Despite signs of infection, the involvement of the oral cavity in COVID-19 is poorly understood. To address this, single-cell RNA sequencing datasets were integrated from human minor salivary glands and gingiva to identify 11 epithelial, 7 mesenchymal, and 15 immune cell clusters. Analysis of SARS-CoV-2 viral entry factor expression showed enrichment in epithelia including the ducts and acini of the salivary glands and the suprabasal cells of the mucosae. COVID-19 autopsy tissues confirmed in vivo SARS CoV-2 infection in the salivary glands and mucosa. Saliva from SARS-CoV-2-infected individuals harbored epithelial cells exhibiting ACE2 expression and SARS-CoV-2 RNA. Matched nasopharyngeal and saliva samples found distinct viral shedding dynamics and viral burden in saliva correlated with COVID-19 symptoms including taste loss. Upon recovery, this cohort exhibited salivary antibodies against SARS-CoV-2 proteins. Collectively, the oral cavity represents a robust site for COVID-19 infection andimplicates saliva in viral transmission.
A substantive body of scholarship now recognizes that Native American populations declined precipitously in size following European conquest and colonization. The precise magnitude of demographic collapse continues to spark heated debate, but consensus is emerging where dissent prevailed before. That consensus attributes Indian depopulation in large part to the introduction of Old World disease. Many factors besides imported sickness caused aboriginal demise, but disease proved the most destructive agent of a fatal complex. This paper examines the role disease played in depopulating the Spanish Indies, from first contact to the early seventeenth century. Analysis focuses on five distinct geographical settings: Hispaniola, central Mexico, northwestern Mexico, Guatemala south of the Petén rainforest, and the central Andes. For each of these settings, literature is reviewed that illuminates problems of data, chronology, impact, and identification that have charged discussion of the issues for some time. An attempt is made to situate regional findings in hemispheric context and to appraise the status of the disease factor in quincentennial consciousness.
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