VACCINATION OF DOGS AGAINST BABESIA-CANIS INFECTION

This paper describes the clinico-pathological parameters measured in d ogs that were vaccinated against Babesia canis using soluble parasite antigens (SPA) and then challenged. The packed cell volume (PCV) and t he plasma creatinine value decreased immediately after challenge. Actu al PCV values could be predicted in the first 5-6 days of the infectio n, assuming that creatinine values were modulated by increase of plasm a volume:. This association no longer existed after that time, and obs ervations indicated splenic involvement in reduction of numbers of cir culating erythrocytes. The anaemia due to B. canis infection appears t o be the result of a multifactorial process including plasma volume in crease, erythrocyte retention in the spleen and erythrocyte destructio n, partly due to parasite proliferation. Vaccination Limited the reduc tion of PCV values, and the development of splenomegaly. Differences i n protection between vaccinated and control animals became apparent 6 days after infection, when a memory immune response becomes operative, and the onset of recovery of vaccinated animals correlated with the o nset of antibody production against SPA. (C) 1997 Elsevier Science B.V .