Death from Primary Amebic Meningoencephalitis After Recreational Water Exposure During Recent Travel to India — Santa Clara County, California, 2020

Background In February 2020, a man returned to the United States after an 11-day trip to India and died of primary amebic meningoencephalitis (PAM), caused by nasal exposure to the free-living ameba Naegleria fowleri found in warm water. We identified potential exposures, confirmed etiology, and described molecular epidemiology of the infection. Methods We reviewed medical records to describe his clinical course and interviewed his family to determine water exposures. Genotyping was performed on the N. fowleri strain and compared with North American strains through repetitive non-polymorphic nuclear loci analysis to identify differences. We reviewed N. fowleri strains in the National Center for Biotechnology Information database (GenBank) to determine genotypes present in India. Results The patient became acutely encephalopathic 3 days after returning; the only known nasal water exposure was at an indoor swimming pool in India 5 days earlier. Cerebrospinal fluid (CSF) testing demonstrated neutrophil predominant pleocytosis and low glucose, but negative Gram stain and culture. CSF microscopy revealed trophozoites; N. fowleri was detected by real-time polymerase chain reaction. Classical genotyping confirmed genotype I, common in the United States and among Indian strains in GenBank. The North American N. fowleri strains and the patient’s strain varied at five non-polymorphic loci. Conclusion A man died from PAM after likely exposure at a vacation rental pool in India. We recommend including PAM in the differential diagnosis when CSF studies suggest bacterial meningitis, but Gram stain is negative. Genotyping can advance understanding of N. fowleri molecular epidemiology and support future investigations.

Effect of a Commercial Disinfectant CLORICAN® on Acanthamoeba spp. and Naegleria fowleri Viability

Swimming pool water treatment by chemicals is an essential step to avoid microbial proliferation and infections namely caused by free living amoeba such as, for example, primary amebic meningoencephalitis and Acanthamoeba keratitis. In the present study, a commercial reactive, CLORICAN, based on chlorine dioxide, was evaluated against Acanthamoeba spp. and Naegleria fowleri. We observed that CLORICAN could eliminate in a short period of incubation time both amoebae. Furthermore, Naegleria fowleri’s trophozoites were more sensitive than those of Acanthamoeba spp. By means of inverted microscopy, the chlorine dioxide was found to greatly affect morphology shape by increasing the cell size shrinkage.

Draft Chromosome Sequences of a Clinical Isolate of the Free-Living Ameba Naegleria fowleri

ABSTRACT We present the chromosome sequences of a Naegleria fowleri isolate from a human primary amebic meningoencephalitis (PAM) case. The genome sequences were assembled from Illumina HiSeq and PacBio sequencing data and verified with the optical mapping data. This led to the identification of 37 contigs representing 37 chromosomes in N. fowleri.

Primary Amebic Meningoencephalitis due to Naegleria fowleri: Literature Review

Background: Primary Amebic Meningoencephalitis is an acute purulent meningoencephalitis caused by Naegleria fowleri. The main route of transmission occurs through the inhalation of trophozoites present in the water, which cross the cribriform plate, reach the olfactory bulbs and destroy the nerve and nervous tissue. Objectives: This study aims to provide greater knowledge and updates on the topic. Design and setting: This is a literature review from the Escola de Medicina Souza Marques’s, and Universidade Federal Fluminense’s students, Brazil. Methods: The used articles were published between 2013 to 2021, from the UptoDate, Scielo, and Pubmed databases. Results: This protozoan’s distribution is worldwide. The clinical picture includes fever, headache, photophobia, emesis, convulsions, and dysfunctions of smell and taste; if untreated, it progresses rapidly to death. There is an incubation period of 2 to 7 days. Diagnosis should be considered when there is a picture of meningoencephalitis, negative results for viruses and bacteria, and there are motile trophozoites in the CSF sample. The main differential diagnosis is bacterial meningitis. Conclusion: The rarity of the disease, delay in diagnosis, and fulminant clinical course affect the evaluation of treatment models. Currently, the indicated therapy is Amphotericin B, Rifampicin, Fluconazole, Miltefosine, and Azithromycin, ranging from 9 to 30 days duration.

A Newborn with Brain-Eating Ameba Infection

Naegleria fowleriis a thermophilic free-living ameba that is found in warm, fresh water and causes primary amebic meningoencephalitis (PAM) in humans with high mortality rate. Here we report a case of newborn admitted with destructive clinical features of PAM after having bath with unchlorinated well water on a summer day.

Primary Amebic Meningoencephalitis Related to Groundwater in Costa Rica: Diagnostic Confirmation of Three Cases and Environmental Investigation

During the first trimester of 2020, the Ministry of Health of Costa Rica reported the first three cases of primary amebic meningoencephalitis (PAM). In two cases, laboratory personnel of the hospitals preliminarily identified amoeboid forms in cerebrospinal fluid (CSF) samples. For the molecular confirmation of species, CSF samples were sent to our laboratory. We carried out microscopic analyses and exflagellation assays. Besides, samples were cultured in 2% casein hydrolysate medium and in non-nutrient agar plates supplemented with Escherichia coli. Finally, PCR and sequencing were employed for the molecular diagnosis and species identification. In all cases, the presence of Naegleria fowleri was confirmed. An environmental investigation to identify the possible infection sources was also performed. Water samples from hot springs and groundwater from an artisan well were collected and after filtration and culture in non-nutrient agar plates supplemented with E. coli, thermotolerance and exflagellation assays were carried out. For the positive samples, PCR and sequencing were performed, confirming the presence of N. fowleri in several water samples. The report of these cases and the possible association with hot springs has had a significant impact on the population and health authorities of Costa Rica.