Salmonella poisoning from eggs is on the rise and the federal Centers for Disease Control and Prevention is calling for tighter controls over the egg industry to curb infections.

Salmonella is a bacteria that can contaminate meats and eggs and cause fever and diarrhea. It can be fatal in people with weak immune systems.

A CDC report out Thursday shows the percentage of salmonella cases that are linked to eggs rose from 5% in 1976 to 25% in 1994, and officials say the rate continues to rise.

Egg transmission "has become the most common type" of salmonella infection, says the CDC's Dr. Patricia Griffin. "We need to have quality assurance programs for our egg-laying flocks, and they should meet a national standard that includes surveillance and microbiological testing."

From 1985 to 1995, 582 egg-related salmonella enteriditis (SE) breaks were reported, resulting in 24,058 illnesses, 2,290 hospitalizations and 70 deaths. In 1995 alone, SE accounted for 10,201 of the total 41,222 salmonella cases. But the numbers reflect only reported cases, Griffin says. Studies suggest there are 99 cases for every case reported.

That means there were 2 million to 4 million salmonella illnesses last year, and SE was responsible for about 25 of them, Griffin says. SE illnesses are rising most rapidly in California, where they accounted for24 of cases in the USA in 1994.

Risk of contamination is highest in eggs that have not been refrigerated. They should be refrigerated from the time they are laid until they are consumed, Griffin says.

There is some evidence that controlling rodents in hen houses may cut down on SE infection of chicken flocks. Griffin says, but "a lot more work is needed to look at the control measures that would work."