With State Officials expecting the deadly West Nile Virus to reach California this summer, a local veterinarian says horses need to be vaccinated against the disease.

Doctor Roderick Eck of Columbia says the vaccine is about 90% effective when administered properly. He says the medical community isn´t sure why horses and humans are more likely to get the disease than other animals.

Last year, 274 Americans died in the worst outbreak of the mosquito-borne encephalitis ever recorded in this country. Eck says about 4,500 horses died from the disease.