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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].
Sulfonamides
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
Natasha E. Holmes, M. Lindsay Grayson
Effective combination therapy including trimethoprim–sulfamethoxazole or sulfadiazine has been reported for Acanthameba cerebral abscess and meningoencephalitis (Singhal et al., 2001; Petry et al., 2006; Zamora et al., 2014), although there is no established treatment regimen or duration. Successful treatment, in conjunction with surgical excision, has also occurred in patients with liver transplantation (Fung et al., 2008) or AIDS (Seijo Martinez et al., 2000). Cutaneous acanthamebiasis has been treated with trimethoprim–sulfamethoxazole, diaminodiphenyl sulfone, and sulfadiazine (Steinberg et al., 2002; Paltiel et al., 2004; Gee et al., 2011). Survivors of Balamuthia amebic encephalitis have had treatment combinations including sulfadiazine, which has some amebicidal activity in vitro (Deetz et al., 2003; Jung et al., 2004; Tavares et al., 2006).
Laboratory Diagnosis of CNS Viral Infections
Published in Sunit K. Singh, Daniel Růžek, Neuroviral Infections, 2013
Alexander C. Outhred, Jen Kok, Dominic E. Dwyer
Parasites from the phylum Apicomplexa that should be considered in the differential diagnosis of encephalitis include Toxoplasma and Plasmodium sp. Toxoplasma gondii can cause mass lesions and encephalitis, particularly in immunocompromised (including HIV/AIDS) hosts. Although their pathological process is largely confined to the vasculature, Plasmodium sp. are worth emphasizing, as the global burden of malaria is huge, and early therapeutic intervention for cerebral malaria is critical. The major parasites from the phylum Euglenozoa that should be considered in the differential diagnosis are Trypanosoma sp., particularly T. brucei but also T. cruzi. Parasites from the phylum Amoebozoa that can cause encephalitis include Naegleriafowleri, Balamuthia mandrillaris, and Acanthamoeba sp. Helminths associated with encephalitis include Baylisascaris procyonis and Angiostrongylus cantonensis.
Epidemiology of free-living amoebae infections in Africa: a review
Published in Pathogens and Global Health, 2023
Giovanni D. Milanez, Karlo B. Carlos, Mary Erika Adao, Bernadette B Ayson, Ariela V. Dicon, Rhonette Anne M. Gahol, Sharmaine Kaye S. Lacre, Franchesca Pauline E. Marquez, April Jane M. Perez, Panagiotis Karanis
The World Health Organization (WHO) has named four important genera under this group considered to be pathogenic: Naegleria, which causes primary amoebic meningoencephalitis (PAM), Acanthamoeba causing granulomatous amoebic encephalitis (GAE), Balamuthia causing Balamuthia amoebic encephalitis (BAE), and Sappinia which causes Sappinia amoebic encephalitis (SAE). Acanthamoeba spp., however, is known to cause non-fatal Acanthamoeba keratitis (AK) infection [8]. The challenge for health practitioners in the case of FLA infection is the inability to provide a fast definitive diagnosis due to the rapid progression of the symptoms upon the onset of the disorder, and clinical features presented by FLA-caused meningitis are the same compared with bacterial and viral CNS infection. The Centers for Disease Control and Prevention (CDC) has declared that conditions from FLA-related infections as rare diseases, with only 34 documented cases from the last ten years (2010 to 2019) [9]. FLAs exist as free-living forms in the environment; it is highly pathogenic once it infects mammalian hosts. Despite its public health concerns: surveillance and epidemiologic report of cases have gone behind over the years in several countries [10,11].
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
Acanthamoeba spp. infect the CNS, causing granulomatous amoebic encephalitis (GAE), and can also cause a sight-threatening eye infection known as Acanthamoeba keratitis (AK) [10, 11, 12]. B. mandrillaris is known to instigate Balamuthia amoebic encephalitis (BAE) in the CNS and infect other organs such as the lungs and skin, in both immunocompetent and immunocompromised individuals [11]. N. fowleri infects the CNS, causing primary amoebic meningoencephalitis (PAM), triggering a prompt onset of disease and leading to death within days [11, 13]. Treatment of CNS infection with amoebae is complicated and hampered by the selectivity of the blood-brain barrier (BBB) that affects drug permeability into the brain. The purpose of this review is to briefly describe the epidemiology, presentation, diagnosis and management of CNS complications due to free-living amoeba and keratitis caused by pathogenic Acanthamoeba.