Scientists still 'don't know the source' of Wuhan coronavirus

As China takes measures to stop the spread of the virus, health officials are working to understand how it is transmitted. DW spoke with infectious disease expert Raina MacIntyre about what could happen next.

DW: On Thursday, the World Health Organization (WHO) said it was "too early" to declare the coronavirus outbreak a global health emergency. Do you agree with this assessment?

Raina MacIntyre: I think there are not enough cases to prove that substantial personto-person transmission has happened, so that is probably what stopped the WHO from declaring a public health emergency of international concern. Another contributing factor is that China has taken the measure of locking down Wuhan and other cities.

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Do you consider the measures that China has taken, including locking down Wuhan and other cities in Hubei province, to be an e ective way of preventing the virus from spreading?

Yes, because at this point, most of the cases are still in Wuhan. Although there is some person-to-person transmission, the level is currently minimal. Whatever is causing the infection is still in Wuhan. The virus is going to spread through travel, especially when people go from Wuhan to somewhere else. For example, this happened with the cases in Thailand, Singapore and the US. So if the lockdown is enforced, it will have an impact on the transmission of the disease. There shouldn't be as many cases occurring overseas later on.

Do you think the information that has come out of China over the last few days is providing more evidence of how the virus is transmitted?

I think China's measures have mostly focused on people's movement, which reduces the likelihood of infection being spread through travel. These measures include the lockdown of the city, screening at airports

and giving passengers information on who to contact if they develop symptoms.

A second way to stop the spread is through the healthcare system. People with fever or a minor cough who go to the doctor or the hospital must be asked about their travel history.

If they have traveled to China, particularly to Wuhan, they must be isolated until further tests can be done. These simple measures will prevent outbreaks happening in hospitals, since coronavirus does have the tendency of causing hospital outbreaks.

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Comparing to how China handled the SARS epidemic in 2002, how would you assess the Chinese government's response to the current crisis right now?

Compared to SARS, China is definitely a lot more open about the development of the current epidemic. For example, the sequencing of the virus and genome were done in collaboration between Chinese and international scientists. That was made public so other people can use them and study them, and develop diagnostic tests and vaccine research. China has also been working closely with the WHO on controlling the epidemic.

I also think that since the SARS outbreak, China has developed a surveillance system, which they didn't have at the time of SARS. They should be able to pick up new cases very rapidly now.

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How do you think the international community should respond?

I think robust disease surveillance is critical for identifying new cases as they arise. Also, countries should continue to do research and analysis to identify the source of the infection, because so far we still don't know what the source of this coronavirus is. To control the epidemic, we need to know where the virus comes from.

We also need to understand its transmission, because that will guide the best disease control and intervention. It's still a mixed picture right now. Most cases are not spread through human-to-human contact, but there are some cases reflecting that tendency.

China needs to do more work and to publish epidemiological analysis to understand the main causes for this disease. Obviously, the development of drugs and vaccines will help as well, but there is a lot that can be done by identifying cases quickly, isolating them, tracking their contacts and restricting and monitoring travel.

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Raina MacIntyre is a professor of global biosecurity at the University of New South Wales in Australia. She also heads theBiosecurity Programat the Kirby Institute, which conducts research in epidemiology, vaccinology and public health.

The interview was conducted by William Yang.