Papers by Govinda Visvesvara
Journal of the Pediatric Infectious Diseases Society, 2013
Balamuthia mandrillaris causes granulomatous amoebic encephalitis, which is frequently fatal. The... more Balamuthia mandrillaris causes granulomatous amoebic encephalitis, which is frequently fatal. There are few reports of survival in children. A 4-year-old child developed severe meningoencephalitis with multiple intracranial ring-enhancing lesions. Empiric therapy was commenced after a biopsy was performed, and the patient had a good clinical response. Molecular testing and indirect immunofluorescence later confirmed the diagnosis of Balamuthia encephalitis. Diagnosis of Balamuthia encephalitis is often delayed. The literature is reviewed with particular reference to reported survival. Prompt tissue diagnosis and initiation of therapy are common features among survivors. In previous reports, miltefosine was not used to treat children, but it was well tolerated in this case and should be considered as a therapeutic option.
Parasites & vectors, Jan 9, 2017
Microsporidia are intracellular obligate parasites traditionally associated with immunosuppressed... more Microsporidia are intracellular obligate parasites traditionally associated with immunosuppressed patients; their detection in immunocompetent patients has increased, highlighting their possible importance as emerging pathogens. Detection of spores in stools, urine, body fluids and tissues is difficult and immunological techniques such as immunofluorescence have proved to be a useful and reliable tool in the diagnosis of human microsporidiosis. For this reason, we have produced and characterized monoclonal antibodies (MAbs) specific for Encephalitozoon intestinalis (the second most frequent microsporidian infecting humans), and other Encephalitozoon species, that can be used in different diagnostic techniques. Seven MAbs were selected in accordance with their optical density (OD). Four (4C4, 2C2, 2E5 and 2H2) were isotype IgG2a; two (3A5 and 3C9) isotype IgG3, and one Mab, 1D7, IgM isotype. The selected monoclonal antibody-secreting hybridomas were characterized by indirect immunofl...
Clinical microbiology reviews, 2018
This Practical Guidance for Clinical Microbiology document on the laboratory diagnosis of parasit... more This Practical Guidance for Clinical Microbiology document on the laboratory diagnosis of parasites from the gastrointestinal tract provides practical information for the recovery and identification of relevant human parasites. The document is based on a comprehensive literature review and expert consensus on relevant diagnostic methods. However, it does not include didactic information on human parasite life cycles, organism morphology, clinical disease, pathogenesis, treatment, or epidemiology and prevention. As greater emphasis is placed on neglected tropical diseases, it becomes highly probable that patients with gastrointestinal parasitic infections will become more widely recognized in areas where parasites are endemic and not endemic. Generally, these methods are nonautomated and require extensive bench experience for accurate performance and interpretation.
Clinical Microbiology Newsletter
Balamuthia mandrillaris, unlike Acanthamoeba, cannot be cultivated on bacterium-coated agar plate... more Balamuthia mandrillaris, unlike Acanthamoeba, cannot be cultivated on bacterium-coated agar plates, and its food source in nature is not clearly known (20). It has, however, been isolated from the environment and is believed to feed on small amebae because it can feed on Acanthamoeba and Naegleria in vitro (20). It can be isolated from human or animal tissue using mammalian cell cultures, such as monkey kidney (E6), human lung fibroblasts (HLF), and human brain microvascular endothelial cells (HBMEC). In an elegant study using phase-contrast microscopy and movies, Dunnebacke (60) has shown that Balamuthia trophozoites invade cultured mammalian cells by extending pseudopodia into the cytoplasm of the cells and causing visible damage to the cells upon retracting the pseudopodia. Sometimes whole amebae enter and move around the mammalian cell and then remain quiescent for hours. Balamuthia can also be grown axenically in a complex cell-free medium containing fetal bovine serum (20). In another study, Matin et al. (61) showed that when Balamuthia was cocultured with monkey kidney fibroblast-like cells (COS-7), HBMEC, Acanthamoeba, and Escherichia coli, optimal growth occurred on HBMEC compared to COS-7 cells. Balamuthia, however, did not grow on E. coli, but when co-cultured with Acanthamoeba trophozoites, B. mandrillaris caused partial damage to Acanthamoeba. Acanthamoeba, however, encysted, and Balamuthia did not ingest the Acanthamoeba cysts. Diagnosis: clinical and laboratory methods B. mandrillaris, like Acanthamoeba spp., is not readily isolated from the cerebrospinal fluid (CSF). Only in one case has it been isolated from the CSF obtained at autopsy (62). CSF examination, in general, reveals lymphocytic pleocytosis with mild to severe elevation (≥1,000 mg/dl) of protein and normal or low glucose concentrations. B. mandrillaris has been identified antemortem in brain biopsy specimens from several patients; in the majority of cases, however, final diagnosis was made only at autopsy. It is difficult to differentiate B. mandrillaris from Acanthamoeba spp. in tissue sections by light microscopy because they look similar. However, they can be differentiated by immunofluorescence analysis of the tissue sections using rabbit anti-Acanthamoeba or anti-B. mandrillaris sera. They can also be differentiated by transmission electron microscopy because ultrastructurally, the two amebae differ in their cyst morphology. Balamuthia can be isolated from clinical specimens provided fresh specimens are inoculated onto mammal
Clinical Microbiology Newsletter
According to the classical taxonomic system, Acanthamoeba, Balamuthia, and Sappinia were classifi... more According to the classical taxonomic system, Acanthamoeba, Balamuthia, and Sappinia were classified under phylum Protozoa, sub-phylum Sarcodina, super class Rhizopodea, class Lobosea, order Amoebida, and Naegleria under the
The American Journal of Tropical Medicine and Hygiene
Laboratorio de Microcirugia de Base de Craneo, Departamento de Neurologia y Neurocirugia, Hospita... more Laboratorio de Microcirugia de Base de Craneo, Departamento de Neurologia y Neurocirugia, Hospital Civil de Guadalajara, Guadalajara, Mexico; Departamento de Patologia, Centro Medico de Occidente, Instituto Mexicano ... Guadalajara, Mexico; ...
The American Journal of Tropical Medicine and Hygiene
ABSTRACT
The Journal of Eukaryotic Microbiology, Feb 1, 2001
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Oct 28, 2016
During 2009 and 2010, two clusters of organ transplant-transmitted Balamuthia mandrillaris, a fr... more During 2009 and 2010, two clusters of organ transplant-transmitted Balamuthia mandrillaris, a free-living ameba, were detected by recognition of severe unexpected illness in multiple recipients from the same donor. We investigated all recipients and the two donors through interview, medical record review, and testing of available specimens retrospectively. Surviving recipients were tested and treated prospectively. In the 2009 cluster of illness, two kidney recipients were infected and one died. The donor had Balamuthia encephalitis confirmed on autopsy. In the 2010 cluster, the liver and kidney-pancreas recipients developed Balamuthia encephalitis and died. The donor had a clinical syndrome consistent with Balamuthia infection and serologic evidence of infection. In both clusters, the two asymptomatic recipients were treated expectantly and survived; one asymptomatic recipient in each cluster had serologic evidence of exposure that decreased over time. Both donors had been presu...
Journal of the Helminthological Society of Washington, 1992
Reviews of Infectious Diseases, May 1, 1990
Clinical Infectious Diseases, May 1, 1995
Acanthamoeba infection has been described as an opportunistic infection in persons with AIDS. We ... more Acanthamoeba infection has been described as an opportunistic infection in persons with AIDS. We report two cases of patients with AIDS and acanthamoeba infection and review the manifestations of this protozoan infection in patients infected with human immunodeficiency virus. The diagnosis of this infection requires a high index of suspicion because the clinical and histologic manifestations may be confused with those of disseminated fungal or algal disease. Clinicians and laboratory personnel should be aware of this potentially fatal condition so that appropriate diagnostic studies can be performed and treatment can be urgently administered. Early initiation of therapy may alter the clinical outcome of the disease.
