Effect of dimethyl sulfoxide in the treatment of sheep experimentally infected with Ehrlichia ruminantium.
To evaluate the clinical response of sheep experimentally infected with Ehrlichia ruminantium to treatment with dimethyl sulfoxide (DMSO). 32 Merino crossbred sheep. 16 sheep were infected with E ruminantium; 8 of these were treated twice daily with a 10% solution of DMSO (1 g/kg, i.v.) in polyionic fluid for 3 consecutive days. Treatment was initiated 2 days after the onset of clinical disease. Eight uninfected control sheep were similarly treated with DMSO. Placebo treatments (polyionic fluid administrations) were given to 8 infected and 8 uninfected sheep. Arterial and venous blood samples for blood gas and total plasma protein concentration measurements were collected daily (data from 5 days before until 6 days after onset of clinical disease were analyzed); physiologic variables and food consumption were also monitored. Gross pathologic findings and cytologic confirmation of the disease were recorded for the 16 infected sheep. Infected sheep treated with DMSO were able to maintain pulmonary gas exchange and had reduced pleural effusion and plasma protein loss, compared with infected untreated sheep that became hypoxic. Infected treated sheep developed an uncompensated metabolic acidosis. Uninfected treated sheep had reduced appetite, whereas uninfected untreated sheep maintained normal food intake. Results of DMSO treatment in sheep with experimentally induced heartwater disease indicated that administration of this agent, in combination with specific antimicrobial treatment, may be of some benefit in treatment of naturally occurring disease.