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The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City.

Diaz-Badillo A, Bolling BG, Perez-Ramirez G, Moore CG, Martinez-Munoz JP, Padilla-Viveros AA, Camacho-Nuez M, Diaz-Perez A, Beaty BJ, Munoz Mde L - Parasit Vectors (2011)

Bottom Line: Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City.The presence and abundance of these WNV competent vectors is a cause for concern.Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Madero, México DF, México.

ABSTRACT

Background: Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids.

Results: Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected.

Conclusions: Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.

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Related in: MedlinePlus

Location of mosquito sampling sites and species detected in Mexico City for 2004. The map of Mexico City displays the distribution of the mosquito species identified in the collection sites with some climatic and geographic features including humidity, isohyets, isotherms and surrounding states. Numbers in black indicate morphological identification of Culex spp.; in blue Culex spp., Culiseta and Ochlerotatus; in red Culex spp. and Culiseta; in purple Culex spp. and Ochlerotatus; and in brown Culex spp. and Cx. tarsalis.
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Figure 2: Location of mosquito sampling sites and species detected in Mexico City for 2004. The map of Mexico City displays the distribution of the mosquito species identified in the collection sites with some climatic and geographic features including humidity, isohyets, isotherms and surrounding states. Numbers in black indicate morphological identification of Culex spp.; in blue Culex spp., Culiseta and Ochlerotatus; in red Culex spp. and Culiseta; in purple Culex spp. and Ochlerotatus; and in brown Culex spp. and Cx. tarsalis.

Mentions: A total of 202,148 mosquito larvae belonging to the genera Culex (77%), Culiseta (18%) and Ochlerotatus (5%) were collected from 3,955 containers from cemeteries in 16 Districts in Mexico City (Additional file 1). Larvae were collected in all sites; 49.5% of the collected sites yielded Cx. pipiens complex mosquitoes exclusively; 40.7% of the sites yielded Ochlerotatus mosquitoes, and 33.9% of the sites yielded Culiseta mosquitoes. Interestingly, Cx. tarsalis was identified only in Peñon de los Baños (site 87-VC) close to the international airport (Figure 2, 3) coexisting with Cx. p. quinquefasciatus. Furthermore, Cx. pipiens complex were coexisting with Culiseta and Ochlerotatus in 25 sites, with Culiseta in 10 sites, and with Ochlerotatus in 17 sites (Figure 2). In this study, we used 3 different land cover classes, urban, suburban and rural areas (Figure 1A-C) to characterize the landscape in different regions of Mexico City. The locations of all mosquitoes belonging to the different genera are displayed in Figure 2.


The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City.

Diaz-Badillo A, Bolling BG, Perez-Ramirez G, Moore CG, Martinez-Munoz JP, Padilla-Viveros AA, Camacho-Nuez M, Diaz-Perez A, Beaty BJ, Munoz Mde L - Parasit Vectors (2011)

Location of mosquito sampling sites and species detected in Mexico City for 2004. The map of Mexico City displays the distribution of the mosquito species identified in the collection sites with some climatic and geographic features including humidity, isohyets, isotherms and surrounding states. Numbers in black indicate morphological identification of Culex spp.; in blue Culex spp., Culiseta and Ochlerotatus; in red Culex spp. and Culiseta; in purple Culex spp. and Ochlerotatus; and in brown Culex spp. and Cx. tarsalis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117809&req=5

Figure 2: Location of mosquito sampling sites and species detected in Mexico City for 2004. The map of Mexico City displays the distribution of the mosquito species identified in the collection sites with some climatic and geographic features including humidity, isohyets, isotherms and surrounding states. Numbers in black indicate morphological identification of Culex spp.; in blue Culex spp., Culiseta and Ochlerotatus; in red Culex spp. and Culiseta; in purple Culex spp. and Ochlerotatus; and in brown Culex spp. and Cx. tarsalis.
Mentions: A total of 202,148 mosquito larvae belonging to the genera Culex (77%), Culiseta (18%) and Ochlerotatus (5%) were collected from 3,955 containers from cemeteries in 16 Districts in Mexico City (Additional file 1). Larvae were collected in all sites; 49.5% of the collected sites yielded Cx. pipiens complex mosquitoes exclusively; 40.7% of the sites yielded Ochlerotatus mosquitoes, and 33.9% of the sites yielded Culiseta mosquitoes. Interestingly, Cx. tarsalis was identified only in Peñon de los Baños (site 87-VC) close to the international airport (Figure 2, 3) coexisting with Cx. p. quinquefasciatus. Furthermore, Cx. pipiens complex were coexisting with Culiseta and Ochlerotatus in 25 sites, with Culiseta in 10 sites, and with Ochlerotatus in 17 sites (Figure 2). In this study, we used 3 different land cover classes, urban, suburban and rural areas (Figure 1A-C) to characterize the landscape in different regions of Mexico City. The locations of all mosquitoes belonging to the different genera are displayed in Figure 2.

Bottom Line: Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City.The presence and abundance of these WNV competent vectors is a cause for concern.Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Madero, México DF, México.

ABSTRACT

Background: Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids.

Results: Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected.

Conclusions: Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.

Show MeSH
Related in: MedlinePlus