10.1371/journal.pntd.0004413.g002 David M. Bland David M. Bland B. Joseph Hinnebusch B. Joseph Hinnebusch Feeding frequency influences colonization of the cat flea digestive tract by <i>Y</i>. <i>pestis</i>. Public Library of Science 2016 cat fleas Yersinia pestis parasitize animal reservoirs Ctenocephalides felis BackgroundThe cat flea vector Xenopsylla cheopis vector competence infection midgut contents results mechanism rat flea vectors cat flea foregut 2016-02-01 00:38:24 Figure https://plos.figshare.com/articles/figure/Feeding_frequency_influences_colonization_of_the_cat_flea_digestive_tract_by_i_Y_i_i_pestis_i_/2619151 <p>Fleas that took a single infectious blood meal that contained ~ 2x10<sup>8</sup> CFU/ml of <i>Y</i>. <i>pestis</i> were subsequently provided uninfected maintenance feeds at low frequency (twice weekly for 4h), moderate frequency (five times weekly for 4h), or high frequency (daily for 18-22h) according to the schedule shown in (<b>A</b>). Black and grey bars indicate the infectious and maintenance blood meals, respectively; and the width of the bar corresponds to the 4h or 18-22h feeding period. (<b>B</b>) The bacterial load in individual fleas from the low-, moderate-, and high-frequency groups was determined in samples of 10–20 fleas collected immediately after the 4h infectious blood meal (day 0) or at 7–28 days after infection. The low- and high-frequency groups fed on the same infectious blood meal prior to segregating them. Horizontal bars represent the mean CFU/flea; dotted lines indicate the limit of detection (40 CFU). The cumulative results of three independent experiments are shown (Day 0, n = 60; Day 7, n = 60; Day 14, n = 54, 60, 60); Day 28 n = 50, 60, 40). *<i>p</i> <0.05 by Student’s t-test (Day 0) or by Kruskal-Wallis test with Dunn’s multiple comparison (Day 7–28). (<b>C</b>) Infection rate (percentage of fleas from which CFUs were recovered) at different times after infection. The mean and range of 3 experiments are indicated; *<i>p</i> <0.0166 by chi-square test with Bonferonni’s post-test. (<b>D</b>) Cumulative mortality of infected fleas and uninfected control fleas at the end of the 28-day experiments. The mean and standard deviation of 2–3 experiments with each of the three feeding frequency groups are indicated (low, n = 312, 310; moderate, n = 292, 276; high, n = 184, 214; cumulative number of infected fleas and uninfected control fleas, respectively). *<i>p</i> <0.0055 by chi-square test with Bonferonni post-test; NS = not significant.</p>