Journal of Environmental Health, Apr 1, 2013
Primary amebic meningoencephalitis (PAM) is a rare but nearly always fatal infection of the centr... more Primary amebic meningoencephalitis (PAM) is a rare but nearly always fatal infection of the central nervous system caused by the thermophilic, free-living ameba Naegleria fowleri. Since its first description in 1965 through 2010, 118 cases have been reported in the U.S.; all cases are related to environmental exposure to warm freshwater; most have occurred in children and adolescents and are associated with recreational water activities, such as swimming, diving, or playing in freshwater lakes, ponds, or rivers. Over one-fourth of all national PAM cases have occurred in Florida. The authors describe here a fatal case of PAM in a resident of northeast Florida and the ensuing environmental and public health investigation; they also provide a review of all cases of PAM in Florida from 1962 to 2010 and discuss public health responses to PAM in Florida, highlighting opportunities for positive collaboration between state and local environmental health specialists, epidemiologists, and the Centers for Disease Control and Prevention.
Infection, 2001
This report describes the first dual microsporidial infection with Encephalitozoon cuniculi and E... more This report describes the first dual microsporidial infection with Encephalitozoon cuniculi and Enterocytozoon bieneusi in an HIV-positive patient. In view of clinical and epidemiological findings, our E. cuniculi isolate was deduced to be of the dog strain. The patient's occupational involvement with dogs indicates that canines should be considered as a reservoir of human infections for both microsporidial species. Furthermore, our report provides detailed clinical and radiological information on a rare case of a symptomatic pulmonary infection by E. cuniculi and its improvement after treatment with albendazole.
Clinical Infectious Diseases, 2015
Primary amebic meningoencephalitis (PAM) is a fulminant central nervous system infection caused b... more Primary amebic meningoencephalitis (PAM) is a fulminant central nervous system infection caused by the thermophilic free-living ameba Naegleria fowleri. Few survivals have been documented and adequate treatment is lacking. We report 2 PAM cases, 1 fatal and 1 surviving, treated with the novel antiparasitic agent miltefosine. Keywords. primary amebic meningoencephalitis; Naegleria fowleri; miltefosine. Primary amebic meningoencephalitis (PAM) is a fulminant central nervous system infection caused by the thermophilic free-living ameba Naegleria fowleri. The infection occurs when freshwater containing the ameba enters the nose, crosses the cribriform plate, and enters the brain. PAM is often clinically indistinguishable from bacterial meningitis, with early symptoms of headache, fever, nausea, and vomiting progressing rapidly to altered mental status, seizures, coma, and death [1]. Despite the availability of several antimicrobial agents that show in vitro activity against N. fowleri, use of these agents clinically, even when administered early in the course of illness, has resulted in few survivors. Amphotericin B has been the mainstay of PAM treatment, and all of the well-documented survivors have received it as part of their treatment regimen [2-5]. The antiparasitic agent miltefosine has shown some promise for the treatment of free-living ameba infections [6]. CASE REPORT 1 A 12-year-old boy presented to a local community hospital on 7 August 2013 with a 1-day history of headache, weakness, vomiting, fever (39.4°C), and altered mental status. The patient lived
Encyclopedia of Environmental Microbiology, 2003
Journal of clinical microbiology, 1996
The ribosomal DNA internal transcribed spacer (ITS) region of a recently cultured human Encephali... more The ribosomal DNA internal transcribed spacer (ITS) region of a recently cultured human Encephalitozoon cuniculi isolate was analyzed by gene amplification and DNA sequencing. Restriction endonuclease digestion (FokI) and double-stranded DNA heteroduplex mobility shift analysis were performed to determine their utility for strain differentiation. The human E. cuniculi isolate was identical to E. cuniculi III, which had been isolated only from domestic dogs until now. The patient providing the isolate owned a pet dog, but no microsporidia were detected in the pet's urine.
Clinical Microbiology Newsletter, 2008
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Papers by Govinda Visvesvara