Coronavirus are common viruses that infect humans and animals.
A novel coronavirus is a new strain that has not been previously identified in humans. Six coronaviruses infect humans. The 2019-nCoV is the seventh.
There are four common human coronaviruses that usually cause upper respiratory tract illnesses, like the common cold which almost everyone gets at some time in their lives. These illnesses are usually of short duration.
Sometimes, the human coronaviruses may cause lower respiratory tract illnesses like bronchitis and/or pneumonia. This is more likely in those with heart/lung disease, poor immunity, infants and older adults.
Two other human coronaviruses, Severe Acute Respiratory Syndrome (SARS-CoV) and Middle East Respiratory Syndrome (MERS-CoV) often cause severe illness. The former virus was transmitted to humans through the civet cat, and the latter, through camels.
The 2019-nCoV virus is structurally closely related to SARS-CoV.
There is no vaccination or specific treatment for human coronaviruses infections. Most of those infected usually recover on their own. Symptoms can be relieved with pain and fever medicines. Resting at home and drinking of plenty of fluids are helpful.
Although much is known about the 2019-nCoV infection, there is plenty more that is unknown.
The features of the initial 41 cases of 2019-nCoV were reported in The Lancet on January 24,2020 – 73% (30 of 41) were men; 32% (13) had underlying diseases including 20% (8) with diabetes, 15% (6) high blood pressure and 15% (6) cardiovascular disease.
The median age was 49 years; 66% (27) were exposed to the Huanan seafood market, which also sold wild animals. There were five patients in one family cluster.
The common symptoms at the onset of illness were fever (98%), cough (76%) and muscle aches or fatigue (44%). Less common symptoms were sputum production (28%), headache (8%), coughing out blood (5%) and diarrhoea (3%).
All 41 patients had pneumonia with abnormal findings on chest CT.
The complications included acute respiratory distress syndrome (29%), anaemia (15%), acute cardiac injury (12%) and secondary infection (10%); 32% were admitted to an intensive care unit (ICU) and six (15%) died.
The infection was initially thought to have been from animal to human.
However, human-to-human transmission has been confirmed.
The transmissibility of 2019-nCoV ranges from WHO’s estimate of 1.4-2.5 to the 3.6-4.0 calculation from Jonathan Read et al of Lancaster University, Britain, who reported their preliminary results on January 24,2020. This means that every infected person can infect 1.4-2.5 persons or 3.6-4.0 persons respectively.
In contrast, the transmissibility of MERS is <1 and that of SARS was 2.0-3.5.
Read et al also estimated that only about 5.1% of cases in Wuhan have been identified.
This is probably not because of cover-up but because those who have mild or no symptoms probably would not have consulted a doctor, much less get tested for the virus.
Chinese officials reported that the 2019-n-CoV is infectious during the incubation period i.e. before there are symptoms, similar to measles, chicken pox and even influenza. This calls into question the effectiveness of temperature screening at entry points and would make containment of the virus harder and challenging.
The fundamental questions about 2019-nCoV that will inform its surveillance are: What is the disease pyramid? What proportion of those infected develop the disease? And what proportion of those seek healthcare?
There are currently no answers to these questions.
Advice for the public
There is no cure or vaccine for 2019-nCoV. As such, general measures that reduce the risk of transmission of acute respiratory infections are recommended. They include:
- Avoid close contact with people suffering from acute respiratory infections.
Close contact has been defined as the Centers for Disease Control and Prevention of the United States as (a) being within approximately 2m, or within the room or care area, of a n-CoV case for a prolonged period of time while not wearing recommended personal protective equipment like gowns, gloves, disposable N95 respirator and eye protection. It can include caring for, living with, visiting, or sharing a health care waiting area or room with a n-CoV case; or (b) having direct contact with infectious secretions of a n-CoV case e.g. being coughed on while not wearing recommended personal protective equipment.
- Avoid unprotected contact with live animals including poultry and birds.
- Avoid consumption of raw and uncooked meats.
- Frequent hand-washing, especially after direct contact with ill people or their environment; before, during and after preparing food or eating; after going to the toilet; when the hands appear dirty; or after handling animals or animal waste. A hand sanitiser containing 60-95% alcohol is an effective alternative.
- People with symptoms of acute respiratory infection should practise cough etiquette (maintain distance, cover coughs and sneezes with disposable tissues or clothing, not hands, and wash hands).
- Use a mask whenever there is a cough or difficulty breathing.
- If there is concern about any symptom, particularly upon return from China, early medical attention should be sought.
- If one has been to China and has fever, cough or difficulty breathing within 14 days after leaving China, one should seek immediate medical attention, avoid contact with others and not use public transport. Do not share food or utensils, use a mask, wash hands and practise cough etiquette as stated previously.
- Some infectious disease specialists recommend that if one has been to China but has no symptoms, it is advisable to self-isolate, not go to public places for at least 14 days, not share food or personal utensils, wash hands and practise cough etiquette as stated previously.
- Check with travel advisories from regulators and airlines prior to going to China.
The situation is constantly evolving. Updated information and guidance can be found at the following dedicated websites, among others:
- World Health Organisation
- Centres for Disease Control and Prevention, United States
- Centre for Health Protection, Department of Health, Hong Kong
- Ministry of Health, Malaysia
Dr Milton Lum is a past president of the Federation of Private Medical Practitioners Associations and the Malaysian Medical Association. The views expressed do not represent that of organisations that the writer is associated with. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
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