Aedes aegypti (Diptera: Culicidae) in a tree hole in Brazil

Dear Editor,

Aedes aegypti aegypti, commonly abbreviated as Ae. aegypti, can be differentiated from Ae. aegypti formosus, a purely sylvatic species in sub-Saharan Africa, whose immature forms mostly inhabit holes in stones and trees, and have also been collected in bamboo traps¹. Aedes aegypti eggs show good adaptation ability to other vessels and strong resistance to desiccation, which has facilitated its transportation to several regions worldwide by humans². It invaded the American continent through trading and slaving ships, subsequently adapting to a large area and transmitting yellow fever virus in cities across the continent, ranging from Baltimore in the United States to Buenos Aires in Argentina³, and has since been incriminated in the transmission of several arboviruses⁴. It has also been reported to rarely invade sylvatic environments in Rio de Janeiro⁵, as well as in rock holes in Anguilla and in tree holes in New Orleans⁶, and was found in tree holes in the Caribbean among 12 types of habitats⁷. Furthermore, Ae. aegypti was found in 12 of 30 tree holes containing water, with one found only 300m from an urban area in Salta, Argentina⁸.

Between January and May 2016, three larvae of Ae. aegypti were obtained from a hole in a Tipuana tree on three different occasions. The tree is located in a partially preserved area of an aquatic club in an urban area in the City of Ijuí, in the State of Rio Grande do Sul, Brazil. The cavity could hold 2L of water with a 20-cm diameter external aperture, and was situated at a height of 1.5m. The 5-ha park is contiguous to houses on the Eastern and Southern sides and to farms in the other directions; the vegetation is constituted by scattered trees, without understory, and frequenters of the club regularly walk among the trees.

This occurrence of Ae. aegypti, the first to be reported in Brazil besides one report of Ae. aegypti being predated by a tipulid in a tree hole⁹, is most likely attributed to the plasticity of the mosquito. This finding raises concern owing to the potential for interactions with other sylvatic mosquitoes, mostly of the genus Haemagogus, which are sylvatic vectors of yellow fever in Brazil¹⁰. Such interspecies interactions could facilitate the transmission of arboviruses, and may cause difficulty in vector control due to a reservoir of immature forms that are out of reach of insecticides and destruction of breeding sites. The recent findings of positive serology for dengue in patas monkeys (Erythrocebus patas) and rhesus macaques (Macaca mulatta) in Puerto Rico¹¹ and of marmosets (Callithrix jacchus) and capuchin-monkeys (Sapajus libidinosus) infected by Zika virus in the State of Ceara¹² emphasize the need for thorough surveys in natural habitats in the region of Ijui and others throughout Brazil.

• ¹
  Lounibos LP. Genetic-control trials and the ecology of Aedes aegypti at the Kenya coast. Takken W, Scott TW, editors. Ecological aspects for application of genetically modified mosquitoes. Kluwer Academic Publishers, Dordrecht, The Netherlands, 2003. p. 33-43.
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  Powell JR, Tabachnick WJ. History of domestication and spread of Aedes aegypti - a review. Mem Inst Oswaldo Cruz 2013; 101(supl 1):11-17.
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  Marcondes CB, Ximenes MFFM. Zika virus in Brazil and the danger of infestation by Aedes (Stegomyia) mosquitoes. Rev Soc Bras Med Trop 2016; 49:4-10.
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  Lourenço-de-Oliveira R, Castro MG, Braks MAH, Lounibos LP. The invasion of urban forest by dengue vectors in Rio de Janeiro. J Vector Ecol 2004; 29:94-100.
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  Wallis GP, Tabachnick WJ. Genetic analysis of rock hole and domestic Aedes aegypti on the Caribbean island of Anguilla. J Am Mosq Control Assoc 1990; 6:625-630.
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  Chadee DD, Ward RA, Novak RJ. Natural habitats of Aedes aegypti in the Caribbean - a review. J Am Mosq Control Assoc 1998; 14:5-11.
• ⁸
  Mangudo C, Aparicio JP, Gleiser RM. Tree holes as larval habitats for Aedes aegypti in urban, suburban and forest habitats in a dengue affected area. Bull Entomol Res 2015; 105:679-684.
• ⁹
  Shannon RC. Encyc Ent B 11, Diptera 1929; 5:155-162 (in article by C. P. Alexander). Apud Christophers SR. Aedes aegypti (L.), the yellow fever mosquito: its life history, bionomics and structure. Cambridge Univ. Press, 1960.
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  Vasconcelos PFC. Febre amarela. Rev Soc Bras Med Trop 2003; 36:295-293.
• ¹¹
  Hemme RR, Lopez-Ortiz R, Garcia BR, Sharp TM, Galloway RL, Elrod MG, et al. Serological evidence of infection with endemic human pathogens among free-ranging Old World monkeys in Puerto Rico. Am J Trop Med Hyg 2016; 94:1095-1099.
• ¹²
  Favoretto S, Araújo D, Oliveira D, Duarte N, Mesquita F, Zanotto P, et al. First detection of Zika virus in neotropical primates in Brazil: a possible new reservoir. bioRxiv preprint first posted online Apr. 20, 2016; doi: http://dx.doi.org/10.1101/049395
  » http://dx.doi.org/10.1101/049395

Publication Dates

• Publication in this collection
  May-Jun 2016

History

• Received
  07 June 2016
• Accepted
  09 June 2016