Your browser doesn't support javascript.

Portal Regional da BVS

Informação e Conhecimento para a Saúde

Home > Pesquisa > (ti:malaria or mj:c03.752.530$ or "plasmodium falciparum" or antimalari$ or ti:paludismo o... (1.500)
Detalhe da pesquisa
Imprimir Exportar

Formato de exportação:

Exportar

Exportar:

Email
Adicionar mais destinatários

Enviar resultado
|
Resultados 1 - 20 de 1.500
1.

Vector competence, vectorial capacity of Nyssorhynchus darlingi and the basic reproduction number of Plasmodium vivax in agricultural settlements in the Amazonian Region of Brazil.

Malar J; 18(1): 117, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30947726

RESUMO

BACKGROUND: Brazilian malaria control programmes successfully reduced the incidence and mortality rates from 2005 to 2016. Since 2017, increased malaria has been reported across the Amazon. Few field studies focus on the primary malaria vector in high to moderate endemic areas, Nyssorhynchus darlingi, as the key entomological component of malaria risk, and on the metrics of Plasmodium vivax propagation in Amazonian rural communities. METHODS: Human landing catch collections were carried out in 36 houses of 26 communities in five municipalities in the Brazilian states of Acre, Amazonas and Rondônia states, with API (> 30). In addition, data on the number of locally acquired symptomatic infections were employed in mathematical modelling analyses carried out to determine Ny. darlingi vector competence and vectorial capacity to P. vivax; and to calculate the basic reproduction number for P. vivax. RESULTS: Entomological indices and malaria metrics ranged among localities: prevalence of P. vivax infection in Ny. darlingi, from 0.243% in Mâncio Lima, Acre to 3.96% in Machadinho D'Oeste, Rondônia; daily human-biting rate per person from 23 ± 1.18 in Cruzeiro do Sul, Acre, to 66 ± 2.41 in Lábrea, Amazonas; vector competence from 0.00456 in São Gabriel da Cachoeira, Amazonas to 0.04764 in Mâncio Lima, Acre; vectorial capacity from 0.0836 in Mâncio Lima, to 1.5 in Machadinho D'Oeste. The estimated R for P. vivax (PvR ) was 3.3 in Mâncio Lima, 7.0 in Lábrea, 16.8 in Cruzeiro do Sul, 55.5 in São Gabriel da Cachoeira, and 58.7 in Machadinho D'Oeste. Correlation between P. vivax prevalence in Ny. darlingi and vector competence was non-linear whereas association between prevalence of P. vivax in mosquitoes, vectorial capacity and R was linear and positive. CONCLUSIONS: In spite of low vector competence of Ny. darlingi to P. vivax, parasite propagation in the human population is enhanced by the high human-biting rate, and relatively high vectorial capacity. The high PvR values suggest hyperendemicity in Machadinho D'Oeste and São Gabriel da Cachoeira at levels similar to those found for P. falciparum in sub-Saharan Africa regions. Mass screening for parasite reservoirs, effective anti-malarial drugs and vector control interventions will be necessary to shrinking transmission in Amazonian rural communities, Brazil.
2.

Avian host composition, local speciation, and dispersal drive the regional assembly of avian malaria parasites in South American birds.

Mol Ecol; 2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30959568

RESUMO

Identifying the ecological factors that shape parasite distributions remains a central goal in disease ecology. These factors include dispersal capability, environmental filters, and geographic distance. Using 520 haemosporidian parasite genetic lineages recovered from 7,534 birds sampled across tropical and temperate South America we tested 1) the latitudinal diversity gradient hypothesis and 2) the distance-decay relationship (decreasing proportion of shared species between communities with increasing geographic distance) for this host-parasite system. We then inferred the biogeographic processes influencing the diversity and distributions of this cosmopolitan group of parasites across South America. We found support for a latitudinal gradient in diversity for avian haemosporidian parasites, potentially mediated through higher avian host diversity towards the equator. Parasite similarity was correlated with climate similarity, geographic distance, and host composition. Local diversification in Amazonian lineages followed by dispersal were the most frequent biogeographic events reconstructed for haemosporidian parasites. Combining macroecological patterns and biogeographic processes, our study reveals that haemosporidian parasites are capable of circumventing geographic barriers and dispersing across biomes, although constrained by environmental filtering. The contemporary diversity and distributions of haemosporidian parasites are mainly driven by historical (speciation) and ecological (dispersal) processes, whereas the parasite community assembly is largely governed by host composition and to a lesser extent by environmental conditions. This article is protected by copyright. All rights reserved.
3.

