Picture 1. Various stages of Amblyoma ticks similar to those that transmit Heartwater. Each stage of the tick from the very smallest to the fully-grown adults can carry the rickettsia.

The reason for concern is that the Bont Ticks having been showing up in the US. The ticks have been found in Florida on imported tortoises. Often pet owners become disenchanted with their exotic pets and release them into the wild. Released turtles with tick could easily transfer the ticks to other wild hosts. The ticks would certainly seek out other hosts, as they require three hosts to complete their life cycle. There is also the potential for infected ticks to arrive on Cattle Egrets (Picture 2) flying in on hurricane winds from the Caribbean Islands. Each hurricane season brings new egrets to the US. These birds are seen commonly in California as they search for food in fields being irrigated.

Picture 2. Cattle Egret are known carriers of the Heartwater ticks.

Our cattle and wild ruminants are completely susceptible to Heartwater as it is a foreign animal disease that currently does not occur in the US. It has been estimated that we could expect between a 40% and 100% death rate if Heartwater entered the US. Clinical signs of Heartwater can be seen within 14 to 28 days after an infected tick feeds on a ruminant host. The death rate could be reduced by early treatment with tetracyclines if the disease is rapidly detected and properly diagnosed.

Heartwater exists in four different forms across the world. Upon entry into the susceptible populations, such as the US livestock, the peracute form would probably be seen. This form is characterized by sudden death preceded by only fever and convulsions. Later on Heartwater would be seen as fever followed by decreased eating, depression, listlessness and rapid breathing. Soon after, nervous signs such as chewing movements, twitching of eyelids, protrusion of tongue and circling would appear. Death usually occurs within a week after the onset of these signs. This clinical picture could be confused with anthrax, rabies, tetanus, strychnine, lead or organophosphate poisoning.

The disease gets is name from the accumulation of fluid that is found around the heart in dead animals. Excess fluids are also found in the other body cavities and edema is frequently seen.

The intent here is just to increase the level of awareness of the dairy industry to this potential disease threat. Actions are now being taken to prevent the entry of potential reptile carriers of the Bont Tick. Veterinary diagnostic laboratories across the southern US are on alert for the presence of the Bont Tick on cattle and wildlife. Diagnosticians are watching for dead animals with the clinical signs of Heartwater. All these actions will clearly minimize the risk of a Heartwater outbreak in the US. For more information on Heartwater and other foreign animal diseases click on the USDA Animal Plant Health Inspection Service website at http://www.aphis.usda.gov/oa/new/ah.html or talk with your local veterinarian.