The usual symptoms of infection caused by Covid-19 are fever, cough and difficulty breathing. However, some rarer cases complain of headaches, but also nausea and vomiting. According to a Chinese study, the coronavirus could affect the central nervous system.
You should know that headaches, nausea and vomiting are often associated with a neurological condition. In addition, Covid-19 patients are 8% to suffer from headaches and 1% nausea and vomiting. In his study published in the Journal of Medical Virology of February 27, 2020, Yan-Chao Li, researcher at the University of Jilin (China) asked himself a question. Are the symptoms mentioned the marker of an attack of the Covid-19 coronavirus on the central nervous system?
Recall that coronaviruses are generally known to attack the respiratory system. However, previous studies have shown that some of them also have the ability to affect the central nervous system and thus cause neurological disorders (neutropism). However, this is precisely the case with betacoronaviruses, a category to which SARS, MERS and therefore Covid-19 belong.
One example is HEV 67N, a coronavirus affecting pigs, the very first identified for its attacks on the brain. Importantly, this one is very similar to HCoV-OC43, another coronavirus that causes the common cold in humans. The study evokes a homology of approximately 91% between the two strains!
How coronaviruses can affect the central nervous system remains unclear. These could use the synapses to pass from the cardiorespiratory system to the spinal cord. The gateway to the central nervous system would be embodied by the mechanoreceptors and chemoreceptors of the peripheral nerve endings in the lower respiratory tract.
Recently, doctors have mentioned several cases of Covid-19 patients also having anosmia. This is a loss of sense of smell , often going hand in hand with a loss of taste. However, anosmia can be caused by damage to the olfactory nerve, the first cranial nerve connecting the nasal cavity to the olfactory bulb present at the base of the brain. However, this problem is very common in respiratory diseases and does not necessarily represent one of the symptoms associated with Covid-19.
Finally, the neurotropism of Covid-19 is still speculative for one simple reason. The coronavirus has not yet been observed in the brainstem patients. However, this was already the case during tests carried out on mice concerning the SARS and MERS coronaviruses.
