Future directions for vaccine-related onchocerciasis research.

Although the general perception has been that Onchocerca volvulus infection is well on its way towards extinction, it is becoming increasingly clear that without an additional therapeutic or preventative modality (separate from ivermectin distribution or vector control), elimination of onchocercal infection will remain an unfulfilled goal. Vaccination aimed at preventing infection (directed toward infective-stage or adult worms), transmission and/or pathology (directed toward skin microfilariae) could provide the necessary 'final punch' to knockout human infection with O. volvulus altogether. Thus, efforts toward the development of a useful vaccine need to be redoubled rather than shelved, and, to this end, major gaps in our knowledge need to be filled.