The Centers for Disease Control and Prevention have added six new symptoms to the syndrome caused by SAR-CoV2 virus. The classic signs of COVID-19 are fever followed by dry cough and shortness of breath/difficulty breathing.
The six new signs and symptoms of COVID-19 added by the CDC are:
Loss of sense of smell or taste
Except for the loss of smell/taste, these are not surprising additions. Assuming that shaking occurs in conjunction with chills, they can occur with just about any viral respiratory infection. Why, however, do people lose their sense of smell with coronavirus infection?
Airborne disease-causing organisms such as viruses and
bacteria enter the nasal and oral cavities all the time. In most instances, our
immune system stops the invaders before they can get into the bloodstream.
Not always, though. If a pathogen enters the nose, it might attack the nerve responsible for the sense of small, known as the “olfactory nerve”. Besides SARS-CoV2, flu and herpes viruses are also known to affect this and other nerves. Destroy a certain percentage of olfactory nerve cells and you lose your sense of smell, a condition known as “anosmia”.
Olfactory nerve damage may be an early sign of COVID-19 infection, but loss of taste can occur as well. We’re born with thousands of taste buds on the tongue, throat, and the roof of the mouth. Our sensation of taste starts with the smells or odors around us that stimulate nerves in a small area located high in the nose. The sweet, sour, or other smells stimulate the brain and affect the actual flavor of the foods we eat.
The loss of taste is associated with the inability to smell. Sweet, sour, and other smells stimulate the brain and contribute greatly to the sensation of taste and the experience of “flavor”. Anosmia decreases this sensation.
Fortunately for COVID-19 patients, olfactory cells that die
are replaced relatively quickly, so permanent anosmia is unlikely. The time to
recovery varies from person to person.
In severe cases, it might be suggested that altered mental status or bluish discoloration (“cyanosis“) of lips and fingertips, both caused by lack of oxygen, are also part of COVID-19.
Some symptoms seen in severe cases of COVID-19 have not yet
been added to the symptom list. Among these are gastrointestinal problems like
nausea, diarrhea, or vomiting, with or without fever and cough, which is seen
in a percentage of patients. More recently, discolored lesions on young victims’
feet or toes known as “COVID Toes” have been described.
Studies have shown that patients may be most infectious in the days before they begin showing symptoms, which usually manifest 2-14 days after exposure. This has been problematic, as most testing sites require patients to complain of symptoms before testing is done. Abatement of symptoms and the presence of blood antibodies, a milestone of recovery for most viruses, has also not been proven to confer immunity on patients.
It’s clear that we have a lot more to learn about SARS-CoV2. As more research is done, we’ll have a better chance to combat this complex and puzzling virus.