scholarly journals Various brain-eating amoebae: the protozoa, the pathogenesis, and the disease

2021 ◽  
Author(s):  
Hongze Zhang ◽  
Xunjia Cheng
Keyword(s):  
Clinical Manifestations ◽  
Healthy Children ◽  
Public Attention ◽  
Free Living ◽  
Laboratory Findings ◽  
Granulomatous Amoebic Encephalitis ◽  
Serious Infections ◽  
Present Information ◽  
Causative Agents ◽  
Children And Young Adults

AbstractAmong various genera of free-living amoebae prevalent in nature, some members are identified as causative agents of human encephalitis, in which Naegleria fowleri followed by Acanthamoeba spp. and Balamuthia mandrillaris have been successively discovered. As the three dominant genera responsible for infections, Acanthamoeba and Balamuthia work as opportunistic pathogens of granulomatous amoebic encephalitis in immunocompetent and immunocompromised individuals, whereas Naegleria induces primary amoebic meningoencephalitis mostly in healthy children and young adults as a more violent and deadly disease. Due to the lack of typical symptoms and laboratory findings, all these amoebic encephalitic diseases are difficult to diagnose. Considering that subsequent therapies are also affected, all these brain infections cause significant mortality worldwide, with more than 90% of the cases being fatal. Along with global warming and population explosion, expanding areas of human and amoebae activity in some regions lead to increased contact, resulting in more serious infections and drawing increased public attention. In this review, we summarize the present information of these pathogenic free-living amoebae, including their phylogeny, classification, biology, and ecology. The mechanisms of pathogenesis, immunology, pathophysiology, clinical manifestations, epidemiology, diagnosis, and therapies are also discussed.

scholarly journals Encystment Induces Down-Regulation of an Acetyltransferase-Like Gene in Acanthamoeba castellanii

Pathogens ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 321 ◽  
Author(s):  
Steven Rolland ◽  
Luce Mengue ◽  
Cyril Noël ◽  
Stéphanie Crapart ◽  
Anne Mercier ◽  
...  
Keyword(s):  
Bioinformatics Analysis ◽  
Acanthamoeba Castellanii ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Adverse Conditions ◽  
Genetic Modifications ◽  
Granulomatous Amoebic Encephalitis ◽  
Free Living Amoeba ◽  
Causative Agents

Acanthamoeba castellanii is a ubiquitous free-living amoeba. Pathogenic strains are causative agents of Acanthamoeba keratitis and granulomatous amoebic encephalitis. In response to adverse conditions, A. castellanii differentiate into cysts, which are metabolically inactive and resistant cells. This process, also named encystment, involves biochemical and genetic modifications that remain largely unknown. This study characterizes the role of the ACA1_384820 Acanthamoeba gene during encystment. This gene encodes a putative N-acetyltransferase, belonging to the Gcn5-related N-acetyltransferase (GNAT) family. We showed that expression of the ACA1_384820 gene was down-regulated as early as two hours after induction of encystment in A. castellanii. Interestingly, overexpression of the ACA1_384820 gene affects formation of cysts. Unexpectedly, the search of homologs of ACA1_384820 in the Eukaryota gene datasets failed, except for some species in the Acanthamoeba genus. Bioinformatics analysis suggested a possible lateral acquisition of this gene from prokaryotic cells. This study enabled us to describe a new Acanthamoeba gene that is down-regulated during encystment.

Free Living Amoebic Infections: Review

2021 ◽  
Author(s):  
Aaron Kofman ◽  
Jeannette Guarner
Keyword(s):  
Infectious Disease ◽  
Neurological Disease ◽  
Clinical Microbiology ◽  
Clinical Manifestations ◽  
Infectious Agents ◽  
Free Living ◽  
Granulomatous Amoebic Encephalitis ◽  
Amoebic Meningoencephalitis ◽  
Treatment Mortality ◽  
Prompt Diagnosis

Infections caused by Naegleria fowleri , Acanthamoeba spp., and Balamuthia mandrillaris result in a variety of clinical manifestations in humans. These amoebae are found in water and soil worldwide. Acanthamoeba spp. and B. mandrillaris cause granulomatous amoebic encephalitis, which usually presents as a mass, while N. fowleri causes primary amoebic meningoencephalitis. Acanthamoeba spp. can also cause keratitis, and both Acanthamoeba spp. and B. mandrillaris can cause lesions in skin and respiratory mucosa. These amoebae can be difficult to diagnose clinically as these infections are rare and, if not suspected, can be misdiagnosed with other more common diseases. Microscopy continues to be the key first step in diagnosis but the amoeba can be confused with macrophages or other infectious agents if an expert in infectious disease pathology or clinical microbiology is not consulted. Although molecular methods can be helpful in establishing the diagnosis, these are only available in referral centers. Treatment requires combination of antibiotics and antifungals and, even with prompt diagnosis and treatment, mortality for neurological disease is extremely high.

