DOI: 10.5061/dryad.7wm37pw5z
title: Data from: Disentangling the role of parasite infectivity and environmental density in infection development and parasite proliferation

description: Understanding the environmental drivers of host-parasite interactions is a
 major concern for human health and conservation, particularly in the
 context of emerging infectious diseases. The likelihood of contracting an
 infection can be related to both the rate of contact between host and
 parasite, as well as innate features of hosts (susceptibility/resistance)
 and parasites (infectivity, virulence, within-host proliferation rate).
 This study uses a host-parasite system with a matching allele model for
 host susceptibility and parasite infectivity to disentangle contact rate
 from parasite infectivity while accounting for the effects of host
 susceptibility. Using three exposure doses from several parasite isolates
 to hosts with known susceptibility, we find significant differences in
 parasite infectivity (in terms of number of successful infections) and
 proliferation rate inside the host among parasite isolates, after
 controlling for exposure rate and host genotype. Exposure dose did not
 impact the number of infections but had a modest effect on infection
 intensity, while host known susceptibility accounted for nearly half of
 the variance in infectivity and a third of the variance in proliferation.
 No significant relationship between infection success and parasite
 proliferation rate was detected, indicating an independent variability
 among isolates for both variables.
description: # Data from: Disentangling the role of parasite infectivity and
 environmental density in infection development and parasite proliferation
 Dataset DOI: [10.5061/dryad.7wm37pw5z](10.5061/dryad.7wm37pw5z) ##
 Description of the data and file structure Nine clones of *Daphnia magna*
 were exposed to three calculated doses of six isolates of their parasite,
 *Pasteuria ramosa,* in a full factorial design, replicated at the
 individual level ten times for a total of 1620 individuals in isolated
 jars. Individuals were then monitored three times per week for 28 days,
 and at the end of the experiment, all individuals showing any signs of
 infection (no eggs, reddish colour, large size) were frozen in Eppendorf
 tubes with 1 mL of water. Tubes were then defrosted, their contents
 crushed with a pestle, and shaken at 4500 rpm for 2 hours to separate
 parasite spores, and a sample was placed in a hemocytomer. This was used
 to 1: confirm the presence of parasite spores to determine that the
 individual had been infected, and 2: count the spore density to determine
 the total number of parasite spores produced over the course of infection.
 ### Files and variables #### File: DVE.csv **Description:** This file
 describes the data presented in DVE.csv. This experiment used a range of
 *Daphnia magna* clones exposed to a range of *Pastueria ramosa* isolates
 at three different initial doses of *P. ramosa* spores to disentangle
 parasite infectivity, growth rate and density from host susceptibility.
 *Daphnia* were kept in individual jars and monitored for 28 days, after
 which any with potential signs of infection were preserved in 1mL of
 water. Preserved individuals were then crushed, shaken at 4500 rpm for 2
 hours to separate *Pastueria* spores, and the density of spores in that
 1mL was counted twice using a hemocytometer. This data describes the
 identifying information of each individual and their parasite dose and
 spore treatment, as well as whether or not they became infected over 28
 days (parasite infectivity) and their estimated final spore load counts
 (parasite proliferation). ##### Variables * ID: Jar ID in which individual
 *Daphnia* was kept * Clone: clonal line of *Daphnia* used * parasite: *P.
 ramosa* isolate used * dose: number of *P. ramosa* spores introduced to
 the jar * preserved: y= yes (individual showed signs of infection within
 28 days); n: individual showed no signs of infection and was not preserved
 for spore counts * total: number of *Daphnia* (in two jars, it was
 determined after the fact that two individuals were accidentally placed
 inside instead of 1) * finalspore1: 1st hemocytometer count; not
 applicable (NA) if final spores were not counted because individual showed
 no signs of infection * finalspore2: 2nd hemocytometer count; NA if final
 spores were not counted because individual showed no signs of infection *
 finalsporeavg: average of the two hemocytometer counts, used to estimate
 spore density; NA if final spores were not counted because individual
 showed no signs of infection * adjfinalspore: final spore desnity per
 individual (for the jars that contained two individuals the total spore
 density was divided by 2); NA if final spores were not counted because
 individual showed no signs of infection ## Code/software All analyses were
 conducted in R. No original code/packages were written to analyse the data