Aedes aegypti on Madeira Island (Portugal): genetic variation of a recently introduced dengue vector

The increasing population of Aedes aegypti mosquitoes on Madeira Island (Portugal) resulted in the first autochthonous dengue outbreak, which occurred in October 2012. Our study establishes the first genetic evaluation based on the mitochondrial DNA (mtDNA) genes [cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 4 (ND4)] and knockdown resistance ( kdr ) mutations exploring the colonisation history and the genetic diversity of this insular vector population. We included mosquito populations from Brazil and Venezuela in the analysis as putative geographic sources. The Ae. aegypti population from Madeira showed extremely low mtDNA genetic variability, with a single haplotype for COI and ND4. We also detected the presence of two important kdr mutations and the quasi-fixation of one of these mutations (F1534C). These results are consistent with a unique recent founder event that occurred on the island of Ae. aegypti mosquitoes that carry kdr mutations associated with insecticide resistance. Finally, we also report the presence of the F1534C kdr mutation in the Brazil and Venezuela populations. To our knowledge, this is the first time this mutation has been found in South American Ae. aegypti mosquitoes. Given the present risk of Ae. aegypti re-invading continental Europe from Madeira and the recent dengue outbreaks on the island, this information is important to plan surveillance and control measures.

Neurotoxic activity and ultrastructural changes in muscles caused by the brown widow spider Latrodectus geometricus venom / Actividad neurotóxica y cambios ultraestructurales en musculos causados por el veneno de la araña viuda marrón Latrodectus geometricus

Brown widow spider (Latrodectus geometricus) venom (BrWSV) produces few local lesions and intense systemic reactions such as cramps, harsh muscle pains, nausea, vomiting and hypertension. Approximately 16 protein bands under reducing conditions and ~ 14 bands under non-reducing conditions on a 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis were observed. Neurotoxic clinical manifestations were confirmed in vivo, while proteolytic activity was demonstrated on gelatine film. Severe ultrastructural damages in mice skeletal muscles were observed at 3, 6, 12 and 24 h postinjection with at total of 45 µg of venom protein. Infiltration of eosinophils and ruptures of the cellular membranes were observed in the muscles along with swelling of the nuclear cover and interruption of the collagen periodicity. Altered mitochondrias and autophage vacuoles, nuclear indentation and mitochondria without cristae, slight increment of intermyofibrillar and subsarcolemic spaces and myelinic figures formation were also observed. In the capillary, endothelial membrane unfolding into the lumen was noticed; along with myelinic figures compatible with a toxic myopathy. Swollen sarcotubular systems with lysis of membrane, intense mitochondria autophagia and areas without pinocytic vesicles were observed. Swollen mitochondria surrounded by necrotic areas, myofibrillar disorganization and big vacuolas of the sarcotubular system, degenerated mitochondrium with formation of myelinic figure was seen. Glycogenosomes with small particulate, muscle type glycogen was noticed. Autophagic vacuole (autophagolysosomes) and necrotic areas were also noticed. These damages may be due to interactive effects of the multifactorial action of venom components. However, Latrodectus geometricus venom molecules may also be utilized as neuro therapeutic tools, as they affect neuronal activities with high affinity and selectivity. To our knowledge, the present study...

El veneno de la araña viuda marrón (Latrodectus geometricus) produce pocas lesiones locales pero intensas reacciones sistémicas, tales como calambres, dolores musculares severos, nauseas, vómitos e hipertensión arterial. Se observaron ~ 16 bandas de proteina bajo condiciones reducidas y ~14 bandas bajo condiciones no reducidas en electroforesis en geles de poliacrilamida al 12.5%. Las manifestaciones neurotóxicas clínicas fueron confirmadas in vivo, mientras que la actividad proteolítica fue demostrada en una placa de gelatina. Los músculos de ratón se estudiaron durante las 3, 6, 12 y 24 horas después de ser inyectados con 45 µg de proteina de veneno. Los músculos fueron seriamente dañados por este veneno. Se demostró una infiltracción de células eosinofílicas y rupturas de membranas celulares en tejido muscular, al mismo tiempo un fuerte incremento de la membrana nuclear y una interrupción de la periodicidad del colágeno. Se observaron daños en la mitocondria y sin cristaes, vacuolas autofágicas e indentación nuclear. Se notó un aumento de la luz de los espacios intermiofibrilares y subsarcolemicos. En los capilares fue visible un desdoblamiento de la membrana endotelial hacia el lúmen vascular. Del mismo modo, fue visto un hinchamiento del sistema sarcotubular con lisis de las membranas; intensa autofagia de mitocondrias y áreas sin vesículas pinocíticas. Fue además observado, glucogenosomas con glucogeno particulado. Se observaron vacuolas autofágicas (autofagolisosomas) y áreas de necrosis. Estos daños podrían ser atribuídos a los efectos interactivos de una acción multifactorial de los componentes del veneno.