Virulent
            <i>Naegleria fowleri</i>
            in an Indoor Swimming Pool

Kadlec, V; Cerva, L; Škvárová, Jiřina

doi:10.1126/science.684423

Cited by 34 publications

(20 citation statements)

References 5 publications

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“…FLA are amphizoic protozoa that are ubiquitous in nature. They have been found in soil, fresh water lakes (Johan and De Jonckheere 1985), swimming pools (Janitschke et al 1980;Kadlec 1981), therapeutic pools, tap water (Visvesvara and Stehr-Green 1990), natural thermal water (Rivera et al 1990), and air samples (Rodriguez-Zaragoza and Magana-Becerrs 1997) from all over the world. These amoebae can survive severe conditions by forming resistant cysts.…”

Section: Introductionmentioning

confidence: 98%

The identification of free-living environmental isolates of amoebae from Bulgaria

Tsvetkova

Schild

Panaiotov

et al. 2004

Parasitology Research

141

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A survey was carried out in Bulgaria to determine the presence of free-living amoebae (FLA) from environmental sources. In 171 (61.1%) of 280 samples, isolates of Acanthamoeba with group II or III morphology, as well as Hartmannella spp. were recovered. Five isolates named "6" (artificial lake), Ep (lake), G2 (soil), R4* (river) and PK (spring water)--all exhibiting a highly efficient proliferation in axenic cultures--were subsequently cloned and subjected to molecular analyses for identification and genotyping In accordance with morphological findings, PCR-based analyses identified four isolates (6, Ep, G2, R4*) belonging to the genus Acanthamoeba. Confirmation of these findings was obtained by phylogenetic analysis using partial sequencing of the 18S rDNA (ASA.S1) Acanthamoeba-gene. Comparison of these sequences with corresponding regions from other Acanthamoeba strains available from GenBank sorted all four isolates into the sequence type group T4 that contains most of the pathogenic Acanthamoeba strains already identified. The fifth isolate (PK) exhibited morphological characteristics matching those of Hartmannella, and scored negative in the Naegleria fowleri and Acanthamoeba PCRs.

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Section: Introductionmentioning

confidence: 98%

The identification of free-living environmental isolates of amoebae from Bulgaria

Tsvetkova

Schild

Panaiotov

et al. 2004

Parasitology Research

141

View full text Add to dashboard Cite

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“…Outbreak coincided with the annual turnover of the lake caused by the weakening of the lake's thermocline. At least 20 deaths among HIV-infected people due to cryptosporidiosis) associated with a contaminated swimming pool in the Czech Republic (Kadlec et al 1980; Table 6). Acanthamoeba was the causative agent of an outbreak associated with a contaminated municipal water supply in the USA (Meier et al 1998; Table 5) and has a marked seasonality (peaking in June and November) and may be affected by climatic conditions (Rose et al 2001).…”

mentioning

confidence: 99%

Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt

Karanis

Kourenti

Smith

2006

Journal of Water and Health

713

403

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At least 325 water-associated outbreaks of parasitic protozoan disease have been reported.North American and European outbreaks accounted for 93% of all reports and nearly two-thirds of outbreaks occurred in North America. Over 30% of all outbreaks were documented from Europe, with the UK accounting for 24% of outbreaks, worldwide. Giardia duodenalis and Cryptosporidium parvum account for the majority of outbreaks (132; 40.6% and 165; 50.8%, respectively), Entamoeba histolytica and Cyclospora cayetanensis have been the aetiological agents in nine (2.8%) and six (1.8%) outbreaks, respectively, while Toxoplasma gondii and Isospora belli have been responsible for three outbreaks each (0.9%) and Blastocystis hominis for two outbreaks (0.6%). Balantidium coli, the microsporidia, Acanthamoeba and Naegleria fowleri were responsible for one outbreak, each (0.3%). Their presence in aquatic ecosystems makes it imperative to develop prevention strategies for water and food safety. Human incidence and prevalence-based studies provide baseline data against which risk factors associated with waterborne and foodborne transmission can be identified. Standardized methods are required to maximize public health surveillance, while reporting lessons learned from outbreaks will provide better insight into the public health impact of waterborne pathogenic protozoa.

