ABSTRACT In recent years, the number of cases with severe Plasmodium vivax malaria has shown an increasing trend. It is, therefore, important to identify routine laboratory markers that best characterize the acute disease phase and can serve as a tool for clinical follow-up of patients. In a cohort study, we followed 87 patients with acute P. vivax monoinfection acquired in an endemic region of the Brazilian Amazon. Forty-two different biochemical and hematological parameters frequently tested in clinical routine were evaluated at the acute phase and the convalescent phase. A total of 42 laboratory tests were performed: biochemical parameters measured were serum lipids levels, aminotransferases, bilirubin, amylase, glucose, urea, creatinine, albumin, globulin, uric acid, C-reactive protein, and alpha-1-acid glycoprotein. Hematological parameters included total and differential white blood cell and platelet counts, hemoglobin concentration, mean platelet volume, platelet width distribution, and plateletcrit. Our results show that several biochemical and hematological parameters were associated with acute phase P. vivax malaria and these parameters reverted to normal values in the convalescent phase. The use of these parameters during diagnosis and follow-up of the infection is a useful clinical tool to evaluate the clinical course and therapeutic response of patients with uncomplicated vivax malaria.

Abstract INTRODUCTION Uric acid is one of the compounds associated with the inflammatory process in malaria. It acts as an indicator of cellular damage by activating the immune response and inflammatory process. METHODS: We measured serum concentrations of uric acid in 60 symptomatic patients before and after treatment for malarial infections caused by Plasmodium vivax. RESULTS: Lower serum concentrations of uric acid were found during the acute phase of P. vivax malaria compared to those in its convalescent phase (p < 0.0001). CONCLUSIONS: Patients in the acute phase of malaria had lower uric acid levels than those in its convalescent phase.

Resumo O objetivo deste artigo é analisar o monóxido de carbono exalado, a carboxihemoglobina e as variáveis cardiopulmonares em idosos praticantes de exercícios em ambientes externos e correlacionar com clima e poluição. Estudo ecológico temporal com 118 idosos ativos em Cuiabá. Foram obtidas informações sobre uso de medicamentos, tabagismo, antropometria, espirometria, peak-flow, saturação de oxigênio, frequência cardíaca, monóxido de carbono exalado, carboxihemoglobina, além de dados climáticos, queimadas e poluição. Temperatura ambiental, umidade relativa do ar e queimadas correlacionaram com monóxido de carbono exalado e carboxihemoglobina (p < 0,05). Frequência cardíaca correlacionou com alterações de temperatura ambiental, tempo de exposição solar e umidade relativa (p < 0,05). Idosos sofrem influências ambientais alterando níveis de monóxido de carbono, carboxihemoglobina e frequência cardíaca, sendo necessário monitoramento destes durante os exercícios, sugerindo-se o uso do monoxímetro para avaliação de exposição a poluentes.

Abstract This article aims to analyze levels of exhaled carbon monoxide, carboxyhemoglobinand cardiopulmonary variables in old people practicing exercise in external environments, and correlate them with climate and pollution factors. Temporal ecological study with118 active elderly people in the city of Cuiabá, in the state of Mato Grosso, Brazil. Data were obtained on use of medication, smoking, anthropometric measurements, spirometry, peak flow, oxygen saturation, heart rate, exhaled carbon monoxide, carboxyhemoglobin, climate, number of farm fires and pollution. Correlations were found between on the one hand environmental temperature, relative humidity of the air and number of farmers’ fires, and on the other hand levels of carbon monoxide exhaled and carboxyhemoglobin (p < 0.05).There was a correlation between heart rate and changes in environmental temperature, time of exposure to the sun and relative humidity (p < 0.05). In elderly people, environmental factors influence levels of exhaled carbon monoxide, carboxyhemoglobin and heart rate. There is thus a need for these to be monitored during exercise. The use of a carbon monoxide monitor to evaluate exposure to pollutants is suggested.

Resumo O objetivo deste artigo é analisar o monóxido de carbono exalado, a carboxihemoglobina e as variáveis cardiopulmonares em idosos praticantes de exercícios em ambientes externos e correlacionar com clima e poluição. Estudo ecológico temporal com 118 idosos ativos em Cuiabá. Foram obtidas informações sobre uso de medicamentos, tabagismo, antropometria, espirometria, peak-flow, saturação de oxigênio, frequência cardíaca, monóxido de carbono exalado, carboxihemoglobina, além de dados climáticos, queimadas e poluição. Temperatura ambiental, umidade relativa do ar e queimadas correlacionaram com monóxido de carbono exalado e carboxihemoglobina (p < 0,05). Frequência cardíaca correlacionou com alterações de temperatura ambiental, tempo de exposição solar e umidade relativa (p < 0,05). Idosos sofrem influências ambientais alterando níveis de monóxido de carbono, carboxihemoglobina e frequência cardíaca, sendo necessário monitoramento destes durante os exercícios, sugerindo-se o uso do monoxímetro para avaliação de exposição a poluentes.

