Aedes albopictus in northeast Mexico: Update on adult distribution and first report of parasitism by Ascogregarina taiwanensis

Background: Aedes albopictus has been known as efficient vector of dengue in Asian countries and its wide displacement of A. aegypti has been documented in many parts of the world. The present survey was carried out to update the distribution of A.  albopictus in Northeast Mexico and report the first record of parasitism of mosquitoes by Ascogregarina taiwanensisin Mexico.

Methods: Human landing collections were conducted in May every year between 2007 and 2009 across the three States, Nuevo Leon (NL), Tamaulipas and Coahuila in Northeast Mexico. Six human bait collections were also organized at the Cemetery of Gomez Farias (GF), a village in Southern Tamaulipas during the rainy and dry seasons in 2010. A. albopictuscaught in 2010 were dissected for parasitic protozoan gregarines.

Results: The results of human landing collections carried out during 2007-2010 across the three States of Northeast zone of Mexico revealed that A. albopictus is invading along the route between Monterrey city in NL and Tampico, Tamaulipas, but not into the arid state of Coahuila. A. albopictus was recorded in nine new municipalities in addition to the fifteen municipalities reported before 2005. Furthermore, six human-bait collections performed during the dry and rainy seasons in 2010 at the cemetery of Gomez Farias (GF) suggest the exclusion of A. aegypti on that site. Dominance was shared by Aedes quadrivittatus, another container-inhabitant but indigenous species, and A. albopictus during the dry and rainy seasons, respectively. The results of dissection of the mosquitoes for gregarines revealed the parasitism of A. albopictus by A. taiwanensis.

Conclusion: The results of this study showed that A. albopictus has spread to all the municipalities in Northeastern Mexico except the arid area and reported the first record of parasitic protozoan A. taiwanensis in Mexico. We recommend further studies on larval and adult populations of natural container-occupant mosquitoes in Northeastern Mexico in order to have a better documentation of the impact of A. albopictusupon the indigenous species community, and its epidemiological role in dengue transmission.

Keywords: Aedes albopictus, distribution, Aedes aegypti, Aedes quadrivittatus, Ascogregarina taiwanensis.