Initial and long-term efficacy of a lipid emulsion of amphotericin B desoxycholate in the management of canine leishmaniasis.

Sixteen dogs in which canine leishmaniasis (CL) was diagnosed by positive identification of Leishmania amastigotes in bone marrow samples were treated with a mixture of amphotericin B (AmB) desoxycholate in soybean oil. To prevent the toxicity of AmB, dogs were pretreated with saline (50 mL/kg) and mannitol (2 g/kg). Dogs were treated twice weekly with an increasing dosage of amphotericin (0.8-2.5 mg/kg) for between 8 and 10 sessions. Transient adverse effects (anorexia, vomiting, or both) appeared in 81% of the dogs during therapy. At the end of the course, all dogs were clinically cured, with no parasites observed in bone marrow smears. Six of the 16 dogs (38%) were positive by polymerase chain reaction (PCR) in bone marrow samples at some stage of their follow-up, but only 2 were positive at the first test after treatment, which was performed within 5 months after the end of the therapy. The other 4 dogs were initially negative and became PCR-positive at subsequent examinations. Three of these 6 dogs also experienced a clinical relapse. Four dogs had at least 3 consecutive negative PCR tests during a minimum period of 18 months and were clinically cured. The results of the present study indicate that despite having a high initial effectiveness in the treatment of CL, relapses can occur with the described protocol. Also, a single negative PCR result in a recently treated dog cannot be interpreted as a complete cure.