Correction to: Use and retention of long-lasting insecticidal nets (LLINs) in a malaria risk area in the Brazilian Amazon: a 5-year follow-up intervention.

Malar J; 18(1): 125, 2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30967138

RESUMO

Following publication of the original article [1], the corresponding author flagged that the particle 'de' in their name had been placed incorrectly.
4.

A comprehensive analysis of malaria transmission in Brazil.

Pathog Glob Health; 113(1): 1-13, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30829565

RESUMO

Malaria remains a serious public health problem in Brazil despite a significant drop in the number of cases in the past decade. We conduct a comprehensive analysis of malaria transmission in Brazil to highlight the epidemiologically most relevant components that could help tackle the disease. We consider factors impacting on the malaria burden and transmission dynamics including the geographical occurrence of both autochthonous and imported infections, the distribution and abundance of malaria vectors and records of natural mosquito infections with Plasmodium. Our analysis identifies three discrete malaria transmission systems related to the Amazon rainforest, Atlantic rainforest and Brazilian coast, respectively. The Amazonian system accounts for 99% of all malaria cases in the country. It is largely due to autochthonous P. vivax and P. falciparum transmission by mosquitoes of the Nyssorhynchus subgenus, primarily Anopheles darlingi. Whilst P. vivax transmission is widespread, P. falciparum transmission is restricted to hotspot areas mostly in the States of Amazonas and Acre. This system is the major source of P. vivax exportation to the extra-Amazonian regions that are also affected by importation of P. falciparum from Africa. The Atlantic system comprises autochthonous P. vivax transmission typically by the bromeliad-associated mosquitoes An. cruzii and An. bellator of the Kerteszia subgenus. An. cruzii also transmits simian malaria parasites to humans. The third, widespread but geographically fragmented, system is found along the Brazilian coast and comprises P. vivax transmission mainly by An. aquasalis. We conclude that these geographically and biologically distinct malaria transmission systems require specific strategies for effective disease control.
5.

Investigation of a possible malaria epidemic in an illegal gold mine in French Guiana: an original approach in the remote Amazonian forest.

Malar J; 18(1): 91, 2019 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-30902054

RESUMO

BACKGROUND: In April 2017, Suriname's Ministry of Health alerted French Guiana's Regional Health Agency (RHA) about an increase of imported malaria cases among people coming from an illegal gold mining site called Sophie, in French Guiana, a French overseas territory located in the Amazonian forest. METHODS: Due to safety issues and the remoteness of Sophie, the RHA requested the collaboration of the French Armed Forces for the epidemiological investigation. A medical unit, and six soldiers to ensure the security of the mission, were transported by helicopter. RESULTS: During the investigation, two malaria episodes were diagnosed among 46 persons. Twenty-six of them were from Sophie, where PCR-Plasmodium prevalence was estimated at 60% (15/26). This result was concordant with previous studies revealing high malaria endemicity in the gold miner population. The increase of imported cases in Suriname may have resulted from decreased access to under-the-counter anti-malarials and increased migration of gold miners to Suriname following a decline of the profitability of gold mining in a context of increased repression against illegal mining by the French army. CONCLUSION: This investigation of a suspicious malaria epidemic confirms the importance of malaria among illegal gold miners. Their mobility along the Guiana Shield and their health-seeking behaviour are likely to spread malaria in populations for which significant efforts are undertaken to fight against this disease. Fighting malaria in this population remains more relevant than ever. A pilot study (Malakit project) is currently in progress to evaluate the efficacy of kits for self-diagnosis and self-treatment.
6.

Regional variation in life history traits and plastic responses to temperature of the major malaria vector Nyssorhynchus darlingi in Brazil.

