Factbox: Key facts about salmonella

WASHINGTON (Reuters) - Eggs from a farm in Iowa have been linked to a salmonella outbreak that has sickened hundreds of people in California, Colorado and Minnesota over the last three months, the U.S. government said.

Nationwide, salmonella outbreaks have increased fourfold since May, which has sparked an investigation of the food borne illness in 13 states, the U.S. Food and Drug Administration said. No deaths have been reported.

Here are some key facts about salmonella:

* Every year, approximately 40,000 cases of salmonella are reported in the United States, and 400 people die.

* People infected with salmonella usually have symptoms that include diarrhea, fever, nausea and stomach cramps that generally start within 12 to 72 hours after they ate infected food. The sickness usually lasts four to seven days.

* Severe infections are possible if salmonella spreads from the intestines to the bloodstream. Infants, the elderly and people with weaker immune systems are more susceptible, and antibiotics may be needed. The infection can cause death unless a person is treated with antibiotics.

* Raw or undercooked meat, poultry and eggs should not be eaten. Fruits, such as tomatoes, should be washed thoroughly.

* Meat and other foods should be kept separate to avoid cross contamination.

Source: Centers for Disease Control and Prevention

(Compiled by Lisa Shumaker; Editing by Gary Hill)