Clinicopathologic findings in an experimental spirocerca lupi infection in dogs

Spirocerca lupi is primarily a parasite of dogs, which typically causes esophageal nodules, aortic aneurysms and spondylitis. In this study, the hematology and serum biochemistry parameters in experimental canine spirocercosis were investigated. Ten beagle dogs were orally challenged with 40 infectious S. lupi larvae. One dog did not become infected. Two dogs died within 2 months post infection (PI) due to rupture of an aortic aneurism. Seven dogs became infected, presented with esophageal nodules and worm eggs in their feces. All were then treated with doramectin, survived and were followed for 21 months PI. Blood and fecal samples and esophagoscopy were performed periodically. Significant differences in the eosinophil counts were noticed in repeated measures between different time points during the study course. Eosinophil counts increased significantly (P<0.018) two weeks PI and their relative and absolute counts were above the reference interval (RI) (18.8%; RI: 0-10%; 2.19x10⁹/L; RI: 0.1-1.0x109/L, respectively). Both relative and absolute counts decreased significantly (P<0.018) at 4 weeks PI (8.9% and 0.75x10⁹/L, respectively) and remained within RI throughout the study course. Appearance of esophageal nodules, number of eggs shed in the feces and doramectin treatment had no association with eosinophil counts. There were no other significant differences in any hematologic and serum biochemistry analytes between different time points in repeated measures during the study course. In conclusion, with exception of a transient moderate eosinophilia, 14 days PI, hematologic and serum biochemistry abnormalities were absent in the early disease stages of experimental canine spirocercosis.