title: Paratransgenesis to control malaria vectors: a semi-field pilot study.
abstract: BACKGROUND
  Malaria still remains a serious health burden in developing countries, causing more than 1 million deaths annually. Given the lack of an effective vaccine against its major etiological agent, Plasmodium falciparum, and the growing resistance of this parasite to the currently available drugs repertoire and of Anopheles mosquitoes to insecticides, the development of innovative control measures is an imperative to reduce malaria transmission. Paratransgenesis, the modification of symbiotic organisms to deliver anti-pathogen effector molecules, represents a novel strategy against Plasmodium development in mosquito vectors, showing the potential to reduce parasite development. However, the field application of laboratory-based evidence of paratransgenesis imposes the use of more realistic confined semi-field environments.
  
  
  METHODS
  Large cages were used to evaluate the ability of bacteria of the genus Asaia expressing green fluorescent protein (Asaia (gfp)), to diffuse in Anopheles stephensi and Anopheles gambiae target mosquito populations. Asaia (gfp) was introduced in large cages through the release of paratransgenic males or by sugar feeding stations. Recombinant bacteria transmission was directly detected by fluorescent microscopy, and further assessed by molecular analysis.
  
  
  RESULTS
  Here we show the first known trial in semi-field condition on paratransgenic anophelines. Modified bacteria were able to spread at high rate in different populations of An. stephensi and An. gambiae, dominant malaria vectors, exploring horizontal ways and successfully colonising mosquito midguts. Moreover, in An. gambiae, vertical and trans-stadial diffusion mechanisms were demonstrated.
  
  
  CONCLUSIONS
  Our results demonstrate the considerable ability of modified Asaia to colonise different populations of malaria vectors, including pecies where its association is not primary, in large environments. The data support the potential to employ transgenic Asaia as a tool for malaria control, disclosing promising perspective for its field application with suitable effector molecules.
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Maria Vittoria
authors.initials: MV
authors.lastname: Mancini
authors.affiliation: Department of Experimental Medicine, Centro di Genomica Funzionale, University of Perugia, Perugia, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Spaccapelo
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Damiani
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Accoti
authors.affiliation: Department of Experimental Medicine, Centro di Genomica Funzionale, University of Perugia, Perugia, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Tallarita
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Petraglia
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Rossi
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Cappelli
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Aida
authors.initials: A
authors.lastname: Capone
authors.affiliation: Department of Experimental Medicine, Centro di Genomica Funzionale, University of Perugia, Perugia, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Peruzzi
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Valzano
authors.affiliation: Department of Experimental Medicine, Centro di Genomica Funzionale, University of Perugia, Perugia, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Picciolini
authors.affiliation: Institut de Recherche en Sciences de la Sante (IRSS), Direction Regionale de l'Ouest (DRO), BP 390, Bobo Dioulasso, Burkina Faso.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Diabaté
authors.affiliation: Department of Experimental Medicine, Centro di Genomica Funzionale, University of Perugia, Perugia, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Facchinelli
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Ricci
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino, Italy. guido.favia@unicam.it.
authors.forename: Guido
authors.initials: G
authors.lastname: Favia
mesh_terms: D016947:Acetobacteraceae / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D000818:Animals; D000852:Anopheles / Q000382:microbiology* / Q000502:physiology*; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D007303:Insect Vectors; D008856:Microscopy, Fluorescence; D008967:Molecular Biology; D010865:Pilot Projects; D011994:Recombinant Proteins / Q000032:analysis / Q000235:genetics; D013194:Staining and Labeling
chemical_list: D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins
keywords: Anopheles; Asaia; Large cages trials; Paratransgenesis