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Central nervous system viral infections complicating immunosuppression
Published in Avindra Nath, Joseph R. Berger, Clinical Neurovirology, 2020
New assays to identify obscure pathogens help clinicians navigate the increasing range of conditions affecting the growing population of patients with altered immunity. Unbiased metagenomic next-generation sequencing (mNGS) implemented currently in a few facilities can identify nonhuman sequences the human genome within minutes, pinpointing pathogens rapidly and effectively in situations in which conventional selective serology or polymerase chain reaction for selected microbiological testing has been unrevealing [78]. This technique has helped to identify both well recognized (West Nile virus) and unusual causes of encephalitis such as Balamuthia mandrillaris [79,80]. In a recent series from the Wilson group at UCSF, 35 CNS infections were identified in 151 patients (23.32%) more than a third of which would not have been detected by conventional testing [81].
Dermatological emergencies in tropical infections and infestations
Published in Biju Vasudevan, Rajesh Verma, Dermatological Emergencies, 2019
Anup Kumar Tiwary, Niharika Ranjan Lal, Piyush Kumar
Several species cause severe human disease and include Acanthamoeba species, Naegleria fowleri, and Balamuthia mandrillaris [49]. Individuals prone to infection with Acanthamoeba are usually chronically ill, debilitated, diabetic, alcoholic, or immunosuppressed in some other way [50]. Cutaneous involvement can occur as primary cutaneous acanthamoebiasis and cutaneous involvement after dissemination [51].
Miltefosine
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Andrew Stewardson, Douglas Johnson
Miltefosine has activity in vitro and in experimental models of infection with Acanthamoeba, Balamuthia, and Naegleria infection. These free-living ameba (FLA) cause infections including primary amebic meningoencephalitis (PAM) caused by Naegleria fowleri and GAE caused by Balamuthia mandrillaris and Acanthamoeba species. Despite several drugs having in vitro activity against FLA, mortality from these infections remains > 90% despite treatment with combinations of drugs. Given emerging evidence, in August 2013, miltefosine became available from the CDC as an investigational drug for the treatment of FLA infections used in combination with other antimicrobial drugs (CDC, 2013; Cope, 2013).
Inhibition studies of the protozoan α-carbonic anhydrase from Trypanosoma cruzi with phenols
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Alessandro Bonardi, Seppo Parkkila, Claudiu T. Supuran
Protozoans are microscopic, nonfilamentous protists belonging to a multitude of phyla, with many genera and species described so far, many of which possess ecological and industrial relevance. However, they sometimes produce disease in vertebrates, which may range from mild to moderate, such as those induced by Toxoplasma gondii or Entamoeba histolytica, or may lead to more serious conditions, in the case of infections due to Cryptosporidium parvum, Giardia lamblia, Trichomonas vaginalis, Babesia spp., but also very serious and widespread ones, such as malaria, leishmaniasis, Chagas disease, and African sleeping disease1,2. Although rare, there are also several fatal protozoal diseases, mostly provoked by amoebae belonging to Naegleria fowleri, Acanthamoeba spp. and Balamuthia mandrillaris genera/species1. Few effective therapeutic approaches are available so far for treating most diseases provoked by protozoans1. Albeit all 12 protozoans genera which produce human disease are well studied by now, there are few drugs useful for treating them. Furthermore, these drugs have been available for many decades, generally show high toxicity and low therapeutic indexes, and more concerning, extensive resistance to these treatment options has developed in the last period1,2.
Epidemiology of free-living amoebae in the Philippines: a review and update
Published in Pathogens and Global Health, 2022
Giovanni D. Milanez, Frederick R. Masangkay, Gregorio L. Martin I, Ma. Frieda Z Hapan, Edilberto P. Manahan, Jeffrey Castillo, Panagiotis Karanis
Among the FLAs, the genera belonging to Naegleria, Acanthamoeba, Balamuthia, and Sappinia are considered by the World Health Organization (WHO) as medically important due to the morbidity or mortality reports in humans [16]. The route of cerebral infections for pathogenic FLA, in particular Naegleria spp., is initiated by the entry of the amoeba via the nasal cavity usually upon inhalation of contaminated water [17]. Upon reaching the brain via the cribriform plate, FLAs can mediate cytopathic effects resulting in the inflammation of the brain known as meningitis [18]. Depending on the FLA species or genotype and type of infection, conditions have been referred to as Primary Amoebic Meningoencephalitis (PAM) for Naegleria spp. infections [19], Granulomatous Amoebic Meningoencephalitis (GAE) for Acanthamoeba spp. infection [20], Balamuthia Amoebic Encephalitis (BAE) for Balamuthia mandrillaris infection, and Sappinia Amoebic Encephalitis (SAE) for Sappinia spp. infections [21]. Clinical conditions have almost equal morbidity to mortality ratio due to the rapid progression of the disease following the onset of symptoms [22]. Further, the symptoms presented by FLA-related meningitis mimic viral and bacterial forms, thus, making diagnosis and management of the disease challenging for clinicians and almost always leads to death [23]. Among the FLAs, pathogenic genotypes of Acanthamoeba spp. can inflict extra-cerebral infections like Acanthamoeba keratitis, and in rare cases, disseminated cutaneous infection [24–27].
Opportunistic free-living amoebal pathogens
Published in Pathogens and Global Health, 2022
Mohammad Ridwane Mungroo, Naveed Ahmed Khan, Sutherland Maciver, Ruqaiyyah Siddiqui
Pathogenic free-living amoebae, such as Acanthamoeba spp., Naegleria fowleri and Balamuthia mandrillaris, cause infection of the central nervous system (CNS) [1, 2]. The detection of brain-eating amoebae in drinking water supplies is of concern, which further indicates the severe threat posed by free-living amoebae to communities [3–6]. Furthermore, infection of the CNS with Acanthamoeba spp., Naegleria fowleri and Balamuthia mandrillaris almost always leads to mortality [7]. Moreover, cases of amoebic infection are under-reported worldwide, because of lack of awareness and diagnostic modalities, as well as misdiagnosis, due to similarity in symptoms, of amoebic infection of CNS to other common CNS infections such as bacterial meningitis, and thus, the true burden of cases due to these amoebae is unknown [8,9].