Fig. 2

Viability of cryopreserved D. immitis microfilariae (mf)-infected total blood. aIn vitro motility was scored over a range of blood volumes (X-axis) in CultureSure (1 ml total volume) and compared to purified mf at 0, 1 and 3 days post-thawing (dpt). Scoring was at four levels as follows: inactive or dead (-), less active (+), moderately active (++) and highly active (+++). An asterisk indicates a significant difference (P < 0.05) by one-way ANOVA, followed by Tukey’s multiple comparisons test. Error bars indicate ± SD. b Percent positive PI staining of mf-infected total blood on 3 dpt. An asterisk indicates a significant difference by Chi-square test and adjusted residual (AR). AR ≥ 1.96 was considered significant (P < 0.05). c Fluorescent images of propidium iodide (PI) staining of mf-infected total blood on 3 dpt (exposure, 100 ms; gain, 0.5). PI image (left) and bright field (BF) image (right). Abbreviation: PC, positive control. Scale-bars: 100 µm