What do you call the transmission of rickettsial pathogens from adult ticks through the egg?

• A. Chemical.
• B. Transovarial.
• C. Mechanical.
• D. Infection through interrupted feeding.

Answer: (B)

Transovarial transmission describes the passing of a pathogen from a female tick to her offspring through the eggs. In rickettsial infections, this means the bacteria can be transmitted to the next generation of ticks, so larvae may hatch already infected. This differs from transstadial transmission, where the pathogen remains through the tick’s molting stages (larva to nymph to adult) but is not passed through the eggs. Mechanical transmission would involve carrying the pathogen on the tick’s mouthparts without a biological replication cycle, and interrupted feeding refers to a different, non-vertical context. So, the term for transmission from adult ticks through the egg is transovarial transmission.