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

Abstract

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.

Heterogeneities in the Ecoepidemiology of Trypanosoma cruzi Infection in Rural Communities of the Argentinean Chaco

“…Titers 1:16 (IHA), titers 1:32 (IFAT), or optical absorbance 0.17 (ELISA) were used as cutoff values. Non-reactive and reactive sera were clearly differentiated, with higher degrees of agreement between ELISA and IHA in dogs (copositivity = 100%, conegativity = 90%) than cats (copositivity = 94%, conegativity = 78%); sensitivities of ELISA and IHA were 100%, and specificity was 96% for both tests [22][23][24] ; 16 dogs and 10 cats that were both seronegative and xenodiagnosisnegative were also negative by a polymerase chain reaction assay targeted to minicircle DNA. 22 Seropositive refers to samples reactive by at least two different serologic tests.…”

“…22 Failure to examine some of the animals was mainly because they were absent, ran away, or could not be handled. Only one householder refused having his animals examined for infection, because they were aggressive.…”

“…19,22 Infected means that animals had a positive xenodiagnosis and/or were seropositive to T. cruzi. The results of serodiagnosis and xenodiagnosis were combined to calculate the composite prevalence of T. cruzi infection.…”

“…Dog and cat sera were tested for antibodies to T. cruzi using an indirect hemagglutination assay (IHA) following the manufacturer's instructions (Wiener Laboratories S.A.I.C., Buenos Aires, Argentina) and an in-house enzyme-linked immunosorbent assay (ELISA) as described. 22 Sera from 32 dogs and 14 cats with discordant results between IHA and ELISA were tested with an indirect immunofluorescence test (IFAT; Ififluor Parasitest Chagas, Laboratorio IFI, Buenos Aires, Argentina). Titers 1:16 (IHA), titers 1:32 (IFAT), or optical absorbance 0.17 (ELISA) were used as cutoff values.…”

Evidencia serológica de infección por Trypanosoma cruzi en perros atendidos en clínicas veterinarias del área conurbada de Cuernavaca, Morelos

“…1 Varios estudios realizados en perros domésticos y de la calle en varios países de Latinoamérica han demostrado la infección por T. cruzi mediante la presencia de anticuerpos específicos. 2,3 La EC en los perros es clínicamente similar a la de los humanos: la fase aguda puede ser fatal en los animales jóvenes o presentar la fase crónica con cardiopatía y muerte súbita. 4 Algunos estudios realizados en zonas endémicas han demostrado que la EC en los perros tiene una mayor prevalencia que en las personas.…”