Deadly “brain-eating amoeba” infections have historically occurred in the southern United States. According to a new study, more cases have appeared further north in recent years, probably due to climate change.
Researchers at the Centers for Disease Control and Prevention (CDC) examined cases of this brain-eating amoeba, known as Naegleria fowleri, for a period of four decades in the US.
They found that while the number of cases occurring each year has remained almost the same, the geographical range of these cases has shifted northward, with more cases appearing in the midwestern states. than before.
N. fowleri it is a unicellular organism found naturally in warm freshwater, such as lakes and rivers, according to the CDC. It causes a devastating brain infection known as primary amoebic meningoencephalitis (PAM), which is almost universally fatal.
Infections occur when contaminated water rises through a person’s nose, allowing the body to enter the brain through the olfactory nerves (responsible for their sense of smell) and destroy brain tissue. Ingestion of contaminated water will not cause any infection, according to the CDC.
Because N. fowleri thrive in warm waters, up to 113 degrees Fahrenheit (45 degrees Celsius), it is possible that global warming may affect the geographical range of organisms, according to the authors.
In the new study, published Wednesday (December 16) in the journal Emerging infectious diseases, researchers analyzed U.S. cases of N. fowleri linked to recreational exposure to water, such as swimming in lakes, ponds, rivers or reservoirs, from 1978 to 2018.
They identified a total of 85 cases of N. fowleri that meet their criteria for the study (i.e., cases related to recreational exposure to water and that included location data).
During this time, the number of cases reported annually was fairly constant, ranging from zero to six per year.
The vast majority of cases, 74, occurred in the southern states; but six were reported in the Midwest, including Minnesota, Kansas, and Indiana. Of those six cases, five occurred after 2010, according to the report.
(CDC, Emerging Infectious Diseases, 2021)
At the top: cases of N. fowleri infections related to recreational water, from 1978 to 2018.
In addition, when the team used a model to examine trends in the maximum latitude of cases per year, they found that the maximum latitude had shifted to 13.3 kilometers north toward the year during the d ‘study.
Finally, the researchers analyzed meteorological data from the date each case occurred and found that, on average, daily temperatures in the two weeks prior to each case were higher than the historical average for each location.
“It is possible that rising temperatures and consequent increases in recreational water use, such as swimming and water sports, may contribute to changing the epidemiology of WFP,” the authors wrote.
Efforts to characterize PAM cases, such as knowing when and where these cases occur, and being aware of changes in their geographic range, could help predict when it is riskier to visit natural swimming holes, the authors said.
Since there is no quick test of N. fowleri in the water, the only safe way to prevent these infections is to avoid swimming in warm fresh water, the CDC says.
If you decide to go swimming with hot fresh water, you can try to prevent the water from rising through your nose by keeping your nose closed, using nose clips, or keeping your head above water.
This article was originally published by Live Science. Read the original article here.