The hypothesis that the SARS-CoV-2 virus could affect not only the immune system but also the social behavior of the host to ensure its survival, come to researchers at New York University
Could viruses, such as the worldwide SARS-CoV-2, affect the behavior of those affected by affecting the central nervous system in a way that “ensures” their survival and reproduction?
This is the theory put forward by researchers from New York University in Albany, stating that the coronavirus could affect an area of the brain called the adrenal cortex, which is involved in social behavior and emotional regulation.
Through changes in the anterior cortex of the adductor, patients could be “attracted” to socialising rather than following social distancing measures, the researchers report in Medical Hypotheses.
It is hypothesized that this behavior change may occur during the incubation period, when people have been infected with COVID-19 without yet showing symptoms of the disease, making them more likely to transmit the virus.
They clearly emphasize that their hypotheses are based on the effects of other infections on the behavior change of patients and there are no known changes in behavior associated with COVID-19.
“Only time will tell how the virus treats the host for its own survival and reproduction,” they say.
The ability of viruses to cause behavioral changes – to manipulate host behavior – is not new and has been reported in cases mainly of rabies but also influenza, among other viruses.
The theory is that pathogens do this to maximize their rate of reproduction and consequently their spread and survival.
The virus that has attracted the most attention in the field of research on behavioral effects is rabies, a viral disease of the central nervous system caused in humans by the bite or scratch of an infected animal.
The rabies virus has been found to affect the central nervous system and make animals more aggressive and more likely to bite, increasing the spread of the disease that kills 59,000 people each year worldwide.
A 2017 University of Alaska study published in Scientific Reports found that the virus blocks chemicals in humans that play a key role in regulating behavior.
Meanwhile, in a 2010 study that used a flu vaccine (since it is morally not allowed to deliberately infect people), which contained a modified form of the virus, researchers in the United States found that in the two days following their exposure, the number of people who met patients increased to 101 from an average of 54, compared to the two days before immunisation, the Annals of Epidemiology reported.
The two days immediately after exposure to the flu virus are important because it is the period during which people who are more contagious but do not show symptoms are therefore more likely to spread the disease.
In a study published in the Annals of Epidemiology, researchers ruled out that participants felt safer after the vaccine and therefore more social, as four weeks later, their rate of socialization had returned to pre-vaccination levels.
“Human social behavior has changed with the introduction of the virus. This is the strongest indicator that has been discovered so far for pathogen-related behavior change in humans,” the scientists said.
However, there is no evidence that only viruses can manipulate behavior. An illustrative example is Toxoplasma gondii, a single-celled parasite whose natural host is the cat without any problem with it. But infected mice and rats start to be less afraid of cats and therefore more likely to kill them.
Toxoplasma gondii is thought to infect one in three people worldwide, and researchers have found that it can make them less frightened, reckless, and affect their driving behavior. According to a 2007 study by parasitologists at Charles University in Prague, carriers of the parasite are 2.65 times more likely to be involved in road accidents. One theory behind this is that it raises testosterone levels and possibly makes people more adventurous.