Serologic survey for exposure following fatal Balamuthia mandrillaris infection

Molecular identification of Acanthamoeba spp., Balamuthia mandrillaris and Naegleria fowleri in soil samples using quantitative real-time PCR assay in Turkey; Hidden danger in the soil!

Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri are pathogenic free-living amoeba (FLA) and are commonly found in the environment, particularly soil. This pathogenic FLA causes central nervous system-affecting granulomatous amebic encephalitis (GAE) or primary amebic meningoencephalitis (PAM) and can also cause keratitis and skin infections. In the present study, we aimed to determine the quantitative concentration of Acanthamoeba spp., B. mandrillaris, and N. fowleri in soil samples collected from places where human contact is high by using a qPCR assay in Izmir, Turkey. A total of 45.71% (n=16) of Acanthamoeba spp., 20% (n=7) of B. mandrillaris, and 17.4% (n=6) of N. fowleri were detected in five different soil sources by the qPCR assay. The quantitative concentration of Acanthamoeba spp., B. mandrillaris, and N. fowleri in various soil sources was calculated at 10 × 10⁵ - 6 × 10², 47 × 10⁴ to 39 × 10³, and 9 × 10³ - 8 × 10² plasmid copies/gr, respectively. While the highest quantitative concentration of Acanthamoeba spp. and B. mandrillaris was determined in garden soil samples, N. fowleri was detected in potting soil samples. Three different genotypes T2 (18.75%), T4 (56.25%), and T5 (25%) were identified from Acanthamoeba-positive soil samples. Acanthamoeba T4 genotype was the most frequently detected genotype from soil samples and is also the most common genotype to cause infection in humans and animals. To the best of our knowledge, the present study is the first study to identify genotype T5 in soil samples from Turkey. In conclusion, people and especially children should be aware of the hidden danger in the garden and potting soil samples that come into contact most frequently. Public health awareness should be raised about human infections that may be encountered due to contact with the soil. Public health specialists should raise awareness about this hidden danger in soil.

Successful Treatment of Balamuthia mandrillaris Granulomatous Amebic Encephalitis with Nitroxoline

A patient in California, USA, with rare and usually fatal Balamuthia mandrillaris granulomatous amebic encephalitis survived after receiving treatment with a regimen that included the repurposed drug nitroxoline. Nitroxoline, which is a quinolone typically used to treat urinary tract infections, was identified in a screen for drugs with amebicidal activity against Balamuthia.

Facial Balamuthia mandrillaris infection with neurological involvement in an immunocompetent child

Cutaneous infection by Balamuthia mandrillaris is a rare condition that is sometimes complicated by life-threatening CNS involvement. It often evades timely diagnosis due to its rarity and non-specific clinical manifestations. Patients can be either immunocompetent or immunocompromised. It is probably transmitted via inhalation or inoculation through broken skin, and then spreads to the brain and other organs through haematogenous spread. It is important for clinicians to be aware of this disease because rapid diagnosis and subsequent therapy has, in some cases, been associated with survival. In this Grand Round, we report the case of a 7-year-old boy who presented with large, chronic plaques on his face. Several biopsies showed non-specific granulomatous inflammation. The patient deteriorated rapidly and died within 1 month of displaying abnormal symptoms in the CNS. Immunohistochemical staining of skin tissue identified B mandrillaris as the infectious agent. The diagnosis was confirmed with PCR, which detected B mandrillaris DNA in formalin-fixed skin tissue sections. B mandrillaris infection should be considered in the differential diagnosis of patients with chronic granulomatous lesions. We also reviewed the epidemiology, B mandrillaris in nature and in the laboratory, clinical manifestations, histopathology, diagnosis, and treatment of infection.

Cutaneous balamuthiasis: A clinicopathological study

Introduction

Methods

Results

Conclusion

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.

USE OF A HUMAN INDIRECT IMMUNOFLUORESCENCE ANTIBODY ASSAY FOR BALAMUTHIA MANDRILLARIS IN A GROUP OF CAPTIVE NORTHWEST BORNEAN ORANGUTANS (PONGO PYGMAEUS PYGMAEUS)

