Resumo A criação bem sucedida de animais em condições de laboratório para processos comerciais ou experimentais é uma cadeia complexa que inclui vários fatores de estresse (ex. coleta e transporte) que tem como consequência a redução das condições naturais do animal, prejuízos econômicos e resultados biológicos inconsistentes. Desde a invasão do bivalve Limnoperna fortunei (Dunker, 1857) na América do Sul, vários estudos têm sido realizados para ajudar no controle e gestão dessa praga em plantas industriais que utilizam água. Relativamente pouca atenção tem sido dada ao processo de criação de L. fortunei em laboratório, sua condição quando exposta ao estresse e sua aclimatação a condições de laboratório. Considerando estes aspectos, os objetivos deste estudo foram: (i) investigar as respostas fisiológicas de L. fortunei submetidos ao processo de depuração e subsequente transporte (sem água/condição seca) em duas temperaturas, analisando as diferentes concentrações de glicogênio e (ii) monitorar as concentrações de glicogênio nos diferentes grupos, quando mantidos por 28 dias em condições de laboratório. Com base nos resultados obtidos, a depuração não afetou nenhum grupo quando eles foram submetidos a oito horas de transporte. A variação da concentração de glicogênio entre os espécimes do campo quando depurados e não depurados, foi significativa apenas em relação à primeira semana em laboratório para o grupo não depurado e à segunda semana para o grupo depurado. Além disto, a temperatura testada não afetou os grupos submetidos ao transporte. As concentrações de glicogénio foram semelhantes as dos espécimes do campo a partir da terceira semana, o que sugere que os espécimes estão aclimatados às condições de laboratoriais neste período de tempo. Assim, os resultados indicam que o transporte ao ar e o tempo de aclimatação podem ser incorporados com sucesso aos estudos experimentais com L. fortunei. Finalmente, o conhecimento sobre a tolerância de L. fortunei ao estresse pode ajudar a entender a capacidade invasiva deste durante o processo de estabelecimento.

Abstract Successful animal rearing under laboratory conditions for commercial processes or laboratory experiments is a complex chain that includes several stressors (e.g., sampling and transport) and incurs, as a consequence, the reduction of natural animal conditions, economic losses and inconsistent and unreliable biological results. Since the invasion of the bivalve Limnoperna fortunei (Dunker, 1857) in South America, several studies have been performed to help control and manage this fouling pest in industrial plants that use raw water. Relatively little attention has been given to the laboratory rearing procedure of L. fortunei, its condition when exposed to a stressor or its acclimation into laboratory conditions. Considering this issue, the aims of this study are to (i) investigate L. fortunei physiological responses when submitted to the depuration process and subsequent air transport (without water/dry condition) at two temperatures, based on glycogen concentrations, and (ii) monitor the glycogen concentrations in different groups when maintained for 28 days under laboratory conditions. Based on the obtained results, depuration did not affect either of the groups when they were submitted to approximately eight hours of transport. The variation in glycogen concentration among the specimens that were obtained from the field under depurated and non-depurated conditions was significant only in the first week of laboratory growth for the non-depurated group and in the second week for the depurated group. In addition, the tested temperature did not affect either of the groups that were submitted to transport. The glycogen concentrations were similar to those of the specimens that were obtained from the field in third week, which suggests that the specimens acclimated to laboratory conditions during this period of time. Thus, the results indicate that the air transport and acclimation time can be successfully incorporated into experimental studies of L. fortunei. Finally, the tolerance of L. fortunei specimens to the stressor tested herein can help us understand the invasive capacity of this mussel during the establishment process.

Objective: To evaluate the efficacy of and resistance to mebendazole (500 mg) and levamisole (40 or 80 mg), alone or in combination, for the treatment of Ascaris lumbricoides, Trichuris trichiura and hookworm infections on Pemba Island - an area exposed to periodic school-based mebendazole treatment since 1994. Methods: A randomized, placebo-controlled trial was carried out in 914 children enrolled from the first and fifth grades of primary schools. Stool samples collected at baseline and 21 days after treatment were examined by the Kato-Katz technique to assess the prevalence and intensity of helminth infection. Findings: Efficacies of mebendazole and levamisole as single treatments against intestinal nematode infections were comparable with those in previous trials, but mebendazole treatment of hookworm infections gave significantly lower cure (7.6%) and egg reduction (52.1%) rates than reported in a study undertaken before the beginning of periodic chemotherapy (cure rate, 22.4%; egg reduction rate, 82.4%). Combined treatment with mebendazole and levamisole had a significantly higher efficacy against hookworm infections (cure rate, 26.1%; egg reduction rate, 88.7%) than either drug given alone. No difference in mebendazole efficacy was found in children who had been treated repeatedly compared with those who had not been treated previously. Conclusion: The overall efficacy of mebendazole against hookworm infections after periodic chemotherapy is reduced. The efficacy of benzimidazoles in chemotherapy-based control programmes should be monitored closely. Combined treatment with mebendazole and levamisole may be useful as a tool to delay the development of benzimidazole resistance.

