Evans Blue as a Simple Method to Discriminate Mosquitoes' Feeding Choice on Small Laboratory Animals

Author(s)

Maciel, Ceres ^[1] ; Fujita, Andre ^[2] ; Gueroni, Daniele I. ^[1] ; Ramos, Anderson D. ^[1] ; Capurro, Margareth L. ^{[3, 4]} ; Sa-Nunes, Anderson ^{[3, 1]}

Affiliation

^[1] Univ Sao Paulo, Inst Ciencias Biomed, Dept Imunol, Lab Imunol Expt, BR-05508 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Matemat Estat, Dept Ciencia Comp, BR-05508 Sao Paulo - Brazil

^[3] INCT EM, Rio De Janeiro - Brazil

^[4] Univ Sao Paulo, Inst Ciencias Biomed, Dept Parasitol, Lab Mosquitos Geneticamente Modificados, BR-05508 Sao Paulo - Brazil

• Document type: Journal article
• Source: PLoS One; v. 9, n. 10 OCT 21 2014.
• Web of Science Citations: 3

Abstract

Background: Temperature, humidity, vision, and particularly odor, are external cues that play essential roles to mosquito blood feeding and oviposition. Entomological and behavioral studies employ well-established methods to evaluate mosquito attraction or repellency and to identify the source of the blood meal. Despite the efficacy of such methods, the costs involved in the production or acquisition of all parts, components and the chemical reagents involved are unaffordable for most researchers from poor countries. Thus, a simple and relatively low-cost method capable of evaluating mosquito preferences and the blood volume ingested is desirable. Principal Findings: By using Evans blue (EB) vital dye and few standard laboratory supplies, we developed and validated a system capable of evaluating mosquito's choice between two different host sources of blood. EB-injected and PBS-injected mice submitted to a number of situations were placed side by side on the top of a rounded recipient covered with tulle fabric and containing Aedes aegypti mosquitoes. Homogenates from engorged mosquitoes clearly revealed the blood source (EB- or PBS-injected host), either visually or spectrometrically. This method was able to estimate the number of engorded mosquitoes, the volume of blood ingested, the efficacy of a commercial repellent and the attractant effects of black color and human sweat. Significance: Despite the obvious limitations due to its simplicity and to the dependence of a live source of blood, the present method can be used to assess a number of host variables (diet, aging, immunity, etc) and optimized for several aspects of mosquito blood feeding and vector-host interactions. Thus, it is proposed as an alternative to field studies, and it could be used for initial screenings of chemical compound candidates for repellents or attractants, since it replicates natural conditions of exposure to mosquitoes in a laboratory environment. (AU)

• FAPESP's process: 09/53637-0 - Anopheles-Plasmodium interaction: a multidisciplinary approach
• Grantee: Margareth de Lara Capurro-Guimarães
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 10/18216-1 - Role of host immunity on biological fitness of Aedes aegypti mosquito vector
• Grantee: Ceres Maciel de Miranda
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 09/09892-6 - Functional immunome of Aedes aegypti saliva
• Grantee: Anderson de Sá Nunes
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 11/22669-4 - Immunomodulation of experimental autoimmune encephalomyelitis by salivary gland extract of Aedes aegypti
• Grantee: Anderson Daniel Ramos
• Support Opportunities: Scholarships in Brazil - Doctorate