Refeeding activity of immature ticks of Ixodes persulcatus and transmission of Lyme disease spirochete by partially fed larvae.

The refeeding activity of immature ticks of Ixodes persulcatus was studied under laboratory conditions. BALB/c mice were used as blood sources. Feeding larvae and nymphs spontaneously detached themselves from parasitized mice when the mice were killed 1 or 2 days after tick exposure. Partially fed ticks were reexposed on other mice. Both larvae and nymphs were able to refeed on mice. The resultant engorged ticks normally molted to the next developmental stages. We also examined the transmission of the Lyme disease spirochete, Borrelia garinii, by bites of partially fed ticks. Larvae that had fed on infected mice for 1 or 2 days transmitted the spirochete to mice by refeeding.