Integrating Parasitological and Entomological Observations to Understand Malaria Transmission in Riverine Villages in the Peruvian Amazon.

BACKGROUND: Remote rural riverine villages account for most of the reported malaria cases in the Peruvian Amazon. As transmission decreases due to intensive standard control efforts, malaria strategies in these villages will need to be more focused and adapted to local epidemiology. METHODS: By integrating parasitological, entomological, and environmental observations between January 2016 and June 2017, we provided an in-depth characterization of malaria transmission dynamics in 4 riverine villages of the Mazan district, Loreto department. RESULTS: Despite variation across villages, malaria prevalence by polymerase chain reaction in March 2016 was high (>25% in 3 villages), caused by Plasmodium vivax mainly and composed of mostly submicroscopic infections. Housing without complete walls was the main malaria risk factor, while households close to forest edges were more commonly identified as spatial clusters of malaria prevalence. Villages in the basin of the Mazan River had a higher density of adult Anopheles darlingi mosquitoes, and retained higher prevalence and incidence rates compared to villages in the basin of the Napo River despite test-and-treat interventions. CONCLUSIONS: High heterogeneity in malaria transmission was found across and within riverine villages, resulting from interactions between the microgeographic landscape driving diverse conditions for vector development, housing structure, and human behavior.

Economic costs analysis of uncomplicated malaria case management in the Peruvian Amazon.

BACKGROUND: Case management is one of the principal strategies for malaria control. This study aimed to estimate the economic costs of uncomplicated malaria case management and explore the influence of health-seeking behaviours on those costs. METHODS: A knowledge, attitudes and practices (KAP) survey was applied to 680 households of fifteen communities in Mazan-Loreto in March 2017, then a socio-economic survey was conducted in September 2017 among 161 individuals with confirmed uncomplicated malaria in the past 3 months. Total costs per episode were estimated from both provider (Ministry of Health, MoH) and patient perspectives. Direct costs were estimated using a standard costing estimation procedure, while the indirect costs considered the loss of incomes among patients, substitute labourers and companions due to illness in terms of the monthly minimum wage. Sensitivity analysis evaluated the uncertainty of the average cost per episode. RESULTS: The KAP survey showed that most individuals (79.3%) that had malaria went to a health facility for a diagnosis and treatment, 2.7% received those services from community health workers, and 8% went to a drugstore or were self-treated at home. The average total cost per episode in the Mazan district was US$ 161. The cost from the provider's perspective was US$ 30.85 per episode while from the patient's perspective the estimated cost was US$ 131 per episode. The average costs per Plasmodium falciparum episode (US$ 180) were higher than those per Plasmodium vivax episode (US$ 156) due to longer time lost from work by patients with P. falciparum infections (22.2 days) than by patients with P. vivax infections (17.0 days). The delayed malaria diagnosis (after 48 h of the onset of symptoms) was associated with the time lost from work due to illness (adjusted mean ratio 1.8; 95% CI 1.3, 2.6). The average cost per malaria episode was most sensitive to the uncertainty around the lost productivity cost due to malaria. CONCLUSIONS: Despite the provision of free malaria case management by MoH, there is delay in seeking care and the costs of uncomplicated malaria are mainly borne by the families. These costs are not well perceived by the society and the substantial financial impact of the disease can be frequently undervalued in public policy planning.

Malaria risk assessment and mapping using satellite imagery and boosted regression trees in the Peruvian Amazon.

This is the first study to assess the risk of co-endemic Plasmodium vivax and Plasmodium falciparum transmission in the Peruvian Amazon using boosted regression tree (BRT) models based on social and environmental predictors derived from satellite imagery and data. Yearly cross-validated BRT models were created to discriminate high-risk (annual parasite index API > 10 cases/1000 people) and very-high-risk for malaria (API > 50 cases/1000 people) in 2766 georeferenced villages of Loreto department, between 2010-2017 as other parts in the article (graphs, tables, and texts). Predictors were cumulative annual rainfall, forest coverage, annual forest loss, annual mean land surface temperature, normalized difference vegetation index (NDVI), normalized difference water index (NDWI), shortest distance to rivers, time to populated villages, and population density. BRT models built with predictor data of a given year efficiently discriminated the malaria risk for that year in villages (area under the ROC curve (AUC) > 0.80), and most models also effectively predicted malaria risk in the following year. Cumulative rainfall, population density and time to populated villages were consistently the top three predictors for both P. vivax and P. falciparum incidence. Maps created using the BRT models characterize the spatial distribution of the malaria incidence in Loreto and should contribute to malaria-related decision making in the area.