The Role of Free-Living Amoebae Occurring in Heated Effluents as Causative Agents of Human Disease

1983 ◽  
Vol 15 (10) ◽  
pp. 135-147
Author(s):  
Maurice A Shapiro ◽  
Meryl H Karol ◽  
Georg Keleti ◽  
Jan L Sykora ◽  
A J Martinez
Keyword(s):  
Human Disease ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Human Subjects ◽  
Cooling Towers ◽  
Free Living ◽  
Cooling Systems ◽  
Delayed Onset ◽  
Source Of Infection ◽  
Causative Agents

It has been shown that several pathogenic organisms may be frequently found in thermal effluents and cooling systems of coal fired power plants. One of them is pathogenic Naegleria fowleri, the causative agent of an acute fatal human disease - primary amoebic meningoencephalitis (PAM). In our study two out of eight power plants investigated, harbored pathogenic N. fowleri in heated water or cooling towers. The occurrence of this organism was related to elevated temperatures. No significant correlation was found for other biological and chemical parameters. In addition, pathogenic Acanthamoeba which causes granulomatous amoebic encephalitis (GAE) was found in the tested heated effluents from coal fired power plants. Non-pathogenic strains of N. fowleri as well as other free-living and “harmless” amoebae were also very abundant in effluents from all investigated coal fired power plants and cooling towers. It has been reported that several species of nonpathogenic amoebae were isolated from humidifiers and air conditioning systems. Serological testing of symptomatic human subjects has indicated that these organisms may be one of the causative agents of hypersensitivity pneumonitis. An experimental study performed in our laboratory involved testing of guinea pigs sensitized by injection of axenic, non-pathogenic N. gruberi. Delayed onset skin reactivity was apparent in all animals injected with the antigen. Antibodies were detected in all sensitized animals. Bronchial provocation challenge employed to investigate pulmonary hypersensitivity was also used, and yielded positive results. All the sensitized animals displayed delayed onset respiratory responses. The results of this study indicate that not only pathogenic but also non-pathogenic free-living amoebae may be important causative agents of human disease. The occurrence of these organisms in cooling systems from coal fired power plants indicates that these facilities may be an important source of infection.

scholarly journals Clinical presentations and long term prognosis of childhood onset polyarteritis nodosa in single centre of Korea

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeong-Seon Lee ◽  
Joong-Gon Kim ◽  
Soyoung Lee
Keyword(s):  
Polyarteritis Nodosa ◽  
Clinical Manifestations ◽  
Long Term Outcomes ◽  
Childhood Onset ◽  
Laboratory Findings ◽  
Clinical Presentations ◽  
Long Term Prognosis ◽  
Digital Amputation

AbstractChildhood-onset polyarteritis nodosa (PAN) is a rare and systemic necrotising vasculitis in children affecting small- to medium-sized arteries. To date, there have been only a few reports because of its rarity. Thus, we aimed to investigate the clinical manifestations, laboratory findings, treatment, and long-term outcomes in patients with childhood-onset PAN and to evaluate the usefulness of the paediatric vasculitis activity score (PVAS). We retrospectively analysed the data of nine patients with childhood-onset PAN from March 2003 to February 2020. The median ages at symptom onset, diagnosis, and follow-up duration were 7.6 (3–17.5), 7.7 (3.5–17.6), and 7.0 (1.6–16.3) years, respectively. All patients had constitutional symptoms and skin manifestations, while five exhibited Raynaud’s phenomenon. Organ involvement was observed in one patient. The median PVAS at diagnosis was 7 (range: 2–32). Prednisolone was initially used for induction in all patients, and other drugs were added in cases refractory to prednisolone. All patients survived, but three patients with high PVAS at diagnosis experienced irreversible sequelae, including intracranial haemorrhage and digital amputation. In conclusion, early diagnosis and treatment may minimise sequelae in patients with childhood-onset PAN. This study suggests that high PVAS score at diagnosis may be associated with poor prognosis.

