Experimental transmission of Cowdria ruminantium by the Gulf coast tick Amblyomma maculatum: danger of introducing heartwater and benign African theileriasis onto the American mainland.

The tick Amblyomma maculatum proved to be an experimental vector of Cowdria ruminantium, the cause of heartwater of ruminants. Transstadial transmission from larva to nymph and from larva through nymph to adult was successful; however, an experiment on transovarial transmission gave negative results. Neither A americanum nor A cajennense transmitted the infection. There is a potential danger of the disease gaining access to the American mainland from the Caribbean where it is known to occur and of maintaining itself in areas where A maculatum occurs. Transstadial transmission experiments, using 3 American Amblyomma spp and an African strain of Theileria mutans, which is thought to occur in the Caribbean, were unsuccessful.