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El estudio de la fauna parasitológica de roedores silvestres constituye una clave importantepara enfrentar situaciones de riesgo en salud pública, conservación y producción animal,debido al impacto que algunos de estos parásitos pueden producir en la salud de sereshumanos, animales silvestres y animales de producción y compañía. En mayo de 2011 secolectaron muestras de materia fecal de ratones silvestres en los municipios de Garzón y ElAgrado (Huila, Colombia), con el fin de identificar, mediante evaluación coprológica, lasespecies de parásitos gastrointestinales presentes en roedores de dicha zona. Se capturaronsiete ratones de la especie Sigmodon hirsutus, se tomaron muestras de materia fecal y losanimales fueron liberados posteriormente. En las muestras se observaron huevos de lafamilia Hymenolepididae, con características morfológicas que los ubican en los génerosHymenolepis o Rodentolepis. El hallazgo de estos parásitos en las heces de roedores silvestresen áreas de hábitat compartido con seres humanos sugiere un factor de riesgo zoonótico. Sinembargo, se requieren investigaciones adicionales que permitan establecer asociación entreel parasitismo gastrointestinal en humanos y la presencia de roedores en el área de estudio.

El estudio de la fauna parasitológica de roedores silvestres constituye una clave importantepara enfrentar situaciones de riesgo en salud pública, conservación y producción animal,debido al impacto que algunos de estos parásitos pueden producir en la salud de sereshumanos, animales silvestres y animales de producción y compañía. En mayo de 2011 secolectaron muestras de materia fecal de ratones silvestres en los municipios de Garzón y ElAgrado (Huila, Colombia), con el fin de identificar, mediante evaluación coprológica, lasespecies de parásitos gastrointestinales presentes en roedores de dicha zona. Se capturaronsiete ratones de la especie Sigmodon hirsutus, se tomaron muestras de materia fecal y losanimales fueron liberados posteriormente. En las muestras se observaron huevos de lafamilia Hymenolepididae, con características morfológicas que los ubican en los génerosHymenolepis o Rodentolepis. El hallazgo de estos parásitos en las heces de roedores silvestresen áreas de hábitat compartido con seres humanos sugiere un factor de riesgo zoonótico. Sinembargo, se requieren investigaciones adicionales que permitan establecer asociación entreel parasitismo gastrointestinal en humanos y la presencia de roedores en el área de estudio.

Exposure studies in the laboratory are the predominantly used method to evaluate environmental impact of insecticides, but translating the results to risk assessment for an ecosystem involves many uncertainties. A risk factor that has received an increasing concern is the combined effects of various pesticides in the environment, each present in supposedly non-harmful concentrations but may together have a joint effect. The recent losses of managed honey bees (Apis mellifera) have raised the attention to the combined effect from pesticide cocktails, and the use of neurotoxic insecticides. As a result a restriction of Imidacloprid and two other neonicotinoid insecticides, has been implemented in the European Union. However, this group of insecticides alone does not seem to carry the responsibility of the decline in bee populations, and a combined effect of mite infestations, virus infections and insecticides is suggested to be the cause of the bee colony collapse. In this study we are using the established parasite Hymenolepis diminuta – host Tenebrio molitor model to evaluate combined effects of a parasitic infection and exposure to sub-lethal doses of insecticides. To evaluate toxic effects of the insecticides directly on the parasite, mature cysticercoids were exposed to Lambda-Cyhalothrin and Chlorphyriphos whereupon cysticercoid viability was estimated by the quantity of successful excystations. No indication of negative effects to cysticercoids as a consequence of exposure was found. To determine joint effects of parasitism and insecticide exposure on the beetles, these were divided into four groups: control, infected, exposed, and infected and exposed. The exposed groups were treated with Lambda-Cyhalothrin at a concentration of 2 ng/beetle (dose estimated from a dose response experiment) and the parasite infection was obtained by exposing the beetles to a dose of approximately 120 parasite eggs. No effect of insecticide exposure to the host was found

Exposure studies in the laboratory are the predominantly used method to evaluate environmental impact of insecticides, but translating the results to risk assessment for an ecosystem involves many uncertainties. A risk factor that has received an increasing concern is the combined effects of various pesticides in the environment, each present in supposedly non-harmful concentrations but may together have a joint effect. The recent losses of managed honey bees (Apis mellifera) have raised the attention to the combined effect from pesticide cocktails, and the use of neurotoxic insecticides. As a result a restriction of Imidacloprid and two other neonicotinoid insecticides, has been implemented in the European Union. However, this group of insecticides alone does not seem to carry the responsibility of the decline in bee populations, and a combined effect of mite infestations, virus infections and insecticides is suggested to be the cause of the bee colony collapse. In this study we are using the established parasite Hymenolepis diminuta – host Tenebrio molitor model to evaluate combined effects of a parasitic infection and exposure to sub-lethal doses of insecticides. To evaluate toxic effects of the insecticides directly on the parasite, mature cysticercoids were exposed to Lambda-Cyhalothrin and Chlorphyriphos whereupon cysticercoid viability was estimated by the quantity of successful excystations. No indication of negative effects to cysticercoids as a consequence of exposure was found. To determine joint effects of parasitism and insecticide exposure on the beetles, these were divided into four groups: control, infected, exposed, and infected and exposed. The exposed groups were treated with Lambda-Cyhalothrin at a concentration of 2 ng/beetle (dose estimated from a dose response experiment) and the parasite infection was obtained by exposing the beetles to a dose of approximately 120 parasite eggs. No effect of insecticide exposure to the host was found

We investigated the relative biological effectiveness (RBE) of fast neutrons compared with X-rays in impeding development of immunity to an infective agent, the intestinal cestode Hymenolepis nana. Mice were irradiated with neutrons or X-rays and 2 days later given an immunizing dose of H. nana eggs. After another 2 days, the mice received a challenge dose of the eggs. Challenge egg doses were also given to sham-irradiated unimmunized and immunized controls., All mice were killed 90 to 92 hours after challenge, and the H. nana larvae (cysticercoids) that developed in the intestinal tissue were counted. An increased cysticercoid count in the irradiated mice, as compared with the count in unirradiated immunized controls, reflects suppression of immune capacity by the radiation. The results indicate a neutron RBE of 4 at 50 and 101 rad.