Ascension Parish officials are counting on a tiny fish to help control a huge mosquito infestation problem that reaches a peak each fall, bringing with it the ever-present problem of the West Nile virus and growing concern of other insect-borne diseases such as Zika.

Parish workers are breeding and growing the Gambusia minnow, commonly known as a mosquito fish, to be released in area ditches and insect breeding grounds. The parish also intends to make the fish available to residents for their backyard ponds by fall.

“Fall is the worst time of year,” Kyle Gautreau, Ascension Parish chief of staff, said about mosquito infestations. “It’s another way for us to expand our capacity for mosquito control.”

This will be the first time Ascension Parish will use the minnows for mosquito control, but it’s been a tool other parishes have used for years. The practice of putting these fish in unmaintained swimming pools and ponds gained momentum in parts of the state after Hurricane Katrina turned so many pools in New Orleans into perfect breeding grounds.

Used sporadically in East Baton Rouge Parish for years, the practice really gained momentum after residents learned of the fish being used in New Orleans, said Randy Vaeth, assistant director of the East Baton Rouge Parish Mosquito Abatement Program.

East Baton Rouge Parish has a worker who breeds and even delivers these minnows to residents who want better mosquito control in their ponds.

“They are very effective for eating mosquito larvae,” Vaeth said.

It’s part of East Baton Rouge Parish’s robust $4.9 million yearly budget to control the pest.

The parish has three or four trucks spraying pesticides four days a week and also performs mosquito trapping to test for diseases like West Nile Virus.

“This year, our concern too is the Zika virus,” Vaeth said.

There have been six cases of Zika in Louisiana — all of whom have recovered, and all have come from people who traveled to regions where the disease is present in mosquitoes, the Louisiana Department of Health reported.

There have been 756 cases in the United States, but no cases of Zika transmission have occurred in Louisiana or any other state. The disease has spread quickly in Puerto Rico, a U.S. territory, and there are concerns that health problems to babies there might increase.

Zika infects someone primarily through a mosquito bite and can cause fever, joint pain and a rash. The real concern for many is a suspected connection between pregnant women who get infected with Zika and resulting brain birth defects.

On Thursday, the Centers of Disease Control and Prevention reported it will begin reporting pregnancy problems connected with Zika infections in the United States and U.S. territories.

“We are prepared in case we get locally acquired cases,” Vaeth said. “Our role in this whole scenario is to control the mosquito.”

The virus has not shown up in the mosquito tests, and so far, there have been no East Baton Rouge Parish mosquitoes testing positive for West Nile Virus, but that could change, he said.

“We don’t know it until it happens,” Vaeth said.

In addition to the trucks spraying, the department also has two airplanes that can each treat up to 10,000 acres a night and treat between 12,000 and 14,000 homes every year.

In Livingston Parish, the parishwide mosquito program ended last year after voters rejected two tax proposals and an annual fee ended on Dec. 31, 2014. That means that the cities, towns and villages in the parish are on their own when it comes to mosquito control.

Smaller areas, like Springfield, don’t have any programs right now.

Several cities purchased parish equipment when the program was disbanded and now are running their own spray programs.

“It’s not a full-fledged program like East Baton Rouge Parish has,” said Gerard Landry, Denham Springs mayor.

Because the city already had equipment, there was an initial mosquito spray done in fall 2014, with the main spraying program beginning in spring 2015 after a second truck was purchased from the former parish program.

“It does what it’s supposed to do,” Landry said, adding that response from residents has been great.

The benefit of the spraying compared with the cost — about $7,000 last year and $10,000 this year for chemicals — is small compared with the damage mosquito-borne diseases can do to a person, he said.

Walker Mayor Rick Ramsey also picked up one of the parish program’s spray trucks, and the city mimics the schedule and routes of the parish program.

“We actually started spraying this spring,” Ramsey said.

The spray trucks run every two weeks, but they don’t have the ability like the parish did to treat ditches or take mosquito samples to test for disease. However, he said, even with the parish program, there were many rural areas that didn’t get treatment because there was no aerial spraying.

Follow Amy Wold on Twitter, @awold10.