Isolation and habitat analysis of Balamuthia mandrillaris from soil.

Balamuthia mandrillaris is a free-living amoeba that causes meningoencephalitis in mammals. Over 200 cases of infection were reported worldwide, with a fatality rate of over 95%. A clear route of infection was unknown for a long time until a girl died of granulomatous amoebic encephalitis (GAE) in California, USA, in 2003 due to infection with B. mandrillaris detected in a potted plant. Since then, epidemiological studies were conducted worldwide to detect B. mandrillaris in soil and other environmental samples. We previously reported the isolation of B. mandrillaris from the soil in Japan; however, the existing B. mandrillaris culture method with BM3 medium and COS-7 cells was unsuccessful. Therefore, in this study, we aimed to conduct soil analysis to determine the growth conditions of B. mandrillaris. B. mandrillaris-positive soils were defined as soils from which B. mandrillaris was isolated and environmental DNA was PCR-positive. Soils inhabited by B. mandrillaris were alkaline, with high electrical conductivity and characteristics of nutrient-rich soils of loam and clay loam. The results of this study suggest a possible reason for the high prevalence of GAE caused by B. mandrillaris among individuals employed in agriculture-related occupations.

Acanthamoeba Infection and Nasal Rinsing, United States, 1994-2022.

We describe 10 patients with nonkeratitis Acanthamoeba infection who reported performing nasal rinsing before becoming ill. All were immunocompromised, 7 had chronic sinusitis, and many used tap water for nasal rinsing. Immunocompromised persons should be educated about safe nasal rinsing to prevent free-living ameba infections.

Unexpected trends of amoebic encephalitis in Pakistan.

Annual reported cases of Naegleria fowleri (NF), popularly known as brain eating amoeba, are becoming a huge challenge for Pakistani health authorities. Karachi has seen cases regularly up till the present but Lahore has not. The spread of this amoeba in non-chlorinated water is a major concern for the authorities. NF is an amoeba commonly found in warm freshwater environments such as lakes, hot springs and poorly chlorinated swimming pools. It poses a significant risk during hot weather when water-related recreational activities are popular. Where there is a non-chlorinated water supply, its spread is aggravated.

Clinical manifestations and outcome of patients with primary amoebic meningoencephalitis in Pakistan. A single-center experience.

Primary amoebic meningoencephalitis (PAM) is a rapidly progressing central nervous system (CNS) infection caused by Naegleria fowleri, a free-living amoeba found in warm freshwater. The disease progression is very rapid, and the outcome is nearly always fatal. We aim to describe the disease course in patients admitted with PAM in a tertiary care center in Karachi, Pakistan between the periods of 2010 to 2021. A total of 39 patients were included in the study, 33 males (84.6%). The median age of the patients was 34 years. The most frequent presenting complaint was fever, which was found in 37 patients (94.9%) followed by headache in 28 patients (71.8%), nausea and vomiting in 27 patients (69.2%), and seizures in 10 patients (25.6%). Overall, 39 patients underwent lumbar puncture, 27 patients (69.2%) had a positive motile trophozoites on CSF wet preparation microscopy, 18 patients (46.2%) had a positive culture, and 10 patients had a positive PCR. CSF analysis resembled bacterial meningitis with elevated white blood cell counts with predominantly neutrophils (median, 3000 [range, 1350-7500] cells/µL), low glucose levels median, 14 [range, 1-92] mg/dL), and elevated protein levels (median, 344 [range, 289-405] mg/dL). Imaging results were abnormal in approximately three-fourths of the patients which included cerebral edema (66.7%), hydrocephalus (25.6%), and cerebral infarctions (12.8%). Only one patient survived. PAM is a fatal illness with limited treatment success. Early diagnosis and prompt initiation of treatment can improve the survival of the patients and reduce mortality.

Fatal Primary Amebic Meningoencephalitis in Nebraska: Case Report and Environmental Investigation, August 2022.

