From the day after dosing (31 dpi), twice weekly auscultatory respiratory assessments were performed with the quality (normal/deepened normal sound/stertor/stridor/rhonchus/wheeze/crackle), and intensity of inspiratory and expiratory sounds graded on a scale from

0 (no abnormal sound) to 3 (severe sound). In addition, faecal sampling was performed from 40 dpi until a dog was confirmed to be shedding larvae using the methods described above (Baermann, 1917). Dogs were euthanized and necropsied on Days 26–28 post-treatment (56–58 dpi). Post-necropsy examinations were carried out following Schnyder et al. (2009). For each dog, the heart and lungs were examined in detail to determine the presence or absence of adult A. vasorum. All worms were counted and identified to gender

and stage of development, whenever possible. If worm fragments were present, they selleck compound were only included in the count if the head was present. Efficacy calculations were based on the total number of adult worms recovered from each dog at necropsy in the treated and control groups to determine whether or not treatment had prevented development of infections with adult A. vasorum. To show adequate infection, a minimum of five A. vasorum must have been present in at least 6 control dogs. For each treatment group, the total number of adult A. vasorum along with the group geometric mean (GM) was calculated. The mean worm counts were determined and compared post-treatment between treated (spinosad/MO combination) and control (placebo) groups. Efficacy was calculated based on GM using the formula: %Efficiency=meancontrol−meantreatedmeancontrol×100 learn more To demonstrate prevention, both of the following criteria must have been satisfied: 1. Efficacy ≥90% against A. vasorum with the combination tablet, based on GM. A logarithmic transformation (ln[count + 1]) was applied to the post-treatment counts for each dog to address skewness of the data, as well as zero counts. Back transformed geometric means were calculated by ex − 1, where x¯ equals log transformed treatment mean. Transformed GM worm counts were analyzed with a general linear mixed ADP ribosylation factor model with

fixed effect treatment. A contrast between spinosad/MO and the placebo groups was conducted to confirm effectiveness. A covariance structure allowing for heterogeneous error variance between treatment groups was considered via a test for heterogeneity but was not deemed necessary in the final analysis. There were no adverse events within the 8 h post treatment period, and no abnormal respiratory signs were detected in any of the dogs treated with spinosad/MO. Auscultation revealed minor intensity respiratory sounds in two dogs in the placebo group, one on Days 7 and 12, and one on Day 12. No other physical abnormalities were observed in any dog during the study period, and a pre-necropsy physical examination of each dog did not detect any clinical abnormalities.