The number of horses testing positive for equine piroplasmosis in Florida has jumped to 18, with a similar number of properties under quarantine.
Authorities are working to contain the first outbreak of the parasitic disease in 20 years.
Five of the infected horses "have been either humanely euthanized or sent to the National Veterinary Services Laboratories in Ames, Iowa, for further study", the agriculture department said.
There are now 18 premises under quarantine and about 160 horses have been tested for the disease.
All of the positive premises - there are four - have been directly linked together via movement of one or more of the positive horses.
Four of the quarantined premises are expected to be released as exposure occurred more than 60 days ago and all testing for EP has been negative.
The current evidence indicates that ticks have not played a role in the spread of the disease. Tick surveillance is continuing with more than 60 ticks having been collected from positive or surrounding premises. No foreign or exotic ticks capable of transmitting this disease have been found.
Facebook
Twitter
HOME SITES 