Primary amebic meningoencephalitis (PAM) is a rare and lethal infection caused by Naegleria fowleri. We report an epidemiological and environmental investigation relating to a case of PAM in a previously healthy boy age 8 years. An interview of the patient's family was conducted to determine the likely exposure site and to assess risk factors. Data from the United States Geological Survey site at Waterloo, NE, on the Elkhorn River were used to estimate water temperature and streamflow at the time and site of exposure. Data from the National Weather Service were used to estimate precipitation and ambient air temperature at the time and site of exposure. Despite conventional treatment, the patient died 2 days after hospital admission. The patient participated in recreational water activities in the Elkhorn River in northeastern Nebraska 5 days before symptom onset. In the week before exposure, water and ambient air high temperatures reached annual highs, averaging 32.4°C and 35.8°C, respectively. The day before infection, 2.2 cm of precipitation was reported. Streamflow was low (407 ft3/s). Infections in several northern states, including Nebraska, suggest an expanding geographic range of N. fowleri transmission, which may lead to increased incidence of PAM in the United States. Similar environmental investigations at suspected exposure sites of future cases will allow data aggregation, enabling investigators to correlate environmental factors with infection risk accurately.

Prevalence of amoebiasis and associated risk factors among population in Duhok city, Kurdistan Region, Iraq.

INTRODUCTION: Entamoeba histolytica, a protozoan parasite, is the third major contributor to human mortality and morbidity outside of malaria and schistosomiasis. The purpose of this cross-sectional study was to estimate the prevalence of Entamoeba spp. among outpatients of two teaching hospitals in Duhok city who agreed to participate in the study from April 2021 to March 2022 to assess the impact of associated risk variables on the infection rate. METHODOLOGY: Stool specimens were collected from outpatients suffering from diarrhea and other gastrointestinal symptoms in two teaching hospitals: Azadi and Heevi Pediatric in Duhok city, Kurdistan Region- Iraq. The collected stool specimens were examined macroscopically, followed by microscopic examination using the direct wet mount and zinc sulfate flotation methods, respectively. RESULT: Infection with Entamoeba species was recorded in 21.68% (562/2592) of the analyzed specimens. Males had a significantly higher infection rate than females (67.43% vs. 32.56%). This difference was statistically significant (p < 0.000). The highest rate was seen in the age group 1-10 years (p < 0.001). Lower levels of education, low incomes, eating unwashed fruits and vegetables, drinking well water, eating frequently outside of homes, not using antidiarrheal medications and living in overcrowded families were risk factors that showed high levels of infection (p < 0.0001). CONCLUSIONS: The present study concluded that improving living conditions, providing clean water, and promoting health education programs are essential to reduce the rate of this disease among the population.

Amebic encephalitis and meningoencephalitis: an update on epidemiology, diagnostic methods, and treatment.

PURPOSE OF REVIEW: Free-living amebae (FLA) including Naegleria fowleri , Balamuthia mandrillaris , and Acanthamoeba species can cause rare, yet severe infections that are nearly always fatal. This review describes recent developments in epidemiology, diagnosis, and treatment of amebic meningoencephalitis. RECENT FINDINGS: Despite similarities among the three pathogenic FLA, there are notable variations in disease presentations, routes of transmission, populations at risk, and outcomes for each. Recently, molecular diagnostic tools have been used to diagnose a greater number of FLA infections. Treatment regimens for FLA have historically relied on survivor reports; more data is needed about novel treatments, including nitroxoline. SUMMARY: Research to identify new drugs and guide treatment regimens for amebic meningoencephalitis is lacking. However, improved diagnostic capabilities may lead to earlier diagnoses, allowing earlier treatment initiation and improved outcomes. Public health practitioners should continue to prioritize increasing awareness and providing education to clinicians, laboratorians, and the public about amebic infections.

Growth characteristics and morphology of Paramoeba perurans from Atlantic salmon Salmo salar L. and ballan wrasse Labrus bergylta in Norway.