Granulomatous amoebic encephalitis caused by the free-living amoeba Balamuthia mandrillaris is a highly fatal disease that was first isolated from a mandrill (Mandrillus sphinx), and has since been diagnosed in several nonhuman primates including orangutans. Indirect immunofluorescence antibody (IFA) techniques for Balamuthia have been used in the fields of human medicine and epidemiology both for exposure assessment and screening of clinical patients for antemortem diagnosis. Stored serum samples from five captive Northwest Bornean orangutans (Pongo pygmaeus pygmaeus), including one who had died from B. mandrillaris infection, housed at a single facility were screened with a human IFA assay for B. mandrillaris. Only the single, clinically affected individual was seropositive, and the results suggest that the use of the available human B. mandrillaris IFA assay is a novel diagnostic option for detection of Balamuthia antibodies in this species. A validated screening serological test could be used in individuals exhibiting signs consistent with granulomatous amoebic encephalitis to facilitate earlier antemortem diagnosis of Balamuthia infection, which is critical if treatment is to be pursued. This pilot study presents the use of serological detection methods for B. mandrillaris screening in a nonhuman primate. Subsequent use of the B. mandrillaris IFA assay in the larger captive population should be pursued for validation of the test and to provide further information on seroprevalence and evaluation of risk factors for exposure to Balamuthia and subsequent development of disease.

Diagnostic evaluation of fatal Balamuthia mandrillaris meningoencephalitis in a captive Bornean orangutan (Pongo pygmaeus) with identification of potential environmental source and evidence of chronic exposure

A female Bornean orangutan (Pongo pygmaeus) aged 11 years and 6 months was examined by veterinarians after caretakers observed lethargy and facial grimacing. Within 72 h the primate had left-sided hemiparesis that worsened over the next week. An MRI revealed a focal right-sided cerebral mass suspected to be a neoplasm. Ten days after onset of clinical signs, the orangutan died. On postmortem exam, the medial right parietal lobe was replaced by a 7 × 4 × 3.5 cm focus of neuromalacia and hemorrhage that displaced the lateral ventricle and abutted the corpus callosum. Histopathology of the cerebral lesion revealed pyogranulomatous meningoencephalitis with intralesional amoeba trophozoites and rare cysts. Fresh parietal lobe was submitted to the Centers for Disease Control and Prevention lab for multiplex free-living amoebae real-time PCR and detected Balamuthia mandrillaris DNA at a high burden. Mitochondrial DNA was sequenced, and a 760-bp locus 19443F/20251R was compared to several human infections of B. mandrillaris and shown to be identical to the isolates from four human cases of encephalitis: 1998 in Australia, 1999 in California, 2000 in New York, and 2010 in Arizona. Indirect immunofluorescent antibody testing of stored serum samples indicated exposure to B. mandrillaris for at least 2 years prior to death. Within 1 week of the orangutan's death, water from the exhibit was analyzed and identified the presence of B. mandrillaris DNA, elucidating a possible source of exposure. B. mandrillaris, first reported in a mandrill in 1986, has since occurred in humans and animals and is now considered an important emerging pathogen.

The Epidemiology and Clinical Features of Balamuthia mandrillaris Disease in the United States, 1974-2016

BACKGROUND

Balamuthia mandrillaris is a free-living ameba that causes rare, nearly always fatal disease in humans and animals worldwide. B. mandrillaris has been isolated from soil, dust, and water. Initial entry of Balamuthia into the body is likely via the skin or lungs. To date, only individual case reports and small case series have been published.

METHODS

The Centers for Disease Control and Prevention (CDC) maintains a free-living ameba (FLA) registry and laboratory. To be entered into the registry, a Balamuthia case must be laboratory-confirmed. Several sources were used to complete entries in the registry, including case report forms, CDC laboratory results, published case reports, and media information. SAS© version 9.3 software was used to calculate descriptive statistics and frequencies.

RESULTS

We identified 109 case reports of Balamuthia disease between 1974 and 2016. Most (99%) had encephalitis. The median age was 36 years (range 4 months to 91 years). Males accounted for 68% of the case patients. California had the highest number of case reports, followed by Texas and Arizona. Hispanics constituted 55% for those with documented ethnicity. Exposure to soil was commonly reported. Among those with a known outcome, 90% of patients died.

CONCLUSIONS

Balamuthia disease in the United States is characterized by a highly fatal encephalitis that affects patients of all ages. Hispanics were disproportionately affected. The southwest region of the United States reported the most cases. Clinician awareness of Balamuthia as a cause of encephalitis might lead to earlier diagnosis and initiation of treatment, resulting in better outcomes.

Balamuthia mandrillaris-Related Primary Amoebic Encephalitis in China Diagnosed by Next Generation Sequencing and a Review of the Literature

BACKGROUND

Encephalitis is caused by infection, immune mediated diseases, or primary inflammatory diseases. Of all the causative infectious pathogens, 90% are viruses or bacteria. Granulomatous amoebic encephalitis (GAE), caused by Balamuthia mandrillaris, is a rare but life-threatening disease. Diagnosis and therapy are frequently delayed due to the lack of specific clinical manifestations.

