The lack of routine surveillance of Parvovirus B19 infection in pregnancy prevents an accurate understanding of this regular cause of fetal loss and the risks posed by occupational exposure

Parvovirus B19 remains an underestimated pathogen among infections during gestation in Argentina: Insights through the study of symptomatic and asymptomatic pregnant patients and newborns from Córdoba

BACKGROUND

Parvovirus B19 (B19 V) infection during pregnancy can cause adverse fetal outcomes. Our aim was to characterize both clinical and asymptomatic maternal and neonatal cases by studying virological and serological markers of B19 V infection, and to sequence the complete genome of the circulating virus in Argentina.

METHODS

Symptomatic patients were included based on maternal and/or fetal-neonatal signs attributable to B19 V infection during gestation. Pregnant patients were analyzed in either the timely diagnosis group (TD, samples obtained when symptoms were present and infection was suspected) or the retrospective diagnosis group (RD, samples collected immediately postpartum), and newborns were analyzed at birth. A sample of asymptomatic individuals was also analyzed. Diagnostic tests (PCR/qPCR/serology) and sequencing were performed on archived serum samples from 2018 to 2023, and clinical data were obtained from medical records.

RESULTS

We studied 328 symptomatic patients, including 185 pregnant patients (73 TD and 112 RD) and 143 newborns. Among them, we identified 27/328 (8.2 %) positive cases (B19V+): 12/73 (16.4 %) in the TD group, 6/112 (5.4 %) in the RD group, and 9/143 (6.3 %) newborns. Within the 77 mother-newborn pairs included, there were 8 (10.4 %) B19 V infections and 6 cases of vertical transmission. Additionally, B19 V infection was detected in 26/310 (8.4 %) asymptomatic patients. Phylogenetic analysis identified genotype 1a as a circulating strain in Argentina.

CONCLUSIONS

Our findings highlight the need to raise awareness and enhance diagnostic approaches in Argentina to more effectively identify and manage B19 V infections during pregnancy in our region.

Human parvovirus B19 infection in a pregnant patient resulting in severe hydrops, foetal death and persistent infection

Human parvovirus B19 (B19V) is the aetiological agent of erythema infectiosum. Primary infection during pregnancy can be transmitted to the foetus and cause foetal abnormalities related to depletion of erythrocyte progenitor cells, including congenital anaemia, hydrops, and foetal death. In this paper we report the detection of B19V infection in a pregnant patient, which onset occurred without appreciable signs and symptoms until she developed inappropriate contractions for gestational age and fluid loss. B19V infection resulted in severe hydrops fetalis with a fatal course for the foetus, while persisted in the mother at least 12 months after foetal death. The objective of this report is to highlight the importance of optimizing B19V diagnosis through early suspicion and testing during pregnancy. Knowing the mother’s immune status before or at the beginning of gestation can contribute, together with early diagnosis, to improve the management of patients at risk.

Congenital Viral Infection: Traversing the Uterine-Placental Interface

Why certain viruses cross the physical barrier of the human placenta but others do not is incompletely understood. Over the past 20 years, we have gained deeper knowledge of intrauterine infection and routes of viral transmission. This review focuses on human viruses that replicate in the placenta, infect the fetus, and cause birth defects, including rubella virus, varicella-zoster virus, parvovirus B19, human cytomegalovirus (CMV), Zika virus (ZIKV), and hepatitis E virus type 1. Detailed discussions include ( a) the architecture of the uterine-placental interface, ( b) studies of placental explants ex vivo that provide insights into the infection and spread of CMV and ZIKV to the fetal compartment and how these viruses undermine early development, and ( c) novel treatments and vaccines that limit viral replication and have the potential to reduce dissemination, vertical transmission and the occurrence of congenital disease.

Parvovirus B19 infection in pregnancy-awareness and opportunities

Parvovirus B19 (B19V) is a human pathogenic virus associated with a wide range of clinical conditions. In pregnancy, B19V poses a potential hazard to the fetus as crossing the placental barrier and infecting erythroid progenitor cells in bone marrow and liver, it blocks fetal erythropoiesis leading to profound anemia, hydrops and/or fetal death. The virus is not regarded as a teratogen, however more scientific awareness is emerging on mechanisms and consequences of intrauterine infection and possible sequelae in the neonatal development. Reliable diagnostic procedures and fetal management strategies, including intrauterine transfusion, are established. In spite of being a recognized fetotropic agent possibly leading to fetal loss, testing for B19V is not routinely included in preconception or antenatal screenings, possibly delaying the management of B19V-complicated pregnancies. Continuous advances in B19V research will provide for better diagnostic methods and algorithms, as well as for the development of effective prophylactic interventions and novel therapeutic options.

