In vitro efficacy of 5-aminolevulic acid against Babesia gibsoni by solo-use and combined use with atovaquone

Babesia gibsoni is a tick-borne parasite of dogs. Atovaquone (ATV) is used to treat B. gibsoni infections, but recurrent with a single-nucleotide polymorphism (M121I) is a serious concern. The present study aimed to evaluate the effect of 5-aminolevulinic acid (5-ALA) on inhibiting in vitro growth of B. gibsoni and to evaluate the effect of combined use of ATV and 5-ALA on suppressing in vitro growth and regrowth. The growth of B. gibsoni was suppressed by nearly 85% with 1250 mu M 5-ALA. Although the growth of B. gibsoni was suppressed after the combined exposure, the regrowth was observed. M121I was not detected in the regrowth population. 5-ALA might be useful in preventing the development of refractory canine babesiosis due to ATV.