Twelve new West Nile cases in the past week bring the year's total to 133, with just over half of them serious infections of the brain or spinal cord.

Associated Press

File photo.

The "neuro-invasive" diagnoses -- three in New Orleans, two in Jefferson Parish and one each in Rapides, East Baton Rouge and Calcasieu parishes -- bring the year's total for those seriousinfections to 67. That's well below the 102 at the same time last year.

Another 47 people, including four this week, have been diagnosed with the flu-like West Nile fever. In addition, a St. Tammany Parish case previously reported as neuro-invasive has since been reclassified as fever, said Dr. Raoult Ratard, the state epidemiologist.

All of the people diagnosed this past week had symptoms. But 19 diagnosed this year had had no symptoms, and were diagnosed after giving blood or having routine medical tests.

That is a major reason this year's total so far is above the 129 at this time last year, when the end-of-year totals included 16 such "asymptomatic" cases.

The number of neuro-invasive cases diagnosed is the second-lowest at this time of the year. Over the past several years, the weekly diagnoses have peaked in late August and early September, but there may be a few each week through November.

The worst year for West Nile cases in Louisiana was 2002, when 204 of the 329 cases were neuro-invasive, and 25 patients died.

In addition to the West Nile virus cases, two cases of LaCrosse virus and a case of Eastern Equine encephalitis have been reported this year. Mosquitoes spread all three viruses. Most infected people don't get sick at all or get a mild flu-like illness.

Health officials say that to avoid West Nile virus, apply mosquito repellant, wear long sleeves and long pants and avoid wearing perfumes or colognes when outside for prolonged periods of time.

Officials also recommend removal of any standing water around homes and putting secure screens on doors and windows.

(Copyright 2006 by The Associated Press. All Rights Reserved.)