Coronaviruses

Coronaviruses are types of viruses that typically affect the respiratory tracts of birds and mammals, including humans. Doctors associate them with the common cold, bronchitis, pneumonia, and severe acute respiratory syndrome (SARS), and they can also affect the gut.

These viruses are typically responsible for common colds more than serious diseases. However, coronaviruses are also behind some more severe outbreaks.

Over the last 70 years, scientists have found that coronaviruses can infect mice, rats, dogs, cats, turkeys, horses, pigs, and cattle. Sometimes, these animals can transmit coronaviruses to humans.

Most recently, authorities identified a new coronavirus outbreak in China that has now reached other countries. It has the name coronavirus disease 2019, or COVID-19.

In this article, we explain the different types of human coronaviruses, their symptoms, and how people transmit them. We also focus on three particularly dangerous diseases that have spread due to coronaviruses: COVID-19, SARS, and MERS.

What is a coronavirus?

Researchers first isolated a coronavirus in 1937. They found a coronavirus responsible for an infectious bronchitis virus in birds that had the ability to devastate poultry stocks.

Scientists first found evidence of human coronaviruses (HCoV) in the 1960s in the noses of people with the common cold. Two human coronaviruses are responsible for a large proportion of common colds: OC43 and 229E.

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. People regularly become ill with a cold due to a coronavirus and may catch the same one about 4 months later.

This is because coronavirus antibodies do not last for a long time. Also, the antibodies for one strain of coronavirus may be ineffective against another one.

Symptoms

Cold- or flu-like symptoms usually set in from 2–4 days after a coronavirus infection and are typically mild. However, symptoms vary from person-to-person, and some forms of the virus can be fatal.

Symptoms include:

  • sneezing
  • runny nose
  • fatigue
  • cough
  • fever in rare cases
  • sore throat
  • exacerbated asthma

Scientists cannot easily cultivate human coronaviruses in the laboratory unlike the rhinovirus, which is another cause of the common cold. This makes it difficult to gauge the impact of the coronavirus on national economies and public health.

There is no cure, so treatments include self-care and over-the-counter (OTC) medication. People can take several steps, including:

  • resting and avoiding overexertion
  • drinking enough water
  • avoiding smoking and smoky areas
  • taking acetaminophen, ibuprofen, or naproxen for pain and fever
  • using a clean humidifier or cool mist vaporizer

A doctor can diagnose the virus responsible by taking a sample of respiratory fluids, such as mucus from the nose, or blood.