BACKGROUND: Paramoeba perurans is the causative agent of amoebic gill disease (AGD) in Atlantic salmon Salmo salar L. and many other farmed marine fish species worldwide. The first cases of AGD in Norway were reported in 2006, and it has subsequently become established as a significant gill disease that affects the country's salmonid aquaculture industry. Despite several decades of research on AGD, there is still a lack of knowledge of the biology of P. perurans and its interactions with its hosts and the environment. METHODS: The growth and morphology of 10 clonal isolates of P. perurans were studied. The isolates were from farmed Atlantic salmon and ballan wrasse that had been obtained from different sites along the Norwegian coast between 2013 and 2015. The morphology and population growth patterns of these clonal amoeba isolates were examined in vitro using light microscopy and real-time reverse transcription polymerase chain reaction under a range of temperatures (4, 12, 15 and 21 °C) and salinities (20, 25, 30 and 34 ‰). RESULTS: We found distinct morphological differences between both locomotive and floating forms of the amoeba isolates. The locomotive amoebae of the clonal isolates varied in size (area) from 453 µm2 to 802 µm2. There were differences in the growth patterns of the clonal amoeba isolates under similar conditions, and in their responses to variations in temperature and salinity. While most of the isolates grew well at salinities of 25-34 ‰, a significant reduction in growth was seen at 20 ‰. Most of the amoeba isolates grew well at 12 °C and 15 °C. At 4 °C, amoebae grew slower and, in contrast to the other temperatures, no extended pseudopodia could be seen in their floating form. The isolates seemed to reach a plateau phase faster at 21 °C, with a higher number of smaller, rounded amoebae. CONCLUSIONS: The differences observed here between clonal isolates of P. perurans should be further examined in experimental in vivo challenge studies, as they may be of relevance to the virulence and proliferation potential of this amoeba on gills. Potential differences in virulence within P. perurans could have implications for management strategies for AGD.

Epidemiology of free-living amoebae infections in Africa: a review.

FLA-related conditions are a rare medical occurrence. Despite their rarity, they are considered a public health concern for two reasons: the absence of a regular treatment regimen in the case of central nervous system infections and the fast progression of the symptoms leading to fatal outcomes. A total of 358 articles were retrieved from different databases (91 from PubMed, 26 from NCBI, 138 from Academia, 102 from Science Direct, and one from IJMED). 7 (46.6%) clinical cases came from Egypt, 2 (13.3%) cases of FLA infection came from Nigeria, 3 (20%) cases came from the Gambia, and 1 (6.6%) case was reported from African countries like Algeria, Tunisia, South Africa, and Zambia. Medical conditions caused by free-living amoeba are considered significant public health concerns. These ubiquitous organisms can cause both fatal and debilitating health conditions. Immediate diagnosis of cases and proper hygienic practices are necessary to provide direct medical intervention. They may be the key to reducing the morbidity and mortality rates from FLA-acquired infections. Although several government-led initiatives have been implemented to mitigate a plethora of parasitic diseases, the case of FLA-related conditions in African countries has yet to be realized.

Occurrence of Naegleria fowleri and their implication for health - a look under the One Health approaches.

One Health approaches are becoming increasingly necessary in the world we live in. Human beings, animals, plants and the environment are intrinsically interconnected and when some intervention occurs, mainly through the action of man himself, everyone suffers the consequences. The objective of this review was to collect data about the occurrence and dispersion of Naegleria fowleri, an amphizoic free-living amoeba, and its implications for health approaches through the One Health concept. N. fowleri is an opportunistic amoeba, better known as brain-eating amoeba, which causes Primary Amoebic Meningoencephalitis. This amoeba is widely distributed around the world, being isolated from different matrices of natural or anthropogenic environments with temperatures above 30 °C with an upper limit of 45-46 °C. Highly lethal, it has claimed numerous humans patients and only five people have survived the disease so far. Our results indicate that climate change plays a major role in the growth and dispersion of the pathogen in the environment, causing damage to humans and animals. Changes in temperature, antimicrobial resistance, possible transport of other microorganisms by the amoeba, conventional treatments with chlorination, among others, were addressed in our study and should be considered in order to raise questions and possible solutions to this problem that involves health as a whole. The diagnostic methods, prospection of new anti-Naegleria drugs and the control of this parasite in the environment are specific and urgent issues. We know that the human-animal-plants-environment spheres are inseparable, so it is necessary to turn a directed look at the One Health approaches related to N. fowleri.

