The ongoing outbreak of the 2019 novel coronavirus in China, also called the Wuhan coronavirus, has now affected at least 17 countries. Approximately 6,000 cases have been reported with the majority being diagnosed in China.
The total fatalities have crossed 130, a majority of them in the Hubei Province in which Wuhan is located. Nepal has reported its first confirmed case: of a student studying in China who had been visiting Nepal when diagnosed.
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Viruses of the coronavirus family have historically caused diseases of the respiratory tract in human populations worldwide. Recent outbreaks included the Severe Acute Respiratory Syndrome (SARS) in 2002 and the Middle Eastern Respiratory Syndrome (MERS) in 2012. Both affected thousands of people and were fatal in some cases.
SARS killed 10% of infected individuals while MERS was fatal in 37% of the infected population. The current fatality rate due to the Wuhan Coronavirus is 2.2%. If we are to describe this statistic in reverse, about 98 percent of those infected with this virus do not die.
The question then is, why is there so much concern regarding this outbreak, given the relatively low mortality rate in comparison to previous coronavirus outbreaks?
The first reason is that the Wuhan coronavirus is ‘novel’. This term is used in viral epidemiology to indicate a new strain, one which has not been detected previously in the population. Scientists therefore do not have adequate information regarding the characteristics of the virus to provide evidence-informed public health instructions on containment and treatment.
Second, unlike SARS and MERS, this virus has an incubation period of up to 14 days and asymptomatic infected individuals can transmit the disease to others during that time. Even infected individuals who show improvement can continue to transmit the virus.
The R0 (pronounced ‘r naught’) value of this virus is estimated at 3, meaning that an infected person on average will transmit to three other persons. This is considered a high infectivity number, but still lower than that of SARS or MERS.
The Chinese authorities have put in place strict measures in Wuhan to try to contain the spread of the virus. However, this may not be enough as many infected individuals might have already traveled out of town by the time the measures were put in.
Wuhan has a population of 10 million, and many had begun to travel in advance of the Chinese New Year this week. Experts at Imperial College London have estimated infected population numbers to be already at around at 100,000.
We can therefore expect more cases around the world as infected individuals travel and transmit the disease. However, once again, the question emerges of what the reported fatalities so far are among this large number of infected individuals. Could it be that the virus is spreading but not causing too many deaths?
Nepal has seen regular outbreaks of respiratory diseases including seasonal influenza, ‘avian influenza’ and ‘swine flu’. The Nepali media often reports cases of ‘unknown viral disease’. The Nepal government had established screening centres for the coronavirus at airport and border checkpoints even before the first infected person was diagnosed in Tibet on Monday.
The National Public He