Probable vertical transmission of Alpha variant of concern (B.1.1.7) with evidence of SARS-CoV-2 infection in the syncytiotrophoblast, a case report.

Introduction: Definitive vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection has been rarely reported. We present a case of a third trimester pregnancy with fetal distress necessitating cesarean section that demonstrated maternal, placental, and infant infection with the SARS-CoV-2 Alpha variant/B.1.1.7. Methods: CDC's Influenza SARS-CoV-2 Multiplex RT-PCR Assay was used to test for SARS-CoV-2 in a maternal NP swab, maternal plasma, infant NP swab, and formalin-fixed paraffin-embedded (FFPE) placental tissue specimens. Whole genome sequencing (WGS) was performed on maternal plasma, infant, and placental specimens to determine the SARS-CoV-2 genotype. Histopathological evaluation, SARS-CoV-2 immunohistochemistry testing (IHC), and electron microscopy (EM) analysis were performed on placenta, umbilical cord, and membrane FFPE blocks. Results: All specimens tested positive for SARS-CoV-2 by RT-PCR. WGS further revealed identical SARS-CoV-2 sequences from clade 20I/501Y.V1 (lineage Alpha/B.1.1.7) in maternal plasma, infant, and placental specimens. Histopathologic evaluation of the placenta showed histiocytic and neutrophilic intervillositis with fibrin deposition and trophoblast necrosis with positive SARS-CoV-2 immunostaining in the syncytiotrophoblast and electron microscopy evidence of coronavirus. Discussion: These findings suggest vertical transmission of SARS-CoV-2, supported by clinical course timing, identical SARS-CoV-2 genotypes from maternal, placental, and infant samples, and IHC and EM evidence of placental infection. However, determination of the timing or distinction between prepartum and peripartum SARS-CoV-2 transmission remains unclear.

Probable vertical transmission of Alpha variant of concern (B.1.1.7) with evidence of SARS-CoV-2 infection in the syncytiotrophoblast, a case report

Introduction Definitive vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection has been rarely reported. We present a case of a third trimester pregnancy with fetal distress necessitating cesarean section that demonstrated maternal, placental, and infant infection with the SARS-CoV-2 Alpha variant/B.1.1.7. Methods CDC's Influenza SARS-CoV-2 Multiplex RT-PCR Assay was used to test for SARS-CoV-2 in a maternal NP swab, maternal plasma, infant NP swab, and formalin-fixed paraffin-embedded (FFPE) placental tissue specimens. Whole genome sequencing (WGS) was performed on maternal plasma, infant, and placental specimens to determine the SARS-CoV-2 genotype. Histopathological evaluation, SARS-CoV-2 immunohistochemistry testing (IHC), and electron microscopy (EM) analysis were performed on placenta, umbilical cord, and membrane FFPE blocks. Results All specimens tested positive for SARS-CoV-2 by RT-PCR. WGS further revealed identical SARS-CoV-2 sequences from clade 20I/501Y.V1 (lineage Alpha/B.1.1.7) in maternal plasma, infant, and placental specimens. Histopathologic evaluation of the placenta showed histiocytic and neutrophilic intervillositis with fibrin deposition and trophoblast necrosis with positive SARS-CoV-2 immunostaining in the syncytiotrophoblast and electron microscopy evidence of coronavirus. Discussion These findings suggest vertical transmission of SARS-CoV-2, supported by clinical course timing, identical SARS-CoV-2 genotypes from maternal, placental, and infant samples, and IHC and EM evidence of placental infection. However, determination of the timing or distinction between prepartum and peripartum SARS-CoV-2 transmission remains unclear.

