MEXICO · HEALTH
Key Facts
- —What is happening Yucatán’s state health authorities announced on Wednesday, 14 October, that tests found Naegleria amoebae in six of nine artificial lakes in Mérida, and they suspended all contact with the water at those six sites.
- —Why it matters The finding widens surveillance that began after a man linked to the Plaza La Isla lake died of a Naegleria infection in September, and the six sites include a zoo, two parks and a shopping centre.
- —The numbers Six of nine lakes tested positive and three negative, 361 people watched after the September case finished surveillance on 4 October with no illness, and the United States records fewer than 10 cases a year of the rare brain infection.
- —Who is who The Servicios de Salud de Yucatán (SSY) is the state health service that ran the tests, and each lake is run by Mérida’s city hall, the federal government or a private operator.
- —What to watch Surveillance continues at more artificial lakes in Mérida, and the six sites stay closed to water contact until they meet sanitary conditions and a laboratory confirms the result.
- —Power Index Mexico ranks 2nd of 14 in The Rio Times Latin America Power Index, with 71.4 points (October 2026 edition).
- —What it means for you Visitors can still use the parks and zoos, which remain open, but should stay out of the water at the six lakes and keep water away from the nose in any freshwater lake.
Yucatán’s health authorities found Naegleria amoebae in six of nine artificial lakes in Mérida and suspended water contact there. Parks and zoos stay open, and none of the lakes is used for swimming.
Yucatán health authorities said on Wednesday, 14 October, that the Mérida amoeba tests found Naegleria in six of nine artificial lakes. They suspended all contact with the water at those six sites and ordered barriers and signs.
The tests followed a fatal Naegleria case in September linked to the Plaza La Isla lake. Parks and zoos stay open, and only contact with the water is suspended.
What the Mérida Amoeba Tests Found
The state health service, SSY, analysed nine artificial water bodies in Mérida and announced the results on 14 October. Governor Joaquín Díaz Mena had ordered the surveillance to be widened.
Naegleria was detected at the Plaza La Isla lake and at the eastern and main lakes of the Cabo Norte complex. It was also found in the Centenario Zoo lake, the Gran Parque La Plancha lake and the Parque Ecológico del Poniente.
Plaza La Isla is a shopping centre in northern Mérida, and Cabo Norte is a real estate complex. The Centenario Zoo and the two parks are public spaces.
Three sites tested negative: the central lake at Cabo Norte, Acuaparque and the lake at the Animaya zoo. The state says none of the nine is used for swimming, and Animaya’s catamaran rides involve no contact with the water.
What Happened at Plaza La Isla in September
On 14 September the state said the national reference laboratory InDRE confirmed Naegleria fowleri as the cause of a 34-year-old man’s death. It also said the amoeba was found in samples from the artificial lake where he had been active.
Diario de Yucatán and El Financiero reported that he was a wakeboard instructor at the Plaza La Isla lake. They said he was admitted on 2 September and died on 8 September.
The state says 361 people who had been at that lake were placed under health surveillance. They completed it on 4 October, and none fell ill.
The new tests extend that surveillance from one lake to nine artificial water bodies across the city. Background on the September case is in an earlier Rio Times report.
What Naegleria Is and Why It Matters
Naegleria is a genus of single-celled amoebae that commonly live in warm fresh water. The US Centers for Disease Control and Prevention (CDC) says one species, Naegleria fowleri, lives in warm lakes, rivers and hot springs.
Infection occurs when contaminated water travels up the nose to the brain, the CDC says. Swallowing the water does not cause it, and it does not pass from person to person.
The CDC lists headache, fever, nausea and vomiting as early symptoms, and the state also names neck stiffness. The CDC says more than 97% of people with the Naegleria fowleri brain infection have died, though cases are very rare.
Who Runs the Lakes and the Cleanup
Each lake’s operator handles its cleanup, and an operator can be Mérida’s city hall, the federal government or a private party. Specialists from the Autonomous University of Yucatán (UADY) and the Cinvestav research centre advise them.
A lake can return to use only when it meets the health authority’s conditions and a laboratory confirms the result. An inter-agency water safety group, including the national water commission Conagua, is drafting a permanent rule for artificial lakes.
What the Authorities Say About the Risk
The state says infection happens only when contaminated water enters the nose, for example when a person is submerged. It says the amoeba does not spread from person to person, by drinking water or through splashes.
Anyone who touched the lake water should seek care at once if fever, severe headache, nausea, vomiting or neck stiffness follow. The state’s guidance line is 999 947 2198 for callers in Mexico.
The state’s general advice is to keep water away from the nose in any lake or pond, positive or not. Officials call the infection extremely rare and describe the water rule as permanent, like those for dengue or heatstroke.
What It Means for US Readers
The six lakes are at a zoo, two parks, a shopping centre and the Cabo Norte complex. The state says the parks and zoos stay open, and only contact with the water is suspended.
Visitors should respect the barriers and signs at the six lakes. The state’s standing advice is to keep water away from the nose in any lake or pond, tested or not.
The CDC says fewer than 10 people a year in the United States get the infection, called primary amebic meningoencephalitis. It counts 167 reported US cases from 1962 to 2024.
What Is Not Known
The state release names only Naegleria and never says Naegleria fowleri, the species confirmed in the September case. La Silla Rota said the analyses could not determine the species, and UnoTV said fowleri is unconfirmed.
The release does not say how many samples were taken or which laboratory analysed them. It mentions no sanctions and does not name the operators of the six lakes.
None of the sources reports a new case since September, and the state has not said when any lake will reopen. More artificial lakes are still being tested.
What Comes Next
Surveillance continues at more artificial water bodies in Mérida, and each result will be published with its measures and operator. The six lakes stay closed to contact until they meet the sanitary conditions and a laboratory confirms them.
Frequently Asked Questions
Which Mérida lakes tested positive for the amoeba?
Naegleria was found at Plaza La Isla, Cabo Norte’s eastern and main lakes, and the Centenario Zoo. It was also found at Gran Parque La Plancha and the Parque Ecológico del Poniente.
Are Mérida’s parks and zoos closed?
No, the state says parks and zoos remain open. Only contact with the water at the six lakes is suspended.
Which species of Naegleria was found in the lakes?
The state release names only Naegleria and does not name the species. The state confirmed Naegleria fowleri in the September death.
Can the amoeba spread from person to person?
No, the state and the CDC both say it does not spread between people. Drinking the water does not cause infection either.
What should I do after contact with the water?
Seek medical care at once if fever, severe headache, nausea, vomiting or neck stiffness follow. The state’s guidance line is 999 947 2198 for callers in Mexico.
How common is the infection in the United States?
The CDC says fewer than 10 people a year in the United States get it. It counts 167 reported US cases from 1962 to 2024.
Sources: Yucatán state government, press release 26-1671, 14 October 2026; Yucatán state government, press release 26-1511, 14 September 2026; Por Esto, 14 October; Infolliteras, 14 October; La Silla Rota, 14 October; El Financiero, 14 October; Diario de Yucatán, 13 October; UnoTV, 15 October; US Centers for Disease Control and Prevention, Naegleria fowleri (all accessed 15 October 2026).