Transmission of microfilariae and infective larvae of Dipetalonema viteae (Filarioidea) among vector ticks, Ornithodoros tartakowskyi (Argasidae), and loss of microfilariae in coxal fluid.

During studies on the acquisition and transmission of infection with the filaria Dipetalonema viteae by Ornithodoros tartakowskyi, it was found that young nymphs and starved medium-sized ticks feed on recently engorged larger ticks. In this manner young ticks acquired the infection with microfilariae, and the microfilariae thus taken developed normally and after 30 days of development were transmitted to a jird. Ticks harboring infective larvae were able to transfer them to other engorged ticks when attempting to feed on them. Although it is not known whether this occurs in nature, it could be a supplementary mechanism in the natural maintenance of this species of filaria. Ticks eliminated microfilariae in the coxal fluid in small numbers during the 1st hr after the infective meal and in increasing numbers with time, reaching a peak between 3 and 5 hr. This mechanism may prevent some ticks from becoming hyperinfected.