Babesia major: abomasal transmural potential difference, and antroduodenal motility changes associated with experimental infection in calf.

Transmural potential difference, pH and ionic concentrations of the abomasal contents were measured in three calves. Antroduodenal motor patterns were recorded using electrodes and strain-gauge transducers fixed on the antrum and the duodenum. The calves were infected with 8 x 10(9) Babesia major intravenously and a significant drop in transmural potential difference, concomitant with a steady increase in Na+ and K+ concentrations of the abomasal contents occurred within 2 days. The onset of fever on the 5th day after infection was associated with an increased frequency of duodenal migrating myoelectric complexes and episodes of bradygastria on the distal antrum. These changes disappeared at the end of fever. We conclude that transmural potential difference changes and Na+-K+ concentrations in the abomasal fluid could reflect changes in the ionic permeability of the gastric wall. These effects may represent early signs of Babesia infection.