Individual risk factors for Plasmodium vivax infection in the residual malaria transmission focus of Oaxaca, Mexico

Abstract

Objective. To identify individual risk factors for malaria infection of inhabitants in the residual transmission focus on the Pacific coast of Oaxaca, Mexico. Materials and Methods. A population-based, matched case-control study was conducted from January 2002 to July 2003 comparing the frequency of exposure to individual risk factors in subjects presenting clinical malaria and uninfected controls. A malaria case was defined as an individual living in the study area presenting malaria symptoms and a Plasmodium vivax-positive thick blood smear; controls were individuals negative to P. vivax parasites and antibodies of the same gender and with ± five years as the case. A standardized questionnaire was used to record information about the individual risk factors associated with malaria episodes in cases and two controls for each case. Results. In a multiple conditional logistic regression model analysis of data from 119 cases and 238 controls, 18 out of 99 variables were significantly associated (p< 0.05) with increased risk of malaria, including: being born in another locality (RM 3.16, ResumenObjetivo. Identificar los factores de riesgo individuales determinantes para contraer paludismo en habitantes del foco residual de transmisión de paludismo localizado en la costa del Pacífico de Oaxaca. Material y métodos. Se realizó un estudio pareado de casos y controles, con base poblacional de enero de 2002 a julio de 2003, comparando la frecuencia de exposición a diversos factores de riesgo individuales en sujetos que presentaron un cuadro clínico de paludismo y controles no infectados. Un caso de paludismo fue definido como un individuo que vive en el área de estudio que presentó síntomas de paludismo y diagnosticado positivo a P. vivax en examen de gota gruesa de sangre, los controles fueron individuos negativos a parásitos y anticuerpos anti-P. vivax del mismo sexo y ± cinco años la edad del caso. Se usó un cuestionario estandarizado para registrar información de factores de riesgo individuales asociados a episodios de paludismo en casos y dos controles por caso. Resultados. El análisis en un modelo de regresión logística condicional múltiple, 18 de 99 variables fueron significativamente asociadas (p< 0.05) con el incremento en el riesgo de paludismo, incluyendo: nacer fuera de la localidad (RM 3.16, 95% IC 1.16-6.13); hablar sólo un idioma autóctono (RM= 2.48, 95% IC 1.19-3.77); pobre conocimiento de cómo se transmite y trata el paludismo (RM= 2.26 95% IC 1.10-4.66 P< 0.02);

Using WeChat official accounts to improve malaria health literacy among Chinese expatriates in Niger: an intervention study

“…Video materials were developed to explain how to obtain and use DEET in Niger for staff as a reference whenever they need. Individual, ecological and environmental risk factors are regarded as targets of control efforts to achieve further reduction and elimination of malaria [57, 58]. Messages on the infection process of malaria under various conditions were explained via the intervention using onsite photographs to stimulate greater interest among staff in changing risky behaviours and habits.…”

Population Movement as a Risk Factor for Malaria Infection in High-Altitude Villages of Tahtay–Maychew District, Tigray, Northern Ethiopia: A Case–Control Study

“…Similar findings were documented from prior studies elsewhere. 10,11,26 Thus, travel away from home is a significant predictor of malaria infection in highaltitude villages in northern Ethiopia. Nevertheless, that notable number of cases (19.2% from the 130 cases) did not travel outside their home village to malaria-risk areas may indicate some level of transmission in low-malaria transmission settings (i.e., high-altitude villages) as the vectors of malaria are identified at 2,200 masl in some highlands of Ethiopia 29 or many of the P. vivax infection reported in this study may have originated not from the initial sporozoite inoculations, but rather as relapses.…”

“…These interventions are highly effective in reducing both the transmission and exposure to infectious mosquito bites and also the concomitant burden of malaria disease. 11,12 However, conventional vector control interventions such as IRS and ITNs protect the household but are less effective for individuals who are away from their homes during the peak times of transmission, or away from personal control measures. 12,13 Human movement is known to have an impact on infectious disease transmission.…”

Respuesta de Anopheles albimanus a compuestos volátiles de casas del sur de Chiapas, México

“…Esta distribución de las viviendas se ha vinculado con su posición en relación con los criaderos y la dirección del viento. 32 En este estudio, la distribución de las casas atrayentes o repelentes no presentó un patrón defi nido respecto de los criaderos ni la dirección del viento, lo cual puede indicar que cada casa tiene características propias que las hacen atractivas para los mosquitos, tal y como se informó para las viviendas donde la abundancia de mosquitos se correlacionó con el número de habitantes. 33 Los resultados de esta investigación podrían contribuir a explicar que ciertas casas tienen mayor densidad que otras y que el uso constante de fogones, la combustión de basura y la acumulación de ropa impregnada con sudor son las posibles fuentes de atracción.…”