By Jan Worth-Nelson
A fatal chain of events simultaneous with the Flint water crisis — an outbreak of Legionella’s disease which killed 12 and sickened scores of others during a 2014-15 outbreak—has now been scientifically correlated to low levels of residual chlorine during the crisis.
The outbreak can be associated with the change in the City of Flint’s drinking water supply to the Flint River beginning in 2014, according to two scientific papers published this month in top-tier peer reviewed academic journals.
Put simply, the trigger in the scientific whodunit were interactions involving chlorine, routinely added to inhibit the growth of pathogenic [disease-causing] bacteria. When Flint’s water supply was switched from treated Lake Huron water to Flint River water, circumstances resulting from improper treatment and associated corrosion of the pipes resulted in conditions that reduced the level of chlorine such that Legionella bacteria could thrive, the scientists explained.
One of the papers specifically looked at chlorine levels in residents’ homes, called “premise plumbing” in the report. Researchers found that the lower residents’ chlorine levels at the tap, the more likely would be their chance of contracting Legionnnaires.
The city switched to the Flint River from Lake Huron as its water source in April, 2014 when the city was being run by state-appointed emergency manager Darnell Earley.
The scientists responsible for the research are a multi-disciplinary consortium called the Flint Area Community Health and Environment Partnership (FACHEP) who have been intensely collecting and analyzing data in Flint since the Legionella outbreak drew the community’s attention, suspicions and alarm in 2016.
Four members of the consortium presented their findings Thursday to the FACT Community Partners, a group of community representatives who meet monthly under the dome in City Hall to share information, resources and concerns around the water crisis and the city’s attempted recovery.
The lead presenter was Michele Swanson, professor of microbiology and immunology from the University of Michigan.
She was joined by Shawn McElmurry, associate professor of civil and environmental engineering from Wayne State University; Paul Kilgore, an M.D. and associate professor with a specialization in infectious diseases and epidemiology, also at Wayne State; and Ben Pauli, assistant professor of social sciences at Kettering University.
“Changes in the drinking water source and treatment-altered water quality,” the scientists wrote, “as measured by a reduced chlorine residual, increased residents’ risk of Legionnaire’s disease, likely by enhancing legionellae growth in the water distribution system.”
Chlorine is routinely added to keep bacterial concentrations down, Swanson explained, but there was a catch: there were heavy metals and organic material in the river water which have the effect of binding up chlorine, reducing its concentration. Legionella, a bacteria normally present in manageable proportions in nature, thus was given a boost by the change.
The story of the FACHEP’s response to the outbreak is a real life application of the scientific method propelled by a perplexing and deadly spike in the occurrence of the disease during a 17-month period after the change in the water source. It centered in detailed studies tracking chlorine levels around the city and the existence of two “serogroups” of the Legionnaire’s bacteria.
In previous years, the typical number of Legionella cases in Genesee County were between six and 13. In 2014-2015, the total jumped to an estimated 91 – with some diagnoses increasing the total as the situation became clearer.
Key elements of the findings—the evidence leading to the research conclusions–included the following:
- The odds of a Flint neighborhood reporting a case of Legionnaires increased seven-fold after the switch to the Flint River.
- After boil water advisories, the odds of a case decreased by 40 percent.
- The risk of the disease returned to pre-Flint water crisis levels after the switch back to Lake Huron water.
- 80 percent of the Legionnaires’ cases in Flint could be attributed to the change in water source and treatment.
- When all cases associated with McLaren Hospital—where a number of patients were diagnosed and treated, and which had been speculated as a source of the outbreak—were omitted from the analysis, the switch to the Flint River still increased by six-fold the odds of Flint residents contracting the disease.
- The lower the residual chlorine was at the tap, the greater the likelihood that someone would contract Legionnaires disease.
For months state officials resisted the suggestion that there was any link between the Legionnaire’s occurrences and the water crisis and declined to investigate it directly.
Asked by East Village Magazine if there had been a moral failure in the Legionnaires’ aspect of the water crisis, Swanson, McElmurry and Kilgore emphasized their job is to provide scientific data, hoping that “the free press” would get out information allowing the public to decide.
However, Pauli, a social scientist, stated, “We all know that there were some folks who were well aware that there was something weird going on with Legionella all the way back to the summer of 2014.
“Let’s suppose hypothetically there had been a careful investigation of what was happening at that time — we may very well have learned a lot that would be useful to us now in terms of understanding why people got sick and why people died.”
“Unfortunately because we only just now starting to take this issue seriously, there is a real paucity of useful data when you’re trying to do that careful detailed retrospective analysis. You can do the big bird’s eye statistical view, You can see patterns that you wish had been detected earlier on and should have been detected early on.
“As far as the deep digging goes, we’re able to do it now that people are taking it seriously. But we missed our opportunity to do that back in 2014 and 2015.
“I absolutely think that you could make a moral critique of the conditions that led to the neglect of that issue during those two years,” Pauli said.
Two top state officials, Nick Lyon, director of the Michigan Department of Health and Human Services and Chief Medical Executive Eden Wells have been indicted on manslaughter charges in the Legionnaire’s outbreak by State Attorney General Bill Schuette. Both have vehemently denied the charges and the cases are working their way through the courts.
Darnell Earley, the emergency manager when the city made the switch, also has been indicted. The three are among 15 state and local officials indicted so far in connection with the crisis.
As to culpability, Swanson offered an observation about systemic conditions.
“A fair question is, who’s responsible for monitoring the chlorine levels and does that trigger an action that should follow from data,” she said. “Do we have sufficient funding and expertise in our water utilities and our public agencies?”
Swanson emphasized, following a presentation by Rebecca Fedewa from the Flint River Watershed Coalition celebrating the river, that the river water itself was not the culprit – and that residents should not be afraid of enjoying it.
The papers published were “Assessment of the Legionnaires’ disease outbreak in Flint Michigan,” in the February 2018 Proceedings of the National Academy of Science, and “Prevalence of Infection-Competent Serogroup 6 Legionella pneumophila with Premise Plumbing in Southeast Michigan” published in the February issue of mBio, the journal of the American Society for Microbiology.