-stage parasites, called hypnozoites. This study developed a panel of serological exposure markers capable of classifying individuals with recent P. vivax infections who have a high likelihood of harboring hypnozoites. We measured IgG antibody responses to 342 P. vivax proteins in longitudinal clinical cohorts conducted in Thailand and Brazil and identified candidate serological markers of exposure. Candidate markers were validated using samples from year-long observational cohorts conducted in Thailand, Brazil and the Solomon Islands and antibody responses to eight P. vivax proteins classified P. vivax infections in the previous 9 months with 80% sensitivity and specificity. Mathematical models demonstrate that a serological testing and treatment strategy could reduce P. vivax prevalence by 59-69%. These eight antibody responses can serve as a biomarker, identifying individuals who should be targeted with anti-hypnozoite therapy.


Assuntos
Biomarcadores/sangue , Malária Vivax/diagnóstico , Testes Sorológicos/métodos , Adulto , Brasil/epidemiologia , Criança , Estudos de Coortes , Diagnóstico Precoce , Humanos , Imunoglobulina G/análise , Imunoglobulina G/sangue , Controle de Infecções/métodos , Estudos Longitudinais , Malária Vivax/sangue , Malária Vivax/epidemiologia , Melanesia/epidemiologia , Plasmodium vivax/fisiologia , Prevalência , Sensibilidade e Especificidade , Testes Sorológicos/normas , Tailândia/epidemiologia , Fatores de Tempo
18.
Trends Parasitol ; 36(6): 560-570, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32407682

RESUMO

Plasmodium vivax is an important cause of malaria, associated with a significant public health burden. Whilst enhanced malaria-control activities have successfully reduced the incidence of Plasmodium falciparum malaria in many areas, there has been a consistent increase in the proportion of malaria due to P. vivax in regions where both parasites coexist. This article reviews the epidemiology and biology of P. vivax, how the parasite differs from P. falciparum, and the key features that render it more difficult to control and eliminate. Since transmission of the parasite is driven largely by relapses from dormant liver stages, its timely elimination will require widespread access to safe and effective radical cure.


Assuntos
Malária Vivax/epidemiologia , Animais , Antimaláricos/uso terapêutico , Erradicação de Doenças , Humanos , Incidência , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Malária Vivax/tratamento farmacológico , Malária Vivax/parasitologia , Malária Vivax/prevenção & controle , Plasmodium falciparum/fisiologia , Plasmodium vivax/fisiologia
19.
Lancet Infect Dis ; 20(8): 953-963, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32277908

RESUMO

BACKGROUND: Passively collected malaria case data are the foundation for public health decision making. However, because of population-level immunity, infections might not always be sufficiently symptomatic to prompt individuals to seek care. Understanding the proportion of all Plasmodium spp infections expected to be detected by the health system becomes particularly paramount in elimination settings. The aim of this study was to determine the association between the proportion of infections detected and transmission intensity for Plasmodium falciparum and Plasmodium vivax in several global endemic settings. METHODS: The proportion of infections detected in routine malaria data, P(Detect), was derived from paired household cross-sectional survey and routinely collected malaria data within health facilities. P(Detect) was estimated using a Bayesian model in 431 clusters spanning the Americas, Africa, and Asia. The association between P(Detect) and malaria prevalence was assessed using log-linear regression models. Changes in P(Detect) over time were evaluated using data from 13 timepoints over 2 years from The Gambia. FINDINGS: The median estimated P(Detect) across all clusters was 12·5% (IQR 5·3-25·0) for P falciparum and 10·1% (5·0-18·3) for P vivax and decreased as the estimated log-PCR community prevalence increased (adjusted odds ratio [OR] for P falciparum 0·63, 95% CI 0·57-0·69; adjusted OR for P vivax 0·52, 0·47-0·57). Factors associated with increasing P(Detect) included smaller catchment population size, high transmission season, improved care-seeking behaviour by infected individuals, and recent increases (within the previous year) in transmission intensity. INTERPRETATION: The proportion of all infections detected within health systems increases once transmission intensity is sufficiently low. The likely explanation for P falciparum is that reduced exposure to infection leads to lower levels of protective immunity in the population, increasing the likelihood that infected individuals will become symptomatic and seek care. These factors might also be true for P vivax but a better understanding of the transmission biology is needed to attribute likely reasons for the observed trend. In low transmission and pre-elimination settings, enhancing access to care and improvements in care-seeking behaviour of infected individuals will lead to an increased proportion of infections detected in the community and might contribute to accelerating the interruption of transmission. FUNDING: Wellcome Trust.


Assuntos
Infecções Assintomáticas/epidemiologia , Reservatórios de Doenças/estatística & dados numéricos , Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Adolescente , Adulto , África/epidemiologia , Idoso , Idoso de 80 Anos ou mais , América/epidemiologia , Ásia/epidemiologia , Teorema de Bayes , Criança , Pré-Escolar , Análise por Conglomerados , Estudos Transversais , Reservatórios de Doenças/parasitologia , Feminino , Instalações de Saúde/estatística & dados numéricos , Humanos , Lactente , Estudos Longitudinais , Malária Falciparum/transmissão , Malária Vivax/transmissão , Masculino , Pessoa de Meia-Idade , Prevalência , Vigilância em Saúde Pública/métodos , Estações do Ano , Adulto Jovem
20.
Malar J ; 19(1): 156, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32299426

RESUMO

BACKGROUND: India has launched the malaria elimination initiative in February 2016. Studies suggest that estimates of malaria are useful to rationalize interventions and track their impact. Hence, a national study was launched to estimate burden of malaria in India in 2015. METHODS: For sampling, all 624 districts of India were grouped in three Annual Parasite Incidence (cases per thousand population) categories, < two (low); two-five (moderate) and > five (high) API. Using probability proportional to size (PPS) method, two districts from each stratum were selected covering randomly 200,000 persons per district. Active surveillance was strengthened with 40 trained workers per study district. Data on malaria cases and deaths was collated from all health care providers i.e. pathological laboratories, private practitioners and hospitals in private and public health sectors and was used for analysis and burden estimation. RESULTS: Out of 1215,114 population under surveillance, 198,612 (16.3%) tests were performed and 19,386 (9.7%) malaria cases were detected. The malaria cases estimated in India were 3875,078 (95% confidence interval 3792,018-3958,137) with API of 3.05 (2.99-3.12) including 2789,483 (2740,577-2838,389) Plasmodium falciparum with Annual Falciparum Incidence of 2.2 (2.16-2.24). Out of 8025 deaths investigated, 102 (1.27%) were attributed to malaria. The estimated deaths in India were 29,341 (23,354-35,327) including 19,067 (13,665-24,470) confirmed and 10,274 (7694-12,853) suspected deaths in 2015-2016. CONCLUSIONS: Estimated malaria incidence was about four folds greater than one million reported by the national programme, but three folds lesser than thirteen million estimated by the World Health Organization (WHO). However, the estimated deaths were 93 folds more than average 313 deaths reported by the national malaria programme in 2015-2016. The 29,341 deaths were comparable with 24,000 deaths in 2015 and 22,786 deaths in 2016 estimated by the WHO for India. These malaria estimates can serve as a benchmark for tracking the success of malaria elimination campaign in India.


Assuntos
Monitoramento Epidemiológico , Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Plasmodium falciparum/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Vigilância da População , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Índia/epidemiologia , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Prevalência , Adulto Jovem
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