Research Article: Urban and semi-urban mosquitoes of Mexico City: A risk for endemic mosquito-borne disease transmission

Date Published: March 6, 2019

Publisher: Public Library of Science

Author(s): Eduardo Dávalos-Becerril, Fabián Correa-Morales, Cassandra González-Acosta, Rene Santos-Luna, Jorge Peralta-Rodríguez, Crescencio Pérez-Rentería, José Ordoñez-Álvarez, Herón Huerta, Mariana Carmona-Perez, José Alberto Díaz-Quiñonez, María Dolores Mejía-Guevara, Gustavo Sánchez-Tejeda, Pablo Kuri-Morales, Jesús Felipe González-Roldán, Miguel Moreno-García, Zach N. Adelman.

http://doi.org/10.1371/journal.pone.0212987

Abstract

Since past century, vector-borne diseases have been a major public health concern in several states of Mexico. However, Mexico City continues to be free of endemic mosquito-borne viral diseases. The city is the most important politic and economic state of Mexico and one of the most important city of Latin America. Its subtropical highland climate and high elevation (2240 masl) had historically made the occurrence of Aedes species unlikely. However, the presence of other potential disease vectors (Culex spp, Culiseta spp), and the current intermittent introductions of Aedes aegypti, have revealed that control programs must adopt routine vector surveillance in the city. In this study, we provide an updated species list from a five-years of vector surveillance performed in Mexico City. A total of 18,553 mosquito larvae were collected. Twenty-two species from genus Culex, Aedes, Culiseta, Anopheles, Lutzia and Uranotaenia were observed. Nine new mosquito records for the city were found. Ae. albopictus was recorded for the first time in Mexico City. Interestingly, a new record, Ae. epactius was the most frequent species reported. Cx. pipiens quinquefasciatus exhibited the highest number of individuals collected. We detected six areas which harbor the highest mosquito species records in the city. Cemeteries included 68.9% of our collection sites. Temporarily ponds showed the highest species diversity. We detected an increasing presence of Ae. aegypti, which was detected for three consecutive years (2015–2017), predominantly in the warmer microclimates of the city. We found a possible correlation between increasing temperature and Ae. aegypti and Ae. albopictus expanding range. This study provides a starting point for developing strategies related to environmental management for mosquito control. The promotion of mosquito control practices through community participation, mass media and education programmes in schools should be introduced in the city.

Partial Text

Between 225–247 species of mosquitoes from 20 genera are known to occur in the 32 states of México [1,2]. However, throughout the country, Aedes aegypti is the main vector of mosquito-borne viral diseases. Although the presence of Aedes albopictus has also been reported in several states [3], its impact as a relevant vector in Mexico is yet unknown. Interestingly, only Mexico City and the state of Tlaxcala remain without the endemic presence of Aedes spp mosquitoes. Thus far, both states continue to be free of endemic mosquito-borne viral diseases.

Larva collections came from 37 surveys performed across Mexico City over the period of 2012–2016. A total of 163 sites were inspected. Fourth instar larval samples were taken from a variety of habitats (natural and artificial) including: 1) cemeteries, 2) wetlands: non-tidal, semi-permanent wet areas, 3) municipal rain collectors: >25 m2 cement water containers, 4) natural lakes, 5) ponds: permanent bodies of water (natural or artificial) located in public parks or ecological preserves, 6) temporarily pools: seasonal small (< 5m2) bodies of water (natural or artificial) in parks and peri-domestic cemented tanks, 7) streams: natural or human-created shallow tributaries and low flow bodies of water 8) transportation canals: a 100-km network of 10–20 m width and 1–3 m deep canals, commonly used for tourism and food transportation, 8) Olympic canoe canals: a 27 ha and 2m deep artificial canoe sprint and rowing venue. A total of 18,546 mosquito larvae belonging to twenty-two species were collected in urban and semi-urban areas of Mexico City (Fig 2, S1 Fig), including the following genus: Culex (thirteen species), Aedes (one specie;), Culiseta (two species), Anopheles (two species), Lutzia (one species) and Uranotaenia (two species) (Table 1, Fig 3 and S2–S7 Figs). Ae. aegypti and Ae. albopictus were collected as eggs only. Nine new mosquito records for the city were found: Anopheles punctipennis, Aedes albopictus, Aedes epactius, Aedes scapularis, Culex bidens, Culex pinarocampa, Lutzia bigoti, Culex erraticus, and Uranotaenia lowii (Tables 1 and 2). The updated list now includes a total of 26 mosquito species (excluding Cx. peus and Cs. Dugesi, because synonymy) in Mexico City. Nine new records, and the intermittent but increased presence of Ae. aegypti, were documented. The present surveillance effort was the first to sample mosquitoes over a large extension of the city. Since previous collections may not have surveyed all the water bodies as in our present study, the newly recorded species may have been historically present. Our findings provide a starting point to create a suitable plan for mosquito control in Mexico City. A deeper understanding of the spatio-temporal dynamics of breeding sites and microecological habitat characteristics in Mexico City is required. Identifying associations between biological diversity and habitats may us enable to predict how populations will respond to habitat reduction, species competition and climate change.   Source: http://doi.org/10.1371/journal.pone.0212987

 

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