Comparative analyses of different genetic markers for the detection of Acanthamoeba spp. isolates

2014 ◽  
Vol 59 (3) ◽  
Author(s):  
Monika Derda ◽  
Agnieszka Wojtkowiak-Giera ◽  
Edward Hadaś
Keyword(s):  
Genetic Markers ◽  
Tap Water ◽  
Correct Diagnosis ◽  
Specific Marker ◽  
Pcr Assay ◽  
Free Living ◽  
Detection And Identification ◽  
Granulomatous Amoebic Encephalitis ◽  
Free Living Amoeba ◽  
Treatment Of Infection

AbstractAcanthamoeba are widespread free-living amoebae which may cause granulomatous amoebic encephalitis (GAE), keratitis, skin ulcerations and disseminated tissue infection. An important diagnostic and prognostic factor for the treatment of infection is a quick and correct diagnosis of amoebae strains. The aim of our study was to develop a rapid method for detection and identification of pathogenic Acanthamoeba spp. strains from diagnostic material collected from water. In this study we analysed five amplification-based genetic markers (Aca 16S, Ac6/210, GP, JDP, Nelson) used for identification of pathogenic Acanthamoeba spp. strains isolated in water sources in Poland, Iceland and Sweden. Our results demonstrated the presence of pathogenic Acanthamoeba strains in tap water. PCR assay appeared to be a more rapid and sensitive method to detect the presence of amoebae than the limited conventional techniques. Based on our observations, we can confirm that the use of four out of five genetic markers (Aca 16S, Ac 6/210, JDP, GP, Nelson) may be helpful in identification of Acanthamoeba spp. strains, but only one Aca 16S primer pair is a highly specific marker that distinguishes between pathogenic strains of Acanthamoeba and other free-living amoeba families.

Estrogen Receptor α Gene Polymorphisms and Bone Mineral Density in Healthy Children and Young Adults

2004 ◽  
Vol 74 (6) ◽  
pp. 495-500 ◽  
Author(s):  
A. M. Boot ◽  
I. M. van der Sluis ◽  
S. M. P. F. de Muinck Keizer-Schrama ◽  
J. B. J. van Meurs ◽  
E. P. Krenning ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Estrogen Receptor ◽  
Young Adults ◽  
Bone Mineral ◽  
Gene Polymorphisms ◽  
Estrogen Receptor Α ◽  
Healthy Children ◽  
Mineral Density ◽  
Children And Young Adults ◽  
Estrogen Receptor Α Gene

Multifocal, Extranodal Sinus Histiocytosis With Massive Lymphadenopathy: An Overview

2007 ◽  
Vol 131 (7) ◽  
pp. 1117-1121 ◽  
Author(s):  
Sujata Gaitonde
Keyword(s):  
Current Knowledge ◽  
Clinical Manifestations ◽  
Patient Characteristics ◽  
Sinus Histiocytosis ◽  
Massive Lymphadenopathy ◽  
Immune Mediated ◽  
Pathologic Features ◽  
Extranodal Disease ◽  
Children And Young Adults ◽  
Histopathologic Features

Abstract Context.—This article provides an overview of the major pathologic manifestations of sinus histiocytosis with massive lymphadenopathy, including patient characteristics and current knowledge about its pathogenesis, with an emphasis on multifocal and extranodal presentation. Sinus histiocytosis with massive lymphadenopathy is a rare, nonneoplastic, idiopathic, proliferative histiocytic disorder; recognition of this disorder is important to avoid misinterpretation and subsequent unnecessary treatment. This is especially true for primary extranodal manifestation of this rare disorder. Although accurate diagnosis of this entity requires a correlation of clinical, radiologic, laboratory, and pathologic studies in most cases, it remains a disorder primarily defined by its histopathologic features and pathologic manifestations, which are key to the diagnosis. Objective.—To summarize the scientific literature, provide a concise review, and emphasize the diagnostic histopathologic features of extranodal sinus histiocytosis with massive lymphadenopathy. Data Sources.—A comprehensive literature review was undertaken to summarize the clinical and pathologic features of this disorder. Conclusions.—Sinus histiocytosis with massive lymphadenopathy is characterized by a rare, acquired, nonmalignant proliferation of distinctive histiocytes that present with lymphadenopathy or extranodal disease, primarily in children and young adults. It exhibits a broad range of clinical presentations, thus eliciting a wide differential diagnosis. The diverse clinical manifestations and frequent association with subtle or severe immunologic abnormalities suggest an immune-mediated cause. Additional studies are needed to characterize the interplay between death receptors and cytotoxic mediators and to further elucidate the loss of immune hemostasis that may underlie idiopathic histiocytic proliferations such as this.

