Coronaviruses commonly cause symptoms similar to the common cold, such as nasal congestion, sinusitis, or sore throat, and spread through sneezing and coughing. However, they can also lead to more severe respiratory illnesses such as Severe Acute Respiratory Syndrome (SARS) and can be fatal.
The term "coronavirus" originates from the Latin word corona, meaning crown or halo, referring to the characteristic appearance of the virus particles under an electron microscope, with large spikes resembling a royal crown or solar corona. This morphological feature is created by spike proteins (peplomers) on the surface of the virus and determines the host range.
On December 31, 2019, at the Huanan Seafood Wholesale Market in Wuhan City, China, a strain of coronavirus caused an outbreak of pneumonia in humans and quickly spread to several other places worldwide. The Wuhan strain was identified as a new strain of β CoV from group 2B, sharing approximately 80% genetic similarity with the SARS-CoV from 2003. This new strain was named 2019-nCoV by the World Health Organization (WHO). The virus was suspected to originate from wild animals such as snakes and bats, spread through trading at the Huanan Seafood Market in Wuhan.
1. Transmission Routes of Coronavirus
Coronavirus spreads from person to person through two main routes:
- Direct contact: Through tiny respiratory droplets from the cough or sneeze of an infected person. Each time an infected person coughs or sneezes, tens of thousands of these tiny droplets can remain suspended in the air and be inhaled by people within 1-2 meters. Additionally, these droplets can also land on surfaces and objects, becoming a secondary route of transmission. Therefore, proper coughing and sneezing etiquette (covering with elbow or tissue and hand hygiene) is crucial.
- Indirect contact: Through contact with surfaces or objects contaminated by respiratory secretions of an infected person. For example, when an infected person covers their mouth while coughing or sneezing, the hands that touch these secretions can transfer the virus to objects like doorknobs. The next person touching these contaminated surfaces can then transfer the virus to their mouth, eyes, or care for children, spreading the infection further.
2. Environmental Conditions for Coronavirus Transmission
Studies on the survival of SARS virus in different environments have shown that the virus lives longer in colder and drier conditions (low humidity).
- At 4°C, the virus can survive for over a month.
- At room temperature (22-25°C) and 40-50% humidity, the virus can survive on surfaces for up to 5 days, decreasing gradually.
- At higher temperatures (28-33°C), humidity does not significantly affect the virus, which can still survive for 4-5 days.
- At 38°C and 80-90% humidity, the virus's viability decreases significantly within 24 hours.
- At 56°C, the virus is destroyed within 15 minutes.
This explains why regions with cooler and lower humidity climates like Singapore and Hong Kong have had more outbreaks compared to hotter and more humid regions like Thailand, Indonesia, and Malaysia.
3. Preventive Measures against nCoV
To prevent infection:
- Wear a mask to cover the respiratory tract and avoid inhaling droplets containing nCoV; change masks regularly and avoid touching the outer surface.
- Maintain regular hand washing to reduce contact with the virus and avoid touching your face, mouth, or eyes.
Currently, there are many types of nCoV vaccines available for both adults and children. Regular vaccination is the most effective way to protect against nCoV.
4. Signs of nCoV Infection in Humans
- The incubation period is 2-14 days, averaging about 5 days.
- Typical clinical symptoms include:
- High fever of 39-40°C lasting continuously for 1-2 days
- Persistent dry cough
- Difficulty breathing
- Chills
- Body aches
- Fatigue
- Severe respiratory distress leading to death
These symptoms can rapidly progress to acute pneumonia and can be fatal without timely intervention.
5. Treatment of nCoV Infection
Currently, specific antiviral medications are available for coronavirus treatment. Most individuals with regular coronavirus infections recover on their own. However, there are steps to alleviate symptoms if present:
- Take pain and fever-reducing medications (Note: Aspirin should not be given to children).
- Use a humidifier or take hot baths to relieve throat pain and cough.
- Drink plenty of fluids, stay at home, and rest.
- If symptoms do not improve, seek medical attention promptly and undergo isolation.