Detection of Trypanosoma cruzi infection in naturally infected dogs and cats using serological, parasitological and molecular methods

• We assessed the performance of kDNA-PCR to detect Trypanosoma cruzi infection in dogs and cats.
• kDNA-PCR was slightly more sensitive than xenodiagnosis in seropositive dogs and cats.
• kDNA-PCR and xenodiagnosis failed to detect all the seropositive individuals in both host species.
• kDNA-PCR may be used as a complementary method to serodiagnosis to detect infectious hosts.

Domestic dogs and cats are major domestic reservoir hosts of Trypanosoma cruzi and a risk factor for parasite transmission. In this study we assessed the relative performance of a polymerase chain reaction assay targeted to minicircle DNA (kDNA-PCR) in reference to conventional serological tests, a rapid dipstick test and xenodiagnosis to detect T. cruzi infection in dogs and cats from an endemic rural area in northeastern Argentina. A total of 43 dogs and 13 cats seropositive for T. cruzi by an immunosorbent assay (ELISA) and an indirect hemagglutination assay (IHA), which had been examined by xenodiagnosis, were also tested by kDNA-PCR. kDNA-PCR was nearly as sensitive as xenodiagnosis for detecting T. cruzi-infectious dogs and cats. kDNA-PCR was slightly more sensitive than xenodiagnosis in seropositive dogs (91% versus 86%, respectively) and cats (77% against 54%, respectively), but failed to detect all of the seropositive individuals. ELISA and IHA detected all xenodiagnosis-positive dogs and both outcomes largely agreed (kappa coefficient, κ = 0.92), whereas both assays failed to detect all of the xenodiagnosis-positive cats and their agreement was moderate (κ = 0.68). In dogs, the sensitivity of the dipstick test was 95% and agreed closely with the outcome of conventional serological tests (κ = 0.82). The high sensitivity of kDNA-PCR to detect T. cruzi infections in naturally infected dogs and cats supports its application as a diagnostic tool complementary to serology and may replace the use of xenodiagnosis or hemoculture.

Our study documents that kDNA-PCR was slightly more sensitive than xenodiagnosis in Trypanosoma cruzi-seropositive hosts and was nearly as sensitive as xenodiagnosis for detecting T. cruzi-infectious dogs and cats, thus encouraging its application as a diagnostic tool complementary to serology.Figure optionsDownload as PowerPoint slide