RESUMEN
During the first half of 2022, the World Health Organization reported an outbreak of acute severe hepatitis of unknown aetiology (AS-Hep-UA) in children, following initial alerts from the United Kingdom (UK) where a cluster of cases was first observed in previously well children aged <6 years. Sporadic cases were then reported across Europe and worldwide, although in most countries incidence did not increase above the expected baseline. There were no consistent epidemiological links between cases, and microbiological investigations ruled out known infectious causes of hepatitis. In this review, we explore the evidence for the role of viral infection, superimposed on a specific host genetic background, as a trigger for liver pathology. This hypothesis is based on a high prevalence of Human Adenovirus (HAdV) 41F in affected children, together with metagenomic evidence of adeno-associated virus (Adeno-associated viruses)-2, which is a putative trigger for an immune-mediated liver injury. Roles for superantigen-mediated pathology have also been explored, with a focus on the potential contribution of SARS-CoV-2 infection. Affected children also had a high frequency of the MHC allele HLA-DRB1*04:01, supporting an immunological predisposition, and may have been vulnerable to viral coinfections due to disruption in normal patterns of exposure and immunity as a result of population lockdowns during the COVID-19 pandemic. We discuss areas of ongoing uncertainty, and highlight the need for ongoing scrutiny to inform clinical and public health interventions for this outbreak and for others that may evolve in future.
RESUMEN
With over 40 years of history, occult hepatitis B infection (OBI) continues to remain an important and challenging public health problem. Defined as the presence of replication-competent hepatitis B virus (HBV) DNA (i.e., episomal HBV covalently closed circular DNA) in the liver and/or HBV DNA in the blood of people who test negative for hepatitis B surface antigen (HBsAg) in currently available assays, OBI is currently diagnosed using polymerase chain reaction (PCR) and real-time PCR assays. However, all efforts should be made to exclude a false negative HBsAg in order to completely follow the definition of OBI. In recent years, significant advances have been made in understanding the HBV lifecycle and the molecular mechanisms that lead to the persistence of the virus in the occult form. These factors are mainly related to the host immune system and, to a smaller proportion, to the virus. Both innate and adaptive immune responses are important in HBV infection management, and epigenetic changes driven by host mechanisms (acetylation, methylation, and microRNA implication) are added to such actions. Although greater genetic variability in the S gene of HBV isolated from OBIs was found compared with overt infection, the mechanisms of OBI are not mainly viral mutations.
RESUMEN
COVID-19 has proven to be an independent risk factor for secondary infectious complications. Amongst them, mucormycosis has recently been noticed more frequently than in the past. Caused by molds belonging to the Mucorales order, this is a rare, but potentially fatal infection unless adequately treated. Ear, nose and throat involvement is prevalent with often expansion to the orbit, sinuses or brain. Pulmonary, cutaneous and gastrointestinal infections are also recognized. Classical risk factors for progression to angioinvasive disease include poorly controlled diabetes mellitus, defects in phagocytic function (prolonged neutropenia, glucocorticoid treatment), immunosuppressive therapy associated with transplantation, malignancy, elevated levels of free iron as well as iron chelators (deferoxamine). In addition, immune dysregulation rendered by COVID-19 itself may contribute or solely lead to invasive mold disease. The largest experience comes from India, which has dealt with a challenging epidemic of COVID-19-associated mucormycosis (CAM). To our knowledge, no previous studies have reported CAM in Romania. We therefore present a case of severe COVID-19 pneumonia initially complicated by bacterial superinfection and secondary sepsis at admission in an unvaccinated 61-year-old male who presented in our clinic with respiratory failure and digestive symptoms. Although improvement occurred rapidly following antiviral, empiric large spectrum Intraantibiotics and pathogenic medication, unfavorable clinical course ensued later on. Biological and imaging investigations were consistent with pulmonary superinfection in the form of multiple different-sized upper right field opacities, which eventually evolved to form cavities. Differential diagnosis was thoroughly performed. Since unable to sterilize the lung by means of medication alone, the patient underwent major thoracic surgery with removal of the entire right lung. Microscopic study of the damaged tissue was able to determine the presence of broad, aseptate hyphae which morphologically belong to Mucorales. A diagnosis of pulmonary mucormycosis was established and proper antifungal treatment was initiated, with full recovery of the patient.
