Emerging infections: mimickers of common patterns seen in dermatopathology

Potentially pathogenic free-living amoebae at very high altitude: Detection by multiplex qPCR in the Northern Altiplano fascioliasis hyperendemic area in Bolivia

Free-living amoebae (FLA), which are frequently found in the environment, include opportunistic pathogenic genera/species such as Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri and Vermamoeba vermiformis. These pathogenic FLA are causative agents of amoebic encephalitis and keratitis in the case of Acanthamoeba genus and V. vermiformis. In addition, amoebic infections are often related to contamination of domestic and recreational water sources. This study aimed to identify potentially pathogenic FLA in the hyperendemic area of human fascioliasis in a very-high-altitude area (3800-4100 m a.s.l.) of Bolivia and examine whether an association between both pathogens could be established from the environmental point of view. A total of 55 samples (28 soil and 27 water samples) were collected from various locations in the Northern Altiplano of Bolivia. Samples were processed by multiplex qPCR to detect the four pathogenic FLA genera/species. All samples were positive for the presence of V. vermiformis, followed by Acanthamoeba spp. which was positive in 18 soil and 10 water samples. In contrast, B. mandrillaris was only detected in soil sources, whereas N. fowleri was not detected in any of the samples. The coexistence and diverse distribution of multiple FLA species in many locations at such a high altitude is worth mentioning and indicates a potential risk of coinfections. These findings suggest that FLA surveillance is a crucial factor to be considered when implementing preventive measures and improving public health in fascioliasis hyperendemic areas.

Epidemiology of Buruli Ulcer in Victoria, Australia, 2017-2022

Buruli ulcer (BU) is a rare, neglected tropical disease caused by Mycobacterium ulcerans that can lead to severe skin ulcers. To determine the epidemiology of BU in Victoria, Australia, during 2017-2022 we analyzed surveillance data. A total of 1,751 cases of BU were notified; 968 (55%) patients were male and 781 (45%) female (2 were missing sex data), and 984 (56%) resided in established BU-endemic areas, although an increasing number were in new BU-endemic areas. Most cases (83%, 1,301) were classified as category I. Multivariate modeling demonstrated that factors for severe BU included being male, being older, and living in a new BU-endemic or non-BU-endemic area. A relatively shorter interval between first visit to a clinician and receipt of diagnosis was protective against severe disease. The expansion of BU-endemic areas throughout Victoria remains a public health concern and calls for targeted action, particularly for patients and clinicians in new BU-endemic areas.

18F-FDG PET/CT findings in fatal Balamuthia Mandrillaris encephalitis in brain stem: A case report

We presented a case of a 66-year-old female whose initial symptom was headache without obvious inducement. The patient's condition progressed rapidly to a semi-coma state after symptomatic treatment. The 18F-FDG PET/CT scan revealed circular FDG hypermetabolism and central metabolic defect of the pons and left frontal lobe lesions. The combination of clinical findings, MRI, and Metagenomic next-generation sequencing (NGS) of cerebrospinal fluid led to the diagnosis of Balamuthia mandrillaris encephalitis. The patient died 5 days after discharge.

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.