title: Quantifying the contribution of hosts with different parasite concentrations to the transmission of visceral leishmaniasis in Ethiopia.
abstract: BACKGROUND
  An important factor influencing the transmission dynamics of vector-borne diseases is the contribution of hosts with different parasitemia (no. of parasites per ml of blood) to the infected vector population. Today, estimation of this contribution is often impractical since it relies exclusively on limited-scale xenodiagnostic or artificial feeding experiments (i.e., measuring the proportion of vectors that become infected after feeding on infected blood/host).
  
  
  METHODS
  We developed a novel mechanistic model that facilitates the quantification of the contribution of hosts with different parasitemias to the infection of the vectors from data on the distribution of these parasitemias within the host population. We applied the model to an ample data set of Leishmania donovani carriers, the causative agent of visceral leishmaniasis in Ethiopia.
  
  
  RESULTS
  Calculations facilitated by the model quantified the host parasitemias that are mostly responsible for the infection of vector, the sand fly Phlebotomus orientalis. Our findings indicate that a 3.2% of the most infected people were responsible for the infection of between 53% and 79% (mean - 62%) of the infected sand fly vector population.
  
  
  CONCLUSIONS
  Our modeling framework can easily be extended to facilitate the calculation of the contribution of other host groups (such as different host species, hosts with different ages) to the infected vector population. Identifying the hosts that contribute most towards infection of the vectors is crucial for understanding the transmission dynamics, and planning targeted intervention policy of visceral leishmaniasis as well as other vector borne infectious diseases (e.g., West Nile Fever).
authors.affiliation: The Kuvin Center for the Study of Infectious & Tropical Diseases, Department of Microbiology & Molecular Genetics, The Institute of Medical Research, Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel; The Biostatistics Unit, The Gertner Institute for Epidemiology and Health Policy Research, Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel.
authors.forename: Ezer
authors.initials: E
authors.lastname: Miller
authors.affiliation: The Kuvin Center for the Study of Infectious & Tropical Diseases, Department of Microbiology & Molecular Genetics, The Institute of Medical Research, Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Alon
authors.initials: A
authors.lastname: Warburg
authors.affiliation: The Biostatistics Unit, The Gertner Institute for Epidemiology and Health Policy Research, Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel.
authors.forename: Ilya
authors.initials: I
authors.lastname: Novikov
authors.affiliation: Department of Microbiology, Immunology & Parasitology, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: Asrat
authors.initials: A
authors.lastname: Hailu
authors.affiliation: Department of Parasitology, Faculty of Sciences, Charles University, Prague, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Volf
authors.affiliation: Department of Parasitology, Faculty of Sciences, Charles University, Prague, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Seblova
authors.affiliation: The Biostatistics Unit, The Gertner Institute for Epidemiology and Health Policy Research, Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel.
authors.forename: Amit
authors.initials: A
authors.lastname: Huppert
mesh_terms: D000818:Animals; D015331:Cohort Studies; D005002:Ethiopia / Q000453:epidemiology; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology; D007893:Leishmania donovani / Q000302:isolation & purification; D007898:Leishmaniasis, Visceral / Q000469:parasitology / Q000635:transmission*; D016015:Logistic Models; D018512:Parasitemia / Q000635:transmission; D010691:Phlebotomus / Q000469:parasitology; D011576:Psychodidae / Q000469:parasitology