Sci Rep; 9(1): 5356, 2019 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-30926833

RESUMO

The primary Brazilian malaria vector, Nyssorhynchus darlingi (formerly Anopheles darlingi), ranges from 0°S-23°S across three biomes (Amazonia, Cerrado, Mata Atlântica). Rising temperatures will increase mosquito developmental rates, and models predict future malaria transmission by Ny. darlingi in Brazil will shift southward. We reared F Ny. darlingi (progeny of field-collected females from 4 state populations across Brazil) at three temperatures (20, 24, 28 °C) and measured key life-history traits. Our results reveal geographic variation due to both genetic differences among localities and plastic responses to temperature differences. Temperature significantly altered all traits: faster larval development, shorter adult life and overall lifespan, and smaller body sizes were seen at 28 °C versus 20 °C. Low-latitude Amazonia mosquitoes had the fastest larval development at all temperatures, but at 28 °C, average development rate of high-latitude Mata Atlântica mosquitoes was accelerated and equivalent to low-latitude Amazonia. Body size of adult mosquitoes from the Mata Atlântica remained larger at all temperatures. We detected genetic variation in the plastic responses among mosquitoes from different localities, with implications for malaria transmission under climate change. Faster development combined with larger body size, without a tradeoff in adult longevity, suggests vectorial capacities of some Mata Atlântica populations may significantly increase under warming climates.
7.

Use and retention of long-lasting insecticidal nets (LLINs) in a malaria risk area in the Brazilian Amazon: a 5-year follow-up intervention.

Malar J; 18(1): 100, 2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30909924

RESUMO

BACKGROUND: Long-lasting insecticidal nets (LLINs) are one of the main vector control strategies recommended by the World Health Organization for the control and elimination of malaria. This study aimed to evaluate the use and retention of LLINs during the 5 years of implementing an integrated control strategy in a malaria-endemic area in the Brazilian Amazon. METHODS: This intervention study was conducted in localities of the municipality of Barcelos, Amazonas, from 2008 to 2014. Four rural localities situated along the Padauiri River were the object of this study. Two localities (Bacabal-rio Aracá and the São Sebastião district) were used as controls. LLINs were distributed to all residents of the Padauiri River; assessments were made regarding their use and retention via a semistructured questionnaire, a household register, and direct observation during 5 years. RESULTS: Overall, 208 individuals participated in the study. In the baseline pilot study (2008), 9.9% of the subjects in the intervention group had slept with mosquito nets the previous night compared with 37.8% of the subjects in the control group. In 2010, this percentage was 43.2% in the intervention group and 50.9% in the control group. Therefore, 1 year after the implementation of the strategy, although there was an increase in the use of mosquito nets in both groups, this increase was significantly higher in the intervention group. This increase in LLINs use did not persist after 5 years of intervention. The households' evaluation in 2014 showed that 80% of the houses in the intervention group owned at least one LLIN compared with 66% in the control group (p = 0.11); 76% of households in the intervention group owned sufficient LLINs for all family members compared with 50% in the control group (p = 0.007). CONCLUSIONS: High ownership and retention of the LLINs was observed in the intervention group. At 1 year after the distribution of these LLINs, there was a significant increase in their use that was not maintained over the long term. Control strategies must be permanent; however, exploring new strategies is necessary to ensure that the knowledge acquired further modifies the attitudes and behaviours.
8.

Behavior and abundance of Anopheles darlingi in communities living in the Colombian Amazon riverside.

PLoS One; 14(3): e0213335, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30845198

RESUMO

In the past few years, relative frequencies of malaria parasite species in communities living in the Colombian Amazon riverside have changed, being Plasmodium vivax (61.4%) and Plasmodium malariae (43.8%) the most frequent. Given this epidemiological scenario, it is important to determine the species of anophelines involved in these parasites' transmission. This study was carried out in June 2016 in two indigenous communities living close to the tributaries of the Amazon River using protected human bait. The results of this study showed a total abundance of 1,085 mosquitos, of which 99.2% corresponded to Anopheles darlingi. Additionally, only two anopheline species were found, showing low diversity in the study areas. Molecular confirmation of some individuals was then followed by evolutionary analysis by using the COI gene. Nested PCR was used for identifying the three Plasmodium species circulating in the study areas. Of the two species collected in this study, 21.0% of the An. darlingi mosquitoes were infected with P. malariae, 21.9% with P. vivax and 10.3% with Plasmodium falciparum. It exhibited exophilic and exophagic behavior in both study areas, having marked differences regarding its abundance in each community (Tipisca first sampling 49.4%, Tipisca second sampling 39.6% and Doce de Octubre 10.9%). Interestingly, An. mattogrossensis infected by P. vivax was found for the first time in Colombia (in 50% of the four females collected). Analysis of An. darlingi COI gene diversity indicated a single population maintaining a high gene flow between the study areas. The An. darlingi behavior pattern found in both communities represents a risk factor for the region's inhabitants living/working near these sites. This highlights the need for vector control efforts such as the use of personal repellents and insecticides for use on cattle, which must be made available in order to reduce this Anopheline's abundance.
9.