Objetivo: Evaluar la eficacia del mebendazol (500 mg) y el levamisol (40 u 80 mg), solos o combinados, y la resistencia a ellos como tratamiento de las infecciones por Ascaris lumbricoides y Trichuris trichiura y de la anquilostomiasis en la Isla de Pemba, una zona en la que desde 1994 se llevan a cabo periódicamente tratamientos con mebendazol en las escuelas. Métodos: Se llevó a cabo un ensayo aleatorizado y controlado mediante placebo en 914 niños inscritos en alguno de los cinco primeros años de escuela primaria. Las muestras de heces obtenidas en la situación de partida y a los 21 días de tratamiento fueron analizadas mediante la técnica de Kato-Katz a fin de evaluar la prevalencia y la intensidad de las infecciones por helmintos. Resultados: La eficacia del mebendazol y el levamisol como tratamientos únicos de las infecciones intestinales por nematodos fue comparable a la observada en ensayos anteriores, pero la administración de mebendazol contra las infecciones por anquilostoma logró unas tasas de curación (7,6%) y de reducción del número de huevos (52,1%) significativamente inferiores a las notificadas en un estudio emprendido antes del comienzo de la antibioticoterapia periódica (tasa de curación, 22,4%; tasa de reducción del número de huevos, 82,4%). El tratamiento combinado con mebendazol y levamisol tuvo una eficacia significativamente mayor contra las infecciones por anquilostoma (tasa de curación, 26,1%; tasa de reducción del número de huevos, 88,7%) que cualquiera de los medicamentos por separado. No se observó ninguna diferencia en cuanto a la eficacia del mebendazol entre los niños tratados repetidamente y los que no habían sido tratados anteriormente. Conclusión: La eficacia global del mebendazol contra la anquilostomiasis se ve reducida después de la antibioticoterapia periódica. Debería vigilarse estrechamente la eficacia de los benzimidazoles en los programas de control basados en la antibioticoterapia. El tratamiento combinado con mebendazol y levamisol podría ser una valiosa arma para retrasar la aparición de resistencia a los benzimidazoles.

Objectif: Evaluer l'efficacité du mébendazole (500 mg) et du lévamisole (40 ou 80 mg) et la résistance à ces composés administrés seuls ou en association pour le traitement des infections à Ascaris lumbricoides, Trichuris trichiura et les ankylostomes sur l'île de Pemba, une région où sont effectués depuis 1994 des traitements périodiques par le mébendazole en milieu scolaire. Méthodes: Un essai contrôlé randomisé contre placebo a été réalisé sur 914 enfants des premier et cinquième niveaux de l'enseignement primaire. Des échantillons de selles recueillis au début de l'étude et 21 jours après le traitement ont été examinés par la technique de Kato-Katz afin d'évaluer la prévalence et l'intensité des helminthiases. Résultats: L'efficacité du mébendazole et du lévamisole en traitement unique des nématodoses intestinales était comparable à celle observée lors de précédents essais, mais le traitement des ankylostomiases par le mébendazole donnait des taux de guérison (7,6 %) et de réduction du nombre d'œufs (52,1 %) significativement plus faibles que lors d'une étude réalisée avant le début de la chimiothérapie périodique (taux de guérison : 22,4 % ; taux de réduction du nombre d'œufs : 82,4 %). Le traitement associé par le mébendazole et le lévamisole était significativement plus efficace contre les ankylostomiases (taux de guérison : 26,1 % ; taux de réduction du nombre d'œufs : 88,7 %) qu'un traitement par chacun des médicaments administrés séparément. Aucune différence d'efficacité du mébendazole n'a été observée entre les enfants ayant reçu une chimiothérapie périodique et ceux qui n'avaient jamais été traités auparavant. Conclusion: Il semble d'après les résultats que l'efficacité globale du mébendazole contre les ankylostomiases après chimiothérapie périodique soit diminuée. L'efficacité des benzimidazolés dans le cadre des programmes de lutte reposant sur la chimiothérapie doit être étroitement surveillée. Un traitement associant le mébendazole et le lévamisole peut être utile pour retarder le développement de la résistance à cette catégorie de médicaments.

We studied the stool samples of 151 school children in a district of the city of Portoviejo (Ecuador) in order to determine the prevalence and intensity of soil-transmitted helminthiasis (STH) and their relationships with anthropometric indices. The samples were analyzed with the semiquantitative Kato-Katz technique and the intensity of infections was categorized as light, moderate or high according to the thresholds set by the World Health Organization. Prevalence of soil transmitted helmintiasis was 65% (92 out of 141 collected samples), Ascaris lumbricoides was the most common STH (63%) followed by Trichuris trichiura (10%) and hookworm (1.4%). Heavy intensity infections were found in 8.5% of the stool samples, with T. trichiura showing higher worm burdens than A. lumbricoides. Sixteen percent of the children were below the third percentile for weight (wasted), while 27% were below the third percentile for height (stunted). A significant relationship was found between the worm burden and the degree of stunting. This study suggests that the periodic administration of an antihelminthic drug should be targeted to preschool and school children to allow a normal growth spurt and prevent stunting.