title: Interactions between a fungal entomopathogen and malaria parasites within a mosquito vector.
abstract: BACKGROUND
  Mosquitoes are becoming increasingly resistant to the chemical insecticides currently available for malaria vector control, spurring interest in alternative management tools. One promising technology is the use of fungal entomopathogens. Fungi have been shown to impact the potential for mosquitoes to transmit malaria by reducing mosquito longevity and altering behaviour associated with flight and host location. Additionally, fungi could impact the development of malaria parasites within the mosquito via competition for resources or effects on the mosquito immune system. This study evaluated whether co-infection or superinfection with the fungal entomopathogen Beauveria bassiana affected malaria infection progress in Anopheles stephensi mosquitoes.
  
  
  METHODS
  The study used two parasite species to examine possible effects of fungal infection at different parasite development stages. First, the rodent malaria model Plasmodium yoelii was used to explore interactions at the oocyst stage. Plasmodium yoelii produces high oocyst densities in infected mosquitoes and thus was expected to maximize host immunological and resource demands. Second, fungal interactions with mature sporozoites were evaluated by infecting mosquitoes with the human malaria species Plasmodium falciparum, which is highly efficient at invading mosquito salivary glands.
  
  
  RESULTS
  With P. yoelii, there was no evidence that fungal co-infection (on the same day as the blood meal) or superinfection (during a subsequent gonotrophic cycle after parasite infection) affected the proportion of mosquitoes with oocysts, the number of oocysts per infected mosquito or the number of sporozoites per oocyst. Similarly, for P. falciparum, there was no evidence that fungal infection affected sporozoite prevalence. Furthermore, there was no impact of infection with either malaria species on fungal virulence as measured by mosquito survival time.
  
  
  CONCLUSIONS
  These results suggest that the impact of fungus on malaria control potential is limited to the well-established effects on mosquito survival and transmission behaviour. Direct or indirect interactions between fungus and malaria parasites within mosquitoes appear to have little additional influence.
authors.affiliation: Merkle Laboratory, The Pennsylvania State University, University Park, PA, 16803, USA. yxh5118@psu.edu.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Heinig
authors.affiliation: Merkle Laboratory, The Pennsylvania State University, University Park, PA, 16803, USA. mbt13@psu.edu.
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Thomas
mesh_terms: D000818:Animals; D000852:Anopheles / Q000382:microbiology*; D054884:Host-Pathogen Interactions / Q000502:physiology*; D006801:Humans; D006999:Hypocreales / Q000502:physiology*; D016778:Malaria, Falciparum; D051379:Mice; D033661:Oocysts; D010572:Pest Control, Biological; D010963:Plasmodium falciparum / Q000382:microbiology / Q000502:physiology*; D010967:Plasmodium yoelii / Q000382:microbiology / Q000502:physiology*; D034101:Sporozoites; D016019:Survival Analysis