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.

Anticuerpos anti-Trypanosoma cruzi en migrantes latinoamericanos en tránsito por el cruce fronterizo entre México y los Estados Unidos / Anti-Trypanosoma cruzi antibodies in Latin American migrants in transit through the México-USA border

Resumen Introducción. En los últimos años, la tripanosomiasis americana se ha convertido en un problema de salud pública emergente en países receptores de poblaciones migrantes, como México, Estados Unidos, Canadá y los países europeos. Objetivo. Analizar la prevalencia de anticuerpos anti-Trypanosoma cruzi mediante técnicas serológicas, en los migrantes latinos en su paso hacia Estados Unidos y Canadá. Materiales y métodos. Se hicieron análisis serológicos mediante ELISA y la prueba de hemaglutinación indirecta (HAI) para detectar anticuerpos anti-T. cruzi, y encuestas socioeconómicas para determinar los factores asociados a los casos seropositivos que favorecieron la transmisión en el país de origen de los migrantes. Resultados. La seroprevalencia total en la población estudiada fue del 20 % (24/120). La prevalencia más alta se encontró en migrantes de Guatemala, con 37,5 % (6/16), seguidos de los de Honduras (22,6 %; 12/53), El Salvador (16 %; 4/25) y México (8,7 %; 3/23). De los 120 migrantes encuestados, 105 (87,5 %) reconocieron el vector y 62 (59 %) afirmaron haber sido picados por este. La asociación de la infección con los materiales de construcción de las paredes de las viviendas, así como con la presencia de mascotas (perros) en los hogares, fue muy significativa (p≤0,01). La asociación con el material de construcción del patio, los servicios básicos precarios, así como la cría de animales dentro de corrales en la periferia de los hogares, también fue significativa (p≤0,05). Conclusión. Los países no endémicos que reciben migrantes de zonas endémicas deben mejorar o desarrollar políticas de salud para prevenir la transmisión del parásito por transfusión o por vía congénita.

Abstract Introduction: In recent years, American trypanosomiasis has become an emergent public health problem in countries receiving migrant populations such as México, USA, Canada or those in Europe. Objective: To analyze the prevalence of anti-Trypanosoma cruzi antibodies in Latin American migrants on their way to USA and Canada by means of serological techniques. Material and methods: ELISA and IHA were performed to detect anti-T. cruzi antibodies. Also, each participant filled out a socioeconomic questionnaire to determine the associated factors with seropositive cases, which could facilitate the transmission in the migrants' country of origin. Results: Total seroprevalence among the studied population was 20% (24/120). The highest prevalence was found in migrants from Guatemala with 37.5% (6/16), followed by Honduras (22.6%; 12/53), El Salvador (16%; 4/25), and México (8.7%, 3/23). From the total 120 surveyed migrants, 105 (87.5%) recognized the vector of Chagas' disease, and 62 (59%) assured having been bitten by it. Highly significant statistical associations were found between infection and the construction materials for walls and the presence of pets (dogs) inside houses (p≤0.01), as well as with the building materials for backyards, inadequate basic services, and animal breeding inside corrals built around dwellings (p≤0.05). Conclusion: Non-endemic countries receiving migrants from endemic areas should enhance or develop better health policies to prevent transfusion-transmitted Chagas or congenital parasite transmission.

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.