The years 2002 and 2003 have been the years of the horse, as far as West Nile virus (WNV) is concerned, said Robert Restifo, MS, Public Health Entomologist Administrator and chief of Ohio’s Vector-borne Disease Program, at the third annual West Nile Virus Satellite Conference, in late March. “Once WNV gets into an area, it tends to stay there,” he added. “West Nile virus is here, it’s here to stay, and it’s going to manifest itself.”

More than 400 people viewed the live conference broadcast from Columbus, Ohio, at health departments and extension services across the state, and they had the opportunity to call or fax in questions following WNV presentations. Speakers included Restifo, Richard Gary, MS, Assistant Public Health Entomologist of the Vector-borne Disease Program, Jacek Mazurek, MD, MS, E.I.S. Officer in ODH; and William Saville, DVM, PhD, Dipl. ACVIM, of The Ohio State University’s Department of Veterinary Preventive Medicine.

In its North American spread, WNV continues to move not only east and west, but north and south. Nine Canadian provinces have been affected, as far west as Alberta, and 2,630 horses were affected in Mexico last year. According to Restifo, public health officials are expecting California, Washington, and Oregon to get hit hard in 2004.

Hot and dry weather conditions seem to be a key factor in intense WNV activity. However, the virus still propagated under very wet conditions in Ohio last year, but at lower levels than in previous years. Restifo concluded that the constant rain kept washing away mosquito larvae, so there were many young mosquitoes around, but not as many harboring virus