Effectiveness of a Malaria Surveillance Strategy Based on Active Case Detection during High Transmission Season in the Peruvian Amazon.

Background: Faced with the resurgence of malaria, malaria surveillance in the Peruvian Amazon incorporated consecutive active case detection (ACD) interventions using light microscopy (LM) as reactive measure in communities with an unusual high number of cases during high transmission season (HTS). We assessed the effectiveness in malaria detection of this local ACD-based strategy. Methods: A cohort study was conducted in June⁻July 2015 in Mazan, Loreto. Four consecutive ACD interventions at intervals of 10 days were conducted in four riverine communities (Gamitanacocha, Primero de Enero, Libertad and Urco Miraño). In each intervention, all inhabitants were visited at home, and finger-prick blood samples collected for immediate diagnosis by LM and on filter paper for later analysis by quantitative real-time polymerase chain reaction (qPCR). Effectiveness was calculated by dividing the number of malaria infections detected using LM by the number of malaria infections detected by delayed qPCR. Results: Most community inhabitants (88.1%, 822/933) were present in at least one of the four ACD interventions. A total of 451 infections were detected by qPCR in 446 participants (54.3% of total participants); five individuals had two infections. Plasmodium vivax was the predominant species (79.8%), followed by P. falciparum (15.3%) and P. vivax-P. falciparum co-infections (4.9%). Most qPCR-positive infections were asymptomatic (255/448, 56.9%). The ACD-strategy using LM had an effectiveness of 22.8% (detection of 103 of the total qPCR-positive infections). Children aged 5⁻14 years, and farming as main economic activity were associated with P. vivax infections. Conclusions: Although the ACD-strategy using LM increased the opportunity of detecting and treating malaria infections during HTS, the number of detected infections was considerably lower than the real burden of infections (those detected by qPCR).

Primeros auxilios en el nivel comunitario / First aid at the community level

La publicación está conformada por ocho temas, desde las conceptualizaciones hacia las indicaciones del qué hacer o cómo actuar en diversas circunstancias de riesgo o peligro, producto de un accidente o situación específica. El desarrollo de estos temas, permitirá el tránsito dialéctico desde la teoría a la práctica, combinando ambos aspectos para lograr un aprendizaje significativo en la materia.

Vigilancia, prevención y control de enfermedades zoonóticas y metaxénicas selectas / Surveillance, prevention and control of selected zoonotic and metaxenic diseases

La publicación aborda como primer tema las enfermedades metaxénicas que afectan a la población como el Dengue, Chikungunya, Malaria y Leishmaniasis; se revisan sus normas y procedimientos técnicos en la obtención de muestra. COmo segundo tema las Enfermedades Zoonóticas, se dará a conocer las principales que pueden ser trasmitidas por los animales a los seres humanos, como Peste, rabia, hidatidosis, cisticercosis, fasciolosis y leptospirosis; así también se revisan las normas y procedimientos técnicos. Y como tercer tema la Bioseguridad, se da a conocer el conjunto de medidas preventivas, destinadas a proteger la salud y seguridad del personal, durante su trabajo en los laboratorios donde se manipulan productos biológicos y químicos para la obtención de muestras, y para los procesos de vigilancia, prevención y control, que incluyen además, el reconocimiento de zonas de riesgo, la identificación de focos de rabia, peste y otras enfermedades zoonóticas (leptospirosis); la vacunación canina según norma técnica, y los registros de Información de enfermedades zoonóticas que puede manejar el capacitado en salud pública.