Abstract This article aims to analyze levels of exhaled carbon monoxide, carboxyhemoglobinand cardiopulmonary variables in old people practicing exercise in external environments, and correlate them with climate and pollution factors. Temporal ecological study with118 active elderly people in the city of Cuiabá, in the state of Mato Grosso, Brazil. Data were obtained on use of medication, smoking, anthropometric measurements, spirometry, peak flow, oxygen saturation, heart rate, exhaled carbon monoxide, carboxyhemoglobin, climate, number of farm fires and pollution. Correlations were found between on the one hand environmental temperature, relative humidity of the air and number of farmers’ fires, and on the other hand levels of carbon monoxide exhaled and carboxyhemoglobin (p < 0.05).There was a correlation between heart rate and changes in environmental temperature, time of exposure to the sun and relative humidity (p < 0.05). In elderly people, environmental factors influence levels of exhaled carbon monoxide, carboxyhemoglobin and heart rate. There is thus a need for these to be monitored during exercise. The use of a carbon monoxide monitor to evaluate exposure to pollutants is suggested.

Estudo de coorte histórica aberta, construída com informações registradas no Sistema de Informação de Vigilância Epidemiológica da Malária, com objetivo de descrever a incidência e os fatores associados à recidiva de malária causada pelo Plasmodium vivax em Porto Velho, Rondônia, Brasil. Foram notificados 23.365 casos de malária por P. vivax no município, sendo que 23% deles apresentaram recidiva no decorrer de 2009. A densidade de incidência de recidivas foi de 45,1/100 pacientes-ano, ocorrendo, principalmente, entre a 4a e a 13a semana após o início do tratamento. Ser homem, ter menos tempo de sintomas e ter maior nível de parasitemia na infecção inicial aumentaram o risco de recidiva no decorrer do ano, com 10% de redução relativa do risco para maior tempo de sintomas e de 11% e 15% de incremento relativo do risco para o sexo masculino e maiores níveis de parasitemia, respectivamente. Contudo, os resultados demonstram baixa relevância clínica das associações encontradas, comprometendo a sua aplicabilidade na tomada de decisão em nível de saúde pública. Recidiva; Plasmodium vivax; Malária

This open retrospective cohort study aimed to describe the incidence of recurrent Plasmodium vivax malaria and associated factors in Porto Velho, Rondônia State, Brazil, in 2009. Data were collected from the National Information System for Malaria Epidemiological Surveillance. There were 23,365 reported P. vivax malaria cases in 2009, 23% of which were classified as relapses. Incidence density of P. vivax recurrence was 45.1/100 patient-years, mostly occurring between the 4th and 13th week after initiating treatment. Male gender, shorter time since onset of symptoms, and higher parasitemia in the initial infection increased the risk of relapse during the year, with a 10% reduction in relative risk for longer symptoms and 11% and 15% increases in relative risk for males and higher initial parasitemia, respectively. However, the results show low clinical relevance for these associations, thereby limiting their applicability to decision-making at the public health level.

Estudio de cohorte histórica abierta, construida con información registrada en el Sistema de Información de Vigilancia Epidemiológica de la Malaria, con el objetivo de describir la incidencia y los factores asociados a la reaparición de malaria, causada por el Plasmodium vivax, en Porto Velho, Rondônia, Brasil. Se notificaron 23.365 casos de malaria por P. vivax en el municipio, donde un 23% de ellos presentaron recidiva a lo largo del 2009. La densidad de incidencia de recidivas fue de 45,1/100 pacientes-año, produciéndose, principalmente, entre la 4ª y la 13ª semana tras el inicio del tratamiento. Ser hombre, tener menos tiempo síntomas y tener un mayor nivel de parasitemia en la infección inicial aumentaron el riesgo de recidiva a lo largo del año, con un 10% de reducción relativa del riesgo, para un mayor tiempo de síntomas, y de un 11% y 15% de incremento relativo del riesgo para el sexo masculino y mayores niveles de parasitemia, respectivamente. No obstante, los resultados demostraron baja relevancia clínica de las asociaciones encontradas, comprometiendo su aplicabilidad en la toma de decisiones dentro de la salud pública.

