Two cases of West Nile virus are reported in Minnesota — a bit early for the season — both cases are in horses. Machelle Shaffer, spokeswoman for the Iowa Department of Agriculture, says so far, so good, as far as Iowa’s concerned.There are no reported cases of West Nile in Iowa but the mosquito season is just starting. Shaffer urges horse breeders and owners to get their animals vaccinated. She says the vaccine is relatively inexpensive, it’s made in Fort Dodge, and it’s a good “insurance policy” for your horse’s health. Shaffer expects the threat of that disease to increase as the weather gets warmer and the mosquitoes hatch. She says it’s fortunate that most Iowa horse owners have learned and been vigilant in recent years to invest in the vaccines and to make them a part of the annual routine. Just how many horses are in Iowa? Shaffer says there hasn’t been any kind of equine census. She says the population and the industry itself is growing and while she had no specific number, it’s believed the Iowa horse population is in “six figures.” Shaffer says about one-third of horses that become infected with West Nile die from it. In 2004, West Nile virus infected 23 people in Iowa, killing two of them.