“[Nations] implementing additional health measures that significantly interfere with international traffic (refusal of entry or departure of international travelers, baggage, cargo, containers, conveyances, goods, and the like, or their delay, for more than 24 hours) are obliged to send to WHO the public health rationale and justification within 48 hours of their implementation,” the WHO announcement stated.1 “WHO will review the justification and may request countries to reconsider their measures. WHO is required to share with other States Parties the information about measures and the justification received.”
Unfortunately, that was already happening with the rapid expansion of cases, and China will likely become more isolated until cases begin to drop.
“The decision was anticipated. I think it makes formal what had been happening already,” says William Schaffner, MD, an infectious disease physician at Vanderbilt University Medical Center. “Namely, travel to and from China was being interrupted informally in many circumstances. Our own university, for example, has let all students know that they were not to go to China on any kind of scholarly pursuit. That’s prudent of course. This will have major economic implications for China and it’s unfortunate that it has been instituted. In effect, it puts a country in quarantine.”
The WHO will dispatch a multidisciplinary team to China to review and support efforts that will investigate:
• the animal source of the outbreak;
• the clinical spectrum of the disease and its severity;
• the extent of human-to-human transmission in the community and in healthcare facilities;
• the current efforts to control the outbreak.
What Is the Source?
WHO particularly emphasized the importance of finding the source, to rule out hidden transmission and to inform risk management measures. As with SARS and MERS, 2019-nCoV is most likely from an intermediate animal host that contracted the virus from bats. WHO emphasized the need for enhanced surveillance in regions outside the epicenter in Hubei province, including pathogen genomic sequencing, to understand whether local cycles of transmission are occurring.
One infectious disease expert who is closely following the outbreak theorizes2 that 2019-nCoV has been circulating for some time, well before the first cases were discovered in the city of Wuhan. A recently published study3 of 41 cases suggests infections were occurring earlier in November, and perhaps October, but there was no available diagnostic test at that time, says Daniel Lucey, MD MPH, FIDSA, FACP, an infectious diseases physician at Georgetown University Medical Center.
“To tell you the truth, I think this outbreak started before the December outbreaks in the seafood and live animal market,” he says. “That paper shows 41 patients and what day they became symptomatic. The very first patient became sick on Dec. 1. The most important thing is that patient had no exposure to that seafood market. In fact, 14 of the 41 patients had no exposure to the seafood market. It didn’t start with the seafood market in Wuhan. It started somewhere else. How far back does it go? Is there a chain of initial cases that we didn’t know about — maybe from other markets? Also, to me that explains why there is such rapid spread now to all the other provinces and other countries. Because the virus has been around for a while — maybe even since September.”
In the absence of a test, prior cases were likely assumed to be pneumonia and flu that are common in the winter months in China, he says. “They developed the rapid diagnostic test after they first discovered the virus on Jan. 7,” Lucey says. “And now they are testing all of these people in hospitals with pneumonia and they are finding positives. That’s not because all of a sudden in December and January we have this mutated virus that is very contagious. It’s because the virus has been circulating for months in Wuhan.”
On Dec. 30, 2019, China reported an outbreak of respiratory disease in Wuhan City. Reports indicate that some of the first patients in China were at a Wuhan seafood market, which also sold chickens, bats, snakes, marmots, and other wild animals.
The scientific consensus is that both SARS and MERS coronaviruses arose in bats, before transferring, respectively, to palm civet cats in China and camels in Saudi Arabia. The animal reservoir of 2019-nCoV has not been definitively determined, but China has closed all live animal markets in the wake of the outbreak.
A recently published genetic analysis4 by Chinese scientists reported that the 2019-nCoV may be of snake origin via bats. However, the most likely suspect, as this report was filed, was pangolins, scaly ant-eating mammals that are protected, but sold on the black market for presumed medicinal benefits.5
Identifying that the palm civet cat was the intermediary host for SARS led to a mass culling of the animals from markets where they were sold live as food. In addition to that and other aggressive actions, the SARS outbreak ended relatively quickly and the virus has not been seen again. In contrast, the Saudis have resisted culling camels, an animal central to their culture. Thus, MERS is still present in the region, though it has not shown the ability to sustain transmission to other parts of the world.
“Each of these rogue coronaviruses that jump species from animals to humans has its own characteristics and personality,” Schaffner says. “From a scientific point of view and a better comprehensive understanding, we would like to figure out the animal source for the people in China.”
Though the animal source may yet be found, the situation has evolved from a suspected point-source outbreak at the Wuhan market to general widespread transmission in the community, the Centers for Disease Control and Prevention (CDC) reported recently.
“When the outbreak began, there was an indication that many of the cases had been at a seafood and live animal market in Wuhan province,” says Timothy Uyeki, MD, MPH, MPP, the Clinical Team Lead for the CDC response to 2019-nCoV. “However, as the weeks ensued, fewer and fewer cases reported that exposure. So, increasingly, reports out of China do not indicate specific exposure to a market or animal markets in general. So this, coupled with some of the other available information, suggests the virus is spreading person-to-person in China.”
Unknowns
WHO acknowledged that there are still many unknowns, as cases now have been reported in five WHO regions in one month, and human-to-human transmission has occurred outside Wuhan and outside China.
“The Committee believes that it is still possible to interrupt virus spread, provided that countries put in place strong measures to detect disease early, isolate and treat cases, trace contacts, and promote social distancing measures commensurate with the risk,” WHO stated.
The committee emphasized that the declaration of a PHEIC should “be seen in the spirit of support and appreciation for China, its people, and the actions China has taken on the frontlines of this outbreak, with transparency, and, it is to be hoped, with success. In line with the need for global solidarity, the Committee felt that a global coordinated effort is needed to enhance preparedness in other regions of the world that may need additional support for that.”
Priority measures are rapid development and access to potential vaccines, diagnostics, and antiviral medicines, which will be needed particularly if the virus spreads to countries with few resources.
“It is expected that further international exportation of cases may appear in any country,” the WHO stated. “Thus, all countries should be prepared for containment, including active surveillance, early detection, isolation and case management, contact tracing and prevention of onward spread of 2019-nCoV infection, and to share full data with WHO.”
- World Health Organization. Statement on the second meeting of the International Health Regulations (2005) Emergency Committee regarding the outbreak of novel coronavirus (2019-nCoV). Jan. 30, 2020. Available at: https://bit.ly/37D5iZU. Accessed Feb. 7, 2020.
- Lucey, D. An evidence-based hypothesis that the epidemic began in November 2019 or earlier and at a location other than the Wuhan Huanan seafood market: Major implications. Science Speaks: Global ID News. Jan. 25, 2020. Available at: https://bit.ly/38BqBey. Accessed Feb. 7, 2020.
- Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet 2020; Jan. 24. [Online ahead of print].
- Ji W, Wang W, Zhao X, et al. Homologous recombination within the spike glycoprotein of the newly identified coronavirus may boost cross-species transmission from snake to human. J Med Virol 2020; Jan. 22. [Online ahead of print].
- Cyranoski D. Did pangolins spread the China coronavirus to people? Nature. Feb. 7, 2020. Available at: https://go.nature.com/37iR4fQ. Accessed Feb. 12, 2020.
