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Water Research Aug 2024Legionella is an opportunistic waterborne pathogen that causes Legionnaires' disease. It poses a significant public health risk, especially to vulnerable populations in...
Legionella is an opportunistic waterborne pathogen that causes Legionnaires' disease. It poses a significant public health risk, especially to vulnerable populations in health care facilities. It is ubiquitous in manufactured water systems and is transmitted via inhalation or aspiration of aerosols/water droplets generated from water fixtures (e.g., showers and hand basins). As such, the effective management of premise plumbing systems (building water systems) in health care facilities is essential for reducing the risk of Legionnaires' disease. Chemical disinfection is a commonly used control method and chlorine-based disinfectants, including chlorine, chloramine, and chlorine dioxide, have been used for over a century. However, the effectiveness of these disinfectants in premise plumbing systems is affected by various interconnected factors that can make it challenging to maintain effective disinfection. This systematic literature review identifies all studies that have examined the factors impacting the efficacy and decay of chlorine-based disinfectant within premise plumbing systems. A total of 117 field and laboratory-based studies were identified and included in this review. A total of 20 studies directly compared the effectiveness of the different chlorine-based disinfectants. The findings from these studies ranked the typical effectiveness as follows: chloramine > chlorine dioxide > chlorine. A total of 26 factors were identified across 117 studies as influencing the efficacy and decay of disinfectants in premise plumbing systems. These factors were sorted into categories of operational factors that are changed by the operation of water devices and fixtures (such as stagnation, temperature, water velocity), evolving factors which are changed in-directly (such as disinfectant concentration, Legionella disinfectant resistance, Legionella growth, season, biofilm and microbe, protozoa, nitrification, total organic carbon(TOC), pH, dissolved oxygen(DO), hardness, ammonia, and sediment and pipe deposit) and stable factors that are not often changed(such as disinfectant type, pipe material, pipe size, pipe age, water recirculating, softener, corrosion inhibitor, automatic sensor tap, building floor, and construction activity). A factor-effect map of each of these factors and whether they have a positive or negative association with disinfection efficacy against Legionella in premise plumbing systems is presented. It was also found that evaluating the effectiveness of chlorine disinfection as a water risk management strategy is further complicated by varying disinfection resistance of Legionella species and the form of Legionella (culturable/viable but non culturable, free living/biofilm associated, intracellular replication within amoeba hosts). Future research is needed that utilises sensors and other approaches to measure these key factors (such as pH, temperature, stagnation, water age and disinfection residual) in real time throughout premise plumbing systems. This information will support the development of improved models to predict disinfection within premise plumbing systems. The findings from this study will inform the use of chlorine-based disinfection within premise plumbing systems to reduce the risk of Legionnaires disease.
Topics: Disinfectants; Chlorine; Legionella; Disinfection; Chlorine Compounds; Water Microbiology; Chloramines; Water Supply; Oxides; Water Purification
PubMed: 38824796
DOI: 10.1016/j.watres.2024.121794 -
Parasitology Research Mar 2024Free-living amoebae (FLA) include amphizoic microorganisms important in public health, widely isolated from air, water, and soil. However, its occurrence in... (Meta-Analysis)
Meta-Analysis
Free-living amoebae (FLA) include amphizoic microorganisms important in public health, widely isolated from air, water, and soil. However, its occurrence in sewage-related environments still needs to be systematically documented. This study summarizes the occurrence of FLA in sewage-related environments through a systematic review with meta-analysis. A total of 1983 scientific article were retrieved from different databases, of which 35 were selected and analyzed using a random effects forest plot model with a 95% confidence interval (IC). The pooled overall prevalence of FLA in sewage across 12 countries was 68.96% (95% IC = 58.5-79.42). Subgroup analysis indicates high prevalence in all environments analyzed, including sewage water from the sewage treatment plant (81.19%), treated sewage water (75.57%), sewage-contaminated water (67.70%), sediment contaminated by sewage (48.91%), and sewage water (47.84%). Prevalence values of Acanthamoeba spp., Hartmanella/Vermamoeba spp., and Naegleria spp. are 47.48%, 28.24%, and 16.69%, respectively. Analyzing the species level, the distribution is as follows: Acanthamoeba palestinensis (88%), A. castellanii (23.74%), A. astronyxis (19.18%), A. polyphaga (13.59%), A. culbertsoni (12.5%), A. stevensoni (8.33%), A. tubiashi (4.35%) and A. hatchetti (1.1%), Naegleria fowleri (28.4%), N. gruberi (25%), N. clarki (8.33%), N. australiensis (4.89%) and N. italica (4.29%), Hartmannella/Vermamoeba exundans (40%) and H.V. vermiform (32.61%). Overall, our findings indicate a high risk associated with sewage-related environments, as the prevalence of FLA, including pathogenic strains, is high, even in treated sewage water. The findings of this study may be valuable both for risk remediation actions against amoebic infections and for future research endeavors.
