Comparison of Standard Protocols for the Treatment of Canine Leishmaniasis in an Endemic Area with and Without Zinc Oral Supplementation

Successful treatment of canine leishmaniasis (CanL) depends on an effective cellular immune response. Zinc is an essential trace element for the immune system and in dogs with clinical leishmaniasis low serum zinc levels have been reported. The aim of this work was to evaluate the effect of zinc oral administration during treatment of CanL. Eighteen dogs from an endemic area were enrolled showing clinical signs of leishmaniasis and diagnosed by positive parasitological and serological tests. Dogs were subdivided in three treatment groups: MA, meglumineantimoniate 50 mg/kg SC for 30 days with allopurinol 10 mg/kg PO BID for 7 months; MZ, meglumineantimoniate 50 mg/kg SC BID for 30 days with zinc 2.2 mg/kg/die PO for 12 months; MAZ, same as MA group plus supplemented with zinc 2.2 mg/kg/die PO for 12 months. Each dog was monitored for 12 months using clinical and skin scores and some blood biochemical markers. Dogs in MZ and MAZ group showed a better and earlier improvement of clinical and skin scores in comparison to control dogs (MA group). Among few blood markers studied (hemoglobin, albumin, γ globulins and A/G ratio) dogs in MAZ group did improve and earlier than other groups suggesting that zinc improves the condition where allopurinol is also present. The supplementation of zinc in the treatment protocol for CanL increased the serum zinc concentrations. In addition, preliminary data showed in group MZ and MAZ dogs a faster response to therapy and the elongation of the disease-free interval time.