Folia Parasitologica 49[3] 183-188 (2002) | DOI: 10.14411/fp.2002.035

The role of blood vessels and lungs in the dissemination of Naegleria fowleri following intranasal inoculation in mice

Kirby L. Jarolim¹, Jeffrey K. McCosh¹, Marsha J. Howard²

¹ Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107, USA

² Office of Basic Science, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107, USA

Primary amoebic meningoencephalitis (PAM) was induced in mice by intranasal inoculation of Naegleria fowleri (Singh et Das, 1970) to study the role of the blood vessels and lungs in the early and later stages in this disease. Upon culturing blood and lung tissue obtained at 24-, 36-, 48-, 72-, 96-, and 120-hour time periods, it was found that amoebae grew only from blood and lung tissue obtained at the 96 and 120 hour time periods. Paraffin sections of the head revealed small foci of acute inflammation and amoebae within the olfactory bulb of the central nervous system (CNS) at 24 hours. Amoebae were not observed within blood vessels of the CNS until 96 and 120 hours. Also, amoebae were observed within the connective tissue surrounding blood vessels and sutures of the skull, bone marrow, and venous sinusoids between the skull bone tables at 96 and 120 hours. No amoebae or acute inflammatory reactions were observed in the lung sections from any time period and indirect immunofluorescence microscopy was negative for N. fowleri. This study provides evidence that neither blood vessels nor lungs provide routes for N. fowleri to the CNS during the early stages of PAM and that amoebae enter veins of the CNS and bone marrow during later stages of the disease.

Keywords: Naegleria fowleri, primary amoebic meningoencephalitis, mouse, intranasal inoculation, blood culture, lungs

Received: July 10, 2001; Accepted: February 8, 2002; Published: September 1, 2002  Show citation