The parasiticidal effect of electricity on Leishmania major, both in vitro and in vivo

The effects of low electrical potentials on Leishmania major (MRHO/IR/75/ER) were investigated both in culture (in terms of promastigote viability) and in experimentally infected BALB/c and NMRI mice (in terms of the cure of pre-existing skin lesions). Exposure to direct-current potentials of 3, 6, 9 and 12 V (at 0.2-10.7 mA) killed all promastigotes in <15, <10, <10 and <10 min, respectively. When electrodes were used to pass similar direct currents across skin lesions on the tails of infected mice, all but the lowest voltage (3 V) caused unwanted ulceration. At 3 V, however, 3 weeks of electrotherapy, for 10 min twice weekly, initially appeared to cure all the lesions and the therapy was then halted. If given no electrotherapy, the BALB/c mice showed much greater Leishmania-attributable morbidity and mortality than the NMRI mice, and it was only in the treated BALB/c mice that relapses were observed, about 3 weeks after electrotherapy had ceased. The possible clinical use of electrotherapy in the treatment of human cutaneous leishmaniasis is discussed.