Virginia Tech professor Marc Edwards speaks outside Flint City Hall in this September 2015 Flint Journal file photo.

FLINT, MI -- The Virginia Tech university professor who spent months studying Flint's water problems says the failure to treat Flint River water to make it less corrosive could have set off an outbreak of Legionnaires' disease here.

Gov. Rick Snyder and state officials announced a spike in cases of Legionella bacteria today, Jan. 13, in Genesee County.

Legionella bacteria sometimes infects the lungs and causes pneumonia, resulting in Legionnaires' disease, according to the Centers for Disease Control and Prevention.

The bacteria can also cause a less serious infection known as Pontiac fever that seems more like a mild case of the flu, the CDC says.

Snyder and the state officials said there's no evidence of a clear link between the outbreak and the water system change that's caused a public health crisis here because of elevated blood lead levels in children.

But Edwards, the first expert to sound warnings of about elevated lead in Flint water last year, said, "It's not unexpected that the lack of corrosion control could have triggered that."

"Legionella likes water that has little or no chlorine and has high iron," Edwards said today. "Both those factors would contribute to the growth in Legionella."

The lack of treatment of Flint River water to make it less corrosive has contributed to increasing amounts of lead leaching into the city's water supply since April 2014, when the city changed its water source to the river, according to researchers from Virginia Tech.

After months of saying the state Department of Environmental Quality was following federal protocols in waiting to require corrosion control treatments in Flint, former Director Dan Wyant acknowledged the state incorrectly allowed the city to use the wrong federal standards to treat river water for 17 months.

Wyant resigned his position in December.

In addition to failing to treat water to make it less corrosive, Flint struggled to keep up chlorine levels in river water.

The city added so much chlorine to the water in an effort to boost levels that it was in violation of the Safe Drinking Water Act for total trihalomethanes (TTHM) in 2015.

TTHM is a byproduct of chlorinating water.

"It's quite possible ... that if federal law had been followed this would not have occurred," Edwards said.