title: The prevalence and persistence of sigma virus, a biparentally transmitted parasite ofDrosophila melanogaster.
abstract: OBJECTIVE
  How do vertically transmitted parasites persist?
  Drosophila melanogaster(host) and sigma virus (parasite).
  Peach stands in northern Georgia, USA, on a transect between Macon and Athens.
  We estimated prevalence in the field. We also estimated male and female transmission in the laboratory, using field-collected animals as parents. We further quantified patrilineal (father to son) transmission in the laboratory, and estimated cost of infection (virulence) by quantifying decreased egg production of infected flies.
  Discrete-time, deterministic models for prevalence; analysis of stability of disease-free and endemic equilibria; numerical computation of equilibria based on empirical estimates.
  Random mating, discrete generations, cost of infection to females only.
  The model allows persistence under parameter estimates obtained for this population. Uncertainty in parameters leads to wide confidence intervals on the predicted prevalence, which may be systematically underestimated due to Jensen's inequality. Male transmission is required for persistence, and multiple generations of strictly patrilineal transmission are possible in the laboratory, albeit with decreasing transmission efficiency.
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida, USA ; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA ; UF Genetics Institute, University of Florida, Gainesville, Florida, USA.
authors.forename: Marta L
authors.initials: ML
authors.lastname: Wayne
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida, USA.
authors.forename: Gabriela M
authors.initials: GM
authors.lastname: Blohm
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida, USA.
authors.forename: Mollie E
authors.initials: ME
authors.lastname: Brooks
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida, USA ; Department of Biological Sciences, University of Notre Dame, South Bend, Indiana, USA.
authors.forename: Kerry L
authors.initials: KL
authors.lastname: Regan
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida, USA.
authors.forename: Brennin Y
authors.initials: BY
authors.lastname: Brown
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Barfield
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida, USA ; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Holt
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida, USA ; Department of Mathematics, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Bolker
keywords: Drosophila melanogaster; evolution of virulence; host–pathogen co-evolution; persistence; prevalence; vertical transmission