Novel Kdr mutations (K964R and A943V) in pyrethroid-resistant populations of Triatoma mazzottii and Triatoma longipennis from Mexico and detoxifying enzymes

Although having five different ways of transmission the vector-borne is the principal way of transmission of Chagas disease, which involves insects of the subfamily Triatominae (Hemiptera: Reduviidae). Nineteen of the 31 species that occur in Mexico are associated with humans, and all are capable of transmitting the disease. Pyrethroids are the insecticides recommended for the control of these vectors in Mexico. We determined the susceptibility to the pyrethroids deltamethrin and permethrin of peridomestic populations of Triatoma mazzottii Usinger and two populations of Triatoma longipennis Usinger in comparison with a reference strain for each species. Bioassays were performed for the determination of the LD50 for both field populations and reference strains. A maximum of 27 fold resistance to deltamethrin was observed in T. mazzottii, meanwhile, for permethrin, T. longipennis from Jalisco show the highest value of 3.19 fold. There was significantly increased activity of esterases in field populations in comparison with their corresponding reference strain. The results of the search of kdr mutations related to the resistance to deltamethrin and permethrin in the evaluated species show the presence of mutations in the field populations, as is the case with individuals of T. mazzottii, for which the mutation was found A943V, and for the two populations of T. longipennis included in this study, we report the presence of the kdr mutation K964R. Evaluation of the various mechanisms involved in resistance to pyrethroids in triatomines from Mexico could guide us to the real justification for insecticide resistance monitoring.

Novel Kdr mutations (K964R and A943V) in pyrethroid resistant populations of Triatoma mazzottii Usinger and Triatoma longipennis Usinger from Mexico and detoxifying enzymes

Although having five different ways of transmission the vector-borne is theprincipal way of transmission of Chagas disease, which involves insects of the subfamilyTriatominae (Hemiptera: Reduviidae). Nineteen of the 31 species that occur in Mexico areassociated with humans, and all are capable of transmitting the disease. Pyrethroids are theinsecticides recommended for the control of these vectors in Mexico. We determined thesusceptibility to the pyrethroids deltamethrin and permethrin of peridomestic populationsof Triatoma mazzottii Usinger and two populations of Triatoma longipennis Usinger incomparison with a reference strain for each species. Bioassays were performed for thedetermination of the LD50 for both field populations and reference strains. A maximum of27 fold resistance to deltamethrin was observed in T. mazzottii, meanwhile, for permethrin,T. longipennis from Jalisco show the highest value of 3.19 fold. There was significantlyincreased activity of esterases in field populations in comparison with their correspondingreference strain. The results of the search of kdr mutations related to the resistance todeltamethrin and permethrin in the evaluated species show the presence of mutations inthe field populations, as is the case with individuals of T. mazzottii, for which the mutationwas found A943V, and for the two populations of T. longipennis included in this study,we report the presence of the kdr mutation K964R. Evaluation of the various mechanismsinvolved in resistance to pyrethroids in triatomines from Mexico could guide us to the realjustification for insecticide resistance monitoring.

¿Pueden los mosquitos transmitir el virus de la inmunodeficiencia humana? / Can mosquitoes transmit human immunodeficiency virus?

La transmisión del virus de la inmunodeficiencia humana (VIH) se conoce ocurre por contacto sexual, perinatalmente, y por exposición a sangre infectada o productos sanguíneos entre otros. Preguntarse si existe la posibilidad de transmisión del VIH por insectos hematófagos de personas infectadas a personas no infectadas ha sido y es un punto de intensa discusión. Las rutas clásicas de transmisión de patógenos por artrópodos chupadores de sangre son "mecánica" o "biológica". Ambas rutas son rechazadas, la última porque no existe replicación de retrovirus en el vector y su sobrevivencia en el artrópodo es muy limitada. La persistencia del VIH en un insecto o en sus partes bucales es uno de los numerosos factores necesarios para la transmisión mecánica en la naturaleza. El riesgo de transmisión del VIH por insectos parece ser extremadamente bajo o inexistente. En este artículo de revisión se exponen las razones y evidencias científicas que nos permiten concluir porque la transmisión del virus VIH por mosquitos no es posible.