Monitoring the Efficacy of Chloroquine-Primaquine Therapy for Uncomplicated Malaria in the Main Transmission Hotspot of Brazil.

Artigo em Inglês | MEDLINE | ID: mdl-30782991

RESUMO

Emerging resistance to chloroquine (CQ) may undermine malaria elimination efforts in South America. CQ-resistant has been found in the major port city of Manaus, but not in the main malaria hotspots across the Amazon Basin of Brazil, where CQ is routinely co-administered with primaquine (PQ) for radical cure of vivax malaria. Here we randomly assigned 204 uncomplicated vivax malaria patients from Juruá Valley, northwestern Brazil, to receive either sequential (Arm 1) or concomitant (Arm 2) CQ-PQ treatment. Because PQ may synergize the blood schizontocidal effect of CQ and mask low-level CQ resistance, we monitored CQ-only efficacy in Arm 1 subjects, who had PQ administered only at the end of the 28-day follow up. We found adequate clinical and parasitological responses in all subjects assigned to Arm 2. However, 2.2% of Arm 1 patients had microscopy-detected parasite recrudescences at day 28. When PCR-detected parasitemias at day 28 were considered, response rates decreased to 92.1% and 98.8% in Arms 1 and 2, respectively. Therapeutic CQ levels were documented in 6 of 8 recurrences, consistent with true CQ resistance In contrast, assays provided no evidence of CQ resistance in 49 local isolates analyzed. CQ-PQ co-administration was not found to potentiate the antirelapse efficacy of PQ over 180 days of surveillance; however, we suggest that larger studies are needed to examine whether and how CQ-PQ interactions, e.g. CQ-mediated inhibition of PQ metabolism, modulate radical cure efficacy in different -infected populations.
10.

Lack of quadruple and quintuple mutant alleles associated with sulfadoxine-pyrimethamine resistance in Plasmodium vivax isolates from Brazilian endemic areas.

Mem Inst Oswaldo Cruz; 114: e180425, 2019 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-30726345

RESUMO

BACKGROUND AND OBJECTIVE: Brazil is responsible for a large number of Plasmodium vivax cases in America. Given the emergence of P. vivax parasites resistant to chloroquine and the effectiveness of antifolates in vivax malaria treatment together with a correlation between mutations in P. vivax dhfr and dhps genes and SP treatment failure, the point mutations in these genes were investigated. METHODS: Blood samples from 54 patients experiencing vivax malaria symptomatic episodes in the Amazonian Region were investigated. Genomic DNA was extracted using a DNA extraction kit (QIAGENTM). Nested polymerase chain reaction (PCR) amplification was carried out followed by Sanger sequencing to detect single nucleotide polymorphisms (SNPs). FINDINGS: All tested isolates showed non-synonymous mutations in pvdhfr gene: 117N (54/54, 100%) and 58R (25/54, 46%). Double mutant allele 58R/117N (FRTNI, 28%) was the most frequent followed by triple mutant alleles (58R/117N/173L, FRTNL, 11%; 58R/61M/117N, FRMNI, 5% 117N/173L, FSTNL, 4%) and quadruple mutant allele (58R/61M/117N/173L, FRMNL, 2%). A single mutation was observed at codon C383G in pvdhps gene (SGKAV, 48%). CONCLUSION: No evidence of molecular signatures associated with P. vivax resistance to SP was observed in the Brazilian samples.
11.

Variabilidade dos casos de malária e sua relação com a precipitação e nível d'água dos rios no Estado do Amazonas, Brasil. / Variabilidade dos casos de malária e sua relação com a precipitação e nível d'água dos rios no Estado do Amazonas, Brasil. / Variability in malaria cases and the association with rainfall and rivers water levels in Amazonas State, Brazil.