Topics: Acanthamoeba; Amoeba; Hartmannella; Prevalence; Sewage; Water
PubMed: 38433138
DOI: 10.1007/s00436-024-08164-7 -
Global prevalence of free-living amoebae in solid matrices - A systematic review with meta-analysis.Acta Tropica Nov 2023The ubiquitous free-living amoebae (FLA) are microorganisms of significant medical, sanitary, and ecological importance. However, their characterization within solid... (Meta-Analysis)
Meta-Analysis Review
The ubiquitous free-living amoebae (FLA) are microorganisms of significant medical, sanitary, and ecological importance. However, their characterization within solid matrices such as soil, dust, sediment, mud, sludge, and compost remain to be systematized. In this study, we conducted a systematic review with meta-analysis to explore the global distribution of FLA in solid matrices. From the analysis of 104 out of 4,414 scientific articles retrieved from different databases, it was found that the general global prevalence of FLA in solid matrices was of 55.13% (95% confidence interval (CI) 49.32-60.94). Specifically, FLA prevalence was high in soil (72.40%, 95% CI 69.08-75.73), sediment (57.91%, 95% CI 50.01-65.81), mud (52.90%, 95% CI 24.01-81.78), dust (48.60%, 95% CI 43.00-54.19), and sewage sludge (40.19%, 95% CI 30.68-49.70). In aerosols it was comparatively lower (17.21%, 95% CI 12.76-21.66). Acanthamoeba spp. (52.23%) and Hartmanella/Vermamoeba spp. (36.06%) were found to be more prevalent, whereas Naegleria spp. (34.98%) and Balamuthia spp. (27.32%) were less prevalent. The distribution of the highest global prevalence values for species of Acanthamoeba spp., considering different publication periods of the studies, is as follows: A. hatchetti (51.46%), A. rhysodes (47.49%), A. polyphaga (36.37%), A. culbertsoni (34.31%), A. castellanii (34.21%), and A. lenticulata (32.82%). For other FLA species, the distribution is: Hartmannella/Vermamoeba vermiformis (91.57%), Naegleria fowleri (42.32%), Naegleria gruberi (32.39%), and Balamuthia mandrillaris (25%). The most prevalent Acanthamoeba genotypes were T4 (33.38%) and T3 (23.94%). Overall, the global prevalence of FLA in solid matrices is as high as or greater than that reported in water by previous systematic reviews. Thus, actions aimed at reducing exposure to FLA or exploring their ecological dynamics should consider not only water but also the various solid matrices. The finding outlined here can provide valuable insights for such actions, e.g., informing on the level of exposure to FLA, or on the microbial biodiversity of specific environmental compartments.
Topics: Animals; Amoeba; Prevalence; Sewage; Acanthamoeba; Coleoptera; Dust; Soil; Water
PubMed: 37633571
DOI: 10.1016/j.actatropica.2023.107006 -
Frontiers in Neurology 2023Free-living amoebae (FLA) including spp., and can become pathogenic and cause severe cerebral infections, named primary amoebic meningoencephalitis (PAM),... (Review)
Review
BACKGROUND
Free-living amoebae (FLA) including spp., and can become pathogenic and cause severe cerebral infections, named primary amoebic meningoencephalitis (PAM), granulomatous amoebic encephalitis (GAE), and balamuthia amoebic encephalitis (BAE), respectively. FLA encephalitis has been reported across China, but the clinical data descriptions and analytical results of these different reports vary widely. Currently, no consensus treatment has been established. We conduct a systematic review to evaluate the exposure location, clinical symptoms, diagnosis, treatment, and prognosis of three FLA encephalitis and aim to reveal the differences between three FLA encephalitis in China.
METHODS
We used MEDLINE (PubMed interface), EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang database, and China Biology Medicine disc (CBMdisc) databases for literatures published and manually retrieve the hospital records of our hospital. The search time was up to August 30, 2022, with no language restrictions.
