Six lakes closed in Mérida

Health authorities in the Mexican state of Yucatán have closed six artificial lakes after water tests found Naegleria fowleri, a tiny amoeba that can cause a rare and almost always fatal brain infection. Health officials examined nine bodies of water in the city of Mérida, and six of them contained the amoeba. The lakes sit in luxury residential complexes and shopping centres, where they serve water-skiing, kayaking and stand-up paddleboarding, and they are no longer open to recreational users. The closure followed the death of a man in September from the infection. No general closure of natural bathing waters has been announced, and the parks where the lakes are located remain open.

A September death and an earlier case

A man aged 33 or 34, depending on the report, died in September from primary amoebic meningoencephalitis, the brain infection caused by Naegleria fowleri. He had worked as a water-skiing instructor at an artificial lake where the amoeba was later detected, and he had been hospitalised for several days before he died. This is the first confirmed death from the amoeba in Yucatán. All six affected bodies of water are used for leisure activities. The timeline below sets the Mexican case beside a fatal case in the United States in August.

Authorities urge checks and an investigation

Alberto Alcocer, the state's health secretary, urged residents who may have come into contact with contaminated water to see a doctor quickly. In a video he said that finding the amoeba in the environment does not mean an epidemic exists, nor that people who visited these sites are sick. He explained that infection happens when contaminated water enters the nose, and said preventive action must continue. The regional government has opened an investigation into the companies that maintain the first contaminated lake and monitor its water quality. Authorities also plan stricter monitoring of the cenotes, the natural freshwater pools in limestone that are among the state's main attractions.

Water bodies examined9

Water bodies with Naegleria6

Water bodies examined

9 water bodies

Water bodies with Naegleria

6 water bodies

Data from the article text

A fatal case in Louisiana

In August, an eight-year-old girl in the US state of Louisiana died after an infection with Naegleria fowleri. Her family and health authorities believe she likely came into contact with the organism while swimming in a lake near her home. Louisiana's health department said on 19 August that a female resident had probably been infected while swimming in Lake Claiborne, which lies about 48 kilometres north-west of Ruston, the child's home town. The US Centers for Disease Control and Prevention describes such infections as extremely rare but almost always fatal, and says the organism does not spread from person to person.

How the amoeba infects people

The Robert Koch Institute says the organism is especially widespread in subtropical and tropical regions. It spreads mainly in warm water, and it can reach the brain through the nose during swimming. Once inside, it can cause inflammation of the membranes around the brain, which in most cases leads to coma and death. Typical early symptoms are severe headache, fever, nausea and vomiting.