By Christine Harvey / L’Observateur / July 3, 1999

An outbreak in south Louisiana of Eastern Equine Encephalitis, a severe brain infection, has left one person and at least 14 horses infected with the deadly disease.

Between May 11 and June 21 the disease infected one person near the Assumption-St. Mary Parish line, and reports of horse infections camefrom Assumption, St. Mary, Lafourche, Terrebone, St. James and St.Charles parishes, according to the State Office of Public Health.

Individual incidents of horse infection in the River Parishes area have occurred in the towns of Luling, Lutcher, Paulina and Vacherie, said Fred Duplechin, regional administrator of region three for the State Office of Public Health.

Though these cases are the only ones confirmed by the office, several other cases have gone unconfirmed because horses die before a blood sample can be obtained, said Dr. Tom Farley, medical epidemiologist withthe State Office of Public Health.

“This is very quick and deadly disease for horses,” he said.

The disease follows a specific path to infection. Mosquitos carry thedisease after they bite birds infected with it, then they bite horses and humans, transmitting the disease to them, Farley said.

“Birds are the reservoir for it,” said Dr. Beverly Coyle, a veterinarian atthe Bayou Animal Clinic in Luling.

The disease affects birds living in swampy areas and tends to stay localized there, Farley said.

He said people are unlikely to get the disease, even when bitten by an infected mosquito, but they can get it from just one bite. The Office ofPublic Health received just 25 reports of the disease in humans from 1977-1993.

The office recommends residents in the outbreak areas take several precautions through September to avoid being bitten by mosquitos.

“These viruses tend to become active in the summertime,” Farley said.

People should avoid going outside during the times of the day when mosquitos are at their most active, dawn and dusk. People should alsowear long sleeves and pants when outdoors and spray exposed skin with an insect repellent.

And residents should remove any standing water, a common breeding ground for mosquitos, from their property.

The Office of Public Health also has notified each of the affected parishes’ presidents to increase their mosquito control efforts.

Mosquito Control, Inc., contracts out to control the pests for St. John andSt. Charles parishes, and the company maintains a low mosquitopopulation by spraying both the ground and air, said Wayne Machado, entomologist and general manager of Mosquito Control, Inc.

The company, which also sprays in Jefferson and Ouachita parishes and Hancock and Jackson counties in Mississippi, monitors area mosquitos for encephalitis virus activity as well, he said.

Mosquito infection in the two parishes has turned up negative so far, according to Machado.

To eliminate mosquito larvae before it grows into adult mosquitos, Machado said he employs native Louisiana “Gambusia” fish to feed on it.

“Mosquito larvae is a delicacy to them,” Machado said.

As for St. James Parish, Machado said it is not currently spraying formosquitos, but he is in negotiations with Parish President Dale Hymel to do the work.

People cannot take antibiotics to stave off the disease, which either can have zero or little effect, such as fever and headaches, or can lead to seizures, comas and death, Farley said.

There are also no specific treatments for the disease, though the symptoms can be treated, he said.

Horses become infected much easier than humans and do not fare as well as them against the disease, which can kill horses in two to three days, Duplechin said.

“Pretty much 80 percent of them die,” Coyle said.

Infected horses might tend to press their heads against the stall, show signs of rabies, have a high fever, act depressed, walk in circles or have seizures after contracting the disease, she said.

But owners do not need to fear they will catch the disease when caring for an ill horse, Farley said.

Horses can be vaccinated against the disease, a preventative measure that should be taken by owners at least twice a year, Coyle said.

The vaccinations cost about $16 each, she said.

Besides Eastern equine, other mosquito-borne encephalitis viruses include the St. Louis, Western equine, LaCrosse, California and Japaneseencephalitis viruses.

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