Perhaps you are used to yawning when it comes to global warming? Well, what is there, again about melting ice, tornadoes, hurricanes and a crazy Swedish eco-activist? A new study by American scientists will not let you get bored. Experts from the University of Arizona have warned that the global climate crisis has accelerated the spread of the amoeba Naegleria fowleri, and its range has expanded. This primitive single-celled organism is known for infiltrating the human body and eating its brain.
She’s moving north
Last summer in Nebraska, a child died after swimming in a local river, and American newspapers were full of headlines about a deadly brain-eating amoeba. The cause of death was primary amoebic meningoencephalitis, and it is caused by Naegleria fowleri, which lives in warm fresh water and can enter the human body through the nose.
Negleria lives in warm freshwater reservoirs – lakes, rivers and hot springs. Its favorite water temperature is 25-35°C, but the amoeba can tolerate 46°C. And if the reservoir dries up, it turns into a cyst (a temporary form of the existence of a microorganism that helps to survive difficult conditions) and surrenders to the will of the winds. Air currents carry dried amoebas until they again fall into a favorable environment and come to life.
Scientists from the University of Arizona issued a warning that due to climate change taking place on the planet, the risks of being infected with negleria have increased. After all, the number of floods and droughts has increased (just remember this summer), because of which dangerous amoebas spread faster than usual, and climb into places where they were not there before.
“In summer, they swim in warm surface waters even in northern latitudes. And as the temperature of the waters increases further north every year, we expect more cases of infection in the future, ”says University of Arizona microbiologist Charles Gerba.
Primary amoebic meningoencephalitis is rare, with only 31 cases reported in the US between 2012 and 2021. But the disease has a high mortality rate, reaching up to 97%. And if earlier the range of negleria was limited to the southern states of the United States, then in recent years it has been steadily moving north. A 2021 study points to this: it showed that the amoeba has already moved into areas of the Midwest.
When infected, it remains to live 24 days
As we remember from the school curriculum, amoeba are the simplest single-celled organisms that are constantly changing the shape of the body. They need a moist environment to live, and the human body is also quite suitable. True, most amoebas do not eat brains. But Naegleria fowleri is a special case.
If negleria gets into your body when drinking water, nothing bad will happen. It becomes dangerous when it penetrates the nose, which, as you might guess, happens during bathing. (Infections have not been recorded by other methods, and the amoeba has never been transmitted from person to person.) Through the nasal passages and the olfactory epithelium, the parasite seeps into the olfactory nerve and through it reaches the brain, where it spreads to all its departments and begins to destroy tissues. As if a microscopic zombie, negleria begins to devour brain cells and multiply in it.
Symptoms appear within 2-6 days. The person does not feel well, there is a headache, dizziness, nausea. Then the temperature rises and more serious problems begin: hallucinations, violations of the coordination of muscle movements, difficulties with speech and coordination, seizures like epileptic seizures. Symptoms intensify, a person may even go blind or deaf, after which death occurs.
The maximum life span for an infected person is 24 days. Cases of recovery are known to doctors, but they are few. There are no effective drugs. Most often, doctors prescribe antifungal agents, but, as already mentioned, the lethality of the disease is very high.
Boys at risk
Microbiologist Charles Gerba draws attention to the fact that most cases of infection with primary amoebic meningoencephalitis occur in men under the age of 18 years. He explains this by saying that boys may be more active in playing in the water and diving. As a precaution, he recommends pinching your nose when diving if you are swimming in warm fresh water, or using a nose clip. Better yet, don’t dive at all.
Almost all cases of this rare disease were recorded in North America, mainly in the southern states of the United States. In Europe, the parasite also came across – for example, in the Czech Republic and Great Britain. It is very likely that in the countries of Africa and Asia, infections with a deadly amoeba occur more often, but there they may simply not be noticed, attributing the symptoms to other infections.
In cases of primary amoebic meningoencephalitis have not yet been observed. But given that climate change is more pronounced in our country than the average for the world (the reason is the remoteness of the oceans), and also that more and more alien species are penetrating our natural environment, most of which come just from North America, relax not worth it.