On Tuesday, the Centers for Disease Control and Prevention (CDC) identified raw oysters as the source of a salmonella outbreak that has sickened dozens of individuals across 22 states. This troubling situation has resulted in 20 hospitalizations as of December 23, according to CDC reports.

Efforts are underway among public health officials to trace the outbreak to a specific source of oysters. Investigations involve interviews with affected individuals, revealing that 20 out of 27 interviewed had consumed raw oysters before falling ill.

Though the outbreak spans a wide geographic area, Pennsylvania has been hit hardest, with 10 reported illnesses. New York follows with seven cases, while Virginia has documented six cases, rounding out the states with the highest numbers of reported illnesses.

While the outbreak spans 22 states, Pennsylvania has the most reported illnesses, with 10 overall. New York and Virginia have the second- and third-highest numbers of cases, with seven and six reported cases, respectively. 

Illnesses began on June 21 and continued until Nov. 28, according to the CDC. No deaths have been reported. 

Health officials say the hospitalization rate in this outbreak is higher than what’s typically seen in salmonella cases tied to oysters.

No recall notices tied to the salmonella outbreak have been announced so far. 

Salmonella are bacteria that can make people sick with an illness called samonellosis. The bacteria live in the intestines of people and animals. 

Common ways people get infected include eating contaminated food, drinking or having contact with contaminated water or touching animals, animal feces and the places animals live and roam. 

Most people with salmonella experience diarrhea, fever and stomach cramps. Symptoms usually begin six hours to six days after ingesting the bacteria, and most people recover without treatment after four to seven days. 

Raw oysters should be cooked before eating to reduce the risk of food poisoning, according to the CDC. 

The agency also notes that popular add-ons like hot sauce and lemon juice do not kill germs in raw shellfish. Even oysters that look, smell, and taste normal may still contain Salmonella or other harmful bacteria.