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

Abstract

Background: Parvovirus B19 (B19 V) infection during pregnancy can cause adverse fetal outcomes. Our aim wasto characterize both clinical and asymptomatic maternal and neonatal cases by studying virological and serologicalmarkers 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 B19V infection during gestation. Pregnant patients were analyzed in either the timely diagnosis group (TD, samplesobtained 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 asymptomaticindividuals was also analyzed. Diagnostic tests (PCR/qPCR/serology) and sequencing were performed onarchived 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 143newborns. 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 wasdetected in 26/310 (8.4 %) asymptomatic patients. Phylogenetic analysis identified genotype 1a as a circulatingstrain in Argentina.Conclusions: Our findings highlight the need to raise awareness and enhance diagnostic approaches in Argentinato more effectively identify and manage B19 V infections during pregnancy in our region.