County Issues Pills to Battle Outbreak of Malaria

San Diego County health authorities Thursday began dispensing medication to about 300 Carlsbad-area farm workers to battle an outbreak of malaria that has stricken 20 people.

Dr. Georgia P. Reaser, acting county health officer, said the health department dispensed chloroquine pills as a “suppressive treatment program” to the 300 farm workers who are employed southwest of Carlsbad’s Agua Hedionda Lagoon--the breeding ground for mosquitoes suspected of transmitting malaria.

Although the farm workers may appear healthy, they could be carrying the malaria parasite in their blood because many workers come from malaria-prone areas of Mexico, Reaser said.

County health authorities are asking the farm workers to take the pills voluntarily once a week until the end of mosquito season in mid-October, she said. The aim of the unprecedented step by the county is to kill the parasites in the farm workers’ blood and, thus, prevent the spread of malaria through mosquito bites.

“The foremen are gathering together the farm workers, and it’s being explained to them why we want to give it to them,” Reaser said. “They have information handed to them, and they don’t have to take it (medication) unless they want to. We found out that most of them do want something.”

“I still wouldn’t be surprised to see some cases turn up because they came up from Mexico with it,” she said, adding that the incubation time for malaria can range from two weeks to eight months. “But if they get in line and get the medication, hopefully, we won’t have any problems.”

Since early July, 20 people living and working near the lagoon in Carlsbad have contracted malaria, Reaser said. The latest case was confirmed Wednesday.

The majority of those affected have been farm workers who have been sleeping under bushes near the marshy wetlands, she said.

It is unusual for so many people in the same area to contract malaria, Reaser said. Normally 15 to 20 cases a year are reported in the county.

Reaser also said the current outbreak is of the mildest form of malaria, and its symptoms include chills, a fever and a headache. The female mosquito transmits the disease when it bites people, transferring malaria parasites from one person to another.

Since Aug. 15, the county has been spraying the Agua Hedionda Lagoon to kill adult mosquitoes, and Reaser said health officials haven’t found a female mosquito in a week. The county is also spraying to kill mosquito larvae, she said.

Before this outbreak, the highest number of malaria cases reported in San Diego County is one year was 40 in 1980, when there was an influx of Vietnamese boat people, Reaser said.

The deep-water Agua Hedionda Lagoon--its name means “stinky water” in Spanish--is the only lagoon in the county that is open to recreational uses, such as swimming and water skiing. It is just north of the San Diego Gas & Electric Co. Encina power plant and Carlsbad Car Country.