Covid 19 viral infected smell receptors. Conceptual electron micrograph (SEM). Small viral particles (pink) are seen attached to the olfactory cells in the nose. Temporary loss of smell, or anosmia, is the main neurological symptom and one of the earliest and most commonly reported indicators of COVID-19, People with COVID-19 lose their sense of smell because the virus damages the olfactory receptor nerve endings or supporting olfactory cells within their nose. Magnification: x3000 when printed 10 centimetres wide.