Infection of small ruminants with Ehrlichia spp. in Sicily

In 1991, the experimental infection of a goat with pooled blood from goats that were positive for anti-Ehrlichia canis, E. risticii, E. equi and E. phagocytophila antibodies was monitored (physical examination, cell blood count, microscopical examination of blood smears, serology) for 180 days. The infection produced a clinical condition characterized by intermittent fever, anaemia and leukopenia with neutropenia during the first 40 days. Recurrent leukocytosis with lymphocytosis was noticed afterwards. A permanent high-level thrombocytosis appeared after the 18th day. During the first week, cytoplasmic basophilic inclusion bodies were seen in smears of peripheral venous blood stained with May-Grunwald-Giemsa, first in mononuclear cells and then in neutrophils (in max 3% of circulating leukocytes). Seroconversion occurred during the 2nd week and the highest antibody titre (IFAT) was registered vs E. equi (10,240) at the 19th day, vs E. canis (320) at the 24th and vs E. risticii (80) at the 30th day. At the end of the observation period the infected goat was still positive for E. equi (titre 160) and E. canis (titre 10) only. The preinoculation serum of the infected goat was reactive with E. phagocytophila antigen (serum was tested for IF antibodies to E. phagocytophila at 1:200 dilution only, because of the limited quantities of antigen available), but the qualitative evaluation of fluorescence showed an increase from the 7th day, maximum intensity between the 14th and the 40th day and passed to negative from the 74th day. Although it was based on microscopy and serology only and not carried out in a SPF goat, the above experiment gave evidence of the existence of species of the E. phagocytophila genogroup in Italy for the first time.