RESULTS
After excluding possible duplicate cases, a total of 48 patients of three FLA encephalitis were collected. One from the medical records of our hospital and 47 patients from 31 different studies. There were 11 patients of PAM, 10 patients of GAE, and 27 patients of BAE. The onset of PAM is mostly acute or subacute, and the clinical symptoms are acute and fulminant hemorrhagic meningoencephalitis. Most patients with GAE and BAE have an insidious onset and a chronic course. A total of 21 BAE patients (77.8%) had skin lesions before onset of symptoms. Additionally, 37 cases (77.1%) were diagnosed with FLA encephalitis before death. And there were 4 of PAM, 2 of GAE, and 10 of BAE diagnosed using next generation sequencing. No single agent can be proposed as the ideal therapy by itself. Only 6 cases were successfully treated.
CONCLUSIONS
This review provides an overview of the available data and studies of FLA encephalitis in China and identify some potential differences. FLA encephalitis is a rare but pathogenic infection, and physicians should early identify this encephalitis to improve survival.
PubMed: 36846140
DOI: 10.3389/fneur.2023.1100785 -
International Journal of Environmental... Feb 2023Primary amoebic meningoencephalitis (PAM) is a rare but lethal infection of the brain caused by a eukaryote called (). The aim of this review is to consolidate the... (Review)
Review
INTRODUCTION
Primary amoebic meningoencephalitis (PAM) is a rare but lethal infection of the brain caused by a eukaryote called (). The aim of this review is to consolidate the recently published case reports of infection by describing its epidemiology and clinical features with the goal of ultimately disseminating this information to healthcare personnel.
METHODS
A comprehensive literature search was carried out using PubMed, Web of Science, Scopus, and OVID databases until 31 December 2022 by two independent reviewers. All studies from the year 2013 were extracted, and quality assessments were carried out meticulously prior to their inclusion in the final analysis.
RESULTS
A total of 21 studies were selected for qualitative analyses out of the 461 studies extracted. The cases were distributed globally, and 72.7% of the cases succumbed to mortality. The youngest case was an 11-day-old boy, while the eldest was a 75-year-old. Significant exposure to freshwater either from recreational activities or from a habit of irrigating the nostrils preceded onset. The symptoms at early presentation included fever, headache, and vomiting, while late sequalae showed neurological manifestation. An accurate diagnosis remains a challenge, as the symptoms mimic bacterial meningitis. Confirmatory tests include the direct visualisation of the amoeba or the use of the polymerase chain reaction method.
CONCLUSIONS
infection is rare but leads to PAM. Its occurrence is worldwide with a significant risk of fatality. The suggested probable case definition based on the findings is the acute onset of fever, headache, and vomiting with meningeal symptoms following exposure to freshwater within the previous 14 days. Continuous health promotion and health education activities for the public can help to improve knowledge and awareness prior to engagement in freshwater activities.
Topics: Aged; Humans; Male; Amoeba; Brain; Central Nervous System Protozoal Infections; Fever; Headache; Naegleria fowleri
PubMed: 36833715
DOI: 10.3390/ijerph20043021 -
Animals : An Open Access Journal From... Oct 2022Tilapia has a high socioeconomic value in many countries worldwide. However, it has been identified as a zoonotic parasite reservoir. A systematic literature search and... (Review)
Review
Tilapia has a high socioeconomic value in many countries worldwide. However, it has been identified as a zoonotic parasite reservoir. A systematic literature search and meta-analysis were carried out in order to estimate the global prevalence of zoonotic parasites that affect tilapia. The search was performed by three field experts to avoid reviewer bias. Polled prevalence was estimated using a logistic-normal random-effect regression model in the R software. We dealt with the heterogeneity among studies through subgroup analysis, taking into account the continent, country, genus of the host, parasite taxonomic group, sample origin, and type of diagnostic test as moderator variables. Fifty-two eligible articles were identified covering five tilapia genera with a pooled prevalence of 0.14 (95% CI: 0.10−0.20) showed significant heterogeneity (I2 = 98.4; p < 0.001). The subgroup analysis revealed that the most affected host was Sarotherodon, with a prevalence of 0.42 (95% CI: 0.22−0.65). Cestode was the taxonomic group with the largest prevalence (0.40; 95% CI:0.32−0.48), followed by amoeba (0.24; 95% CI: 0.16−0.35) and nematode (0.22; 95% CI: 0.11−0.38), among which, Schyzocotyle spp., Opistorchis spp., Gnathostoma spp. and Vermamoeba spp. have an impact on public health. Significant differences (p < 0.004) were found among continents and countries, with the highest value of prevalence detected in the African continent (0.28; 95% CI: 0.20−0.37), specifically in Tanzania (0.56; 95% CI: 0.22−0.87) and Egypt (0.43; 95% CI: 0.20−0.55). The origin of samples had a significant effect (p < 0.0001) on the detected prevalence, especially from those that showed the highest prevalence (0.24; 95% CI: 0.17−0.33). Finally, there were no differences in prevalence according to the diagnostic test (p = 0.97). Our results provide useful information on the development of epidemiological programs for the control of zoonoses associated with parasites in tilapia and in the design, planning, and implementation of future research.
