Infection Parameters in the Sand Fly Vector That Predict Transmission of Leishmania major
Figure 4
Environmental conditions and sand fly oviposition status influence transmission.
Ear lesion diameters (A, E, and I), parasite loads per ear (B, F, and J), number of infected or uninfected ears (C, G, and K), and presence or absence of a blood meal in the sand fly (D, H, and L) following exposure of BALB/c mice to L.m.-RYN infected sand flies (4×106 infection dose) under the indicated environmental conditions (A–D, n = 26 ears/group; E–H, n = 22 ears/group; I–L, n = 12 ears/group). Asterisk indicate significant differences versus the 23°C/30% Humidity and Retained Eggs group (*, 0.014<p<0.056; **, 0.008<p<0.010; ***, p = 0.0002). Hash symbols indicate significant differences versus the 26°C/75% Humidity and Retained Eggs group (#, p = 0.033; ###, p = 0.0002) In (C) common odds ratio 0.125, 95% C.I. (0.020–0.764); in (D) n.s., p = 0.246 [common odds ratio 0.683, 95% C.I. (0.386–1.21)]; in (G) common odds ratio 0.175, 95% CI (0.043–0.722); in (H) common odds ratio 0.272, 95% CI (0.137–0.540), Data are from three experiments: (1) flies with retained eggs under different environmental conditions, (2) oviposited flies or flies with retained eggs under the same environmental condition and (3) a 2 by 2 factorial experiment that varies both environmental conditions and oviposition status. Plots (A–H) combine experiments 1 and 3, plots (E–H) combine experiments 2 and 3, and plots (I–L) are experiment 3 alone. In (C, G, and K) the number within the open, infected, bar represents the frequency of transmission.