Because female mosquitoes feed on blood, they have the potential of transmitting disease organisms. World-wide, mosquitoes are responsible for the transmission of disease to millions of people each year. These diseases include encephalitis, dengue, yellow fever, malaria, filariasis, and West Nile Virus. In Berkeley County the principle mosquito-borne diseases we are concerned with are Eastern Equine Encephalitis (EEE), West Nile Virus, and Dog Heartworm. A number of biological and environmental conditions occurring in the current sequence must take place for EEE and WNV transmission into the human population to take place; however, it is very important to keep your horses vaccinated against these arboviruses. Dog heartworm is common to the area; if you don’t keep your dog on heartworm medication it will contract the disease.