PubMed: 36290186
DOI: 10.3390/ani12202800 -
Parasitology Research Nov 2022Free-living amoebae (FLA) are cosmopolitan microorganisms known to be pathogenic to humans who often have a history of contact with contaminated water. Swimming pools... (Meta-Analysis)
Meta-Analysis Review
Free-living amoebae (FLA) are cosmopolitan microorganisms known to be pathogenic to humans who often have a history of contact with contaminated water. Swimming pools and recreational waters are among the environments where the greatest human exposure to FLA occurs. This study aimed to determine the prevalence of FLA in swimming pools and recreational waters, through a systematic review and meta-analysis that included studies published between 1977 and 2022. A total of 106 studies were included and an overall prevalence of FLA in swimming pools and recreational waters of 44.34% (95% CI = 38.57-50.18) was found. Considering the studies published up to 2010 (1977-2010), between 2010 and 2015, and those published after 2010 (> 2010-2022), the prevalence was 53.09% (95% CI = 43.33-62.73) and 37.07% (95% CI = 28.87-45.66) and 45.40% (95% CI = 35.48-55.51), respectively. The highest prevalence was found in the American continent (63.99%), in Mexico (98.35%), and in indoor hot swimming pools (52.27%). The prevalence varied with the variation of FLA detection methods, morphology (57.21%), PCR (25.78%), and simultaneously morphology and PCR (43.16%). The global prevalence by genera was Vahlkampfia spp. (54.20%), Acanthamoeba spp. (33.47%), Naegleria spp. (30.95%), Hartmannella spp./Vermamoeba spp. (20.73%), Stenamoeba spp. (12.05%), and Vannella spp. (10.75%). There is considerable risk of FLA infection in swimming pools and recreational waters. Recreational water safety needs to be routinely monitored and, in case of risk, locations need to be identified with warning signs and users need to be educated. Swimming pools and artificial recreational water should be properly disinfected. Photolysis of NaOCl or NaCl in water by UV-C radiation is a promising alternative to disinfect swimming pools and artificial recreational waters.
Topics: Amoeba; Humans; Prevalence; Sodium Chloride; Swimming Pools; Water
PubMed: 36040629
DOI: 10.1007/s00436-022-07631-3 -
Memorias Do Instituto Oswaldo Cruz 2022Free-living amoeba (FLA) group includes the potentially pathogenic genera Acanthamoeba, Naegleria, Balamuthia, Sappinia, and Vermamoeba, causative agents of human...
Free-living amoeba (FLA) group includes the potentially pathogenic genera Acanthamoeba, Naegleria, Balamuthia, Sappinia, and Vermamoeba, causative agents of human infections (encephalitis, keratitis, and disseminated diseases). In Brazil, the first report on pathogenic FLA was published in the 70s and showed meningoencephalitis caused by Naegleria spp. FLA studies are emerging, but no literature review is available to investigate this trend in Brazil critically. Thus, the present work aims to integrate and discuss these data. Scopus, PubMed, and Web of Science were searched, retrieving studies from 1974 to 2020. The screening process resulted in 178 papers, which were clustered into core and auxiliary classes and sorted into five categories: wet-bench studies, dry-bench studies, clinical reports, environmental identifications, and literature reviews. The papers dating from the last ten years account for 75% (134/178) of the total publications, indicating the FLA topic has gained Brazilian interest. Moreover, 81% (144/178) address Acanthamoeba-related matter, revealing this genus as the most prevalent in all categories. Brazil's Southeast, South, and Midwest geographic regions accounted for 96% (171/178) of the publications studied in the present work. To the best of our knowledge, this review is the pioneer in summarising the FLA research history in Brazil.
