BackgroundImmunoreactive tandem repeat proteins (TRPs) in amino acid sequences were identified and employed in the serologic diagnosis of canine monocytic ehrlichiosis (CME).ObjectivesThis 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.MethodsThe 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.ResultsAmong 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.ConclusionsThe 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.
Caxito MS, Rodrigues FP, Taques IIGG, Aguiar DM. et al. Alterações da medula óssea e a importância do mielograma no diagnóstico da ehrlichiose monocítica canina -Revisão. Vet. e Zootec. 2018 mar.; 25(1): 061-066.
RESUMOA Ehrlichiose Monocítica Canina (EMC) é uma doença multissistêmica e de alta incidência. Contudo, a patogenia da enfermidade ainda não está totalmente esclarecida. Infiltrações plasmocitárias e linfoplasmocitárias são observadas em grande parte dos órgãos de animais acometidos, inclusive na medula óssea. Esses infiltrados sugerem que a maioria das lesões patológicas identificadas na fase crônica pode ser consequência do processo inflamatório originado no início da infecção. Este trabalho tem por objetivo destacar a importância da avaliação medular de cães com EMC. A maior compreensão das alterações medulares na fase aguda poderia esclarecer a origem das alterações observadas na fase crônica. Mais estudos são necessários para verificar se a patogenia da EMC está relacionada apenas a processos imunomediados ou se também há agressões diretas de Ehrlichia canis às células precursoras. Elucidar os mecanismos fisiopatogênicos de E. canis poderia melhorar a terapêutica instituída como também o prognóstico de animais gravemente acometidos.
Palavras-chave:Ehrlichia canis, mielograma, hematopoiese, células precursoras, processo imunomediado.
ABSTRACTCanine Monocytic Ehrlichiosis (CME) is a multisystemic disease with high incidence among dogs. However, its pathogenesis has not been fully elucidated. Plasma cells and lymphoplasmacytic infiltrates are observed in most organs of infected animals, including bone marrow. These infiltrates suggest that most of the pathological lesions identified in the chronic phase may be a consequence of the inflammatory process initiated at the beginning of the infection. This work aims to highlight the importance of the bone marrow evaluation of dogs with CME. A better understanding of the medullary changes in the acute phase could help clarifying the origin of clinical signs observed in the chronic phase. More studies are needed to verify whether the pathogenesis of CME is related to either the immune-mediated processes or the direct aggressions of Ehrlichia canis in precursor cells. Understanding the pathophysiological mechanisms of E. canis will improvement both current therapeutic strategies as well as the prognosis of severely affected animals.
Objectives
To determine the concentrations of total protein (TP), tissue inhibitor of matrix metalloproteinase‐1 (TIMP‐1) and hyaluronic acid (HA) in amniotic membranes (AMs) harvested from placentas of bitches of different ages and cryopreserved for different time points. The outcomes of complicated corneal defects of dogs repaired with AMs stored for the same time points were also evaluated.
Procedures
Ten cryopreserved canine AMs were stored for short term (2–50 days), middle term (92–210 days), or long term (256–357 days). TP was quantified by Bradford’s test, whereas TIMP‐1 and HA were quantified by ELISA. Twenty‐one dogs that had an AM transplantation to restore deep or perforating corneal wounds were selected.
Results
TIMP‐1 levels were lower in AMs cryopreserved for middle term (p = .02) and long term (p = .0009), when compared to AMs stored for short term. TP (p = .39) and HA (p = .18) concentrations in AMs did not differ among the storage time. TIMP‐1 concentration in AMs correlated with storage time (R = −.65, p < .0001), while TP (R = −.33, p = .07) and HA concentrations did not (R = −.15, p = .41). The age of donors did not correlate with the components evaluated in the AMs. Corneal defects repaired with AMs stored for short term healed sooner than the ones repaired with AMs stored for middle (p < .01) and long term (p = .02). Additionally, TIMP‐1 levels in AMs correlated negatively with the epithelization time (R = −.62, p = .002). Graft opacity was severe in 55% of cases. However, the HA levels in AMs correlated negatively with the opacification score (R = −.47, p = .03). Vision was observed in more patients who presented deep ulcers and descemetoceles, than in the ones with perforations (p = .004).
Conclusions
TIMP‐1 concentration in canine AMs significantly decreased over a year storage time, while TP and HA concentrations did not change during the same period. The age of donors did not correlate with the components evaluated in the AMs. Complicated corneal defects repaired with AMs cryopreserved for short term healed sooner and tended to be less opaque; however, satisfactory to optimal outcomes were achieved even in the eyes repaired with AMs stored for up to a year.
Tandem repeat proteins (TRPs) are major immunoreactive proteins of Ehrlichia canis, which have been used in the serological diagnosis of different genotypes of the microorganism. TRP19 is preserved among different E. canis isolates expressed on both reticulate and dense-core cells and observed in the extracellular matrix or associated with the morula membrane. TRP36 is differentially expressed only on the surface of the dense-core form of the bacterium and exhibits more divergence among isolates. The aim of this study was to evaluate the distribution of the American (USTRP36), Brazilian (BrTRP36) and Costa Rican (CRTRP36) genotypes of E. canis in Brazil, using ELISA assays. Serum samples of 814 dogs from 49 municipalities from all over Brazil were analyzed. Our results showed that 33.9% of the samples were reactive to the USTRP36 genotype and 32.6% to the BrTRP36 genotype. The two genotypes appeared to occur equally throughout Brazil, although the frequency of seropositivity was lower in the south than in the country’s other regions. Dogs that reacted to at least one of the synthetic peptides (TRP19 and TRP36) were 456 (56%). A few dogs (n = 5; 0.6%) reactive to the E. canis TRP36 genotype (CRTRP36) were also detected in the northeast and southern regions. We concluded that the American and Brazilian genotypes of E. canis are distributed evenly in Brazil, especially in the tropical region, while the temperate region in the south presented the lowest prevalence rates. This study offers the first report of dogs seropositive for the Costa Rican genotype in Brazil.
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