India, July 29 -- Two separate foodborne illness outbreaks in the US have raised concerns among consumers, with federal health officials tracking a large cyclospora outbreak linked to recalled lettuce and a salmonella outbreak tied to recalled shell eggs.

While both infections can cause stomach problems such as diarrhea, nausea and abdominal cramps, health experts say there are important differences in how quickly symptoms appear, how long they last and the warning signs to watch for.

According to the Centers for Disease Control and Prevention (CDC), more than 4,100 laboratory-confirmed cyclospora cases have been reported across 41 states since May 1. Meanwhile, an ongoing salmonella outbreak linked to recalled shell eggs has sickened 9...