Coronavirus refers to a large group of viruses that cause various diseases in humans, rats, mice, turkey, pigs, chickens, farm animals, felines, ferrets. The name is derived from the Latin word Corona meaning halo or crown. It was first discovered in the 1960s from infected chickens. Two viruses were identified from the specimens taken from the upper respiratory tract in humans. These strains were subsequently named 229E and OC43. Other strains were further identified in 2003, 2004, 2005, 2012 and 2019.
All of these strains were mostly involved in the upper respiratory tract like infections. The evidence of infection by coronavirus has existed in veterinary medicine since the early 1970s. Common diseases among animals include the infection of the upper respiratory and gastrointestinal tract of mammals and birds, bronchitis, gastroenteritis.
Until December 2019, the highest number of cases reported by a coronavirus outbreak was in 2003. A new strain of coronavirus was detected in the central city of Wuhan in China. Similarly, few cases have been reported in the United States as well.
Seven strains of human coronaviruses that have been identified
- Human coronavirus 229E (HCoV-229E)
- Human coronavirus OC43 (HCoV-OC43)
- Human coronavirus NL63 (HCoV-NL63, new haven coronavirus)
- Human coronavirus HKU1
- Middle East respiratory syndrome coronavirus (MERS-CoV) previously labelled as novel coronavirus 2012
- Novel coronavirus (2019-nCoV) also known as Wuhan coronavirus
Whereas MERS-CoV and SARS-Cov are the more dangerous types of this virus
Out of these, there are four common types that cause common cold among humans. They are:
- 229E (alpha coronavirus)
- NL63 (alpha coronavirus)
- OC43 (beta coronavirus)
- HKU1 (beta coronavirus)
The four common human coronaviruses are responsible for causing mild to moderate upper respiratory tract infections with flu-like symptoms. These strains are not responsible for infecting lower respiratory tract. Such mild symptoms last only a short amount of time, making them insignificant. Although associated with mild symptoms, infection with coronavirus does not leave an imprint on the infected person’s immune system. This makes the immune system as unprepared for any number of attacks of the virus as the first one. That is why one person can become infected with the virus again after a short period of time.
Symptoms of Coronaviruses
- Runny nose
- Sore throat
- Body ache
- Feeling of being unwell
Coronavirus infection is not severe in most cases. But there are several groups which are at greater risk for developing serious illness by a coronavirus. These include people with Cardiopulmonary Disease, Diabetes, Cancer, Chemotherapy patients, Chronic lung disease, Chronic heart disease, Chronic kidney disease , Weakened immune systems, and Infants.
Only MERS-CoV and SARS-CoV of the coronavirus is associated with severe symptoms. Underlying conditions such as heart disease or weakened immune system can affect the severity of symptoms, often causing life-threatening illnesses. The severity of the infection is dependent on the main region of infectivity. The dangerous strains have been discovered to cause lower respiratory tract infections.
These severe type of infections lead to classic symptoms like Fever, Cough, Shortness of breath diarrhoea/dehydration, Nausea, vomiting, and ultimately causing pneumonia and kidney failure.
Most infections caused by the coronaviruses are mild. However, the incidence of mortality has been indicated in coronavirus patients. It greatly depends on the patient’s health status prior to being infected. About every 3 out of 10 individual infected with dangerous strains has died. The majority of these people had underlying health conditions that compromised their immunity leading to more severe symptoms.