Estudo de coorte histórica aberta, construída com informações registradas no Sistema de Informação de Vigilância Epidemiológica da Malária, com objetivo de descrever a incidência e os fatores associados à recidiva de malária causada pelo Plasmodium vivax em Porto Velho, Rondônia, Brasil. Foram notificados 23.365 casos de malária por P. vivax no município, sendo que 23% deles apresentaram recidiva no decorrer de 2009. A densidade de incidência de recidivas foi de 45,1/100 pacientes-ano, ocorrendo, principalmente, entre a 4a e a 13a semana após o início do tratamento. Ser homem, ter menos tempo de sintomas e ter maior nível de parasitemia na infecção inicial aumentaram o risco de recidiva no decorrer do ano, com 10% de redução relativa do risco para maior tempo de sintomas e de 11% e 15% de incremento relativo do risco para o sexo masculino e maiores níveis de parasitemia, respectivamente. Contudo, os resultados demonstram baixa relevância clínica das associações encontradas, comprometendo a sua aplicabilidade na tomada de decisão em nível de saúde pública. Recidiva; Plasmodium vivax; Malária

This open retrospective cohort study aimed to describe the incidence of recurrent Plasmodium vivax malaria and associated factors in Porto Velho, Rondônia State, Brazil, in 2009. Data were collected from the National Information System for Malaria Epidemiological Surveillance. There were 23,365 reported P. vivax malaria cases in 2009, 23% of which were classified as relapses. Incidence density of P. vivax recurrence was 45.1/100 patient-years, mostly occurring between the 4th and 13th week after initiating treatment. Male gender, shorter time since onset of symptoms, and higher parasitemia in the initial infection increased the risk of relapse during the year, with a 10% reduction in relative risk for longer symptoms and 11% and 15% increases in relative risk for males and higher initial parasitemia, respectively. However, the results show low clinical relevance for these associations, thereby limiting their applicability to decision-making at the public health level.

Estudio de cohorte histórica abierta, construida con información registrada en el Sistema de Información de Vigilancia Epidemiológica de la Malaria, con el objetivo de describir la incidencia y los factores asociados a la reaparición de malaria, causada por el Plasmodium vivax, en Porto Velho, Rondônia, Brasil. Se notificaron 23.365 casos de malaria por P. vivax en el municipio, donde un 23% de ellos presentaron recidiva a lo largo del 2009. La densidad de incidencia de recidivas fue de 45,1/100 pacientes-año, produciéndose, principalmente, entre la 4ª y la 13ª semana tras el inicio del tratamiento. Ser hombre, tener menos tiempo síntomas y tener un mayor nivel de parasitemia en la infección inicial aumentaron el riesgo de recidiva a lo largo del año, con un 10% de reducción relativa del riesgo, para un mayor tiempo de síntomas, y de un 11% y 15% de incremento relativo del riesgo para el sexo masculino y mayores niveles de parasitemia, respectivamente. No obstante, los resultados demostraron baja relevancia clínica de las asociaciones encontradas, comprometiendo su aplicabilidad en la toma de decisiones dentro de la salud pública.

The polymerase chain reaction (PCR)-based methods for the diagnosis of malaria infection are expected to accurately identify submicroscopic parasite carriers. Although a significant number of PCR protocols have been described, few studies have addressed the performance of PCR amplification in cases of field samples with submicroscopic malaria infection. Here, the reproducibility of two well-established PCR protocols (nested-PCR and real-time PCR for the Plasmodium 18 small subunit rRNA gene) were evaluated in a panel of 34 blood field samples from individuals that are potential reservoirs of malaria infection, but were negative for malaria by optical microscopy. Regardless of the PCR protocol, a large variation between the PCR replicates was observed, leading to alternating positive and negative results in 38% (13 out of 34) of the samples. These findings were quite different from those obtained from the microscopy-positive patients or the unexposed individuals; the diagnosis of these individuals could be confirmed based on the high reproducibility and specificity of the PCR-based protocols. The limitation of PCR amplification was restricted to the field samples with very low levels of parasitaemia because titrations of the DNA templates were able to detect < 3 parasites/µL in the blood. In conclusion, conventional PCR protocols require careful interpretation in cases of submicroscopic malaria infection, as inconsistent and false-negative results can occur.

Introduction: We evaluated the in vitro antimalarial activity of tigecycline as an alternative drug for the treatment of severe malaria. Methods: A chloroquine-sensitive Plasmodium falciparum reference strain, a chloroquine-resistant reference strain, and three clinical isolates were tested for in vitro susceptibility to tigecycline. A histidine-rich protein in vitro assay was used to evaluate antimalarial activity. Results: The geometric-mean 50% effective concentration (EC50%) of tigecycline was 535.5 nM (confidence interval (CI): 344.3-726.8). No significant correlation was found between the EC50% of tigecycline and that of any other tested antimalarial drug. Conclusions: Tigecycline may represent an alternative drug for the treatment of patients with severe malaria.