First national record of Aedes melanimon (Diptera: Culicidae) in Mexico

Aedes (Ochlerotatus) melanimon Dyar 1924 has been considered an important pest in agricultural and rural communities. Aedes melanimon is a vector of WEEV and CEV and is a competent laboratory vector of WNV. The known range of Ae. melanimon extends throughout Southwest Canada, part of Central and most of Western USA. Here we report the first record of Ae. melanimon in Mexico, at Ciudad Juárez, Chihuahua. The collect represents the southernmost distributional record for this species. Its indigenous presence in a highly urbanized and dry area was not expected. A permanent surveillance program to detect and determine the species in border-crossing cities is encouraged.

New records of Triatoma huehuetenanguensis in an urban area of Southwest Mexico

The recently described Triatoma huehuetenanguensis, has been reported in Mexico, Guatemala, Belize and Honduras. In Mexico, the species has been collected primarily in rural areas; it has the potential to colonize human dwellings, however, its contribution to Chagas outbreaks remains unclear. In 2021, T. huehuetenanguensis was first observed at Tuxtla Gutierrez city, Chiapas; then a collection for the species was performed. A total of 308 houses were inspected in the intra and peridomestic structures. Only 3 houses (0.97%) were infested. Triatoma huehuetenangensis was the only triatomine specie recorded and four males were collected. None of the bugs tested positive for Trypanosoma infection. We do not have evidence to suggest that urban human-vector contact still limited, and a possible domestication process is possible. The presence of reservoirs, the vector species and the parasite demonstrate that Tuxtla Gutierrez could be at risk of a Chagas disease outbreak.

COVID-19 y su impacto en el control del mosquito Aedes (Stegomyia) aegypti y la vigilancia epidemiológica de infecciones por arbovirus / COVID-19 and its impact on the control of Aedes (Stegomyia) aegypti mosquito and the epidemiological surveillance of arbovirus infections

Resumen En países americanos, simultáneas a la pandemia de enfermedad por coronavirus 2019 (COVID-19) se están dando epidemias ocasionadas por diferentes arbovirus (del dengue, chikunguña y virus del Zika). En México, varias de las estrategias para control del mosquito Aedes aegypti, transmisor de arbovirus, involucran la interacción del personal salubrista y los moradores. Debido a la pandemia de COVID-19 se han implementado medidas de distanciamiento social y resguardo domiciliario. Para respetar estas medidas y evitar riesgo de contagio por coronavirus 2 del síndrome respiratorio agudo grave (SARS-CoV-2), el Centro Nacional de Programas Preventivos y Control de Enfermedades (CENAPRECE) ha presentado la estrategia de control de vectores en el escenario de transmisión simultánea por dengue y COVID-19 en México. En este trabajo mencionamos las medidas habituales de manejo integral de mosquito y mencionamos las adaptaciones realizadas. De igual forma, discutimos la relevancia de la capacitación y la supervisión al personal médico, esto debido a la similitud entre la sintomatología entre ambas patologías.

Abstract Countries of Latin America are dealing with a simultaneous COVID-19 and vector borne disease (VBDs, Dengue, Zika and Chikungunya) outbreaks. In Mexico, certain activities to control Aedes aegypti mosquito (the main VBDs vector) comprise community participation through the interaction between householders and vector control personnel. Preventive measures against COVID-19 include social distancing and stay-at-home strategy, to obey these policies, and reduce the risk of infection, the National Center for Preventive Programs and Disease Control of Mexico (CENAPRECE) has adapted the vector control approaches in the country. In this paper we mention routine prevention and control activities to control mosquitoes and show the adapted measures. Because, a number of symptoms of the COVID-19 and dengue fever overlap with each other, we also discuss the relevance of accurate disease surveillance and medic’s training and supervision.

