Following a fatal case of primary amebic meningoencephalitis during the dusty harmattan period in an 8-month-old child in whose case Naegleria fowleri was recovered both from the cerebrospinal fluid and from material from the nose in absence of a history of swimming, it was hypothesized that dust during the harmattan might harbor amebic cysts, which may be inhaled by human beings and cause infection. A preliminary survey was thus carried out to examine the nasal passages of children for the presence of soil amebas during the harmattan. In all, 50 children were evaluated for the presence of soil amebas. Positive cultures for the soil amebas were obtained from 12 children (24%). Four species of amebas were isolated singly or in combination with other species. Pathogenic Naegleria fowleri, proved pathogenic for mice, were cultured from specimens from two children.

A case of primary amebic meningoencephalitis due to Naegleria fowleri in a Nigerian child is described. This is probably the first authentic case from West Africa. The clinical manifestations, isolation of the ameba from the cerebrospinal fluid and nasal passages, poor response to amphotericin B, and ultimate fatal outcome all are consistent with the diagnosis of primary amebic meningoencephalitis. Subsequent identification based on morphologic features, flagellation, animal pathogenicity, and nuclear division proved conclusively that the ameba was Naegleria fowleri. The route of entry of the ameba proved to be nasal. In the absence of the history of swimming and in view of the dusty harmattan period during which the child was admitted, a possibility of infection by inhalation of dust harboring amebic cysts is suggested.