The nation is in the midst of an outbreak of West Nile disease that could become the worst ever recorded since the virus was first detected in New York in 1999. The number of cases has risen sharply in recent weeks.

As of Wednesday, more than 1,100 cases and 41 deaths had been reported to the Centers for Disease Control and Prevention, well above the usual caseload for this time of year. Every Wednesday for the next six or so weeks, federal officials will be announcing ever higher tolls as the season for West Nile disease slowly winds down.

How nervous should you be?

For starters, it is important to put West Nile disease in perspective. At most, the death toll might mount into the hundreds (the previous record was 284 in 2002). By contrast, a typical flu season kills 25,000 to 36,000 people.

That does not mean the disease can be shrugged off. So far this year it has driven hundreds of people into the hospital, killing some and leaving others with neurological damage, like paralysis or chronic fatigue, that may last for months or a lifetime.