The unfolding story of how salmonella bacteria infected two giant egg operations in Iowa this summer is the latest chapter of a mysterious narrative about how a minor bacterial annoyance took off 35 years ago to become the second most common cause of food-borne illness in the United States.
Like the things that cause AIDS, Lyme disease, Legionnaire's disease and West Nile fever, the egg-loving germ (whose formal name is Salmonella enterica serovar Enteritidis) is a classic "emerging infectious agent." Sometimes called SE, it's a microbe that has been around a long time and has found a new or better way to reach its human victims.
For more than three decades, the strain of salmonella bacteria with a fondness for eggs has taken advantage of changes in this country's animal husbandry, food distribution and eating habits.
Along the way, scientists and public health officials have paid increasing attention to it, culminating recently in the Food and Drug Administration's 71-page "egg safety rule," which took effect in July. The federal government hopes those regulations will prevent 80,000 of the 142,000 cases of egg-related salmonella infection that occur in the United States each year (out of an estimated 1.54 million cases of food-borne salmonella illness). They hope the rule will cut the number of infected "table eggs," currently estimated at 2.3 million of the 47 billion produced each year. The new standards might even reduce health-care costs by $1.4 billion.
But they are unlikely to eradicate the problem.