NEW ORLEANS (AP) — West Nile virus cases in Louisiana are way down from a year ago but the state epidemiologist says people statewide still need to protect themselves against mosquitoes.

Dr. Raoult Ratard says it's not clear why this year's numbers are down.

Louisiana Department of Health statistics show 12 cases through last week, compared to 79 by the same week in 2018.

That includes six cases of dangerous nervous system infections, down from 48 at this time last year.

Ratard says year-to-year changes involve a multitude of factors, making it hard to say which is key.

He said Thursday that where the virus has been found or where someone's become ill isn't particularly important because the virus is statewide.