Covid-19 people lose sense of taste and smell even when there is no other symptom: Study

A team of researchers has claimed that they have discovered the reason why Covid-19 positive people lose a sense of taste and smell even when they demonstrate no other symptoms related to the virus.

They found extremely high levels of angiotensin-converting enzyme II (ACE-2) only in the area of the nose responsible for smelling. This enzyme proves to be the entrance for the virus from where it comes and infects the whole body.

The scientists believe that studying the ACE-2 area in the nose can help in curating effective treatments of the coronavirus.

The study was carried out by Professor Andrew P Lane, director of the division of rhinology and skull base surgery, and Dr Mengfei Chen, research associate, and colleagues from Johns Hopkins University School of Medicine, Baltimore, USA.

Professor Lane said in a statement: “I specialize in nasal and sinus problems, so the loss of the sense of smell in Covid-19 is of particular clinical interest to me. While other respiratory viruses generally cause loss of the sense of smell through the obstruction of airflow due to swelling of the nasal passages, this virus sometimes causes loss of smell in the absence of other nasal symptoms.”

For the study, tissue samples were taken from 23 patients who were there for endoscopic surgical procedures.

The researchers also analysed biopsies from the trachea (windpipe) of seven patients. None of the patients was coronavirus positive.

The researchers found that the level of ACE2 in the cells present in the nose was between 200-700 times higher than other tissue in the nose and trachea. The scientists found a similar level of ACE2 olfactory epithelium.

Professor Lane added: “We are now doing more experiments in the lab to see whether the virus is indeed using these cells to access and infect the body. If that's the case, we may be able to tackle the infection with antiviral therapies delivered directly through the nose.”