INCIDENCE OF PATENT TOXOCARA-CANIS INFECTION IN BITCHES DURING THE ESTROUS-CYCLE

The incidence of patent Toxocara canis infection as result of reactiva tion of somatic larvae with subsequent tracheal migration was investig ated by faecal examination during 23 oestrous cycles of 15 bitches. Bl ood samples were collected for determination of total and differential leukocyte counts, prolactin concentration, and Toxocara titre, Five p regnant dogs were used as controls. In the cyclic dogs there were no a lterations in white blood cell counts or prolactin concentration, in c ontrast with the pregnant dogs, in which both variables increased, sta rting 10 days after onset of the luteal phase. The difference was sign ificant at day 40 and day 60 (both p<0.005), Two significant differenc es were observed in the number of eosinophils or in the Toxocara antib ody titre, T. canis eggs were only found in the faeces of three 1-year -old, cyclic dogs at 1, 60, and 140 days, respectively, after the onse t of the luteal phase. It is concluded that cyclic beagle bitches, in which prolactin levels increase in the second half of the luteal phase , are unlikely to be at higher risk for patent T. canis infection than in other phases.