By NewsDesk  @bactiman63

According to a new study published in the journal, Emerging Infectious Diseases, Naegleria fowleri is a free-living ameba that causes primary amebic meningoencephalitis (PAM), a rare but usually fatal disease. Researchers with the Centers for Disease Control and Prevention (CDC) analyzed trends in recreational water exposures associated with PAM cases reported during 1978–2018 in the United States. Although PAM incidence remained stable, the geographic range of exposure locations expanded northward.


Primary amebic meningoencephalitis (PAM) is a rare but usually fatal brain infection caused by Naegleria fowleri, a free-living ameba found in soil and warm freshwater. The ameba enters the brain via the nasal passages, causing an acute brain infection that usually results in death within 3–7 days of symptom onset. N. fowleri is frequently detected in warm freshwater; however, <8 cases are reported each year in the United States. Generally, US PAM cases occur after recreational exposure to warm, untreated freshwater in US southern states during the summer.

Read the study HERE

Researchers looked at U.S. cases of N. fowleri linked to recreational water exposure, like swimming in lakes, ponds, rivers or reservoirs during the above time frame and eighty-five cases were identified that met their criteria for the study.

While the bulk of the cases occurred in southern states; six were reported in the Midwest, including Minnesota, Kansas and Indiana. Of these six cases, five occurred after 2010.

Live Science reports, 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 about 8.2 miles (13.3 kilometers) northward per year during the study period.

Finally, the researchers analyzed weather data from around the date each case occurred, and found that on average, daily temperatures in the two weeks leading up to each case were higher than the historical average for each location.

The authors conclude, The rise in cases in the Midwest region after 2010 and increases in maximum and median latitudes of PAM case exposures suggest a northward expansion of N. fowleri exposures associated with lakes, ponds, reservoirs, rivers, streams, and outdoor aquatic venues in the United States. We observed an increase in air temperatures in the 2 weeks before exposures compared with 20-year historic averages. It is possible that rising temperatures and consequent increases in recreational water use, such as swimming and water sports, could contribute to the changing epidemiology of PAM. Although reported incidence of PAM has increased worldwide, the incidence of reported cases of PAM in the United States remained stable during 1978–2018. The worldwide trends might reflect changes in international diagnostic capacity.