OVERVIEW

Salmonellosis, or salmonella, is one of the most common foodborne diseases. Overall, salmonella infections are decreasing in the United States but some types are still increasing.

Salmonella may occur in small, contained outbreaks in the general population or in large outbreaks in hospitals, restaurants, or institutions for children or the elderly. While the disease is found worldwide, health experts most often report cases in North America and Europe. Every year, the Centers for Disease Control and Prevention (CDC) receives reports of 40,000 cases of salmonellosis in the United States. The agency estimates that 1.4 million people in this country are infected, however, and that 1,000 people die each year with salmonellosis. People with AIDS are particularly vulnerable to salmonellosis-often suffering from recurring episodes.

Infectious diseases spread through food or beverages are a common, distressing, and sometimes life-threatening problem for millions of people in the United States and around the world. The CDC estimates 76 million people suffer foodborne illnesses each year in the United States, accounting for 325,000 hospitalizations and more than 5,000 deaths.

Foodborne disease is extremely costly. Health experts estimate that the yearly cost of all foodborne diseases in this country is 5 to 6 billion dollars in direct medical expenses and lost productivity. Infections with Salmonella bacteria alone account for $1 billion yearly in direct and indirect medical costs.

There are more than 250 known foodborne diseases. They can be caused by bacteria, viruses, or parasites. Natural and manufactured chemicals in food products also can make people sick. Some diseases are caused by toxins (poisons) from the disease-causing microbe (germ), others by the human body's reactions to the microbe itself.

To better understand the epidemiology (study of disease origin and spread) of foodborne diseases in the United States, 10 states across the country are collecting annual data on the occurrence of new cases of the most common causes of bacterial and parasitic infections through the Foodborne Diseases Active Surveillance Network, a CDC-sponsored program known as FoodNet (www.cdc.gov/foodnet).

Recently, public health, agriculture, and environmental officials have expressed growing concern about keeping the nation's food and water supply safe from terrorist acts. A number of U.S. agencies, including the National Institutes of Health, CDC, Food and Drug Administration, U.S. Department of Agriculture, and U.S. Environmental Protection Agency, are studying this bioterrorism threat.