Picture: bangkokpost.com
The current cause of respiratory illness originating from Wuhan is a coronavirus. It is a virus and not a bacteria. In recent years, viruses from the coronavirus family have caused outbreaks of pandemic (worldwide) scale, as seen in the Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS).
The coronavirus family is not a new virus. In the current outbreak, the Wuhan strain is. This makes it the 7th strain from the coronavirus family to infect humans. Of the 7 strains, 4 are known common cold viruses. However, the other two, as previously mentioned, are known to cause the SARS and MERS outbreak.
Persons who are infected with the Wuhan coronavirus can present with very mild symptoms of fever, dry cough and runny nose to the more severe form that includes difficulty in breathing. In the more severe form, a patient can clinically present with lung infection or pneumonia. Compared to SARS and MERS coronavirus strain, the Wuhan coronavirus exhibits less runny nose and intestinal symptoms.
The incubation period of the virus can last up to 14 days. Incubation period refers to the time between the patient is infected with the virus till the time the symptoms appear. Therefore, a patient could still show symptoms 14 days after being exposed to the virus. However, the length of the incubation period does not commensurate with the severity of the symptoms. At the moment of writing, there are suggestions that the incubation period could be between 2 to 10 days.
One peculiar characteristic of the Wuhan coronavirus is that it could be infectious during its incubation period. In the SARS coronavirus, the virus was not infectious in the incubation period.
At the moment of this article is written, the death rate for Wuhan coronavirus is approximately 3%. This means that in every 100 infected patients, about 3 will die. For the record, the death rate for SARS and MERS-CoV was 9.6% and 34% respectively.
The current rate of infection is around 1.4 – 2.5. This means, one infected person could spread the virus to 3 contacts (a round up of 2.5). The rate of infection for SARS is between 2 to 5, while for MERS coronavirus is less than 1. To compare further, measles’s rate of infection ranged from 12 to 18.
There is no evidence of superspreaders at the moment. Superspreaders are infected person who spreads the disease disproportionately to a large number of people. For example, one infected person who spreads the disease to another 15 or more people rather than the usual 2 to 3. The presence of a superspreader causes a sudden explosion of infected people within an area and can hasten the speed of spread of infection. For instance, in the MERS coronavirus outbreak in South Korea in 2015, 29 new cases were directly resulted from one imported case. Two of these secondary cases were responsible for 106 new infections. In the end, 75% of the total cases in South Korea can be traced back to these three persons.
The disease can spread directly from person to person. It was confirmed in the 4th generation patients in Wuhan and 2nd generation cases outside of Wuhan. This means that a close contact of the infected person can directly get infected himself through fluid and droplet. Hence, a person who does not practice personal hygiene care are at higher risk of being infected. This is unlike dengue, where the virus is spread through mosquito bites.
There are no specific treatment yet available to treat or to prevent the new Wuhan coronavirus. Antibiotics are not effective for viral infections. They are for bacterial infections. However, a person may be given antibiotics if co-infection with bacteria exists.
There is no vaccine yet to confront this disease since this is a new disease. The available vaccine that was previously delivered are influenza vaccine. Progress is underway to develop the vaccines.
Of the confirmed cases, 25% is reported to be severe. Most of those who exhibit severe form of the disease are those who are not well themselves – such as diabetics, people with cancer and so on. The elderly is also at high risk. At the moment, there are infection among children, however, their symptoms are milder.
The source of disease is not confirmed yet. It is very likely a zoonosis i.e. disease that transmit between human and animal. Snakes and bats have been implicated. However, further study is needed. Although the new coronavirus is a zoonotic disease, there is no evidence at the moment that pets such as cats and dogs can be infected with the new coronavirus.
In the initial cluster of unknown pneumonia in Wuhan City, Hubei Province in China, the patients shared a history of exposure to the Huanan seafood market. This common epidemiological link caused the local authority to shut down the market on 1 January 2020. At the moment of writing, those who are infected in other parts of the world besides China are either those who had travelled to or has a relationship with those who had a travel history to Wuhan.
Medical personnel are some of the infected person too. In fact, medical front liners are frequently reminded and grilled about the importance of complying to the “droplet and contact” prevention steps. Surveillance are also being conducted to ensure that the medical frontliners remain disease free.
Prevention and control at the personal level
In the current outbreak, the world seems to be more prepared than the previous SARS and MERS coronavirus infection. The reporting of disease was not delayed and made known early. This allows early steps of prevention and control to be taken by every country.
At a personal level, it is important to trust and practice the basic principles prevention that has been promoted in the media. Frequent handwashing is a simple yet effective tool to prevent the spread of disease causing microorganisms to others. A simple use of water and soap kills viruses instantly.
The proper cough etiquette is often not well practised. Cough and sneeze should be covered with disposable tissues and then properly thrown away.
In addition, avoid going into crowded places. Any planned visits to China should also be delayed.
Finally, all the news and information should be cross checked with the Malaysian Ministry of Health and the World Health Organization (WHO) website. The Centre for Disease Control (CDC) can also be a wealth of validated information.
Dr Helmy Hazmi is a community medicine specialist with a specialization in Epidemiology and Biostatics. Now, he is serving in his hometown of Kuching, as a medical lecturer. Get to know more about him on The Team page. (All facts quoted in this article was true at the time of writing 28/1/2020 – the situation is still evolving.)
[This article belongs to The Malaysian Medical Gazette. Any republication (online or offline) without written permission from The Malaysian Medical Gazette is prohibited.]