Primary amoebic meningoencephalitis after swimming in the Rio Grande.

We report a case of fatal primary amoebic meningoencephalitis (PAM) with Naegleria fowleri in a 13-year-old male, and review the clinical course and diagnostic autopsy findings. The boy developed the infection after swimming with relatives in the Rio Grande and in a holding tank containing water pumped from the river. The clinical and neuropathologic features of PAM are presented. The microscopic features of motile unicellular organisms with pathognomonic broad, lobate pseudopodia are diagnostic and, if recognized before death, allow for timely treatment. A public health investigation into this case implicated river water from the Rio Grande polluted with sewage as the infection source. Exposure to polluted river water from some areas of the Rio Grande may represent a risk factor for infection with Naegleria fowerli, because the high levels of coliform bacteria found in sewage and the warm, sluggish water of the river are favorable growth conditions for the amoebae. Because the Rio Grande is an international border, this case illustrates the importance of international cooperation in pollution control in the prevention of a potentially fatal infectious disease.