A previously healthy young female of Southeast Asian descent presented with a two-week history of polyarthritis, urticarial rash, sore throat, and 8.6 kg of unintentional weight loss. The initial workup revealed a positive parvovirus B19 polymerase chain reaction with hyperferritinemia. The patient was diagnosed with adult-onset Still\'s disease (AOSD) secondary to parvovirus B19 infection. Bone marrow biopsy also showed evidence of hemophagocytic lymphohistiocytosis. Viral and bacterial infections may trigger AOSD in genetically susceptible hosts either via an unknown mechanism or by direct cytotoxic effect. This case shows an atypical presentation of AOSD, as well as the challenge in diagnosing and treating AOSD complicated by macrophage activation syndrome refractory to standard treatment.

Myocarditis (MC) is defined as an immunological inflammatory reaction with various etiologies, clinical presentations and prognoses within the myocardium. Currently, parvovirus B19 (PVB19) has become the main factor leading to this disease, replacing the previously dominant viruses A and B. In the case of chronic heart failure with subsequent dilated cardiomyopathy, approximately 67% have a viral etiology, and most of them are the result of PVB19 infection. However, the analysis showed a correlation between PVB19 infection and the risk of developing inflammatory dilated cardiomyopathy (DCMi). PVB19 is detected in 23% of patients with DCMi. Chronic infection may also contribute to progressive left ventricular failure in patients with a history of MC. The above effect suggests the active replication of PVB19 only in heart biopsies with inflammation due to MC or DCMi. Moreover, the supply of IFN-β to suppress the active transcription of PVB19 accompanied by DCMi over a period of 6 months results in the normalization of NT-proBNP and an improvement in LVEF along with NYHA performance. The small number of reports on this topic and inaccuracies resulting from constantly conducted research and ongoing changes make it impossible to clearly answer the question of whether PVB19 is a factor inducing de novo MC and DCM or only accompanies the above conditions. However, large clinical cohort studies lead to the perception of PVB19 as a viral etiological agent capable of causing de novo MC together with DCMi.

Human parvovirus B19 (B19V), like most parvoviruses, possesses phospholipase A2 (PLA2) activity, which is thought to mediate endosomal escape by membrane disruption. Here, we challenge this model and find evidence for a mechanism of B19V entry mediated by the glycosphingolipid globoside without endosome disruption and retrograde transport to the Golgi. We show that B19V PLA2 activity requires specific calcium levels and pH conditions that are not optimal in endosomes. Accordingly, endosomal membrane integrity was maintained during B19V entry. Furthermore, endosomes remained intact when loaded with MS2 bacteriophage particles pseudotyped with multiple B19V PLA2 subunits, providing superior enzymatic potential compared to native B19V. In globoside knockout cells, incoming viruses are arrested in the endosomal compartment and the infection is blocked. Infection can be rescued by promoting endosomal leakage with polyethyleneimine (PEI), demonstrating the essential role of globoside in facilitating endosomal escape. Incoming virus colocalizes with Golgi markers and interfering with Golgi function blocks infection, suggesting that globoside-mediated entry involves the Golgi compartment, which provides conditions favorable for the lipolytic PLA2. Our study challenges the current model of B19V entry and identifies globoside as an essential intracellular receptor required for endosomal escape.

UNASSIGNED: Intrauterine transfusion is the treatment for fetal anemia resulting from maternal alloimmunization, infections (parvovirus B19 and cytomegalovirus), single demise of a monochorionic twin, chorioangioma, and other rare conditions. Fetal analgesia is mandatory to reduce movement and pain perception during the procedure. This study aims to evaluate perinatal outcomes for such procedures, following the routine use of fetal analgesia in our clinical practice.
UNASSIGNED: Retrospective analysis of cases from 2009 to 2022, including all confirmed fetal anemia with fetal blood sampling. After fetal analgesia, Rh-negative concentrated red blood cells were transfused, with ultrasonographic follow-up 24 h and 1 week later. In case of suspected brain lesion, magnetic resonance imaging was performed. Elective delivery was considered in case of persistent anemia after 34 weeks. Post-natal follow-up and comprehensive obstetric and perinatal outcomes data were collected.
UNASSIGNED: Altogether 59 anemic fetuses were included, with 34 (57.6%) being hydropic. The causes of anemia were maternal alloimmunization (22, 37.3%), infections (13, 22%), monochorionicity (10, 16.9%), rare conditions (9, 15.3%), and two chorioangiomas (3.4%). The median gestational age at the procedure was 25.2 weeks (18-32 weeks), with no related preterm premature rupture of membranes (<48 h), or side effects from fetal analgesia. Gestational age at delivery was 33 weeks (26-41 weeks), with survival rate of 90%. There were four fetal demises, two termination of pregnancies, and eight neonatal deaths due to persistent severe anemia after preterm delivery. The main contributors to adverse outcome were the type of anemia, and the management with a preterm delivery.
UNASSIGNED: Intrauterine transfusion of red blood cells under analgesia is safe, with low incidence of obstetric complication.