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“…Most infections with N. fowleri occur during the summer months, victims usually are symptomatic within 5 days, and the disease is almost always fatal. Infection usually occurs after the victim swam in warm, fresh, or brackish water or from exposure to contaminated tap water associated with the use of Neti pots for nasal irrigation (4)(5)(6)(7). Amoebic invasion occurs via disruption of the olfactory mucosa, penetration of organisms into the submucosal nervous plexus, and ultimately passage through the cribriform plate to the frontal lobes of the brain (8,9).…”

mentioning

confidence: 99%

Bis-Benzimidazole Hits against Naegleria fowleri Discovered with New High-Throughput Screens

Rice

Colon

Alp

et al. 2015

Antimicrob Agents Chemother

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Naegleria fowleri is a pathogenic free-living amoeba (FLA) that causes an acute fatal disease known as primary amoebic meningoencephalitis (PAM). The major problem for infections with any pathogenic FLA is a lack of effective therapeutics, since PAM has a case mortality rate approaching 99%. Clearly, new drugs that are potent and have rapid onset of action are needed to enhance the treatment regimens for PAM. Diamidines have demonstrated potency against multiple pathogens, including FLA, and are known to cross the blood-brain barrier to cure other protozoan diseases of the central nervous system. Therefore, amidino derivatives serve as an important chemotype for discovery of new drugs. In this study, we validated two new in vitro assays suitable for medium-or high-throughput drug discovery and used these for N. fowleri. We next screened over 150 amidino derivatives of multiple structural classes and identified two hit series with nM potency that are suitable for further lead optimization as new drugs for this neglected disease. These include both mono-and diamidino derivatives, with the most potent compound (DB173) having a 50% inhibitory concentration (IC 50 ) of 177 nM. Similarly, we identified 10 additional analogues with IC 50 s of <1 M, with many of these having reasonable selectivity indices. The most potent hits were >500 times more potent than pentamidine. In summary, the mono-and diamidino derivatives offer potential for lead optimization to develop new drugs to treat central nervous system infections with N. fowleri. The first report of animal pathogenicity by free-living amoebae (FLA) was by Culbertson et al., who identified Acanthamoeba in necrotic lesions of monkeys and mice (1). He later suggested that FLA causes similar disease in humans. Fowler and Carter reported the first cases of an acute fatal disease caused by Naegleria fowleri in four victims in Australia in 1965 (2). Since the identification of primary amoebic meningoencephalitis (PAM), hundreds of cases have been reported worldwide, including 142 cases in the United States (3-5). Most infections with N. fowleri occur during the summer months, victims usually are symptomatic within 5 days, and the disease is almost always fatal. Infection usually occurs after the victim swam in warm, fresh, or brackish water or from exposure to contaminated tap water associated with the use of Neti pots for nasal irrigation (4-7). Amoebic invasion occurs via disruption of the olfactory mucosa, penetration of organisms into the submucosal nervous plexus, and ultimately passage through the cribriform plate to the frontal lobes of the brain (8, 9). Although most cases of PAM occur in warm climates, such as the southern tier states of the United States, pathogenic amoeba found in thermally polluted water sources, hot springs, and poorly chlorinated pools have been linked to infections (10, 11). Interestingly, most of the PAM cases have been diagnosed in developed countries, including the United States, Australia, and Europe. Although sporadic cases have been d...

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Virulent Naegleria fowleri in an Indoor Swimming Pool

Abstract: A reservoir of pathogenic Naegleria fowleri has been located in the cracked wall of a swimming pool where repeated outbreaks of primary amoebic meningoencephalitis were observed between 1962 and 1965.

Cited by 34 publications

References 5 publications

The identification of free-living environmental isolates of amoebae from Bulgaria

The identification of free-living environmental isolates of amoebae from Bulgaria

Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt

Bis-Benzimidazole Hits against Naegleria fowleri Discovered with New High-Throughput Screens

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