Cad Saude Publica; 35(2): e00020218, 2019 Feb 11.
Artigo em Português, Inglês | MEDLINE | ID: mdl-30758451

RESUMO

Understanding the relations between rainfall and river water levels and malaria cases can provide important clues on modulation of the disease in the context of local climatic variability. In order to demonstrate how these relations can vary in the same endemic space, a coherence and wavelet phase analysis was performed between environmental and epidemiological variables from 2003 to 2010 for 8 municipalities (counties) in the state of Amazonas, Brazil (Barcelos, Borba, Canutama, Carauari, Coari, Eirunepé, Humaitá, and São Gabriel da Cachoeira). The results suggest significant coherences, mainly on the scale of annual variability, but scales of less than 1 year and of 2 years were also found. The analyses show that malaria cases display a peak at approximately 1 and a half months before or after peak rainfall and on average 1-4 months after peak river water levels in most of the municipalities studied. Each environmental variable displayed distinct local behavior in time and in space, suggesting that other local variables (e.g. topography) may control environmental conditions, favoring different patterns in each municipality. However, when the analyses were performed jointly it was possible to show a non-random order in these relations. Although environmental and climatic factors indicate a certain influence on malaria dynamics, surveillance, prevention, and control issues should not be overlooked, meaning that government public health interventions can mask possible relations with local hydrological and climatic conditions.
12.

Modeling asymptomatic infections and work-related human circulation as drivers of unstable malaria transmission in low-prevalence areas: a study in the Northern Peruvian Amazon.

Acta Trop; 2019 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-30703339

RESUMO

BACKGROUND: Despite relatively successful control campaigns, malaria remains a relevant public health problem in the Peruvian Amazon. Several studies suggest that malaria persistence in the area can be connected with a high prevalence of asymptomatic infections, which were subsequently shown to be connected with work-related exposure in areas of hyperendemic transmission. In this study, we tested the hypothesis that the infection reservoir represented by asymptomatic carriers in the northern Peruvian Amazon, combined with circular human movement to and from hyperendemic working areas, can capture the observed hypoendemic malaria transmission. METHODS: We designed a set of agent-based models that represent local-scale malaria transmission in a typical riverine community in the northern Peruvian Amazon. The models include asymptomatic individuals as well as a full representation of human movements within the community and between the community and external hyperendemic working places. Several theoretical scenarios are explored to verify if and how malaria clinical immunity prevalence and human work-related movements influence the malaria morbidity registered in the community. RESULTS: Agent-based simulations suggest that malaria incidence observed through passive case detection can be reproduced as exclusively generated by the asymptomatic infection reservoir. Scenarios analysis also show that, even if asymptomatic infections are completely eliminated, human movements to and from hyperendemic working areas generate a flow of imported cases that is enough to permit the persistence of transmission in the community. Simulation results were verified over a wide range of clinical immunity prevalence values and over a wide range of percentages of people working in remote hyperendemic areas. This context of unstable malaria transmission is observed to be vulnerable to severe outbreaks. CONCLUSIONS: Asymptomatic malaria infection and occupational circular human movement to hyperendemic transmission areas are designated by agent-based models as possible exclusive causes of residual hypoendemic malaria transmission observed in the Peruvian Amazon. Control strategies are proposed to decrease asymptomatic infection prevalence and to block transmission from asymptomatic individuals to the malaria susceptible population.
13.

Performance of an immuno-rapid malaria Pf/Pv rapid diagnostic test for malaria diagnosis in the Western Brazilian Amazon.

Rev Soc Bras Med Trop; 52: e20170450, 2019 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-30652783

RESUMO

INTRODUCTION: Rapid diagnostic tests (RDTs) for detecting Plasmodium antigens have become increasingly common worldwide. We aimed to evaluate the accuracy of the Immuno-Rapid Malaria Pf/Pv RDT in detecting Plasmodium vivax infection compared to standard thick blood smear (TBS) under microscopy. METHODS: Hundred and eighty-one febrile patients from the hospital's regular admissions were assessed using TBS and RDT in a blinded experiment. RESULTS: RDT showed a sensitivity of 98.9%, specificity of 100%, and accuracy of 99.5% for P. vivax infection when compared to TBS. CONCLUSIONS: The RDT is highly accurate, making it a valuable diagnostic tool for P. vivax infection.
15.

High-accuracy detection of malaria vector larval habitats using drone-based multispectral imagery.