Autopsy Histopathologic Cardiac Findings in 2 Adolescents Following the Second COVID-19 Vaccine Dose/In Reply

The authors correctly stated that the Centers for Disease Control and Prevention (CDC) performed testing for SARS-CoV-2 and found no evidence of SARS-CoV-2 infection in autopsy tissues from the decedents. Molecular analysis included polymerase chain reaction (PCR) assays on nucleic acid extracted from FFPE heart tissue, including SARS-CoV-2 and enterovirus reverse transcriptase PCR (RT-PCR) assays2,3 and conventional PCR for parvovirus B19. Clostridium septicum produces multiple toxins that cause necrosis of striated muscle cells9,11 and inhibit influx of neutrophils to infected tissues;indeed, paucity of neutrophilic infiltrates in tissues infected with C septicum is considered a hallmark of this disease.9,12 Clostridium septicum is not considered normal flora of the human intestinal tract,13,14 but rather an opportunistic invader of immunologically compromised hosts, particularly persons with colonic adenocarcinoma, leukemia, diabetes, bowel ischemia, or cyclic, congenital, or acquired neutropenia.7,8 Spontaneous infections have been described for a few pediatric patients with no recognized risk factor and for whom microscopic breaches in the mucosa of the large intestine were considered the likely portal of entry.8,15 No representative samples of the small or large intestine were provided to the IDPB for evaluation;however, histologic evidence of bacterial invasion of the external surfaces of the adrenals, kidneys, liver, and spleen support an intraabdominal source of infection. The findings and conclusions in this letter are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. doi: 10.5858/arpa.2022-0084-LE In Reply.-We thank the Centers for Disease Control and Prevention's (CDC's) Infectious Diseases Pathology Branch laboratory for performing these tests and for sharing the full extent of its workup.

Histopathology and localization of SARS-CoV-2 and its host cell entry receptor ACE2 in tissues from naturally infected US-farmed mink (Neovison vison).

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes respiratory disease in mink similar to human COVID-19. We characterized the pathological findings in 72 mink from US farms with SARS-CoV-2 outbreaks, localized SARS-CoV-2 and its host cellular receptor angiotensin-converting enzyme 2 (ACE2) in mink respiratory tissues, and evaluated the utility of various test methods and specimens for SARS-CoV-2 detection in necropsy tissues. Of SARS-CoV-2-positive animals found dead, 74% had bronchiolitis and diffuse alveolar damage (DAD). Of euthanized SARS-CoV-2-positive animals, 72% had only mild interstitial pneumonia or minimal nonspecific lung changes (congestion, edema, macrophages); similar findings were seen in SARS-CoV-2-negative animals. Suppurative rhinitis, lymphocytic perivascular inflammation in the lungs, and lymphocytic infiltrates in other tissues were common in both SARS-CoV-2-positive and SARS-CoV-2-negative animals. In formalin-fixed paraffin-embedded (FFPE) upper respiratory tract (URT) specimens, conventional reverse transcription-polymerase chain reaction (cRT-PCR) was more sensitive than in situ hybridization (ISH) or immunohistochemistry (IHC) for detection of SARS-CoV-2. FFPE lung specimens yielded less detection of virus than FFPE URT specimens by all test methods. By IHC and ISH, virus localized extensively to epithelial cells in the nasal turbinates, and prominently within intact epithelium; olfactory mucosa was mostly spared. The SARS-CoV-2 receptor ACE2 was extensively detected by IHC within turbinate epithelium, with decreased detection in lower respiratory tract epithelium and alveolar macrophages. This study expands on the knowledge of the pathology and pathogenesis of natural SARS-CoV-2 infection in mink and supports their further investigation as a potential animal model of SARS-CoV-2 infection in humans.

Detection of SARS-CoV-2 in Neonatal Autopsy Tissues and Placenta.

Severe coronavirus disease in neonates is rare. We analyzed clinical, laboratory, and autopsy findings from a neonate in the United States who was delivered at 25 weeks of gestation and died 4 days after birth; the mother had asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and preeclampsia. We observed severe diffuse alveolar damage and localized SARS-CoV-2 by immunohistochemistry, in situ hybridization, and electron microscopy of the lungs of the neonate. We localized SARS-CoV-2 RNA in neonatal heart and liver vascular endothelium by using in situ hybridization and detected SARS-CoV-2 RNA in neonatal and placental tissues by using reverse transcription PCR. Subgenomic reverse transcription PCR suggested viral replication in lung/airway, heart, and liver. These findings indicate that in utero SARS-CoV-2 transmission contributed to this neonatal death.