El mosquito del dengue en la Ciudad de México. Invasión incipiente de Aedes aegypti y sus potenciales riesgos / Aedes aegypti, the dengue fever mosquito in Mexico City. Early invasion and its potential risks

Resumen Introducción: La Ciudad de México no tiene presencia endémica de Aedes aegypti, por lo que está libre de enfermedades transmitidas por vector como dengue, Zika y chikunguña. Sin embargo, existe evidencia de la presencia de huevecillos en la urbe desde 2015. Objetivo: Reportar la presencia constante y en aumento de huevecillos de Aedes aegypti en la Ciudad de México de 2015 a 2018. Método: Se realizó vigilancia a través de ovitrampas; se contabilizaron y eclosionaron huevecillos para determinar la especie. Resultados: De 2015 a 2018 fueron identificados 378 organismos como Aedes aegypti. En total fueron colectadas 76 ovitrampas positivas a Aedes aegypti en 50 sitios distintos de 11 alcaldías. El noreste de la Ciudad de México fue el área con mayor positividad. Conclusiones: Los resultados pueden estar indicando un periodo de colonización incipiente y la probable la existencia de colonias crípticas del mosquito, por lo que la Ciudad de México podría estar en riesgo de presentar epidemias de enfermedades transmitidas por vector.

Abstract Introduction: Mexico City has no endemic presence of Aedes aegypti, and it is therefore free of vector-borne diseases, such as dengue fever, Zika and chikungunya. However, evidence has shown the presence of Aedes aegypti eggs in the city since 2015. Objective: To report the constant and increasing presence of Aedes aegypti eggs in Mexico City from 2015 to 2018. Methods: Surveillance was carried out using ovitraps. Eggs were counted and hatched in order to determine the species. Results: From 2015 to 2018, 378 organisms were identified as Ae. aegypti. In total, 76 Aedes aegypti-positive ovitraps were collected at 50 different places in 11 boroughs of the city. Northeastern Mexico City was the area with the highest number of positive traps. Conclusions: The results may be indicating a period of early colonization and the probable existence of cryptic colonies of the mosquito, and Mexico City could be therefore at risk of experiencing vector-borne epidemics.

Experimental infection and vector competence of Zika virus in Aedes aegypti mosquitoes from Acapulco, Guerrero, Mexico / Infección experimental y competencia vectorial del virus Zika en mosquitos Aedes aegypti de Acapulco, Guerrero, México

Abstract: Objective: To gain a better understanding of the Zika virus (ZIKV) vector transmission in Mexico, we determined the vector competence of a local population ofAe. aegypti(Acapulco, Guerrero) for a strain of ZIKV isolated from a Mexican febrile patient. Materials and methods: Eggs were hatched and larvae were reared under controlled conditions. After five days post-emergence, female mosquitoes were fed an infectious blood-meal containing ZIKV. Mosquitoes were analyzed at 4, 7 and 14-day post-infection (dpi). Infection (gut), dissemination (wings, legs and heads) and potential transmission (salivary glands) were assessed by RT-qPCR. The RockefellerAe. aegyptistrain was used as ZIKV infection control. Results: ZIKV infection, dissemination, and potential transmission rates were 96.2, 96.1 and 93.2%, respectively. Conclusions: Ae. aegypti(F1) from Acapulco were very susceptible to ZIKV infection, and showed similar vector competence to that of the susceptible Rockefeller strain. To our knowledge, this is the first report of vector competence for ZIKV performed in a Mexican laboratory.

Resumen: Objetivo: Determinar la competencia vectorial de una población local deAe. aegyptipara transmitir el virus Zika (ZIKV) aislado de un paciente febril mexicano. Material y métodos: Se desarrolló la primera generación (F1) de mosquitosAe. aegyptien el insectario a partir de huevos colectados mediante ovitrampas en la Colonia Renacimiento, Acapulco, Guerrero. Después de cinco días de la emergencia, los mosquitos hembras fueron alimentados con sangre infecciosa con ZIKV. La infección (intestino), la diseminación (alas, piernas y cabezas) y la transmisión potencial (glándulas salivales) se evaluaron mediante RT-qPCR, a los 4, 7 y 14 días después de la alimentación. Resultados: La infección por ZIKV, la diseminación y las tasas potenciales de transmisión fueron de 96.2, 96.1 y 93.2%, respectivamente. Conclusiones: Los mosquitos Ae. aegypti (F1) de Acapulco presentan una alta competencia vectorial (93.2%). Según los autores de este estudio, este es el primer informe de competencia vectorial para ZIKV realizado en un laboratorio mexicano.