Outbreak of uncommon Salmonella strain probed in North Carolina

Lisa Schnirring

Apr 30, 2012 (CIDRAP News) – Health officials in North Carolina and their federal partners are investigating an outbreak of an uncommon Salmonella strain that has sickened 34 people who visited or live in Buncombe County since the end of February.

The Buncombe County Health Department (BCHD) listed the strain as Salmonella enterica serotype Paratyphi B and said it has a genetic fingerprint that is not common.

In a press release today, BCHD officials said lab tests have not yet conclusively identified the source of the outbreak. Gibbie Harris, MPH, the county's health director, said in a statement that until the cause is identified, officials are implementing broad control measures focused on food establishments.

Based on preliminary tests, BCHD environmental health specialists have recommended control measures to the county's food establishments, and the Asheville Independent Restaurant Association is working with the health department to educate food workers on ways to prevent disease spread.

Harris said further tests to characterize the outbreak strain are underway, which may shed more light on ways to control the outbreak. She urged the public to wash their hands before preparing food and see a doctor if they have symptoms. The county launched a hotline number today to offer automated information about the outbreak and connect people experiencing symptoms to a communicable disease nurse.

Symptoms, which can include bloody diarrhea, fever, headache, and abdominal pain, can occur 1 to 10 days after exposure and last 4 to 7 days. Harris said Salmonella Paratyphi B infections may sometimes last longer.

In an earlier statement, the BCDH said lab studies so far suggest that the outbreak strain is unique and has an uncommon genetic fingerprint. It said Salmonella Paratyphi B is found in the intestines of humans, and person-to-person spread can occur from consuming food or water contaminated with the feces of a sick person or a carrier. Salmonella Paratyphi B infection typically begins about 6 days after exposure, but sometimes as long as 30 days after exposure, the agency said.

In early February the Centers for Disease Control and Prevention (CDC) reported an outbreak of Salmonella Paratyphi B infections linked to small pet turtles that sickened at least 132 people in 18 states. In early 2010, health officials in Hawaii reported an Salmonella Paratyphi B outbreak linked to eating imported raw ahi tuna, which sickened at least 13 people.

In a post on ProMed mail, the Internet-based reporting system of the International Society for Infectious Diseases, a moderator wrote that the serotype is likely the d-tartrate-fementing S enterica serovar Paratyphi B dT+, sometimes referred to as Salmonella Java. The organism has well characterized animal reservoirs and has been involved in two recent outbreaks in the United States and one in Europe.