METHOD

A healthy 2 year old Chinese male patient initially presented with a nearly 2 month history of irregular fever. We present this case of granulomatous amoebic encephalitis caused by B. mandrillaris. Next generation sequencing of the patient's cerebrospinal fluid (CSF) was performed to identify an infectious agent.

RESULT

The results of next generation sequencing of the CSF showed that most of the mapped reads belonged to Balamuthia mandrillaris.

CONCLUSION

Next generation sequencing (NGS) is an unbiased and rapid diagnostic tool. The NGS method can be used for the rapid identification of causative pathogens. The NGS method should be widely applied in clinical practice and help clinicians provide direction for the diagnosis of diseases, especially for rare and difficult cases.

Acanthamoeba spp. and Balamuthia mandrillaris leading to fatal granulomatous amebic encephalitis

Acanthamoeba spp. and Balamuthia mandrillaris are free-living amebae known to cause disseminated and fatal central nervous system dysfunction which manifests as granulomatous amebic encephalitis (GAE) with exceedingly rare frequency. We report two lethal cases of infection with free-living amebae: an acute case of Acanthamoeba spp. infection in an immunocompromised female and a subacute case of B. mandrillaris in a Hispanic male. The Acanthamoeba spp. infection presented with an atypical lesion in the thalamus that caused rapid deterioration of the patient while the case of B. mandrillaris had a prolonged clinical course with multifocal lesions beginning in the frontal lobe. Cerebrospinal fluid results were non-specific in both cases, however, post-mortem histology demonstrated the presence of trophozoites along a perivascular distribution of necrosis and infiltrate composed primarily of neutrophils. In addition to detailing the clinical presentations of these infrequent amebic infections, we offer insight into the difficulties surrounding their diagnoses in order to aid the clinician in accurate and timely identification.

Tissue and blood protozoa including toxoplasmosis, Chagas disease, leishmaniasis, Babesia, Acanthamoeba, Balamuthia, and Naegleria in solid organ transplant recipients- Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of tissue and blood protozoal infections in the pre- and post-transplant period. Significant new developments in the field have made it necessary to divide the previous single guideline published in 2013 into two sections, with the intestinal parasites separated from this guideline devoted to tissue and blood protozoa. The current update reflects the increased focus on donor screening and risk-based recipient monitoring for parasitic infections. Increased donor testing has led to new recommendations for recipient management of Toxoplasma gondii and Trypanosoma cruzi. Molecular diagnostics have impacted the field, with access to rapid diagnostic testing for malaria and polymerase chain reaction testing for Leishmania. Changes in Babesia treatment regimens in the immunocompromised host are outlined. The risk of donor transmission of free-living amebae infection is reviewed. Changing immigration patterns and the expansion of transplant medicine in developing countries has contributed to the recognition of parasitic infections as an important threat to transplant outcomes. Medications such as benznidazole and miltefosine are now available to US prescribers as access to treatment of tissue and blood protozoa is increasingly prioritized.

First report of the isolation of Balamuthia mandrillaris in the northern region of Japan

Balamuthia mandrillaris is a free-living amoeba that lives in soil and water near human settlements. B. mandrillaris was first isolated from a mandrill baboon that died at the San Diego Zoo Wildlife Park in California in 1986, and the first human infection was reported in 1990. Although reported B. mandrillaris infections are often not properly characterized, it appears that B. mandrillaris invades the living body from the soil and water, either via a wound or the nasal cavity. Most confirmed infections have originated in South and North America. B. mandrillaris inhabits warm climates and is recognized as a pathogen in warm areas such as desert climates and tropical climates. B. mandrillaris has been isolated from environmental samples since 2000, most of which originated from warm areas such as step climates, tropical climates, and desert climates. However, B. mandrillaris may survive in diverse environments, although fewer granulomatous amebic encephalitis patients have been reported in colder Japanese and Northern European regions. In the present study, we conducted a survey of 13 soil samples in Aomori Prefecture located at the northernmost tip of Japan Honshu and successfully isolated one strain of B. mandrillaris from soil for the first time in Japan. In addition, B. mandrillaris gene was detected from several soils. This confirms that B. mandrillaris is capable of spreading to a wider climatic region.