Rapid development of neutralizing and diagnostic SARS-COV-2 mouse monoclonal antibodies.

The need for high-affinity, SARS-CoV-2-specific monoclonal antibodies (mAbs) is critical in the face of the global COVID-19 pandemic, as such reagents can have important diagnostic, research, and therapeutic applications. Of greatest interest is the ~ 300 amino acid receptor binding domain (RBD) within the S1 subunit of the spike protein because of its key interaction with the human angiotensin converting enzyme 2 (hACE2) receptor present on many cell types, especially lung epithelial cells. We report here the development and functional characterization of 29 nM-affinity mouse SARS-CoV-2 mAbs created by an accelerated immunization and hybridoma screening process. Differing functions, including binding of diverse protein epitopes, viral neutralization, impact on RBD-hACE2 binding, and immunohistochemical staining of infected lung tissue, were correlated with variable gene usage and sequence.

Intersecting Paths of Emerging and Reemerging Infectious Diseases.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shares common clinicopathologic features with other severe pulmonary illnesses. Hantavirus pulmonary syndrome was diagnosed in 2 patients in Arizona, USA, suspected of dying from infection with SARS-CoV-2. Differential diagnoses and possible co-infections should be considered for cases of respiratory distress during the SARS-CoV-2 pandemic.

Evidence of Severe Acute Respiratory Syndrome Coronavirus 2 Replication and Tropism in the Lungs, Airways, and Vascular Endothelium of Patients With Fatal Coronavirus Disease 2019: An Autopsy Case Series.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic continues to produce substantial morbidity and mortality. To understand the reasons for the wide-spectrum complications and severe outcomes of COVID-19, we aimed to identify cellular targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tropism and replication in various tissues. METHODS: We evaluated RNA extracted from formalin-fixed, paraffin-embedded autopsy tissues from 64 case patients (age range, 1 month to 84 years; 21 COVID-19 confirmed, 43 suspected COVID-19) by SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR). For cellular localization of SARS-CoV-2 RNA and viral characterization, we performed in situ hybridization (ISH), subgenomic RNA RT-PCR, and whole-genome sequencing. RESULTS: SARS-CoV-2 was identified by RT-PCR in 32 case patients (21 COVID-19 confirmed, 11 suspected). ISH was positive in 20 and subgenomic RNA RT-PCR was positive in 17 of 32 RT-PCR-positive case patients. SARS-CoV-2 RNA was localized by ISH in hyaline membranes, pneumocytes, and macrophages of lungs; epithelial cells of airways; and endothelial cells and vessel walls of brain stem, leptomeninges, lung, heart, liver, kidney, and pancreas. The D614G variant was detected in 9 RT-PCR-positive case patients. CONCLUSIONS: We identified cellular targets of SARS-CoV-2 tropism and replication in the lungs and airways and demonstrated its direct infection in vascular endothelium. This work provides important insights into COVID-19 pathogenesis and mechanisms of severe outcomes.

Difficulties in Differentiating Coronaviruses from Subcellular Structures in Human Tissues by Electron Microscopy.

Efforts to combat the coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have placed a renewed focus on the use of transmission electron microscopy for identifying coronavirus in tissues. In attempts to attribute pathology of COVID-19 patients directly to tissue damage caused by SARS-CoV-2, investigators have inaccurately reported subcellular structures, including coated vesicles, multivesicular bodies, and vesiculating rough endoplasmic reticulum, as coronavirus particles. We describe morphologic features of coronavirus that distinguish it from subcellular structures, including particle size range (60-140 nm), intracellular particle location within membrane-bound vacuoles, and a nucleocapsid appearing in cross section as dense dots (6-12 nm) within the particles. In addition, although the characteristic spikes of coronaviruses may be visible on the virus surface, especially on extracellular particles, they are less evident in thin sections than in negative stain preparations.