Updates on the worldwide burden of amoebiasis: A case series and literature review.

BACKGROUND: Amoebiasis is an intestinal and tissue parasitic infection caused by the protozoan Entamoeba histolytica. Despite significant medical importance and worldwide dispersion, little is known about the epidemiology and distinct geographical distribution of various clinical forms of amoebiasis in the world. In this study, we present an amoebiasis case series referred to Avicenne Hospital (Bobigny, France) from 2010 to 2022 followed by an overview of the released literature to explore diverse clinico-pathology of amoebiasis and to update the actual epidemiological situation of this parasitosis worldwide. METHODS: The referred patients underwent a combination of clinical and parasitological examinations and imaging. The study was followed by an overview of released literature performed based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline. RESULTS: A total of 15 patients with amoebiasis were diagnosed with an average age of 48.5 years old at the occurrence time of infection. Men (78%) were the most affected patients. Most of the cases were reported following a trip to endemic regions, such as Mali, India, Nepal, Algeria, Cameroon or Congo. All of the processed patients exhibited a hepatic amoebiasis. Amoebic abscess was observed in all cases with an average size of 6.3 cm. Of these patients, seven cases (46.7%) benefited from drainage following a risk of rupture or superinfection of the abscess. A compilation of findings extracted from 390 scientific publications via seven major medical databases, allowed us to update the main epidemiological and clinical events that has led to the current worldwide expansion of amoebiasis. We presented a clinical and epidemiological overview of the amoebiasis accompanied with a worldwide illustrative map displaying the current distribution of known amoebiasis foci in each geographical ecozone of Asia, Europe, Africa, Americas, and Australia. CONCLUSIONS: Although Metropolitan France is not known as an endemic region of amoebiasis, amoebic liver abscess was the most frequent clinical form observed among our 15 patients processed. Most of infected patients had a history of travel to or lived-in endemic areas before arriving in France.

The Epidemiology of Entamoeba histolytica Infection and Its Associated Risk Factors among Domestic and Imported Patients in Taiwan during the 2011-2020 Period.

Background and Objectives: Amebiasis remains an important public health problem worldwide, and immigration and increased international travel have affected incident disease cases. This study assesses the prevalence of Entamoeba histolytica in Taiwan between 2011 and 2020 by analyzing data from surveillance programs conducted by the Centers for Disease Control of Taiwan (TCDC) on laboratory-confirmed cases. Materials and Methods: The E. histolytica infection-related data reported to the National Infectious Diseases Statistics System at the TCDC from 1 January 2011 to 31 December 2020 were collected, including age, gender, place of residence, and the geographic season of exposure for each case. Results: In total, 3066 cases with E. histolytica infections were included in our analysis. Among them, 1735 (57%) cases were imported, and 1331 (43%) were locally acquired. The average annual incidence rate of E. histolytica infections in Taiwan between 2011 and 2020 was 10.6 and 16.1 per 1,000,000 patients. There were statistical differences in gender, age group, and place of residence (p < 0.001) by the source distribution of cases. Also, these differences were found every year (p < 0.05). There were statistical differences in gender and age group (p < 0.001) by place of residence (p < 0.001). The only difference between the distribution of cases and age group was in gender (p < 0.001). Eight patients with amebiasis died, and the fatality rate was 0.3% (8/3066), of whom 75% (6/8) were male, and 75% (6/8) were over 45 years old. This study demonstrates that multiple linear regression analysis shows positive associations between NO2 concentration and amebiasis cases (B value = 2.569, p = 0.019), O3 concentration and amebiasis cases (B value = 0.294, p = 0.008), and temperature and amebiasis cases (B value = 1.096, p = 0.046). Conclusions: This study is the first report of confirmed E. histolytica cases from TCDC surveillance data between 2011 and 2020. This study showed the importance of long periods, air pollutants, and geographically comprehensive analysis for estimating the effect of amebiasis transmission in Taiwan's populations.

A cohort study of gill infections, gill pathology and gill-related mortality in sea-farmed Atlantic salmon (Salmo salar L.): A descriptive analysis.

