Researchers have found that salmonella bacteria causing food poisoning and gastritis -- salmonella enteritidis -- have infected people in Las Vegas at four times the rate of previous years, the Southern Nevada Health District reported Tuesday.
"We don't know what the source is," said Brian Labus, senior epidemiologist of the health district. "We haven't found a common facility. But it is typically associated with improperly cooked and stored eggs and poultry, though other sources of infection, raw milk and sprouts and meat have been identified with it in the past. But our focus now is eggs."
According to Centers for Disease Control and Prevention, salmonella enteritidis "silently infects the ovaries of healthy appearing hens and contaminates the eggs before the shells are formed."
Though most infected hens have been found in the northeastern United States, the CDC said that infection occurs in hens in other parts of the country.
Since January, the Southern Nevada Health District learned that 30 people went to medical practitioners for treatment of symptoms of the disease, which usually are high fever, abdominal cramps and diarrhea starting 12 to 72 hours after consuming a contaminated food or beverage.
For most people, the disease lasts about four to seven days and can be managed without medical help.
But the elderly, infants and those with impaired immune systems might require hospitalization, where antibiotics are used to treat the disease.
According to the CDC, as many as 600 Americans die annually from salmonella enteritidis.
"We have had hospitalizations in Southern Nevada but no deaths," Labus said.
Labus said eggs should be kept refrigerated and cracked or dirty eggs discarded. After contact with raw eggs, people should wash their hands and cooking utensils with soap and water.
Eggs should be cooked, Labus said, until both the white and yolk are firm. And they should be eaten promptly.
People who enjoy "sunny side up eggs" in which the yolk runs are at risk for the disease, he said. So are people who lick the spoon used to mix raw eggs into cookie dough.