PLoS Negl Trop Dis; 13(1): e0007105, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30653491

RESUMO

Interest in larval source management (LSM) as an adjunct intervention to control and eliminate malaria transmission has recently increased mainly because long-lasting insecticidal nets (LLINs) and indoor residual spray (IRS) are ineffective against exophagic and exophilic mosquitoes. In Amazonian Peru, the identification of the most productive, positive water bodies would increase the impact of targeted mosquito control on aquatic life stages. The present study explores the use of unmanned aerial vehicles (drones) for identifying Nyssorhynchus darlingi (formerly Anopheles darlingi) breeding sites with high-resolution imagery (~0.02m/pixel) and their multispectral profile in Amazonian Peru. Our results show that high-resolution multispectral imagery can discriminate a profile of water bodies where Ny. darlingi is most likely to breed (overall accuracy 86.73%- 96.98%) with a moderate differentiation of spectral bands. This work provides proof-of-concept of the use of high-resolution images to detect malaria vector breeding sites in Amazonian Peru and such innovative methodology could be crucial for LSM malaria integrated interventions.
16.

Variabilidade dos casos de malária e sua relação com a precipitação e nível d'água dos rios no Estado do Amazonas, Brasil / Variabilidad de los casos de malaria y su relación con las precipitaciones y nivel del agua de los ríos en el estado del Amazonas, Brasil / Variability in malaria cases and the association with rainfall and rivers water levels in Amazonas State, Brazil

Cad. Saúde Pública (Online); 35(2): e00020218, 2019. graf
Artigo em Português | LILACS-Express | ID: biblio-984141

RESUMO

O entendimento das relações entre as variáveis de precipitação e nível d'água dos rios com os casos de malária podem fornecer indícios importantes da modulação da doença no contexto da variabilidade climática local. No intuito de demonstrar como essas relações variam no mesmo espaço endêmico, realizou-se a análise de coerência e fase de ondeletas entre as variáveis ambientais e epidemiológica no período de 2003 a 2010 para 8 municípios do Estado do Amazonas (Barcelos, Borba, Canutama, Carauari, Coari, Eirunepé, Humaitá e São Gabriel da Cachoeira). Os resultados indicam coerências significativas principalmente na escala de variabilidade anual, contudo, escalas menores que 1 ano e bienal também foram encontradas. As análises mostram que casos de malária apresentam pico com aproximadamente 1 mês e meio antes ou depois dos picos de chuva, e em média 1-4 meses após o pico dos rios para grande parte dos municípios estudados. Foi notado que cada variável ambiental apresentou atuação local distinta no tempo e no espaço, sugerindo que outras variáveis locais (a topografia é um exemplo) possam controlar as condições ambientais favorecendo uma atuação diferenciada em cada município, porém, quando as análises são feitas em conjunto é possível ver uma ordem não aleatória destas relações acontecerem. Embora os fatores ambientais e climáticos denotem certa influência sobre a dinâmica da malária, questões de vigilância, prevenção e controle não devem ser desprezadas, significando que as atuações governamentais de saúde podem mascarar possíveis relações com as condições hidrológicas e climáticas locais.
La comprensión de las relaciones entre las variables de precipitaciones y el nivel de agua de los ríos con los casos de malaria pueden proporcionar indicios importantes sobre la modulación de la enfermedad en el contexto de la variabilidad climática local. Con el fin de demonstrar cómo varían esas relaciones en el mismo espacio endémico, se realizó un análisis de coherencia y fase de ondeletas entre las variables ambientales y epidemiológicas, durante el período de 2003 a 2010, en 8 municipios del estado de Amazonas (Barcelos, Borba, Canutama, Carauari, Coari, Eirunepé, Humaitá y São Gabriel da Cachoeira). Los resultados indican coherencias significativas, principalmente en la escala de variabilidad anual, sin embargo, también se detectaron escalas menores de 1 año y bienal. Los análisis muestran que los casos de malaria presentan un pico con aproximadamente 1 mes y medio antes o después de la pluviosidad más alta, y de media 1-4 meses tras el pico de los ríos para gran parte de los municipios estudiados. Se observó que cada variable ambiental presentó una actuación local distinta en el tiempo y en el espacio, sugiriendo que otras variables locales (la topografía es un ejemplo) puedan controlar las condiciones ambientales, favoreciendo una actuación diferenciada en cada municipio, no obstante, cuando los análisis se realizan en conjunto es posible ver un orden no aleatorio de estas relaciones para que se produzcan. A pesar de que los factores ambientales y climáticos denoten una cierta influencia sobre la dinámica de la malaria, cuestiones de vigilancia, prevención y control no se deben despreciar, lo que significa que las actuaciones gubernamentales de salud pueden enmascarar posibles relaciones con las condiciones hidrológicas y climáticas locales.
Understanding the relations between rainfall and river water levels and malaria cases can provide important clues on modulation of the disease in the context of local climatic variability. In order to demonstrate how these relations can vary in the same endemic space, a coherence and wavelet phase analysis was performed between environmental and epidemiological variables from 2003 to 2010 for 8 municipalities (counties) in the state of Amazonas, Brazil (Barcelos, Borba, Canutama, Carauari, Coari, Eirunepé, Humaitá, and São Gabriel da Cachoeira). The results suggest significant coherences, mainly on the scale of annual variability, but scales of less than 1 year and of 2 years were also found. The analyses show that malaria cases display a peak at approximately 1 and a half months before or after peak rainfall and on average 1-4 months after peak river water levels in most of the municipalities studied. Each environmental variable displayed distinct local behavior in time and in space, suggesting that other local variables (e.g. topography) may control environmental conditions, favoring different patterns in each municipality. However, when the analyses were performed jointly it was possible to show a non-random order in these relations. Although environmental and climatic factors indicate a certain influence on malaria dynamics, surveillance, prevention, and control issues should not be overlooked, meaning that government public health interventions can mask possible relations with local hydrological and climatic conditions.
Biblioteca responsável: BR1.1
17.