Gill disease is an important cause of economic losses, fish mortality and reduced animal welfare in salmonid farming. We performed a prospective cohort study, following groups of Atlantic salmon in Western Norway with repeated sampling and data collection from the hatchery phase and throughout the 1st year at sea. The objective was to determine if variation in pathogen prevalence and load, and zoo- and phytoplankton levels had an impact on gill health. Further to describe the temporal development of pathogen prevalence and load, and gill pathology, and how these relate to each other. Neoparamoeba perurans appeared to be the most important cause of gill pathology. No consistent covariation and no or weak associations between the extent of gill pathology and prevalence and load of SGPV, Ca. B. cysticola and D. lepeophtherii were observed. At sea, D. lepeophtherii and Ca. B. cysticola persistently infected all fish groups. Fish groups negative for SGPV at sea transfer were infected at sea and fish groups tested negative before again testing positive. This is suggestive of horizontal transmission of infection at sea and may indicate that previous SGPV infection does not protect against reinfection. Coinfections with three or more putative gill pathogens were found in all fish groups and appear to be the norm in sea-farmed Atlantic salmon in Western Norway.

Occurrence and genetic evaluation of potentially pathogenic Acanthamoeba genotypes in nasal mucosa of immunocompromised patients: a case-control study in Iran.

BACKGROUND: The occurrence of granulomatous amoebic encephalitis (GAE) was investigated due to the exposure of a large number of immunocompromised patients to opportunistic Acanthamoeba infections, which in most cases are fatal. METHODS: In this case-control study, 160 samples from the nasal mucosa of immunocompromised patients were collected between February 2019 to February 2020 in Isfahan, central Iran, using sterile cotton swabs; 150 ethnically matched controls were included. The pathogenic potential of the identified isolates was evaluated using temperature and osmotolerance assays. The identification of Acanthamoeba infection was confirmed by both morphological and phylomolecular tools. RESULTS: Of 310 collected samples, 32 strains, including 25 (15.6%) and 7 (4.6%) isolates, were positive for the Acanthamoeba genus in the patient and control groups, respectively. The topology of the phylogenetic tree indicated that all the Acanthamoeba strains belonged to the T4 genotype. Only five of the isolates genotyped as T4 were positive for potential pathogenic assays. The heterogeneity analysis of 18S ribosomal RNA sequences of Acanthamoeba in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) and hepatitis B and C patients revealed significant genetic diversity (haplotype diversity [Hd] 0.511) compared with that of healthy individuals (Hd 0.210). CONCLUSIONS: The circulation of pathogenic isolates of Acanthamoeba, particularly in HIV/AIDS patients, along with their genetic traits, indicates that clinicians should be more aware of fatal cases of GAE, especially in suspected encephalitis, in Iran and worldwide.

Prevalence of Amoebiasis and Associated Complications in India: A Systematic Review.

PURPOSE: Intestinal protozoan parasites are responsible for diarrheal diseases causing significant morbidity and mortality. Entamoeba histolytica is the principle protozoan parasite associated with diarrheal infections. The infection is often associated with inaccessibility to clean drinking water and poor sanitary conditions in low- and middle-income countries including India. A comprehensive systematic review was performed to evaluate a reliable nationwide estimate for prevalence and geographic distribution of amoebiasis in India and the complications associated with it. METHODS: We used the PRISMA guidelines to perform a systematic review and meta-analysis of articles published between the year 2001-2020. Two English language databases PubMed and Web of Science were searched to achieve relevant studies. RESULTS: Initial searches resulted in 467 studies out of which 64 eligible articles involving data from 289,659 human subjects from 12 states and 4 union territories were included in the final analysis. Prevalence of amoebiasis ranged from 3-23% in asymptomatic population, 0.64-11% in symptomatic patients and 1-17.5% in HIV-infected patients. Highest prevalence was seen in Tamil Nadu, Andaman Nicobar Island and North East India. Extra intestinal invasion of Entamoeba histolytica leading to complications such as amoebic liver abscess, amoebic colitis, colonic perforation and ameboma were also reported. Such complications have the potential to increase healthcare burden and may prove to be fatal. CONCLUSION: Amoebiasis remains a significant public health issue in India responsible for diarrheal diseases causing significant morbidity and mortality. Entamoeba histolytica is the principle protozoan parasite associated with amoebiasis. Public health efforts should be directed towards its control and better diagnostic methods should be employed for distinguishing between pathogenic and non-pathogenic species of Entamoeba.