Human Parvoviruses

Parvovirus B19 (B19V) and human bocavirus 1 (HBoV1), members of the large Parvoviridae family, are human pathogens responsible for a variety of diseases. For B19V in particular, host features determine disease manifestations. These viruses are prevalent worldwide and are culturable in vitro, and serological and molecular assays are available but require careful interpretation of results. Additional human parvoviruses, including HBoV2 to -4, human parvovirus 4 (PARV4), and human bufavirus (BuV) are also reviewed. The full spectrum of parvovirus disease in humans has yet to be established. Candidate recombinant B19V vaccines have been developed but may not be commercially feasible. We review relevant features of the molecular and cellular biology of these viruses, and the human immune response that they elicit, which have allowed a deep understanding of pathophysiology.

The role of infection in miscarriage

BACKGROUND

Miscarriage is the spontaneous loss of a pregnancy before 12 weeks (early miscarriage) or from 12 to 24 weeks (late miscarriage) of gestation. Miscarriage occurs in one in five pregnancies and can have considerable physiological and psychological implications for the patient. It is also associated with significant health care costs. There is evidence that potentially preventable infections may account for up to 15% of early miscarriages and up to 66% of late miscarriages. However, the provision of associated screening and management algorithms is inconsistent for newly pregnant women. Here, we review recent population-based studies on infections that have been shown to be associated with miscarriage.

METHODS

Our aim was to examine where the current scientific focus lies with regards to the role of infection in miscarriage. Papers dating from June 2009 with key words 'miscarriage' and 'infection' or 'infections' were identified in PubMed (292 and 327 papers, respectively, on 2 June 2014). Relevant human studies (meta-analyses, case-control studies, cohort studies or case series) were included. Single case reports were excluded. The studies were scored based on the Newcastle - Ottawa Quality Assessment Scale.

RESULTS

The association of systemic infections with malaria, brucellosis, cytomegalovirus and human immunodeficiency virus, dengue fever, influenza virus and of vaginal infection with bacterial vaginosis, with increased risk of miscarriage has been demonstrated. Q fever, adeno-associated virus, Bocavirus, Hepatitis C and Mycoplasma genitalium infections do not appear to affect pregnancy outcome. The effects of Chlamydia trachomatis, Toxoplasma gondii, human papillomavirus, herpes simplex virus, parvovirus B19, Hepatitis B and polyomavirus BK infections remain controversial, as some studies indicate increased miscarriage risk and others show no increased risk. The latest data on rubella and syphilis indicate increased antenatal screening worldwide and a decrease in the frequency of their reported associations with pregnancy failure. Though various pathogens have been associated with miscarriage, the mechanism(s) of infection-induced miscarriage are not yet fully elucidated.

CONCLUSIONS

Further research is required to clarify whether certain infections do increase miscarriage risk and whether screening of newly pregnant women for treatable infections would improve reproductive outcomes.

Epidemiological investigation of risk factors of the pregnant women with early spontaneous abortion in Beijing

OBJECTIVE

To determine the risk factors of the pregnant women with early spontaneous abortion in Beijing.

METHODS

A total of 34,417 cases of pregnant women were participated in the survey from January 2000 to December 2013. A questionnaire was informed to each woman. The content of questionnaire includes four parts: general condition, obstetrical history, past history and family history, and living environment and habits. The mental condition was evaluated with Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS).

RESULTS

A total of 32,296 questionnaires were collected. The spontaneous abortion rate in the total sample was 3.0%. There was no significant difference between the normal pregnancy group and spontaneous abortion group in terms of general condition, obstetrical and past history (P>0.05). Significant differences between the two groups were found in terms of decoration during pregnancy, keeping pets, near mobile communication base station within 100 m around the residence, drinking during pregnancy, having a cold during pregnancy and SAS (P<0.05). Having a cold during pregnancy, decoration during pregnancy, near mobile communication base station within 100 m around the residence, keeping pets and high SAS were determined the independent risk factors of spontaneous abortion by Logistic regression analysis.

CONCLUSIONS

Having a cold during pregnancy, decoration, keeping pets, near mobile communication base station within 100 m around the residence and high SAS are the independent risk factors of spontaneous abortion in Beijing.