Biogenic amine levels in acute Babesia bovis infected cattle

Plasma and whole blood from splenectomized calves infected with B. bovis were assayed by fluorimetric techniques for histamine, 5-hydroxytryptamine (5-HT), noradrenaline and dopamine levels. In addition PCV, thrombocyte and parasite counts were also undertaken. Plasma histamine levels rose till day 4 post-infection (p.i.) and were still elevated on day 7 p.i. Wholw blood histamine levels were significantly higher on days 1, 4 and 6 p.i. Plasma 5-HT levels rose to peak levels on day 3 p.i. and were still significantly elevated on day 7 p.i. Whole blood 5-HT levels were significantly higher on days 1 and 2 p.i. but fell to subnormal levels terminally. Dopamine and noradrenaline levels for both whole blood and plasma were unaltered during the disease process. Thrombocyte levels initially rose, reaching maximum values on day 3 p.i. The level fell continuously below normal from day 4 to 7 p.i. The PCV fell continuously from day 1 p.i. The experimental animals suffered a severe and fatal syndrome, all dying 7 days p.i.