Screening of mosquitoes as vectores of F. tularensis in Portugal

Abstract

Background: Francisella tularensis subsp. holartica is the etiologic agent of type B tularemia, an emergent zoonosis that occurred recently in Portugal´s neighboring country Spain, where there was an outbreak in 2007.(1) This fact has propelled the research of this pathogen in Portugal. Mosquitoes Culex spp. and Aedes spp. are considered important vectors of the pathogen in Sweden(2) but in Portugal the presence of F. tularensis subsp. holartica in mosquitoes has never been investigated. Materials and Methods and Materials: In this work wWe investigated the presence of F. tularensis subsp. holartica in 68 pools of mosquitoes with a total of 1373 mosquitos Culex spp., which were captured during the year of 2011 in the North of Portugal and in Alentejo, covering border areas with Spain Spanish affected regions. We also investigated 143 female mosquitoes of the genera Culex spp., Anopheles spp., Culiseta spp., Ochlerotatus spp. and Aedes spp. captured during 2011 all over the national territory. In the total,For the we studied 1516 mosquitos investigated for the presence of F. tularensis subsp. Holartica the distribution was as fallows: of which 97,8% Culex spp. (97,8%)., 0,5% Anopheles spp. (0,5%)., 0,5% Culiseta spp. (0,5%), 0,9% Ochlerotatus spp. (0,9%) and 0,4% Aedes spp. (0,4%) We usedA convenctional PCR for Francisella sp. was used for the specific partial amplification of tul4 gene in mosquito samples screening and the results were evaluated by gel electrophoresis. All samples that amplified fragments with the expected size were analyzed by sequencing sequenced. Results: (Until the moment, all samples investigated had were negative results for the presence of F. tularensis subs. holartica.)