Comparison of the efficacy of long-lasting insecticidal nets PermaNet® 2.0 and Olyset® against Anopheles albimanus under laboratory conditions

Insecticide-treated nets provide a reduction in human-vector contact through physical barrier, mortality and/or repellent effects that protect both users and non-users, thereby protecting the wider community from vector-borne diseases like malaria. Long-lasting insecticide-treated nets (LLINs) are the best alternative. This study evaluated the bioefficacy of LLINs PermaNet® 2.0 and Olyset® under laboratory conditions with Anopheles albimanus. The laboratory strain was evaluated for insecticide susceptibility with selected insecticides used for malarial control. Regeneration time and wash resistance were evaluated with the standard bioassay cone technique following WHO guidelines. Heat assistance was used for Olyset® nets; the nets were exposed to four different temperatures to speed the regeneration process. The regeneration study of PermaNet® 2.0 showed that efficacy was fully recovered by 24 h after one and three washes and wash resistance persisted for 15 washes. Regeneration of Olyset® nets was not observed for nets washed three times, even with the different temperature exposures for up to seven days. Thus, for Olyset® the wash resistance evaluation could not proceed. Differences in response between the two LLINs may be associated with differences in manufacturing procedures and species response to the evaluated LLINs. PermaNet® 2.0 showed higher and continuous efficacy against An. albimanus.

Biologia de las cucarachas: agentes sensibilizantes / Biology of cockroach: sensitized agents

Basándose en evidencias fosilizadas, se calcula que las cucarachas han estado presentes en la tierra por lo menos durante 300 millones de años, adaptándose constantemente a un medio ambiente cambiante. Este indiscutible éxito les permite colonizar cualquier hábitat y lugar del mundo. Es más, están especialmente adaptadas para sobrevivir con éxito en los ámbitos humanos, concretamente son especialistas en encontrar un microclima que favorezca su reproducción, desarrollo y supervivencia en un medio que les es hostil. Mundialmente se han logrado identificar cerca de 3500 especies de cucarachas, de las cuales 19 tienen importancia médica, y de éstas solo siete se pueden considerar realmente como una plaga