Natural SARS-CoV-2 Infection in a Free-Ranging Black-Tailed Marmoset (Mico melanurus) from an Urban Area in Mid-West Brazil

Abstract

The emergence of spillover pathogens such as SARS-CoV-2 is a risk to vulnerable human populations. We report natural SARS-CoV-2 infection in a free-ranging adult female black-tailed marmoset (Mico melanurus) from an urban area of Cuiabá, Mato Grosso State, Brazil. The animal was found after a motor vehicle collision without previous clinical history. Necropsy confirmed polytrauma. Severe multifocal to coalescent haemorrhage and mild multifocal peribronchial lymphocytic hyperplasia were seen in lung sections. The alveolar septa were multifocally expanded by a few lymphocytes. Mild lymphocytic periportal hepatitis and interstitial nephritis were found. The lymphoid nodules of the large intestine showed marked lymphocytic hyperplasia. Infection by SARS-CoV-2 was established by viral RNA detection in a pool of nasopharyngeal and oropharyngeal swabs and liver samples. Immunohistochemistry detected the viral nucleocapsid protein in sections of lung, liver, spleen, lymph nodes and large intestine, and spike protein antigen in lung tissue. This is the first report of naturally occurring SARS-CoV-2 infection in a New World monkey. Platyrrhine species should be included as potential hosts of natural infection of SARS-CoV-2.

Keywords: COVID-19; New World monkey; One Health; SARS-CoV-2; platyrrhines.

Fig. 1

SARS-CoV-2 infection, lung, black-tailed marmoset. Mild thickening of alveolar septa by lymphocytes and macrophages. HE. ×10.

Fig. 2

SARS-CoV-2 infection, lung, black-tailed marmoset. Immunohistochemistry using antibody against nucleocapsid protein of SARS-CoV-2. (A) Positive control human lung tissue. Strong cytoplasmic immunolabelling in pneumocytes in alveolar septa. IHC. ×63. (B) Negative control. Absence of cytoplasmic immunolabelling in pneumocytes or macrophages in alveolar septa. IHC. ×40. (C) Moderate cytoplasmic immunolabelling in macrophages (black arrow) in bronchial lamina propria of SARS-CoV-2-infected marmoset. IHC. ×40.

Fig. 3

SARS-CoV-2 infection, lung, black-tailed marmoset. Immunohistochemistry using antibody against spike protein of SARS-CoV-2. (A) Positive control human lung tissue. Strong cytoplasmic immunolabelling in pneumocytes and macrophages in alveolar septa. IHC. ×63. (B) Negative control. Absence of cytoplasmic immunolabelling in pneumocytes or macrophages in alveolar septa. IHC. ×40. (C) Lung sample. Mild cytoplasmic immunolabelling in pneumocytes (black arrows) and macrophages (white arrow) in alveolar septa in lung of SARS-CoV-2-infected marmoset. IHC. ×40.