Virus World

Although ocular manifestations are reported in patients with COVID-19, consensus on ocular tropism of SARS-CoV-2 is lacking. Here, we infect K18-hACE2 transgenic mice with SARS-CoV-2 using various routes. We observe ocular manifestation and retinal inflammation with production of pro-inflammatory cytokines in the eyes of intranasally (IN)-infected mice. Intratracheal (IT) infection results in dissemination of the virus from the lungs to the brain and eyes via trigeminal and optic nerves. Ocular and neuronal invasions are confirmed using intracerebral (IC) infection. Notably, the eye-dropped (ED) virus does not cause lung infection and becomes undetectable with time. Ocular and neurotropic distribution of the virus in vivo is evident in fluorescence imaging with an infectious clone of SARS-CoV-2-mCherry. The ocular tropic and neuroinvasive characteristics of SARS-CoV-2 are confirmed in wild-type Syrian hamsters. Our data can improve the understanding regarding viral transmission and clinical characteristics of SARS-CoV-2 and help in improving COVID-19 control procedures. 

Published in Nature Comm. (Dec. 12, 2022):

https://doi.org/10.1038/s41467-022-35225-1 

This case study compares a patient previously infected with coronavirus disease 2019 with a control participant in assessment of nucleocapsid protein antigens on the cells of the conjunctiva, iris, and trabecular meshwork. Coronavirus disease 2019 (COVID-19) has been recognized as a pandemic by the World Health Organization. Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can also infect tissues besides the respiratory system, such as the ocular tissues, remains unclear.

To determine whether SARS-CoV-2 exists intracellularly in the ocular tissues of a patient previously infected with COVID-19. This case study analyzed a patient previously infected with COVID-19 who had an acute glaucoma attack during her rehabilitation. Plasma samples and tissue specimens, including ones from the conjunctiva, anterior lens capsular, trabecular meshwork, and iris, were collected during phacoemulsification and trabeculectomy surgery. Specimens from another patient who had glaucoma but not COVID-19 were used as a negative control. Specimens were analyzed using hematoxylin-eosin staining. The nucleocapsid protein antigen of SARS-CoV-2 was measured in the conjunctiva, trabecular meshwork, and iris using immunofluorescence and immunohistochemistry. The expression of angiotensin-converting enzyme 2 receptor on the conjunctiva was measured using immunohistochemistry.

The patient with a previous COVID-19 infection was female and 64 years old, and the control patient without a COVID-19 infection history was male and 61 years old. The nucleocapsid protein antigen of SARS-CoV-2 was detected on the cells of the conjunctiva, trabecular, and iris of the patient infected with COVID-19 but not in the control participant, while angiotensin-converting enzyme 2 receptor proteins were detected on the conjunctiva of both patients. The nucleocapsid protein antigen of SARS-CoV-2 existed intracellularly in the ocular tissues of a patient previously infected with COVID-19. Thus, SARS-CoV-2 can also infect ocular tissues in addition to the respiratory system.

Published in JAMA Ophtalmology (Oct. 8, 2020)

https://doi.org/10.1001/jamaophthalmol.2020.3962