BACKGROUND: We report a case of prenatal coronavirus disease 2019, which evolved 6 days after birth into severe pneumonia with signs of multiple organ failure, in a mother with asymptomatic coronavirus disease 2019.
METHODS: At minute 11 of life, our patient from Afro-Caribbean had polypnea with mild signs of struggle; Silverman\'s index was scored at three. Chest radiography showed bilateral opacities consistent with respiratory distress syndrome. On the 6th day of life, a thoracic computed tomography scan showed bilateral parenchymatous lesions (10-20%) in ground glass, compatible with coronavirus disease 2019-type infection. At the same time, the neonate showed signs of multiple organ failure (elevated liver and cardiac enzyme levels). She was treated with azithromycin (20 mg/kg/day) for 5 days. All the signs recovered fully by day 12. Real-time polymerase chain reaction results were positive in the first 30 min of life, suggesting prenatal transmission. Our patient has been followed until 2 years old and is developing well with no sequelae.
CONCLUSIONS: This case report demonstrates the incompatibility between maternal asymptomatic coronavirus disease 2019 and severe neonatal lung involvement. We emphasize the need for vigilance to avoid missing the most severe forms of neonatal coronavirus disease 2019.

Coronavirus disease 2019 (COVID-19) has had significant impacts on mothers and neonates. In this report, we present four unique cases of COVID-19 infections in pregnancy and its effects on the mother, fetus, and placenta. Four mothers presented to the hospital during their pregnancy. Each had tested COVID-19-positive 1-29 days prior to admission. Gestational age ranged from 16 weeks six days to 36 weeks six days. Three of the four cases resulted in fetal demise or infant expiration. The common finding among all four cases was pathologic changes in the placenta. Most of the placentas were small for gestational age and had extensive villous infarction. There was also histiocytic intervillositis with villous necrosis and perivillous fibrin deposition. The placentas demonstrated positive staining of syncytiotrophoblasts for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike S1 subunit protein. SARS-CoV-2 RNA was detected in tissue samples of two of the fetuses demonstrating vertical transmission. A higher incidence of severe COVID-19 disease course has been observed in pregnant women. Prior to the SARS-CoV-2 pandemic, chorionic histiocytic intervillositis of the placenta was rarely seen, and mostly of unknown etiology. The increase in placental fibrin levels results in decreased maternal placenta blood flow ensuing hypoxic stress in the fetus. Intrauterine hypoxia has been associated with alterations in brain structure and function resulting in defects in motor skills, cerebral palsy, decreased brain weight, schizophrenia, and other forms of cognitive impairment.

Vertebrates evolved in concert with bacteria and have developed essential mutualistic relationships. Gut bacteria are vital for the postnatal development of most organs and the immune and metabolic systems and may likewise play a role during prenatal development. Prenatal transfer of gut bacteria is shown in four mammalian species, including humans. For the 92% of the vertebrates that are oviparous, prenatal transfer is debated, but it has been demonstrated in domestic chicken. We hypothesize that also non-domestic birds can prenatally transmit gut bacteria. We investigated this in medium-sized Rock pigeon (Columba livia), ensuring neonates producing fair-sized first faeces. The first faeces of 21 neonate rock pigeons hatched in an incubator, contained a microbiome (bacterial community) the composition of which resembled the cloacal microbiome of females sampled from the same population (N = 5) as indicated by multiple shared phyla, orders, families, and genera. Neonates and females shared 16.1% of the total number of OTUs present (2881), and neonates shared 45.5% of their core microbiome with females. In contrast, the five females shared only 0.3% of the 1030 female OTUs present. These findings suggest that prenatal gut bacterial transfer may occur in birds. Our results support the hypothesis that gut bacteria may be important for prenatal development and present a heritability pathway of gut bacteria in vertebrates.