CHESTERFIELD COUNTY, Va. — The Chesterfield Health District (CHD) provided an update Thursday into its ongoing investigation of an increase of cases of Legionnaires’ disease in the northeastern portion of the county and the search for possible sources of the Legionella bacteria.
The CHD said there have been 11 confirmed cases of the disease since May 1. The eleventh case was announced August 8. The cases were among older adults and people with certain medical conditions.
The CHD said “because there were no common water or facility exposures identified among cases, cooling towers became a suspected mode of transmission." It added that they have collected samples from 12 sites within a common geographical area.
As of August 6, investigators said they have confirmed the presence of the Legionella pneumophila serogroup 1 (Lp1) of the Legionella bacteria at seven sites, including three Chesterfield County public schools.
The CHD said Legionella bacteria "are found naturally in the environment and are commonly identified in building water systems and devices that are not adequately maintained."
It added they expected to find the bacteria when they tested for it, but added that there were several types of it. It said the Lp1 serogroup is “the type most commonly associated with developing Legionnaires’ disease."
CHD Director Dr. Alexander Samuel spearheaded the investigation and efforts to pinpoint a source of the bacteria.
"My biggest fear is that people will blow this out of proportion. This is not a public health emergency," Samuel stated. "We are still in this phase with this could this be simply his issue of seeing more cases because of enhanced surveillance."
Samuel said they're focusing on cooling towers after studying similarities of the 11 confirmed cases of Legionnaires' disease. Epidemiologists have ruled out the water supply, false negative reports, and common facilities as links to the cases.
"Today, we cannot say we're linking anything to any one source," Samuel said.
The Virginia Department of Health (VDH) has a spreadsheet showing the results and statuses of the tests. The CHD added that testing has not been completed on all 12 sites, and additional testing of these samples is pending.
The five other sites tested include two more county schools -- Meadowbrook High School on Cogbill Road and Hopkins Road Elementary School. Tests on both those schools came back negative.
Results are pending at the other sites: Kaiser Aluminum on Reymet Road, Aleris on Reymet Road, and the US Marine Corps Services Center on Strathmore Road.
The CHD said when Legionella is confirmed, it provides recommendations to the facilities on how to eliminate the bacteria. It added, to date, “facilities have remained cooperative in implementing all remediation recommendations."
CHD Director Dr. Alexander Samuel told CBS 6 they have recommended the sites be cleaned using the Wisconsin Protocol.
"The risk to residents or visitors to Chesterfield County remains small,” said Dr. Samuel. “The health department continues to make every effort to identify cases of Legionnaires’ disease and will continue to work with facilities to remediate any potential source of exposure.”
More information from the VDH about Legionnaires’ disease can be found here.