ABSTRACT
BACKGROUND: Immunoreactive tandem repeat proteins (TRPs) in amino acid sequences were identified and employed in the serologic diagnosis of canine monocytic ehrlichiosis (CME). OBJECTIVES: This study evaluated using TRP19 and TRP36 synthetic protein antigens with enzyme-linked immunosorbent assays (ELISAs) and compared the results with an indirect fluorescent antibody test (IFAT) to diagnose CME in the serum of dogs with suspected CME. METHODS: The sera of 243 dogs that exhibited clinical and hematologic signs suggestive of CME had IFATs performed. An ELISA with synthetic TRP19 and TRP36 antigens from two E canis genotypes (USTRP36 and BrTRP36) that circulate in Brazil were also performed. Canonical correlations and chi-square tests were evaluated on the results of these tests. RESULTS: Among the 243 dogs, 179 (73.6%) were reactive at an IFAT ≥ 40, 167 (68.72%) reacted at the cut-off ≥160, and 149 (61.31%) reacted at ≥640. The ELISA revealed that 172 (70.8%) dogs reacted to TRP19 peptide, 163 (67.1%) reacted to USTRP36, and 114 (46.9%) reacted to BrTRP36. The canonical correlation analyses showed that the TRP19 ELISA was the most effective diagnostic method. Serum total protein levels showed strong positive correlations with the USTRP36 peptide. Qualitative analyses revealed an association between the TRP19 peptide and the presence of anemia, thrombocytopenia, and hyperproteinemia. The IFAT results at titers of ≥160 and ≥640 were associated with thrombocytopenia. CONCLUSIONS: The results of this study indicated that the TRP19 peptide was an excellent antigen and that the IFAT was diagnostically important in confirming the diagnosis of CME in serum samples.
Subject(s)
Dog Diseases , Ehrlichiosis , Animals , Dog Diseases/diagnosis , Dogs , Ehrlichia canis , Ehrlichiosis/diagnosis , Ehrlichiosis/veterinary , Enzyme-Linked Immunosorbent Assay/veterinary , PeptidesABSTRACT
The occurrence of antibodies against canine distemper virus (CDV), parvovirus and Ehrlichia spp. in wild captive carnivores was evaluated in a zoological park in midwestern Brazil. Serum samples were collected between 2007 and 2014 from 45 carnivores. Antibodies were evaluated by virus neutralization assay for CDV, hemagglutination inhibition test for parvovirus, indirect immunofluorescent and Enzyme-linked immunosorbent assay for Ehrlichia spp. Antibodies against CDV and parvovirus were detected in 75% of Canidae and Felidae. Procyonidae were negative for CDV, although one Mustelidae was positive. TwoCanidae presented antibodies reactive to E. canis antigens. The high antibodies rates to CDV and parvovirus suggest the contact with both pathogens, however since no clinical history of disease are registered in the Zoo-UFMT, we can presume that carnivores have responded satisfactorily against the antigens. The low serological rates observed against Ehrlichia spp. may be resulted to the low occurrence of ticks among carnivores.(AU)
A ocorrência de anticorpos contra o vírus da cinomose canina (CDV), parvovírus e Ehrlichia spp. em carnívoros selvagens em cativeiro foi avaliada em um parque zoológico do centro oeste do Brasil. As amostras de soro foram coletadas entre 2007 e 2014 de 45 carnívoros. Os anticorpos foram avaliados por ensaio de neutralização de vírus para CDV, teste de inibição de hemaglutinação para parvovírus, imunofluorescência indireta e ensaio imunoenzimático ligado à enzima para Ehrlichia spp. Anticorpos contra CDV e parvovírus foram detectados em 75% de canídeos e felídeos. Procionídeos foram negativos para CDV, embora um mustelídeo fora positivo. Dois canídeos apresentaram anticorpos reativos aos antígenos de E. canis. As altas taxas de anticorpos para CDV e parvovírus sugerem o contato com ambos os patógenos, entretanto desde que nenhuma história clínica de doença está registrada no Zoo-UFMT, podemos presumir que os carnívoros têm respondido satisfatoriamente contra os antígenos. As baixas taxas serológicas observadas contra Ehrlichia spp. pode ser resultado da baixa ocorrência de carrapatos entre os carnívoros.(AU)
Subject(s)
Animals , Carnivora/immunology , Parvovirus/pathogenicity , Distemper/immunology , Ehrlichia/pathogenicityABSTRACT
We recently characterized a novel genotype of Ehrlichia canis based on the tandem repeat (TR) sequence of the TRP36 gene in Brazil. The TR amino acid sequence of the Brazilian (Br) genotype (ASVVPEAE) was divergent from the previously described US genotype (TEDSVSAPA) of E. canis. In this study, we developed an ELISA based on TRP36 TR synthetic peptides from both Br and US E. canis TRP36 genotypes to serologically detect and distinguish infections caused by these genotypes. Sera from 30 Brazilian dogs naturally infected with E. canis, sera from dogs experimentally infected E. canis (Jake and Cuiabá #1 strains) and E. chaffeensis (Arkansas strain) and 12 seronegative E. canis dogs were evaluated. Fifteen naturally infected Brazilian dogs had antibodies that reacted with the US TRP36 (n=9) or Br TRP36 (n=6) only, and 13 dogs had antibodies that reacted with both TPR36 peptides suggesting that these dogs were exposed to both genotypes. Most dogs (n=28) had antibodies that reacted with the highly conserved E. canis TRP19 peptide; however, two dogs had antibodies to E. canis TRP19, but did not have TRP36 antibodies, raising the possibility that another novel TRP36 genotype is circulating in Brazil. Our results demonstrate that synthetic peptides based on the TR region of E. canis TRP36 can be used to serologically distinguish infections or identify coinfections by different genotypes, and to determine the seroprevalence of various E. canis genotypes in Brazil.