[Long-lasting insecticide - treated bednet ownership, retention and usage one year after their distribution in Loreto, Peru]. / Posesión, retención y uso de mosquiteros tratados con insecticidas de larga duración luego de un año de su distribución en Loreto, Perú

OBJECTIVES: To assess long-lasting insecticide - treated bednet (LLITN) ownership, retention and usage one year after their distribution in Loreto, Peru. MATERIALS AND METHODS: From July to September 2007, 26,185 LLITNs Olyset Net ® were delivered in 194 targeted communities in the Peruvian Amazon region, covering 45,331 people. Two cross-sectional community-based surveys in December 2007 and July 2008 were undertaken in a sample of 60 targeted communities (30.9% out of the total). A semi-structured questionnaire was used to collect necessary data to calculate LLITN ownership, retention and usage indicators. RESULTS: High LLITN household ownership was showed in both surveys (99.9% and 98.7%, respectively). LLITN/ person ratio decreased from 0.58 at the end of the LLITN delivery to 0.51 in the second survey, estimating LLITN retention of 87% after 1 year of intervention. In the first survey, 99.0% of all children <5 years and 96,0% of pregnant women slept under a LLITN the previous night, while in the second survey, 77.7% of children <5 years and 66.3% of pregnant women slept under a LLITN the previous night. Big mesh size of LLITN had low people's acceptability, reaching only 39.0% in the second survey. CONCLUSIONS: Although universal LLITN household ownership remained high, their LLITN usage levels have decreased during one-year follow-up period.

Posesión, retención y uso de mosquiteros tratados con insecticidas de larga duración luego de un año de su distribución en Loreto, Perú / Long-lasting insecticide - treated bednet ownership, retention and usage one year after their distribution in Loreto, Peru

Objetivos. Evaluar la posesión, retención y uso de mosquiteros tratados con insecticida de larga duración (MTILD) luego de un año de su distribución en Loreto, Perú. Materiales y métodos. De julio a septiembre de 2007 se distribuyeron 26 185 MTILD Olyset Net® en 194 comunidades objetivo de Loreto, que protegieron a 45 331 personas. Posteriormente, se realizaron visitas de monitoreo (primera en diciembre de 2007 y segunda en julio de 2008) a los hogares de una muestra de 60 comunidades objetivo (30,9 por ciento del total), colectándose mediante un cuestionario semiestructurado los datos necesarios para el cálculo de indicadores de posesión, retención y uso de los MTILD. Resultados. En ambas visitas, la posesión de MTILD en hogares fue elevada (99,9 por ciento y 98,7 por ciento, respectivamente). La razón MTILD/persona disminuyó de 0,58 al momento de la distribución a 0,51 en la segunda visita, estimándose una retención al año de MTILD de 87 por ciento. En la primera visita, 99,0 por ciento de los niños <5 años y 96,0 por ciento de las embarazadas durmieron bajo un MTILD la noche anterior, mientras que en la segunda visita, 77,7 por ciento de los niños<5 años y 66,3 por ciento de las embarazadas durmieron bajo un MTILD la noche anterior. El tamaño de los agujeros de la trama de los MTILD tuvo una baja aceptabilidad por parte del a población durante la segunda visita (39,0 por ciento). Conclusiones. Si bien la posesión de MTILD en los hogares se ha mantenido elevada, su uso por la población beneficiada ha disminuido durante el año de seguimiento.

Objectives. To assess long-lasting insecticide - treated bednet (LLITN) ownership, retention and usage one year after their distribution in Loreto, Peru. Materials and methods. From July to September 2007, 26,185 LLITNs Olyset Net ® were delivered in 194 targeted communities in the Peruvian Amazon region, covering 45,331 people. Two cross-sectional community-based surveys in December 2007 and July 2008 were undertaken in a sample of 60 targeted communities (30.9 percent out of the total). A semi-structured questionnaire was used to collect necessary data to calculate LLITN ownership, retention and usage indicators. Results. High LLITN household ownership was showed in both surveys (99.9 percent and 98.7 percent, respectively). LLITN/ person ratio decreased from 0.58 at the end of the LLITN delivery to 0.51 in the second survey, estimating LLITN retention of 87 percent after 1 year of intervention. In the first survey, 99.0 percent of all children <5 years and 96,0 percent of pregnant women slept under a LLITN the previous night, while in the second survey, 77.7 percent of children <5 years and 66.3 percent of pregnant women slept under a LLITN the previous night. Big mesh size of LLITN had low people´s acceptability, reaching only 39.0 percent in the second survey. Conclusions. Although universal LLITN household ownership remained high, their LLITN usage levels have decreased during one-year follow-up period.