Parasitic Infections Associated with Unfavourable Outcomes in Transplant Recipients

Introduction. The immunosuppression used after transplantation (Tx) is associated with an increased risk of opportunistic infections. In Europe, parasitic infections after Tx are much less common than viral, bacterial and fungal ones. However, diseases caused by parasites are very common in tropical countries. In the last years the number of travellers with immunosuppression visiting tropical countries has increased. Methods. We performed a literature review to evaluate a risk of parasitic infections after Tx in Europe. Results. There is a real risk of parasitic infection in patients after Tx travelling to tropical countries. Malaria, leishmaniasis, strongyloidiasis and schistosomiasis are the most dangerous and relatively common. Although the incidence of these tropical infections after Tx has not increased, the course of disease could be fatal. There are also some cosmopolitan parasitic infections dangerous for patients after Tx. The greatest threat in Europe is toxoplasmosis, especially in heart and bone marrow recipients. The most severe manifestations of toxoplasmosis are myocarditis, encephalitis and disseminated disease. Diarrhoea is one of the most common symptoms of parasitic infection. In Europe the most prevalent pathogens causing diarrhoea are Giardia duodenalis and Cryptosporidium. Conclusions. Solid organ and bone marrow transplantations, blood transfusions and immunosuppressive treatment are associated with a small but real risk of parasitic infections in European citizens. In patients with severe parasitic infection, i.e., those with lung or brain involvement or a disseminated disease, the progression is very rapid and the prognosis is bad. Establishing a diagnosis before the patient's death is challenging.

Detection of serum antibodies in children and adolescents against Balamuthia mandrillaris, Naegleria fowleri and Acanthamoeba T4

The presence of free-living amoebae of the genera Naegleria, Acanthamoeba and Balamuthia, which contain pathogenic species for humans and animals, has been demonstrated several times and in different natural aquatic environments in the northwest of Mexico. With the aim of continuing the addition of knowledge about immunology of pathogenic free-living amoebae, 118 sera from children and adolescents, living in three villages, were studied. Humoral IgG response against B. mandrillaris, N. fowleri and Acanthamoeba sp. genotype T4, was analyzed in duplicate to titers 1: 100 and 1: 500 by enzyme-linked immunosorbent assay (ELISA). Children and adolescents ages ranged between 5 and 16 years old, with a mean of 9 years old, 55% males. All tested sera were positive for the 1: 100 dilution, and in the results obtained with the 1: 500 dilution, 116 of 118 (98.3%) were seropositive for N. fowleri, 101 of 118 (85.6%) were seropositive for Acanthamoeba sp. genotype T4, and 43 of 118 (36.4%) were seropositive for B. mandrillaris. The statistical analysis showed different distributions among the three communities and for the three species of pathogenic free-living amoebae, including age. Lysed and complete cells used as Balamuthia antigens gave differences in seropositivity.

Isolation of Balamuthia mandrillaris from soil samples in North-Western Iran

Balamuthia mandrillaris is an opportunistic free-living amoebae (FLA) which has been reported as the causative agent of the fatal Balamuthia amoebic encephalitis (BAE). Currently, the transmission dynamics of this pathogen remain poorly understood although the organism has been associated with soils, and thus, soil exposure has been identified as a risk factor for this pathogenic amoeba. Nevertheless, environmental isolation of B. mandrillaris is a rare event and strains of this amoebic species have been isolated from soil and dust sources only in seven previous reports (Iran, Mexico, USA, Peru, Costa Rica, Guinea Bissau, and Jamaica). In Iran, a previous study reported the isolation of B. mandrillaris from dust collected in the city of Tehran and free of known infectious involvement. Therefore, in this work, 55 soil samples collected from public and recreational areas of East Azerbaijan, North-Western Iran, were investigated for the presence of this pathogen. Samples were cultured in 2% non-nutrient agar plates and were monitored for the presence of B. mandrillaris-like trophozoites and/or cysts. Those samples that were positive for these amoebae by microscopic criteria were then confirmed by PCR amplification and DNA sequencing of the mitochondrial 16S ribosomal DNA (rDNA) of B. mandrillaris. The obtained results revealed the presence of this emerging pathogen in 5 of 55 samples included in the study. Homology analysis of the obtained DNA sequences revealed high similarity with previously isolated strains from clinical and environmental sources. To the best of our knowledge, this is the first report on the isolation of B. mandrillaris from soil sources in Iran related to human activity and the second time that this pathogen is isolated from the environment in this country.

Acute encephalitis in the immunocompromised individual

PURPOSE OF REVIEW

This article describes recent advances in the diagnosis and management of encephalitis in immunocompromised individuals.

