Coronaviruses typically affect the respiratory tracts of birds and mammals, including humans. Doctors associate them with the common cold, bronchitis, pneumonia, severe acute respiratory syndrome (SARS), and coronavirus disease 2019 (COVID-19). These viruses can also affect the gut.
Coronaviruses usually cause the common cold, though they can be responsible for more severe illnesses.
Over the past 80 years, scientists have found that these viruses can infect mice, rats, dogs, cats, turkeys, horses, pigs, and cattle. Sometimes, these animals transmit the viruses to humans.
Most recently, authorities identified a new coronavirus outbreak in China that has now reached other countries. The virus is called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and it can cause COVID-19.
In this article, we explain the different types of human coronavirus, their symptoms, and how people transmit them. We also focus on three particularly dangerous diseases caused by coronaviruses: COVID-19, SARS, and Middle East respiratory syndrome
Researchers first identified a coronavirus in 1937, isolating one that was responsible for a type of bronchitis in birds that had the potential to devastate poultry stocks.
Scientists found evidence of human coronaviruses in the 1960s, in the noses of people with the common cold.
Human coronaviruses that are particularly prevalent include 229E, NL63, OC43, and HKU1.
The name “coronavirus” comes from the crown-like projections on their surfaces. “Corona” in Latin means “halo” or “crown.”
Among humans, coronavirus infections most often occur during the winter months and early spring.
In 2019, the Centers for Disease Control and Prevention (CDC) started monitoring the outbreak of a new coronavirus, SARS-CoV-2, which causes COVID-19. Authorities first identified the virus in Wuhan, China.
Since then, the virus has spread to nearly every country, leading the World Health Organization (WHO) to declare a pandemic.
The new coronavirus has been responsible for millions of infections globally, causing hundreds of thousands of deaths. The United States has seen the highest number of these deaths.
The first people with COVID-19 had links to an animal and seafood market. This suggests that animals initially transmitted the virus to humans. Then, people with no connections to the market developed the disease, confirming that humans can pass the virus to each other.
Most people who get COVID-19 will have a mild form of the disease. According to the WHO, around 80% of people who get COVID-19 will recover without needing hospitalization.
The remaining 20% become seriously ill and develop difficulty breathing.
Some groups are more at risk of severe disease, including older adults and people with underlying medical concerns, including high blood pressure, heart and lung problems, diabetes, and cancer.
The mortality rate varies between countries. In the U.S., the death rate is around 6%.
According to the CDC, children are not at higher risk of COVID-19 than adults.
Pregnant women appear to have the same risk of COVID-19 as other adults. However, during pregnancy, women have a higher risk of severe illness from viruses that are similar to SARS-CoV-2 and influenza.
The CDC also reborn to women with suspected or confirmed COVID-19 are put into isolation.