Value of two PCR methods for the diagnosis of canine visceral leishmaniasis and the detection of asymptomatic carriers.
The value of 2 PCR methods, targeting genomic and kinetoplast minicircle DNA respectively, was investigated for both diagnosis and prevalence studies of canine visceral leishmaniasis (CVL). The first method (R) was 5000-fold less sensitive than the second (method KRV). Both were tested for diagnosis of CVL in 44 sick dogs with confirmed disease using different biological samples. Method R was highly efficient when using invasive samples, but the use of method KRV proved necessary for a 100% sensitive diagnosis using peripheral blood. This method was applied to peripheral blood and skin samples in 263 dogs during a mass survey in the Cévennes focus. PCR was compared to serology and all results were analysed according to clinical status. The 'CVL-infection' prevalence was found to be 79.8% by PCR compared with 29.6% by serology: 89.4% of symptomatic and 65.2% of asymptomatic dogs harboured parasites in peripheral blood. This study confirms the high prevalence of asymptomatic carriers of Leishmania. In total, for the diagnosis of CVL in sick dogs, method R is recommended in view of its 100% positive predictive value (compared with 30% for method KRV). A strategy best adapted for prevalence surveys might combine serology and highly sensitive PCR on peripheral blood.
D000818:Animals; D002353:Carrier State / Q000175:diagnosis* / Q000469:parasitology*; D018105:DNA, Kinetoplast / Q000032:analysis / Q000235:genetics; D016054:DNA, Protozoan / Q000032:analysis / Q000235:genetics; D004283:Dog Diseases / Q000175:diagnosis* / Q000469:parasitology*; D004285:Dogs; D005602:France; D018314:Leishmania infantum / Q000235:genetics / Q000302:isolation & purification; D007898:Leishmaniasis, Visceral / Q000175:diagnosis* / Q000662:veterinary*; D016133:Polymerase Chain Reaction / Q000379:methods*; D015995:Prevalence; D012680:Sensitivity and Specificity
D018105:DNA, Kinetoplast; D016054:DNA, Protozoan