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The brain-eating amoeba is thriving because of the climate crisis

The recent unfortunate case of the brain-eating amoeba in Israel is indeed very alarming, but infection with amoebas of this species is still rare. However, with the changing climate, and the warming waters of the Sea of ​​Galilee, the incidence of the deadly amoebas may also increase. opinion

By Dr. Shira Nino, Angle - a news agency for science and the environment

Editor's note, after the publication of this article, there was a report of a fear of "brain-eating amoeba" infection in another patient. A 10-year-old boy, with no underlying disease, is ventilated and anesthetized and the doctors fear the rare infection. At the beginning of July, a 26-year-old man died who suffered from an acute infection in his brain due to the amoeba Naglaria fowleri which he probably contracted on the beach in the Sea of ​​Galilee.

Photomicrographs of amoebas found in springs in the Kinneret region. Photo: Dr. Shira Nino and Dr. Oded Bergman
Photomicrographs of amoebas found in springs in the Kinneret region. Photo: Dr. Shira Nino and Dr. Oded Bergman

Recently, the brain-eating amoeba made headlines When a young man was infected with it After staying at several freshwater resorts, including the Sea of ​​Galilee. An amoeba is a single-celled microscopic creature that is very common in fresh water. In every puddle, reservoir, stream or lake you can find amoebas. Amoebas live in natural water bodies that are free from any contamination. In the research we conducted in the Kinneret region We found dozens of species of amoeba in the lake and the springs around it. The amoebae are An important part of a healthy ecosystem - As predators of bacteria and other microorganisms, they help regulate their populations and contribute to the recycling of nutrients. Despite the prevalence of amoebas, there is no reason to panic; Most of them do not pose a health hazard and exposure to them in places like the Sea of ​​Galilee is usually not problematic. However, there are disease-causing (pathogenic) species of amoeba, and the scariest of them all was called the brain-eating amoeba, or by its scientific name  Naegleria fowleri. According to studies, it can be concluded that with the warming of the water due to the climate crisis, we are expected to find more of this amoeba.

A rare but fatal infection

Unfortunately, infection with the brain-eating amoeba almost always ends in the death of the patient, as happened in the last case, despite the resourcefulness shown by the diagnosing doctor. Nevertheless, it is encouraging to know that contracting it is very rare. This species of amoeba exists naturally in fresh water, yet in Israel there have been only two documented cases to date. Even in the world, infection with the brain-eating amoeba is very rare, and only a few hundred cases of morbidity are known to date, although that the amoeba exists on all continents except Antarctica.

The reason for the low morbidity probably lies in the infection mechanism that is only possible if there is an entry of a stream of infected water into the nostrils. If the water contains the amoeba and is pushed deep into the nostrils, the amoeba can attach to the nasal mucosa, reach the olfactory nerve and pass the trachea that separates the nasal cavity from the brain. Many cases of morbidity reported worldwide have been caused by use In a common method for washing sinuses in which water is injected from one nostril and exits through the other nostril. When non-sterile water or a solution is used, a culture of amoebas may develop in them, and during washing they gain access to the olfactory nerve area. The two cases that have been discovered so far in Israel point to a different mechanism of infection, but apparently also in these cases a situation was created in which a jet of water was effectively splashed into the nostrils. In the first case, which happened about two years ago, a young man rode an ATV over muddy terrain, and without a riding mask. The current case is still under investigation but it is possible that the young man used water facilities or dived, and thus a stream of water entered his nostrils.

The climate crisis may increase the risk

The small number of patients in Israel indicates that the probability of being infected with the brain-eating amoeba is very low; Otherwise we would see many more cases of the disease. Still, it is important to understand - are we witnessing an increase in this likelihood in recent years? If so, can this increase be linked to the climate crisis? The first question is difficult to answer, because fortunately there is very little data on cases of infection in Israel. On the other hand, the impact of the climate crisis on the chance of being infected by the brain-eating amoeba can be learned from many studies that have been done on it.

Laboratory experiments show that the amoeba is resistant to high water temperatures of up to 45 degrees Celsius, which gives it a competitive advantage in the natural environment when the water temperature rises. in the United States We see a strong seasonality in the infection, with more cases in the summer when the water temperature in the streams and lakes is higher. In countries where there are no suitable conditions for growing the brain-eating amoeba, such as in Belgium, the amoeba is only found in freshwater bodies suffering from heat pollution, for example as a result of releasing Cooling water of power plants. That is, the connection between the brain-eating amoeba and water temperature is a strong connection based on many findings.

Processes of the climate crisis affect the fresh water bodies in Israel, and the water on the surface of the Sea of ​​Galilee and other bodies of water that are getting warmer from year to year. The warming of the water is mainly due to the transfer of heat from the air, and is affected by other factors such as the water level. in Lake Kinneret, for example, temperature of the upper water layer increases by about 0.4 degrees Celsius per decade, and is expected to continue the upward trend. The prevalence of pathogens that thrive at high temperatures, such as the brain-eating amoeba, is expected to increase as the water warms, potentially increasing the risk of infection. In the future, sanitary monitoring of resort water may be necessary for the quantification of amoeba in water, as is the practice in other countries. In the meantime, you can continue to enjoy our beautiful Sea of ​​Galilee.

Dr. Shira Nino is a senior microbiology researcher at the Kinneret Research Laboratory, Israel Seas and Lakes Research

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