In vitro antiplasmodial activity and identification, using tandem LC-MS, of alkaloids from Aspidosperma excelsum, a plant used to treat malaria in Amazonia.

J Ethnopharmacol; 228: 99-109, 2019 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-30201230

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Aspidosperma excelsum Benth. (Apocynaceae), a native tree in the Brazilian Amazonia, is traditionally used to treat various diseases, including malaria. AIM OF STUDY: To investigate the chemical constitution, antiplasmodial activity and cytotoxicity of samples obtained from A. excelsum trunk bark by different procedures aiming to evaluate their potential as an antimalarial phytomedicine. MATERIALS AND METHODS: A hydroethanolic extract and alkaloid extracts were prepared and assayed for antiplasmodial activity and cytotoxicity against chloroquine-resistant Plasmodium falciparum (W2 strain) and HepG2 cells, respectively. Taking into account the known occurrence and antimalarial activity of Aspidosperma monoterpene indole alkaloids (MIA), acid-base extractions were carried out and the fractions were assayed for antiplasmodial activity and cytotoxicity. All the samples were analysed by hyphenated chromatographic techniques, such as UPLC-DAD-ESI-MS/MS and HRMS (HPLC-MS MicroTOF), comparing their chemical composition to the literature data. RESULTS: The hydroethanolic extract disclosed a moderate in vitro activity against chloroquine-resistant Plasmodium falciparum (W2 strain) with IC 23.68 ± 3.08 µg/mL), low cytotoxicity to HepG2 cells (> 250 µg/mL) and good SI (> 10.56). A total of 20 known monoterpene indole alkaloids were identified, seven of which are here firstly described for A. excelsum. Known highly active alkaloids, namely demethylaspidospermine, aspidocarpine, and ochrolifuanine are present in active alkaloid fractions and might contribute to their observed antiplasmodial effect. An alkaloid fraction (Ae-Alk2), obtained directly from trunk bark by extraction with dil. aqueous HCl, pointed out for its activity (IC 8.75±2.26 µg/mL, CC 185.14±1.97 µg/mL, SI 21.16) and should be highlighted as the most promising out of the assayed samples. CONCLUSION: The present results represent a preliminary support to the alleged antimalarial use of A. excelsum trunk bark and allowed to highlight alkaloid fractions as promising phytomedicines.
18.

Nyssorhynchus dunhami: bionomics and natural infection by Plasmodium falciparum and P. vivax in the Peruvian Amazon.

Mem Inst Oswaldo Cruz; 113(12): e180380, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30517211

