Diagnostic value of conjunctival swab sampling associated with nested PCR for different categories of dogs naturally exposed to Leishmania infantum infection

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Di Muccio T, Veronesi F, Antognoni MT, Onofri A, Piergili Fioretti D, Gramiccia M.

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J Clin Microbiol. 2012 Aug;50(8):2651-9. Epub 2012 May 30.



Data description: 

Comparison of IFAT, microscopy and PCR testing of conjunctival swabs for CAnL. 253 dogs, Nov 2008 - Sep 2009


Lieshmania infantum, Canine Leishmaniasis, Conjunctival swab 24 nested-PCR, Cross sectional survey, Post-therapy follow up


The objective of the present study was to evaluate the diagnostic performance of a noninvasive assay, conjunctival swab (CS) nested-PCR (n-PCR), for diagnosing canine leishmaniasis (CanL) in different stages of infection in comparison to the performance of the indirect immunofluorescence antibody test (IFAT), lymph node microscopy, and buffy coat n-PCR. To this end, we performed a cross-sectional survey among 253 nonselected dogs in areas of endemicity in central Italy. We also performed a longitudinal study of CS n-PCR among 20 sick dogs undergoing antileishmanial treatment. In the first study, among the 72 animals that were positive by at least one test (28.45%), CS n-PCR showed the best relative performance (76.38%), with a high concordance in comparison to standard IFAT serology (κ = 0.75). The highest positivity rates using CS n-PCR were found in asymptomatic infected dogs (84.2%) and sick dogs (77.8%); however, the sensitivity of the assay was not associated with the presence of clinical signs. In the follow-up study on treated sick dogs, CS n-PCR was the most sensitive assay, with promising prognostic value for relapses. The univariate analysis of risk factors for CanL based on CS n-PCR findings showed a significant correlation with age (P = 0.012), breed size (P = 0.026), habitat (P = 4.9 × 10(-4)), and previous therapy (P = 0.014). Overall, the results indicated that CS n-PCR was the most sensitive assay of the less invasive diagnostic methods and could represent a good option for the early and simple diagnosis of CanL infection in asymptomatic animals and for monitoring relapses in drug-treated dogs.