FACHEP concludes random Legionella sampling in Flint, Genesee County and Wayne County

October 9, 2017

The Flint Area Community Health and Environmental Partnership (FACHEP) team has finished collecting samples from homes as part of a study of the Legionnaires’ disease outbreak and its association with changes in the Flint, Michigan, water system. FACHEP has generally met the sampling goals in both Genesee County and Flint. The team will continue to collect samples in targeted areas or when assisting public health partners to evaluate cases of Legionnaires’ disease, which is caused by bacteria that can live in water systems.

The team collected multiple water samples in more than 790 randomly identified homes and interviewed their residents in Flint, Genesee County and Wayne County, according to Shawn McElmurry, associate professor of environmental engineering at Wayne State University.

In Flint, more than 370 homes have been sampled since the start of the study. Of the homes that received Flint River water during the 2014-15 water supply change, approximately one-third were sampled in 2016 and the remaining two-thirds were sampled May through September of this year. A total of 272 homes in Genesee County, outside of Flint, participated in the study. Of the homes that participated in Genesee County, about 80 percent were sampled in 2017. In 2017, an additional 147 Wayne County homes also participated. Data collected in Genesee County, outside of Flint, and in Wayne County homes provide comparison information to the Flint data.

Multiple samples were collected from each home resulting in more than 2,800 culture tests for Legionella bacteria.  Culturing tests for living bacteria. The analysis of 2017 samples is still underway and results will be presented as soon as they are available.  Previously, FACHEP reported finding culturable Legionella in approximately 12 percent of the homes sampled from Sept. 6 through Oct. 29, 2016.

Preliminary analysis suggests approximately 10 percent of all homes on the Flint municipal water system had chlorine levels less than 0.2 mg/L when measured at the kitchen faucet (bypassing filters when present) after five minutes of flushing.  Chlorine is added to water distribution systems to reduce bacterial growth. While a uniform standard does not exist, regulatory agencies typically recommend maintaining a minimum free chlorine residual of 0.2 to 0.5 mg/L within water distribution systems.

FACHEP has also worked with the Genesee County Health Department to interview County residents who acquired Legionnaires’ disease in 2017. Water samples were also collected from their homes. Analysis of the samples is ongoing and participants will be notified of the results as they are available. Additional results of the study are expected before the end of the year.

In three households where high levels of Legionella were identified, FACHEP worked with local plumbers and Habitat for Humanity to replace hot water heaters and improve household plumbing.

The FACHEP team and its partners appreciate the assistance and patience of residents as we all move toward a better understanding of Legionnaires’ disease. 

FACHEP is a research consortium led by WSU that includes the University of Michigan, Michigan State University, Kettering University, Colorado State University, and Henry Ford Health System.

The study on Legionnaires’ disease is funded by the Michigan Department of Health and Human Services.