Gallium maltolate, a promising low toxicity drug with curative effect on mice chronically infected with Trypanosoma evansi

Abstract

Trypanosoma evansi is a flagellate protozoan that infects a wide range of hosts, especially horses. Clinically, the infection is characterized by rapid weight loss, anemia and mobility disorders. This study evaluated the efficacy of treatment gallium maltolate (GaM) in rats infected with T. evansi in the acute and chronic phases of the disease and its influence on the enzyme and blood parameters. 48 animals (Rattus norvegicus) were divided into 8 groups (A-H) of 6 animals each, namely: A: (negative control) uninfected; B: acutely infected positive control; C: chronically infected positive control; D: acutely infected, treated with GaM for 7 days post infection (p.i.); E: acutely infected treated with GaM for 3 days before infection (b.i) and 7 days p.i.; F: chronically infected, treated with GaM for 7 days p.i.; G: chronically infected, treated with GaM for 3 days b.i. and 7 days p.i.; and H: uninfected treated with GaM for 10 days. Acute infected animals (B, D and E) had a progressive increase in parasitemia and were died or euthanized before completing treatment days (5th days p.i.) as they had high parasitemia (over 100 field trypanosomes in the blood smear). Thus, it can be concluded that GaM was not effective against an acute infection. In untreated chronically infected animals (C) the parasitemia also increased progressively and they were euthanized on the 7th day p.i.. The chronically infected and treated animals (F and G) showed low parasitemia and after treatment became negative, showing no trypanosomes in the bloodstream until the 50th day of the experiment. Thus, we conclude that GaM was effective against chronic infections. In uninfected and treated animals (H) hematological, biochemical and enzymatic parameters had no significant changes when compared to the negative control group (A) demonstrating the low toxicity of GaM.