Epidemiology of free-living amoebae in the Philippines: a review and update.

Free-living amoebae (FLA) are considered environmental pathogens and thus pose a public health threat. Their ubiquity in natural sources may magnify the potential severity of health outcomes in the future. However, less attention was given despite several probable public health risks that arise from the presence of pathogenic strains in the environment. Here, we provide epidemiological data based on investigations involving the distribution and occurrence of free-living amoebae in the Republic of the Philippines. This aims to connect data of fragmented studies of these organisms and provide potential roadmaps in FLA research in the country. The majority of the reviewed articles (n = 19) focused on characterization studies (36.8%; 7/19) while environmental isolation and isolation from biological samples had an equal frequency of 31.6% (6/19) each. There is a great disparity between the established ubiquity in environmental sources and the number of cases of FLA infections in the country. FLA-related research in the Philippines is still in its inceptive stage with several gaps to fill, which can be used to formulate policy briefs in the future regarding its isolation, identification, diagnosis, therapeutic management, and control of FLA infections in the country.

Opportunistic free-living amoebal pathogens.

Pathogenic free-living amoebae affecting the central nervous system are known to cause granulomatous amoebic encephalitis (GAE) or primary amoebic meningoencephalitis (PAM). Although hosts with impaired immunity are generally at a higher risk of severe disease, amoebae such as Naegleria fowleri and Balamuthia mandrillaris can instigate disease in otherwise immunocompetent individuals, whereas Acanthamoeba species mostly infect immunocompromised people. Acanthamoeba also cause a sight-threatening eye infection, mostly in contact lens wearers. Although infections due to pathogenic amoebae are considered rare, recently, these deadly amoebae were detected in water supplies in the USA. This is of particular concern, especially with global warming further exacerbating the problem. Herein, we describe the epidemiology, presentation, diagnosis, and management of free-living amoeba infections.

Three encephalitis-causing amoebae and their distinct interactions with the host.

Naegleria fowleri, Balamuthia mandrillaris, and Acanthamoeba spp. can cause devastating brain infections in humans which almost always result in death. The symptoms of the three infections overlap, but brain inflammation and the course of the disease differ, depending on the amoeba that is responsible. Understanding the differences between these amoebae can result in the development of strategies to prevent and treat these infections. Recently, numerous scientific advancements have been made in the understanding of pathogenicity mechanisms in general, and the basic biology, epidemiology, and the human immune response towards these amoebae in particular. In this review, we combine this knowledge and aim to identify which factors can explain the differences between the lethal brain infections caused by N. fowleri, B. mandrillaris, and Acanthamoeba spp.

Amebiasis and Amebic Liver Abscess in Children.

Although rare in the developed world, amebiasis continues to be a leading cause of diarrhea and illness in developing nations with crowding, poor sanitation, and lack of clean water supply. Recent immigrants or travelers returning from endemic regions after a prolonged stay are at high risk of developing amebiasis. A high index of suspicion for amebiasis should be maintained for other high-risk groups like men having sex with men, people with AIDS/HIV, immunocompromised hosts, residents of mental health facility or group homes. Clinical presentation of intestinal amebiasis varies from diarrhea to colitis and dysentery. Amebic liver abscess (ALA) is the most common form of extraintestinal amebiasis. Various diagnostic tools are available and when amebiasis is suspected, a combination of stool tests and serology should be sent to maximize the yield of testing. Treatment with an amebicidal drug such as metronidazole/tinidazole and a luminal cysticidal agent such as paromomycin for clinical disease is indicated. However, for asymptomatic disease treatment with a luminal cysticidal agent to decrease chances of invasive disease and transmission is recommended.