Isolation of Naegleria fowleri from a domestic water tank associated with a fatal encephalitis in a 4 month-old Venezuelan child

This study describes the association of household water system contamination with the pathogenic Free-Living Amoeba (FLA) Naegleria fowleri and a case of fatal Primary Amoebic Meningoencephalitis (PAM) in a child from the state of Monagas in Venezuela. Amoebae were initially identified by microscopy from a sample of cerebrospinal fluid (CSF) from the child. Direct DNA extraction and specific PCR/sequencing for N. fowleri was also carried out from the same CSF sample. In order to determine a possible environmental source of infection, water samples from the water tank of the child’s home and also water bodies recently visited by the child and his family, were examined for the presence of N. fowleri by culture and PCR/sequencing. The results obtained from the collected water samples revealed that only the water tank of the house was positive for N. fowleri. PCR/sequencing showed that the strains isolated from the patient and the water tanks were 100 % identical. Therefore, the house water tank was confirmed as the source of infection in this case, possibly as a result of the occasional immersion of the child´s head under the water while bathing. This case highlights a novel source of thermally polluted water and another threat of N. fowleri infection.