Use of PCR, IFAT and in vitro culture in the detection of Leishmania infantum infection in dogs and evaluation of the prevalence of canine leishmaniasis in a low endemic area in Tunisia.

The aim of this study was to assess the use of parasitological, serological and molecular methods for the detection of Leishmania infection in blood of 67 dogs and to investigate the prevalence of canine leishmaniasis (CanL) in Kairouan (central Tunisia), an area known to be of reduced endemicity and has not been studied since 1973. Veterinarians clinically examined all dogs, and the titer of anti-Leishmania antibodies was determined by indirect immune-fluorescence antibody test. The presence of Leishmania was performed by PCR and in vitro culture. IFAT was positive in 12% of dogs and promastigote form of the parasite was isolated by in vitro culture from only 4.5% of them. However, DNA of Leishmania was detected by PCR in 20.9% of dogs. PCR was more sensitive than IFAT (p = 0.004) and in vitro culture (p < 10(-5)). A prevalence of 21% was found in Kairouan, which is significant high (p < 10(-3)) when compared to that of thirty years ago. This state is in correlation with the increase in other Mediterranean countries. Furthermore, 50% of positive dogs were asymptomatic. Preventive measures must be taken against these dogs as for symptomatic ones since their role in the transmission of the infection to vectors has been proven.