RECENT FINDINGS

Herpes simplex virus (HSV) and varicella zoster virus (VZV) are common causes of encephalitis in immunocompromised individuals, although clinical manifestations may be atypical, and thus challenging to recognize. Recently, an increased incidence of HSV and VZV central nervous system infections has been reported in association with novel immunosuppressive and immunomodulatory treatments. The free-living ameba Balamuthia mandrillaris causes granulomatous encephalitis predominantly in immunocompromised individuals and is associated with nearly uniform fatality. In the setting of organ transplantation, the recipient's immunocompromised state along with the potential for donor-transmitted infections can result in a unique epidemiology of encephalitis, including infection by human herpes virus-6 and BK virus. Recent studies utilizing next-generation sequencing techniques have identified several pathogens, including Leptospira santarosai and a neurotropic astrovirus, as causes of encephalitis in immunocompromised individuals.

SUMMARY

Diagnosis and management of encephalitis is challenging in immunocompromised individuals, in part because of atypical clinical presentations and the presence of uncommon or novel infectious agents. Unbiased techniques for pathogen discovery are likely to play an increasing role in the diagnosis of central nervous system infections in immunocompromised individuals.

Detection of Balamuthia mandrillaris DNA in the storage case of contact lenses in Germany

Acanthamoeba spp. are frequently the etiological agents of a severe form of sight-threatening keratitis, called Acanthamoeba keratitis. The contact lens storage solution of a patient with keratitis of unknown genesis was screened using our diagnostic tools to detect potentially pathogenic free-living amoebae (FLA). Culture methods and a triplex quantitative real-time polymerase chain reaction (qPCR) targeting Acanthamoeba spp., Naegleria fowleri, and Balamuthia mandrillaris were used in context of this routine screening. While no amoebae were detected by culture, qPCR specifically detected DNA of B. mandrillaris. This FLA is known as the etiological agent of a fatal form of encephalitis in humans and other mammals, Balamuthia amoebic encephalitis (BAE). A fragment of the 18S rDNA gene was amplified from the sample and showed 99 % sequence identity to B. mandrillaris sequences from GenBank. To the best of our knowledge, this is the first report of B. mandrillaris found in association with contact lenses. Although no viable amoeba was obtained by culturing efforts, the verification of B. mandrillaris DNA in the contact lens storage solution demonstrates how easily this pathogen might come into close contact with humans.

Balamuthia mandrillaris therapeutic mud bath in Jamaica

Balamuthia mandrillaris is an emerging cause of encephalitis in humans. The transmission dynamics are poorly understood due to the high fatality rate and the sporadic nature of cases. Seventy-two soil samples were collected from beaches and the banks of lagoons, rivers, ponds, mineral springs and streams from across Jamaica and assayed for the presence of B. mandrillaris. Seventy-nine sites were sampled and the mitochondrial 16S rDNA gene of B. mandrillaris was amplified and sequenced to confirm the presence of the amoeba. One isolate of B. mandrillaris was recovered from soil from mineral spring which hosts an informal therapeutic mud bath business. Although B. mandrillaris is less frequently isolated from soil than other free-living amoebae, rubbing mud containing the organism onto the skin increases the likelihood of exposure and infection. This first report on the isolation of B. mandrillaris in the Caribbean and its presence in soil where human contact is likely warrants further investigation using serological methods to elucidate exposure patterns.

The isolation of Balamuthia mandrillaris from environmental sources from Peru

Balamuthia mandrillaris is an opportunistic free-living amoeba that has been reported to cause skin lesions and the fatal Balamuthia amoebic encephalitis (BAE) in humans and other animals. Currently, around 200 human BAE cases have been reported worldwide, although this number is considered to be underestimated. The highest number of BAE cases has been reported in the American continent, mainly in the southwest of the USA. Peru seems to be another hotspot for BAE with around 55 human cases having been identified, usually involving cutaneous infection, especially lesions in the central face area. The isolation of Balamuthia from environmental sources has been reported on only three prior occasions, twice from Californian soils and once from dust in Iran and so it seems that this amoeba is relatively rarely encountered in samples from the environment. We investigated that possibility of finding the amoebae in soil samples from different regions where clinical cases have been reported in Peru. Twenty-one samples were cultured in non-nutrient agar plates and were checked for the presence of B. mandrillaris-like trophozoites and/or cysts. Those samples that were positive for these amoebae by microscopic criteria were then confirmed by PCR amplification and DNA sequencing of the mitochondrial 16S rDNA gene of B. mandrillaris. We have detected the presence of B. mandrillaris in four samples collected in the regions of Piura (3) and Lima (1) where infection cases have been previously reported. We hypothesize that B. mandrillaris is present in Peru in soil and dust which therefore constitutes a source of the infection for the BAE cases previously reported in this country. Further studies should be carried out in the area to confirm the generality of this finding.