Asymptomatic carriers of Babesia canis in an enzootic area

Dogs latently infected with Babesia canis were systematically detected amongst a population kept in an enzootic area over a year. Detection of parasite was carried out on 43 healthy dogs and identified by two blood cultures in an interval of a few months. A serological study was performed using indirect immunofluorescence and Western blot. This study distinguished two distinct groups: asymptomatic carrier dogs (latently infected or premunised-33%) and non-carrier dogs with sterilising immunity. There is no difference between carrier and non-carrier dogs concerning age, breed or history of babesial infection and 36 out of the 43 dogs studied are seropositive. The antibody titer did not completely correlate with the detection of parasitaemia. All carrier dogs are seropositive to Babesia canis, but half of the seropositive dogs are not carriers. This study confirms that serological detection is not a good indicator of latent babesial infection. This study did not detect any difference between antibody responses (quantitative response (IIF) or qualitative response (WB)), related to latent parasitaemia.