Circulación del parásito Echinococcus granulosus en Los Antiguos, Santa Cruz / Circulation of Echinococcus granulosus in Los Antiguos, Santa Cruz

Resumen La hidatidosis, causada por el parásito Echinococcus granulosus, es una zoonosis endémica en la provincia de Santa Cruz asociada a áreas de producción ganadera. El hombre puede permanecer asintomático durante un largo período luego de la infección. Una vez desarrollada, la enfermedad representa un importante problema de salud pública debido a la complejidad y el costo de su tratamiento. Los objetivos del trabajo fueron determinar la prevalencia de contaminación ambiental por E. granulosus en zona rural y periurbana de la localidad de Los Antiguos, mediante la detección de antígenos específicos en heces caninas, e identificar factores de riesgo de transmisión. Entre mayo-2016 y abril-2017, se visitaron 38 chacras periurbanas y estancias rurales, definidas como "unidades epidemiológicas". Se analizaron 144 muestras de heces de caninos con téc nica copro-ELISA. Se realizó una encuesta epidemiológica de los pobladores rurales sobre patrones culturales relacionados a la hidatidosis. Se encontró un índice de contaminación ambiental del 17.3% y el 44.7% de las unidades epidemiológicas fueron positivas. Se identificaron prácticas de riesgo como faena domiciliaria (34.2%), alimentación de caninos con vísceras crudas (52.6%), y ausencia de desparasitación de perros (86.8%). Alrededor de la mitad de la población encuestada desconocía las formas de contagio y las medidas de prevención de la enfermedad. Este trabajo muestra un índice alto de contaminación y establece una línea de base para realizar comparaciones a futuro. También refuerza la necesidad de implementar medidas de educación, prevención y control de hidatidosis a nivel local de acuerdo a los programas nacionales.

Abstract Hydatidosis − caused by the parasite Echinococcus granulosus − is a zoonosis endemic to the province of Santa Cruz, associated with areas of livestock production. Once infected, man may remain asymptomatic for a prolonged pe riod but the disease has an important impact on public health owing to the complexity and costs of its treatment. This study aimed at assessing the prevalence of environmental E. granulosus infection in rural and peri-urban areas of the town of Los Antiguos, through the detection of antigens in scattered canine feces, and to identify risk factors for transmission. From May-2016 to April-2017, 38 peri-urban and rural farms, defined as "epidemio logical units", were visited; 144 samples of canine feces were analyzed with the copro-ELISA technique. Rural settlers were enrolled in an epidemiological survey on cultural patterns related to hydatidosis. An environmental contamination index of 17.3% was found and 44.7% of the epidemiological units were positive. Risk practices were found, such as domiciliary slaughter (34.2%), canine feeding with raw viscera (52.6%), and lack of dog de worming (86.8%). In turn, about half of the surveyed population ignored the modes of transmission of the infection and the measures to prevent it. This work shows a high infection index in the area and establishes a baseline for future comparisons. It also reinforces the need to implement education, prevention, and control activities at the local level − according to national program guidelines − in order to reduce the prevalence of environmental contamination of the disease.

Comparison of feeding and defecation patterns between fifth-instar nymphs of Triatoma patagonica (Del Ponte, 1929) and Triatoma infestans (Klug, 1934) under laboratory conditions / Comparação dos padrões alimentar e de defecação em ninfas de quinto estádio de Triatoma patagonica (Del Ponte, 1929) e Triatoma infestans (Klug, 1934), em condições de laboratório

Among the vectors of Chagas disease, Triatoma patagonica is a species in the process of adaptation to the human environment. However, its vector competence is not well known. This study had the aim of evaluating and comparing feeding and defecation patterns among fifth-instar nymphs of Triatoma patagonica and Triatoma infestans that were fed ad libitum. The results showed that nymphs of Triatoma patagonica had a feeding pattern similar to that of Triatoma infestans. Sixty nine percent and 58 percent of nymphs of Triatoma patagonica and Triatoma infestans, respectively, produced their first defecation within five minutes after being fed. Triatoma patagonica defecated during feeding, with an average time until first defecation that was shorter than that of Triatoma infestans (3.4 and 6.2 min, respectively). The nymphs of Triatoma patagonica were capable of defecating during or immediately after feeding.

Entre os vetores da doença de Chagas, Triatoma patagonica é uma espécie que se encontra em processo de adaptação ao ambiente humano; embora sua competência vetorial não seja bem conhecida. O estudo teve como objetivo avaliar e comparar padrões de alimentação e defecação em ninfas de quinto estádio de Triatoma patagonica e Triatoma infestans ad libitum. Os resultados mostraram que as ninfas de Triatoma patagonica apresentou padrõe de alimentação semelhante a Triatoma infestans. Sessenta e nove por cento e 58 por cento das ninfas de Triatoma patagonica e Triatoma infestans respectivamente, realizaram a primeira defecação cinco minutos após de serem alimentadas; sendo que a primeira defecou durante a alimentação, com um tempo médio de dejeção menor do que para Triatoma infestans (3,4 vs 6,2 respectivamente). As ninfas de Triatoma patagonica foram capazes de defecar durante ou imediatamente após de se alimentarem.