Third component of complement serum levels in dogs with leishmaniasis.

Radial immunodiffusion was used to determine the concentration of the third component of complement (C3) in the serum of 51 adult dogs with leishmaniasis and, for comparative purposes, in a control group of 30 healthy dogs. Animals in both groups were of different age, sex and breed. The mean concentration in healthy dogs was 93.3 +/- 6.6 (mean +/- SD), and in sick dogs 131.4 +/- 7.1, both expressed as a percentage of a reference standard. Statistically significant differences (P < 0.0004) were found between serum C3 concentrations in leishmania-infected and control groups, but no significant difference was recorded between males and females in either group.