Historically, lethal “brain-eating amoeba” infections have occurred in the southern United States. But in recent years, cases have appeared further north, probably due to climate change, according to a new study.
Researchers at the Centers for Disease Control and Prevention (CDC) looked at cases of this brain-eating amoeba, known as Naegleria fowleri, for four decades in the United States.
They found that although the number of cases occurring each year remained about the same, the geographical range of these cases shifted north, with more cases occurring in the Midwestern states than before.
N. fowleri is a single-celled organism that is found naturally in warm fresh water, 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 into a person’s nose, allowing the body to enter the brain through the olfactory nerves (responsible for the sense of smell) and destroy brain tissue. Swallowing the contaminated water will not cause an infection, says the CDC.
for N. fowleri develops in warm waters, up to 113 degrees Fahrenheit (45 degrees Celsius), it is possible that global warming temperatures will affect the geographical area of organisms, the authors said.
In the new study, published Wednesday (December 16) in the journal Emerging infectious diseases, researchers looked at cases in the US of N. fowleri related 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 who met their study criteria (ie cases that were related to recreational exposure to water and 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, the report said.
Above: cases of N. fowleri infections related to recreational water, in the period 1978-2018.
Moreover, when the team used a model to examine trends in the maximum latitude of cases per year, they found that the maximum latitude moved approximately 13.2 kilometers (13.2 kilometers) north per year during the period. study.
Finally, the researchers analyzed the weather data from the date each case occurred and found that, on average, the daily temperatures in the two weeks preceding each case were higher than the historical average for each location.
“It is possible that rising temperatures and a consistent increase in recreational water use, such as swimming and water sports, could contribute to changing the epidemiology of WFP,” the authors wrote.
Efforts to characterize WFP cases, such as knowing when and where these cases occur and being aware of changes in their geographical area, could help predict when it is most risky to visit natural swimming holes, the authors said.
Because there is no quick test for N. fowleri In the water, the only safe way to prevent these infections is to avoid swimming in warm fresh water, says the CDC.
If you choose to go swimming in warm fresh water, you can try to prevent the water from rising into your nose by keeping your nose closed, using your nose clamps, or keeping your head above the water.
This article was originally published by Live Science. Read the original article here.