Slimmer Ticks, Less Disease: Tick-semen protein is potential vaccine

Pregnant ticks gain a lot of weight. In fact, after females mate and as they feed on a host’s blood, they quickly grow to about 100 times their original size.

BIG MAMA. Unfed female (upper left) and male (upper right) African cattle ticks are dwarfed by a female that has received a protein, originally from semen, that stimulates feeding.