Resumo Plasma de radiofrequência, plasma de RF, tem sido empregado em diversas aplicações industriais. Experimentos de laboratório foram conduzidos para determinar o potencial de plasma de RF no controle de Tribolium castaneum (Herbst). Foram examinados nesse estudo três variáveis de tratamento: (1) plasma de hélio ou argônio; (2) dois níveis de potência (50 e 100 watts); e (3) diferentes tempos de exposição ao plasma de RF (0, 20, 40, 60 e 90 segundos). A suscetibilidade do T. castaneum ao tratamento varia conforme o gás, o nível de energia e o tempo de exposição. Foi encontrada uma correlação positiva dentre a porcentagem de mortalidade de insetos no tratamento de larvas, bem como as pupas tratadas e o tempo de exposição ao plasma de RF, e também o nível de potência da irradiação. Os resultados revelaram que não foram encontrados insetos vivos após 90 segundos, com 100 watts de tratamento com plasmas de hélio e RF. As porcentagens de sobrevivência dos adultos foram desenvolvidas a partir de larvas tratadas, e as pupas tratadas foram significativamente reduzidas pelo aumento do tempo de exposição ou nível de potência. Os dados obtidos indicaram que o tratamento com plasma de RF pode ser considerado como um suplemento ambientalmente compatível ou alternativo aos outros métodos de controle para o manejo de produtos-pragas armazenados.

Abstract Radio frequency plasma, RF plasma, has been applied to a number of industrial applications. Laboratory experiments were conducted to determine the RF plasma potential in Tribolium castaneum (Herbst) control. Three treatment variables: (1) helium or argon plasmas; (2) two power levels (50 and 100 watt); and (3) different RF plasma exposure times (0, 20, 40, 60 and 90 seconds) were examined in this study. The susceptibility of T. castaneum to treatment varies as gas, power level, and the exposure time varies. A positive correlation was found between insect mortality percent in treating larvae as well as treated pupae and exposure time to RF plasma and also the power level of irradiation. The results revealed that no live insects were found after a 90 second, 100 watt helium RF plasma treatment. The survival percents of the adults were developed from treated larvae and treated pupae were significantly reduced by increasing of the exposure time or power level. Obtained data indicated that the treatment with RF plasma might be considered as an environmentally compatible or alternative supplement to the other control methods for stored product-pests management.

OBJECTIVE: To assess the efficacy of chloroquine and sulfadoxine/pyrimethamine in the treatment of uncomplicated Plasmodium falciparum infections in Somalia. METHODS: Patients with clinical malaria in Merca, an area of high transmission of the disease, were treated with the standard regimens of chloroquine (25 mg/kg) or sulfadoxine/pyrimethamine (25 mg sulfadoxine and 1.25 mg pyrimethamine per kg). Similar patients in Gabiley, an area of low transmission, received the standard regimen of chloroquine. The clinical and parasitological responses were monitored for 14 days. FINDINGS: Chloroquine treatment resulted in clinical failure in 33% (n = 60) and 51% (n = 49) of the patients in Merca and Gabiley respectively. There were corresponding parasitological failures of 77% RII/RIII and 35% RII/RIII. Patients who experienced clinical failure had significantly higher initial parasitaemia than those in whom there was an adequate clinical response, both in Merca (t = 2.2; P t = 2.8; P n = 50) of the patients achieved an adequate clinical response despite a parasitological failure rate of 76% RII/RIII. CONCLUSION: Chloroquine should no longer be considered adequate for treating clinical falciparum malaria in vulnerable groups in the areas studied. Doubts about the therapeutic life of sulfadoxine/pyrimethamine in relation to malaria are raised by the high levels of resistance in the Merca area and underline the need to identify suitable alternatives.

OBJETIVO: Evaluar la eficacia de la cloroquina y la sulfadoxina/ pirimetamina en el tratamiento de las infecciones por Plasmodium falciparum sin complicaciones en Somalia. MÉTODOS: Se trató a pacientes con paludismo clínico de Merca, un área de alta transmisión de la enfermedad, con las pautas estándar de cloroquina (25 mg/kg) o sulfadoxina/pirimetamina (25 mg/kg de sulfadoxina y 1,25 mg/kg de pirimetamina). Se administró también el régimen ordinario de cloroquina a pacientes comparables de Gabiley, una zona de transmisión baja. La respuesta clínica y parasitológica se controló por espacio de 14 días. RESULTADOS: El tratamiento con cloroquina no tuvo efecto clínico en el 33% (n = 60) y el 51% (n = 49) de los pacientes de Merca y Gabiley, respectivamente. Los casos correspondientes sin efecto parasitológico (fracasos RII/RIII) representaron el 77% y el 35%. Los pacientes que no respondieron clínicamente presentaron una parasitemia inicial significativamente mayor que la de quienes sí lo hicieron, tanto en Merca (t = 2,2; P t = 2,8; P n = 50) de los pacientes respondieron favorablemente a nivel clínico, pese al 76% de fracasos RII/RIII observado a nivel parasitológico. CONCLUSIÓN: La cloroquina ha dejado de constituir una opción adecuada para tratar el paludismo clínico por falciparum entre los grupos vulnerables de las áreas estudiadas. Los altos niveles de resistencia observados en el área de Merca plantean dudas respecto a la vida terapéutica de la sulfadoxina/pirimetamina como agente antipalúdico y subrayan la necesidad de identificar alternativas adecuadas.

OBJECTIF: Evaluer l'efficacité de la chloroquine et de la sulfadoxine/pyriméthamine dans le traitement des infections non compliquées à Plasmodium falciparum en Somalie. MÉTHODES: Les patients atteints de paludisme clinique dans la région de Merca, où la transmission de la maladie est intense, ont été traités selon le schéma standard par la chloroquine (25 mg/kg) ou la sulfadoxine/pyriméthamine (25 mg/kg de sulfadoxine et 1,25 mg/kg de pyriméthamine). Des patients de mêmes caractéristiques mais dans la région de Gabiley, où la transmission de la maladie est faible, ont reçu le traitement standard par la chloroquine. La réponse clinique et la réponse parasitologique ont été suivies pendant 14 jours. RÉSULTATS: Le traitement par la chloroquine s'est soldé par un échec clinique chez 33 % des patients (n = 60) dans la région de Merca et 51 % des patients (n = 49) dans la région de Gabiley. Les taux d'échec parasitologique correspondants (RII/RIII) étaient respectivement de 77 % et 35 %. Chez les patients ayant présenté un échec clinique, la parasitémie initiale était significativement plus élevée que chez ceux ayant montré une réponse clinique satifaisante, aussi bien dans la région de Merca (t = 2,2 ; p<0,04) que dans celle de Gabiley (t = 2,8 ; p<0,01). Avec la sulfadoxine/pyriméthamine, 98 % des patients (n = 50) ont présenté une réponse clinique satisfaisante malgré un taux d'échec parasitologique (RII/RIII) de 76 %. CONCLUSION: Dans les régions étudiées, la chloroquine ne doit plus être considérée comme traitement adéquat du paludisme clinique à falciparum dans les groupes vulnérables. Les hauts niveaux de résistance observés dans la région de Merca soulèvent des doutes quant à la durée de vie thérapeutique de la sulfadoxine/pyriméthamine pour le traitement du paludisme et soulignent la nécessité d'identifier des alternatives convenables.