Coronavirus: Scientists estimate 44,000 cases in Wuhan

Scientists have estimated more than 44,000 cases of novel coronavirus (2019 n-Cov) in Wuhan, which is the epicentre of the global outbreak of the deadly virus that infected nearly 8000 people in 21 countries and killed 170 of them so far.

Researchers at the University of Hong Kong derived the number on the basis of confirmed cases as of January 25 and what is known about the virus’s transmissibility, according to a report published in the British Medical Journal on Thursday.

“The curves have a very steep exponential shape, indicating that this epidemic is growing at quite a fast rate, and it’s accelerating,” said Gabriel Leung, a researcher at the University of Hong Kong.

The Chinese government suspended all transport links with the city of 11 million and blocked the roads out of the city on January 23, effectively putting a sanitisation cordon in place around Wuhan. Subsequently, it extended the quarantined zone to 15 neighbouring cities, covering a population of approximately 50 million.

But by then an estimated five million people had left the city, ahead of Chinese New Year. Since the 2019-n-Cov has an incubation period between two and 14 days, it is quite possible that a large number of them may harbour the virus when they left the cordoned areas.

As the world struggles to find out ways to tackle the new threat, a series of studies published in the medical journals including BMJ and Lancet shed new lights on the n-Cov, which is one of the seven coronaviruses that are fatal to the human, the other two being SARS and MERS.

In one such study published in the Lancet, researchers at the Shandong First Medical University and Shandong Academy of Medical Sciences, claimed even though bats might be the original host of the virus, an animal sold at the Huanan seafood market in Wuhan may represent an intermediate host that enables the emergence of the virus in humans. The study is based on the analysis of ten genome sequences of the virus collected from nine patients.

“These data are consistent with a bat reservoir for coronaviruses in general and 2019-nCoV in particular. However, despite the importance of bats, it seems likely that another animal host is acting as an intermediate host between bats and humans,” says Guizhen Wu from the Chinese Center for Disease Control and Prevention.

Studying the spike protein of the virus (how it binds then enters human cells), the Shangdong researchers found that 2019-nCoV and human SARS virus have similar structures, despite some small differences. This means 2019-nCoV may be using the same molecular doorway to enter the cells as SARS, but a confirmation would require more studies.