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Platelet dysfunction associated with experimental acute canine ehrlichiosis
Author(s) -
Harrus S.,
Waner T.,
Eldor A.,
Zwang E.,
Bark H.
Publication year - 1996
Publication title -
veterinary record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.261
H-Index - 99
eISSN - 2042-7670
pISSN - 0042-4900
DOI - 10.1136/vr.139.12.290
Subject(s) - platelet , ehrlichia canis , medicine , epinephrine , ehrlichiosis , thrombin , immunology , antibody , endocrinology , serology , virology , tick
To determine whether platelet dysfunction occurs in canine ehrlichiosis, platelet aggregation studies in response to collagen/ epinephrine, thrombin and adenosine diphosphate (ADP) were carried out by the indirect method, using sera from six dogs experimentally infected with Ehrlichia canis . Samples of serum taken before infection and four and 20 days after infection were tested by incubation with platelet‐rich plasma from a seronegative healthy dog. Platelet aggregation was significantly inhibited in five of six infected dogs in response to at least one of the agonists used. A significant increase in preaggregation lag time was recorded in response to collagen/ epinephrine in sera taken 20 days after infection from three of five dogs (P<0.05). When compared with the preinfection values, a significant increase of 45 per cent in the mean preaggregation lag time was detected (P<0.05). Maximal relative aggregation responses to ADP decreased significantly in one serum sample taken four days and one taken 20 days after infection (P<0.01) and there was a significantly lower relative slope for one serum sample 20 days after infection (P<0.05). Maximal relative aggregation responses to thrombin were significantly decreased together with their relative slopes in serum samples from two of four dogs four days after infection (P<0.05). The results suggest that platelet dysfunction may occur in the acute stage of canine ehrlichiosis, and may be a contributing factor to the tendency to bleed commonly observed in this disease. Antiplatelet antibodies directed against platelet glycoproteins may play a role in the inhibition of platelet aggregation.