Which of the following is a vector for heartwater?

• A. Amblyomma variegatum, the tropical bont tick
• B. All of the above
• C. Amblyomma maculatum, the Gulf Coast tick
• D. Amblyomma dissimile, the iguana tick

Answer: (B)

Heartwater is transmitted by ticks in the genus Amblyomma, which become capable vectors when they acquire Ehrlichia ruminantium from an infected host and maintain it through their life stages to pass it on during feeding. Amblyomma variegatum, the tropical bont tick, is a well-established vector in Africa and the Caribbean. The Gulf Coast tick, Amblyomma maculatum, has also been shown to support transmission of the pathogen in certain settings, expanding the range of species known to carry it. Amblyomma dissimile, commonly called the iguana tick, may primarily feed on reptiles but has demonstrated the capacity to harbor and potentially transmit E. ruminantium under research conditions, indicating that multiple tick species can serve as vectors depending on ecological context. Therefore, all three tick species have documented associations with heartwater transmission, making all of the above the best answer.