RESUMO

BACKGROUND Nyssorhynchus dunhami, a member of the Nuneztovari Complex, has been collected in Brazil, Colombia, and Peru and described as zoophilic. Although to date Ny. dunhami has not been documented to be naturally infected by Plasmodium, it is frequently misidentified as other Oswaldoi subgroup species that are local or regional malaria vectors. OBJECTIVES The current study seeks to verify the morphological identification of Nuneztovari Complex species collected in the peri-Iquitos region of Amazonian Peru, to determine their Plasmodium infection status, and to describe ecological characteristics of their larval habitats. METHODS We collected Ny. nuneztovari s.l. adults in 2011-2012, and Ny. nuneztovari s.l. larvae and adults in 2016-2017. When possible, samples were identified molecularly using cytochrome c oxidase subunit I (COI) barcode sequencing. Adult Ny. nuneztovari s.l. from 2011-2012 were tested for Plasmodium using real-time PCR. Environmental characteristics associated with Ny. nuneztovari s.l. larvae-positive water bodies were evaluated. FINDINGS We collected 590 Ny. nuneztovari s.l. adults and 116 larvae from eight villages in peri-Iquitos. Of these, 191 adults and 111 larvae were identified by COI sequencing; all were Ny. dunhami. Three Ny. dunhami were infected with P. falciparum, and one with P. vivax, all collected from one village on one night. Ny. dunhami larvae were collected from natural and artificial water bodies, and their presence was positively associated with other Anophelinae larvae and amphibians, and negatively associated with people living within 250m. MAIN CONCLUSIONS Of Nuneztovari Complex species, we identified only Ny. dunhami across multiple years in eight peri-Iquitos localities. This study is, to our knowledge, the first report of natural infection of molecularly identified Ny. dunhami with Plasmodium. We advocate the use of molecular identification methods in this region to monitor Ny. dunhami and other putative secondary malaria vectors to more precisely evaluate their importance in malaria transmission.
19.

Actividades de vigilancia epidemiológica de la malaria en la red diagnóstica de la frontera colombiana-peruana. / [Epidemiological surveillance activities for malaria in the colombian-peruvian border diagnostic network].

Rev Peru Med Exp Salud Publica; 35(3): 373-381, 2018 Jul-Sep.
Artigo em Espanhol | MEDLINE | ID: mdl-30517496

RESUMO

OBJECTIVE.: To describe the activities of the malaria diagnostic network and its quality control in the Colombian-Peruvian border to characterize the functioning of the epidemiological surveillance system. MATERIALS AND METHODS.: Descriptive study with a research focus on implementation. We visited border communities with health care centers or volunteers trained to diagnose malaria. The visited sites were georeferenced to know their distribution. With information from departmental public health laboratories, the quality component was analyzed and compliance with the national guidelines for malaria diagnostic networks in the border area of the two countries was evidenced. RESULTS.: Twenty-five Colombian and 18 Peruvian sites were visited, of which 25% had only microscopy posts, 56% made a diagnosis for malaria, and 19% only took samples and the plates were sent to a reference point for diagnosis. The Ministry of Health of the Amazon (Colombia) did not carry out direct supervision visits to the malaria diagnostic network during 2016-2017; the Regional Health Directorate of Loreto (Peru) has not carried out visits since 2015. Sixty percent of the diagnosis points in the Amazon and 29% in Loreto participated in quality assurance. CONCLUSIONS.: Lack of opportunity in the diagnosis was identified in 44% of the visited sites and deficiencies in the quality component of the border diagnostic network.
20.

Impacto de diferentes esquemas terapéuticos sobre la malaria en la costa y amazonia peruana, en el marco de una política de medicamentos antimaláricos, 1994-2017. / [Impact on the transmission of malaria with different treatment schemes in the peruvian coast and amazon region within the framework of a policy on antimalarial medications, 1994-2017].

Rev Peru Med Exp Salud Publica; 35(3): 497-504, 2018 Jul-Sep.
Artigo em Espanhol | MEDLINE | ID: mdl-30517511

RESUMO

At the end of the 90s in Peru, after determining the resistance to antimalarial drugs, a change in antimalarial treatment schemes was decided; this change included the combined therapy for P. falciparum, mefloquine/artesunate in the Amazon region, and sulfadoxine pyrimethamine/artesunate in the North coast. After two decades, and aimed at assessing the impact of these schemes on the malaria endemic, a review was conducted of malaria reports in three departments accounting for more than 70% of cases reported in the country. The major impact of the sulfadoxine-pyrimethamine/ artesunate scheme in the North coast was evident since it reduced the number of cases of P. falciparum to virtually zero four years after implementation of the combined therapy. The single dose and the ability to limit the development of sporozoites were crucial in order to achieve this goal. The mefloquine/artesunate scheme had a limited impact because it was not possible to ensure supervised treatment in the health service facilities and the need for three doses. It is important to select an effective and easy-to-administer scheme when choosing the first line of treatment for malaria. This experience is significant for the malaria eradication goals in Peru.
Resultados 1 - 20 de 1.500