UNASSIGNED: Human Erythrovirus (parvovirus) B19 infection can produce symptoms similar to those produced by Dengue, Chikungunya, and Zika viruses, making clinical diagnosis difficult. The importance of erythrovirus B19 in human pathology has been increased and reported in numerous studies published globally.
UNASSIGNED: The B19V infection was investigated by real-time PCR in sera samples from patients with signs and symptoms related to classic arboviral symptoms. This study was conducted to provide information on the genetic diversity of Human Erythrovirus B19 (B19V) circulating in the state of Mato Grosso do Sul, Midwest region of Brazil, from 2017 to 2022. A total of 773 sera samples of patients with negative diagnostic results for Dengue, Chikungunya, and Zika, during the study period were analyzed.
UNASSIGNED: Erythrovirus DNA was found in 10.6% (82/773) of patients, among them 10 were pregnant women. Four samples were completely sequenced, and the other five partially, to genotype by phylogenetic reconstruction. All samples belong to worldwide dispersed genotype 1, subgenotype 1a.
UNASSIGNED: The findings of the study demonstrate the importance of including B19V in differential laboratory diagnosis for epidemiological purposes and appropriate patient management. The diagnosis for B19V should be performed, particularly among pregnant women, immunocompromised patients, and individuals with hemolytic diseases, given that the infection is more severe in these cases.

Parvovirus B19 infection, typically associated with erythema infectiosum in children, presents variably in adults, often leading to misdiagnosis. This case series describes three adult patients diagnosed with parvovirus B19 infection in an internal medicine outpatient clinic in March 2024. Symptoms included fatigue, joint pain, swelling, and skin rash, with misdiagnoses including early rheumatoid arthritis. The diagnosis was confirmed via positive parvovirus antibodies and polymerase chain reaction (PCR). All patients received supportive care, and symptoms resolved within an average of 18 days. This series underscores the need for heightened clinical suspicion and timely serological testing for parvovirus B19 in adults presenting with flu-like symptoms, joint pain, and rash, especially during mini-outbreaks and following contact with infected children.

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From April 2023 to May 2024, an unusual epidemic of parvovirus B19 (B19V) infections occurred in France. The number of B19V IgM-positive serologies was four times higher than in the previous epidemic in 2019. Clinical data from emergency networks corroborated this observation. Morbidity and mortality consequences were observed in children through all data sources. In adults, the increase was only observed in laboratory-confirmed data. Physicians and decisionmakers should be informed in order to better prevent, diagnose and manage at-risk patients.

Parvovirus B19 (B19V) is a human pathogen that is the causative agent of several diseases in infants and adults. Due to a lack of antivirals against this virus, treatment options are limited. The minor capsid protein of B19V has a unique N terminus, named VP1u, which is essential for infection. The VP1u encodes a receptor binding domain (RBD), necessary for host cell entry, and a phospholipase A2 (PLA2) domain, crucial for endosomal escape during cellular trafficking. Both domains are indispensable for infection, making the RBD a plausible drug target for inhibitors against B19V, as it is located on the exterior surface of the virus. To date, no experimental structural information has been available for the VP1u component for any Parvovirus. Here we report the backbone NMR resonance assignments for the RBD of B19V and demonstrate it forms a stable structure. The backbone chemical shifts are in good agreement with a structure predicted by AlphaFold, validating that the RBD contains three helices connected by tight turns. This RBD construct can now be used for further NMR studies, including assignment of full-length VP1u, determination of protein-protein interaction interfaces, and development of B19 antivirals specific to the RBD domain. Database: BMRB submission code: 52440.

We report an epidemic of parvovirus B19 infections in Denmark during the first quarter of 2024, with a peak incidence 3.5 times higher than during the most recent epidemic in 2017. In total, 20.1% (130/648) of laboratory-confirmed cases were pregnant. Severe adverse outcomes were observed among 12.3% (16/130) of pregnant people and included foetal anaemia, foetal hydrops and miscarriage. Parvovirus B19 infection is not systematically monitored, but a national laboratory-based surveillance system is currently being established in Denmark.