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Showing posts with the label pathology

#Tissue #tropism and functional #adaptation of the #SARS-CoV-2 #spike protein in a #fatal case of #COVID19

  ABSTRACT Systemic spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to extrapulmonary tissues has been observed following acute infections. Autopsy studies further indicate tissue-specific virus diversity, including in immune-privileged sites . Questions remain on the viral dynamics leading to the tissue tropism of SARS-CoV-2, including evolutionary trajectories and functional adaptations that could impact persistence and transmission . In this study, we characterized SARS-CoV-2 genomes from 27 distinct tissues collected from an autopsy case where the patient had a primary immune deficiency . We identified tissue-specific virus genotypes , in some instances coexisting within the same sites, with mutations primarily in the receptor-binding domain of the spike protein. Protein simulations and isolation of infectious virus indicate combinations of spike substitutions that would lead to increased protein stability and stronger binding of the virus to host cells. ...

#SARS-CoV-2, the #human #placenta, and adverse perinatal #outcomes

Abstract The relationship among timing and severity of COVID-19 during pregnancy , placental pathology , and adverse pregnancy outcomes is not well understood. A prospective cohort study of 497 pregnant patients with COVID-19 whose placentas underwent systematic pathologic examination was conducted. The main exposure was timing of COVID-19 during pregnancy (first/second versus third trimester). The primary outcome was composite placental pathology that included high grade maternal vascular malperfusion or greater than 25 percent perivillous fibrin deposition. There were 63 patients who had the composite placental pathology outcome. In adjusted analyses that controlled for maternal age, parity, active infection at delivery, interval from time of diagnosis to delivery and COVID-19 variant, timing of COVID-19 during pregnancy was not associated with risk of the composite placental pathology outcome . Among secondary COVID-19 related exposures that were investigated, severity of disease an...

#Pathology of #Influenza A (#H5N1) #infection in #pinnipeds reveals novel tissue #tropism and vertical #transmission.

Abstract In 2023, an unprecedented outbreak of highly pathogenic avian influenza (HPAI) H5N1 resulted in the death of thousands of pinnipeds along the Argentinean coast , raising concerns about its ecological and epidemiological impact . Here, we present clinical, pathological, and molecular findings associated with HPAI H5N1 infection in pinnipeds from Chubut, Argentina . Necropsies were conducted on three South American Sea Lions (SASLs) (Otaria flavescens) and one Southern Elephant Seal (SES) (Mirounga leonina), followed by histopathological, immunohistochemical and RT-sqPCR analyses. Neurological clinical signs were observed in two SASLs, with one also exhibiting respiratory distress . Neuropathological findings included lymphoneutrophilic meningoencephalomyelitis and choroiditis, neuronal necrosis , gliosis, hemorrhages , and perivascular cuffing. Viral antigen was localized in neurons, glial cells, choroid plexus epithelial cells, ependymal cells, and the neuropil. Systemic manif...