Of the seven categories of coronaviruses that affect humans, these three are responsible for the most severe conditions.
Different types of viruses and bacteria can infect the respiratory tract and cause everything from a common cold to more serious diseases, such as pneumonia. One of the viral families responsible for causing the main acute respiratory syndromes is the coronavirus (CoV), whose new type now frightens the world, Sars-CoV-2, responsible for COVID-19. But in addition to this, there are still other serious respiratory diseases caused by the coronavirus family.
Seven categories of coronaviruses affect humans, but the most serious clinical conditions are related to only three of them – Sars, Mers, and COVID-19. When one of these infections occurs in the lungs, the person experiences symptoms such as high fever, cough, shortness of breath, and, eventually, pneumonia.
Acute respiratory syndromes are similar. “The big difference between Sars, Mers, and COVID-19 is that the capacity for infection of the virus that causes the latter is greater than those responsible for the other two,” explains infectious disease specialist Roberto Muniz, from the Hospital Israelita Albert Einstein, in Brazil.
The diagnostic methods are the same: they can be serological (antibody testing, analyzing whether the patient has developed a response to these viruses) or performed using molecular biology. The latter detects the genetic material of the virus in the patient’s body.
Check out the characteristics of each of these diseases:
First detected in China in 2002, SARS spread to several countries, infecting more than 8,000 people and causing more than 800 deaths in 2003. The main symptoms are fever, headache, chills, muscle pain, dry cough, and shortness of breath. Transmission occurs through contact with an infected person or droplets suspended in the air after someone infected has coughed or sneezed.
The Mers virus was identified in 2012 in Jordan and Saudi Arabia and, by the beginning of 2018, more than 2,000 cases and 790 deaths from the disease were recorded. The recurrent signs of Mers are fever, chills, muscle pain, and cough. Some people even experience diarrhea, abdominal pain, and vomiting. This type of infection is more severe in the elderly or people with chronic diseases such as diabetes, heart or kidney problems.
The first case of COVID-19 was diagnosed in China in late 2019 and soon spread worldwide, was classified as a pandemic by the World Health Organization, infected millions of people and caused hundreds of thousands of deaths. It is transmitted through droplets from sneezing or coughing from infected people or by touching the eyes, mouth and nose after contact with any object contaminated by the virus. Generally, infected people have mild symptoms, with high fever and cough, but some patients have more severe clinical conditions, including shortness of breath.
There is still no vaccine or antiviral medication for these three diseases, but several studies are being conducted with different drugs to test their effectiveness against the coronavirus. Meanwhile, supportive care is most appropriate in all three cases.
Prevention is the best way to fight the coronavirus. “People should avoid crowding, wash their hands frequently with soap and water, clean their hands and objects with alcohol, cover their mouths with their elbows or a handkerchief when coughing or sneezing and stay at least one meter away from other people,” concludes Roberto Muniz.