A Meta-Analysis on the Seroprevalence of Parvovirus B19 among Patients with Sickle Cell Disease

The Aplastic Crisis in HbSS: Observations from the Jamaican Birth Cohort

In order to document the prevalence, clinical features, hematology and outcome of the aplastic crisis in homozygous sickle cell disease (HbSS), a cohort study has been conducted from birth. Newborn screening of 100 000 deliveries at the main government maternity hospital, Kingston, Jamaica between 1973 and 1981 detected 311 cases of HbSS who have been followed at the Medical Research Council Laboratories at the University of the West Indies, Kingston, Jamaica. Clinically defined aplastic crises occurred in 118 (38%) patients at a median age of 7.5 years (range 0.5-23.0 years). All but one event seroconverted to parvovirus B19, the exception being a 9.3 year male with classic aplasia but subsequent IgG did not exceed 3 IU. Defined by zero reticulocyte counts, 94 patients presented with a median hemoglobin of 3.7 g/dL (range 18-87 g/L) representing a median fall from steady state levels of 3.8 g/dL. Clear epidemic peaks occurred at 1979-1980, 1984-1986, and 1990-1993 and the admission rate and use of blood cultures fell with each epidemic, reflecting increased familiarity with the complication. Symptoms were usually nonspecific and all but 7 were transfused. No patient had a recurrence and two died from aplasia (one with remote rural residence and the other following an incorrect diagnosis). Of those seroconverting to parvovirus B19, 68% manifested aplasia and 24% had no hematologic change. Correctly diagnosed and managed, the aplastic crisis is essentially benign. (230 words).

Parvovirus B19 Infection and Pregnancy: Review of the Current Knowledge

Parvovirus B19, a member of the Parvoviridae family, is a human pathogenic virus. It can be transmitted by respiratory secretions, hand-to-mouth contact, blood transfusion, or transplacental transmission. Most patients are asymptomatic or present with mild symptoms such as erythema infectiosum, especially in children. In rare cases, moderate-to-severe symptoms may occur, affecting blood cells and other systems, resulting in anemia, thrombocytopenia, and neutropenia. Non-immune pregnant women are at risk for fetal infection by parvovirus B19, with greater complications if transmission occurs in the first or second trimester. Infected fetuses may not show any abnormalities in most cases, but in more severe cases, there may be severe fetal anemia, hydrops, and even pregnancy loss. Maternal diagnosis of intrauterine parvovirus B19 infection includes IgG and IgM antibody testing. For fetal diagnosis, PCR is performed through amniocentesis. In addition to diagnosing the infection, it is important to monitor the peak of systolic velocity of the middle cerebral artery (PVS-MCA) Doppler to assess the presence of fetal anemia. There is no vaccine for parvovirus B19, and fetal management focuses on detecting moderate/severe anemia by fetal PVS-MCA Doppler, which, if diagnosed, should be treated with intrauterine transfusion by cordocentesis. Prevention focuses on reducing exposure in high-risk populations, particularly pregnant women.

Towards the Antiviral Agents and Nanotechnology-Enabled Approaches Against Parvovirus B19

Parvovirus B19 (B19V) as a human pathogenic virus, would cause a wide range of clinical manifestations. Besides the supportive and symptomatic treatments, the only FDA-approved antiviral drug for the treatment of B19V is intravenous immunoglobulins, which however, have limited efficacy and high cost. By far, there are still no virus-specific therapeutics clinically available to treat B19V infection. Therefore, exploiting the potential targets with a deep understanding of the life cycle of B19V, are pivotal to the development of B19V-tailored effective antiviral approaches. This review will introduce antiviral agents via blocking viral invasion, inhibiting the enzymes or regulatory proteins involved in DNA synthesis, and so on. Moreover, nanotechnology-enabled approaches against B19V will also be outlined and discussed through a multidisciplinary perspective involving virology, nanotechnology, medicine, pharmaceutics, chemistry, materials science, and other fields. Lastly, the prospects of the antiviral agents and nanosystems in terms of fabrication, clinical translation and potential breakthroughs will be briefly discussed.

Fifteen-minute consultation: Recognition of sickle cell crises in the paediatric emergency department

Children with sickle cell disease can develop life-threatening and painful crises that require prompt assessment and efficient management by healthcare professionals in the emergency or acute care setting. Due to migration patterns and improved survival rates in high-prevalence countries, there is an increased tendency to encounter these patients across the UK. These factors warrant regular revisions in sickle cell crisis management, along with education for medical personnel and patients to improve clinical care and patient management. The focus of this article is on the initial assessment and management of acute paediatric sickle cell complications in the emergency setting. Specific case studies, including acute pain crises, trauma, splenic sequestration, aplastic crises, acute chest syndrome, infection, avascular necrosis, osteomyelitis and stroke, are discussed. Due to the current COVID-19 pandemic, we have also reviewed specific concerns around this patient group.

Association of parvovirus B19 and myocarditis/dilated cardiomyopathy: A systematic review and meta-analysis

BACKGROUND

The potential association between Parvovirus B19 and heart disease has been controversial. The aim of the present study was to report the prevalence of B19 in myocarditis and dilated cardiomyopathy (DCM) as well as measure the statistical association between them.

METHODS

Our systematic search was carried out to retrieve published articles between January 2000 and March 2021 using three major databases: PubMed, Scopus, and Web of Science, as well as the Google Scholar search engine. The overall prevalence of HAV, pooled odds ratio, and heterogeneity were estimated by comprehensive meta-analysis (V2.2, Biostat) software.

RESULTS

The overall prevalence results in myocarditis and DCM were 23.7% (95% CI: 18.7%-29.5%) and 34.1% (95% CI: 23.8%-46.1%) respectively; in addition, the overall OR for B19 and myocarditis was 4.317 (95% CI, 1.831-10.180) versus 1.163 (95% CI: 0.706-1.916) for B19 and DCM.

CONCLUSION

Our findings have shown a significant association between Parvovirus B19 and myocarditis with a high prevalence. In the case of DCM, no significant association was found while the prevalence of the virus was relatively high.

Enhanced Cell-Based Detection of Parvovirus B19V Infectious Units According to Cell Cycle Status

Human parvovirus B19 (B19V) causes various human diseases, ranging from childhood benign infection to arthropathies, severe anemia and fetal hydrops, depending on the health state and hematological status of the patient. To counteract B19V blood-borne contamination, evaluation of B19 DNA in plasma pools and viral inactivation/removal steps are performed, but nucleic acid testing does not correctly reflect B19V infectivity. There is currently no appropriate cellular model for detection of infectious units of B19V. We describe here an improved cell-based method for detecting B19V infectious units by evaluating its host transcription. We evaluated the ability of various cell lines to support B19V infection. Of all tested, UT7/Epo cell line, UT7/Epo-STI, showed the greatest sensitivity to B19 infection combined with ease of performance. We generated stable clones by limiting dilution on the UT7/Epo-STI cell line with graduated permissiveness for B19V and demonstrated a direct correlation between infectivity and S/G2/M cell cycle stage. Two of the clones tested, B12 and E2, reached sensitivity levels higher than those of UT7/Epo-S1 and CD36⁺ erythroid progenitor cells. These findings highlight the importance of cell cycle status for sensitivity to B19V, and we propose a promising new straightforward cell-based method for quantifying B19V infectious units.