The Centers for Disease Control and Prevention have not yet identified the source of the bacteria but said it has been six weeks since the last patient became ill.

"Although this indicates that this outbreak could be over, CDC continues to work with state public health officials," to identify additional cases and the source of the E.coli, the agency said in a statement.

The CDC confirmed an additional case of illness in Louisiana from Shiga toxin-producing Escherichia coli 0145, a strain of a large group of bacteria commonly abbreviated as E.coli.

That is the same type of E.coli that killed a Louisiana child in May and since April 15 has sickened people in Alabama, Florida, Georgia, Tennessee and California. Four of the patients were hospitalized.

The latest reported victim was sickened April 21, but health officials delayed officially connecting that illness to the outbreak because the E.coli that caused the patient's infection was slightly different than the others, said Dr. Raoult Ratard, Louisiana's state epidemiologist.

After further study, it was determined that the type of E.coli that infected the patient was close enough to the others to be included in the list of victims, Ratard said on Monday.

Louisiana health officials initially thought the child who died from the bacteria might have been infected after visiting a petting zoo. But that theory was dropped because none of the ill adults had been to the zoo.

The additional reported victim from Louisiana also had no connection with the petting zoo, Ratard said.

There have been no reported cases of illness from the strain that have developed in the country after May 12, the CDC said.

Ratard shared the CDC's optimism that the outbreak may have ended. "We don't seem to be seeing any new cases now," he said.

The spread of E.coli bacteria can be prevented by washing hands thoroughly after changing diapers or going to the bathroom and after contact with animals, the CDC said.

Meat should be cooked thoroughly, and people should avoid juices and dairy products that have not been pasteurized. The CDC also warns against swallowing water when swimming.

(Editing By Colleen Jenkins and Greg McCune; editing by Sofina Mirza-Reid)

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