SPECIAL ARTICLE

PEDIATRICS ◽  
1955 ◽  
Vol 15 (5) ◽  
pp. 642-646
Keyword(s):  
General Population ◽  
Rheumatic Fever ◽  
Streptococcal Infection ◽  
Acute Otitis Media ◽  
Clinical Manifestations ◽  
Diagnostic Errors ◽  
White Blood Count ◽  
Streptococcal Infections ◽  
Laboratory Findings ◽  
Adequate Treatment

RHEUMAT1C fever is a recurrent disease which in most instances can be prevented. Since both the initial and recurrent attacks of the disease are precipitated by infections with beta hemolytic streptococci, prevention of rheumatic fever and rheumatic heart disease depends upon the control of streptococcal infections. This may be accomplished by (1) early and adequate treatment of streptococcal infections in all individuals and (2) prevention of streptococcal infections in rheumatic subjects. TREATMENT OF STREPTOCOCCAL INFECTIONS IN THE GENERAL POPULATION In the general population about 3 per cent of untreated streptococcal infections are followed by rheumatic fever. Adequate and early penicillin treatment, however, will eliminate streptococci from the throat and prevent most attacks of rheumatic fever. Diagnosis of Streptococcal Infection In many instances streptococcal infections can be recognized by their clinical manifestations. In some patients, however, it is difficult or impossible to determine the streptococcal nature of a respiratory infection without obtaining throat cultures. The following section on diagnosis has been included in order to reduce diagnostic errors and to assist physicians in avoiding unnecessary therapy. The accurate recognition of individual streptococcal infections, their adequate treatment and the control of epidemics in the community presently offer the best means of preventing initial and recurrent rheumatic fever. Common Symptoms Sore Throat—sudden onset, pain on swallowing. Headache—common. Fever—variable, but generally from 101° to 104°F. Abdominal Pain—common, especially in children; less common in adults. Nausea and Vomiting—common, especially in children. Common Signs Red Throat. Exudate—usually present. Glands—swollen, tender lymph nodes at angle of jaw. Rash—scarlatiniform. Acute Otitis Media and Acute Sinusitis —frequently due to the streptococcus. In the absence of the common symptoms and signs occurrence of any of the following symptoms is usually not associated with a streptococcal infection : simple coryza; hoarseness; cough. Laboratory Findings White Blood Count—generally over 12,000. Throat Culture—positive culture for hemolytic streptococci is almost always diagnostic.

scholarly journals Amplification of the flgE gene provides evidence for the existence of a Brazilian borreliosis

2012 ◽  
Vol 54 (3) ◽  
pp. 153-158 ◽  
Author(s):  
Elenice Mantovani ◽  
Roberta G. Marangoni ◽  
Giancarla Gauditano ◽  
Virgínia L.N. Bonoldi ◽  
Natalino H. Yoshinari
Keyword(s):  
New Species ◽  
Erythema Migrans ◽  
Clinical Manifestations ◽  
Sensu Stricto ◽  
Borrelia Burgdorferi Sensu Lato ◽  
Laboratory Findings ◽  
Blood Samples ◽  
Commercial Kits ◽  
Conserved Gene ◽  
A New Species

INTRODUCTION: The symptoms of Brazilian borreliosis resemble the clinical manifestations of Lyme disease (LD). However, there are differences between the two in terms of epidemiological and laboratory findings. Primers usually employed to diagnose LD have failed to detect Borrelia strains in Brazil. OBJECTIVE: We aimed to identify the Brazilian Borrelia using a conserved gene that synthesizes the flagellar hook (flgE) of Borrelia burgdorferi sensu lato. METHOD: Three patients presenting with erythema migrans and positive epidemiological histories were recruited for the study. Blood samples were collected, and the DNA was extracted by commercial kits. RESULTS: The gene flgE was amplified from DNA of all selected patients. Upon sequencing, these positive samples revealed 99% homology to B. burgdorferi flgE. CONCLUSION: These results support the existence of borreliosis in Brazil. However, it is unclear whether this borreliosis is caused by a genetically modified B. burgdorferi sensu stricto or by a new species of Borrelia spp.

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