CLINICAL AND HEMATOLOGIC VARIABLES IN PONIES WITH EXPERIMENTALLY INDUCED EQUINE EHRLICHIAL COLITIS (POTOMAC HORSE FEVER)

  • 1 January 1987
    • journal article
    • research article
    • Vol. 48  (1) , 63-67
Abstract
The clinical and hematologic variables of 10 ponies with experimentally induced equine ehrlichial colitis (EEC; syn: Potomac horse fever) were studied for a 30-day period (6 ponies) or until death (4 ponies). The earliest clinical sign indicative of EEC was fever (rectal temperature exceeding 39 C). All ponies became depressed (CNS) at various times during the disease, and 90% of the ponies developed diarrhea between 9 and 15 days after infection was induced. The most significant hematologic change was an increase in plasma protein concentration after the onset of fever (P < 0.05). The PCV in all ponies became increased above base line during the diarrheic phase of EEC. Forty percent of the ponies developed anemia (PCV .ltoreq. 23%) during the study. White blood cell counts were highly variable, with 80% of the ponies developing leukopenia (WBC < 5,000/.mu.l) during the illness and 60% of ponies developing leukocytosis (WBC > 14,000/.mu.l) after leukopenia was observed. Differential WBC changes varied widely and included neutropenia with a left shunt, lymphopenia, and included neutropenia with a left shift, which were done for only 1 pony, identified the development of marked thrombocytopenia. Some hematologic changes in ponieswith EEC were similar to those reported in canine monocytic and equine granulocytic ehrlichioses. These data are discussed in the context of the pathogenesis and differential diagnosis of EEC.