Naegleria fowleri: diagnosis, treatment options and pathogenesis

Introduction: Naegleria fowleri are free-living amoebae known to cause devastating primary amoebic meningoencephalitis (PAM). Parasites enter the host via the nasal route and travel to the central nervous system through the olfactory neuroepithelium resulting almost always in death.

Areas covered: Current understanding of clinical diagnosis, treatment options, and pathogenicity of the parasite. A PubMed search using N. fowleri combined with diagnosis, treatment, and pathogenesis as keywords was carried out. In addition, we consulted conference proceedings, original unpublished research undertaken, and discussions in Free-Living Amoebae Meetings over the past 20 years.

Expert opinion: Although considered rare in developed countries, a large number of PAM cases in developing countries go unnoticed. In particular, religious, recreational, and cultural practices can contribute to this devastating infection in significant numbers. As portal of entry is nose, followed by migration along the olfactory neuroepithelial route and infection of the inferior surface of the frontal lobe, it makes sense to analyse nasal mucosal secretions, in addition to cerebrospinal fluid to expedite early diagnosis. Similarly, for treatment, drug delivery via the nasal route would target the parasite route of entry, achieving minimum inhibitory concentration at low dose at the target site, and exhibit limited associated host tissue toxicity.