Topics: Acanthamoeba; Amoeba; Brazil; Cell Movement; Encephalitis; Humans
PubMed: 35792751
DOI: 10.1590/0074-02760210373 -
Advances in Experimental Medicine and... 2022Periodontitis is an inflammatory disease triggered by the infection of the periodontal sulcus by microbes. Together with the abundant eubacterial microbiota, at least... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Periodontitis is an inflammatory disease triggered by the infection of the periodontal sulcus by microbes. Together with the abundant eubacterial microbiota, at least two parasites have often been identified: the amoeba Entamoeba gingivalis and the flagellate Trichomonas tenax. The role of these protists in the pathophysiology of periodontal disease remains to be deciphered. A high diversity in their measured prevalence, mainly due to methodological concerns, prevents further analysis of the aetiological link between these parasites and periodontitis.
METHODS
To determine E. gingivalis and T. tenax prevalence in periodontal pockets as compared to healthy sulci, we have conducted a systematic review, searching 3 remote databases (Pubmed, LILACS, and Google Scholar), restricting to papers in which the diagnostic of the parasite was made using molecular methods. A total of 5 studies for E. gingivalis and 2 studies for T. tenax were included for the meta-analysis.
RESULTS
In the periodontal pockets, the prevalence of parasites is 76.9% (95%-CI: 71.5-81.7%) for E. gingivalis and 38.6% (95%-CI: 27.2-50.0%) for T. tenax . Both parasites are more abundant in periodontal pockets as compared to healthy sulci, with a risk ratio of 3.96 (95%-CI: 1.57-9.98) for E. gingivalis and 21.82 (95%-CI: 6.71-70.96) for T. tenax . The two subtypes of E. gingivalis exhibited the same risk ratio: 3.30 (95%-CI: 1.27-8.55) for ST1 and 3.30 (95%-CI: 0.42-26.03) for ST2, but ST1 was more prevalent (70.6%, 95%-CI: 65.0-76.2%) than ST2 (43.9%, 95%-CI: 35.5-52.4%) in periodontal pockets.
CONCLUSION
Altogether, the data show that parasites are more prevalent in the diseased than in the healthy. However, the differences in prevalence between species and subtypes call for more studies to be able to conclude about their individual contributions in the pathophysiology of periodontal diseases. The heterogeneity in prevalence estimation should be investigated further, in particular to make out biological from methodological heterogeneity.
Topics: Animals; Interleukin-1 Receptor-Like 1 Protein; Parasites; Periodontal Diseases; Periodontal Pocket; Periodontitis; Porphyromonas gingivalis; Trichomonas Infections
PubMed: 35612794
DOI: 10.1007/978-3-030-96881-6_5 -
Journal of Water and Health Aug 2021The occurrence of potentially pathogenic free-living amoebae (FLA) in natural hot springs is considered a public health concern. FLAs are known to cause serious health...
The occurrence of potentially pathogenic free-living amoebae (FLA) in natural hot springs is considered a public health concern. FLAs are known to cause serious health outcomes to a wide spectrum of mammalian hosts. The present study aimed to provide the distribution of isolated cases of FLAs in hot springs through a systematic review process of available published articles online. Relevant studies are published between January 2010 and January 2020 involving the isolation of Naegleria spp., Acanthamoeba spp., Balamuthia spp., Sappinia spp., and Vermamoeba spp. in natural hot springs in the United States, South America, North America, Europe, Asia, and Africa. Articles were identified through a search of PubMed and Google Scholar databases. Out of 94 articles screened, a total of 20 articles are included in the study with consideration of established inclusion and exclusion criteria. The most common FLAs isolated in hot springs are Acanthamoeba spp. (134; 48.5%) and Naegleria spp. (127; 46.0%). Other FLAs isolated in hot springs include Balamuthia spp. (2; 0.7%) and Vermamoeba spp. (13; 4.7%). FLA in hot springs used for recreational and medical purposes is a potential source of infection. It is recommended that strict surveillance and maintenance of hot springs be implemented to prevent potential future infection.
Topics: Acanthamoeba; Amoeba; Animals; Hot Springs; Humans; Naegleria; Prevalence
PubMed: 34371494
DOI: 10.2166/wh.2021.101