title: The influence of dengue virus serotype-2 infection on Aedes aegypti (Diptera: Culicidae) motivation and avidity to blood feed.
abstract: BACKGROUND
  Dengue virus (DENV) is transmitted by Aedes aegypti, a species that lives in close association with human dwellings. The behavior of DENV-infected mosquitoes needs further investigation, especially regarding the potential influence of DENV on mosquito biting motivation and avidity.
  
  
  RESULTS
  We orally challenged 4-5 day-old Ae. aegypti females with a low passage DENV serotype -2 (DENV-2) to test whether the virus influences motivation to feed (the likelihood that a mosquito obtains a blood-meal and the size of its blood meal) and avidity (the likelihood to re-feed after an interrupted first blood-meal). To assay motivation, we offered mosquitoes an anesthetized mouse for 2, 3, 4 or 5 minutes 7 or 14 days after the initial blood meals and measured the time they started feeding. 60.5% of the unexposed mosquitoes fed on the mouse, but only 40.5% of the positive ones did. Exposed but negative mosquitoes behaved similarly to unexposed ones (55.0% feeding). Thus DENV-2 infection decreased the mosquitoes' motivation to feed. To assay avidity, we offered the same mosquitoes a mouse two hours after the first round of feeding, and we measured the time at which they started probing. The exposed (positive or negative) mosquitoes were more likely to re-feed than the unexposed ones and, in particular, the size of the previous blood-meal that kept mosquitoes from re-feeding was larger in the exposed than in the unexposed mosquitoes. Thus, DENV-2 infection increased mosquito avidity.
  
  
  CONCLUSIONS
  DENV-2 significantly decreased the mosquitoes' motivation to feed, but increased their avidity (even after taking account the amount of blood previously imbibed). As these are important components of transmission, we expect that the changes of the blood-feeding behaviour impact the vectorial capacity Ae. aegypti for dengue.
authors.affiliation: Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz, Fiocruz, Brazil. freitas@ioc.fiocruz.br
authors.forename: Rafael
authors.initials: R
authors.lastname: Maciel-de-Freitas
authors.forename: Gabriel
authors.initials: G
authors.lastname: Sylvestre
authors.forename: Mariana
authors.initials: M
authors.lastname: Gandini
authors.forename: Jacob C
authors.initials: JC
authors.lastname: Koella
mesh_terms: D000330:Aedes / Q000821:virology*; D000818:Animals; D003716:Dengue Virus / Q000502:physiology; D005247:Feeding Behavior; D005260:Female; D007303:Insect Vectors / Q000821:virology*; D051379:Mice; D009042:Motivation; D065288:Serogroup