Human-to-human transfer can lead to local epidemics, independent of Wuhan: Hong Kong expert
The novel coronavirus (2019-CoV) outbreak may very well turn into a global epidemic soon, an expert has said.
Gabriel Leung, chair of public health medicine, Hong Kong University presented a bombastic report to the Chinese authorities, the World Health Organization (WHO) and media on January 27, 2020.
There is a possibility that city clusters in China, especially those connected to Wuhan, may develop local epidemics, over and above to those cases that they have imported from Wuhan due to ‘sustained’ human-to-human transmission, he said.
Hence the epicentre of the outbreak, which is currently only Wuhan, may extend to at least Beijing, Guangzhou and Shanghai. The total number of cases in Wuhan alone could be 44,000, he added.
Once local epidemics are established in these cities, which are well connected with the outside world, Leung said, it is very much possible that cities outside mainland China may start developing their own local epidemics. In short, he warned, we are staring at a global epidemic of the new coronavirus.
He also presented a slide in which he countered two possibilities of the total number of cases, showing two panels. One, if lockdown of cities had happened and if it were not.
His calculation showed that both the upper and lower panels had a similar number of cases. “This lockdown of several cities may not be able to change the course of the epidemic in other major city clusters as we might have thought of. This is not to say that they are ineffective but these measures do not show changing epidemic curves in major city clusters,” he said.
However, considering the fact that the world is staring at a global epidemic, he did recommend some measures which he called draconian such as cancellation of mass gatherings, closure of schools, asking people to work from home etc. He re-emphasised that there still remain many critical gaps in the knowledge about the virus.
Globally, the total confirmed cases have gone up to 4,474 and the deaths have climbed up to 107. The government of Canada confirmed its first patient on January 27. Three more cases were confirmed in the United States. These patients recently returned to America from Wuhan.
With this, the tally of cases outside China is as follows:
Sri Lanka, Germany and Ivory Coast confirmed their first cases on January 27. Ecuador has reported its first suspected case. The number of confirmed cases in Beijing increased to 80, with the first death also happening in the city.
Human-to-human transmissibility of 2019- nCoV is sufficient to support ‘sustained’ human transmission, Imperial College, London, said in its third report on the coronavirus outbreak released on January 27.
In a somewhat limited transmission, the virus dies after infecting an individual or cluster. However, that is not the case in sustained transmission.
“Self-sustaining human-to-human transmission of the novel coronavirus (2019-nCov) is the only plausible explanation of the scale of the outbreak in Wuhan. We estimate that, on average, each case infected 2.6,” the Imperial College report said.
While it was established that human-to-human transmission was happening before the report, there were hardly any estimates about the transmissibility.
Incidentally, in its last report published January 22, the institute’s researchers used an estimate of the frequency of international travel from Wuhan to estimate that 4,000 cases had occurred there with onset of symptoms up to January 18.
Reports point to mildly symptomatic but infectious cases of 2019-nCoV, which were not a feature of SARS. A Lancet paper released recently had indicated that detection of the cases may be challenging because the virus may be present in people showing no tangible systems like cough and mild fever, and therefore, quarantine efforts and surveillance were extremely important.
There might be many asymptomatic cases, the WHO also confirmed in a situational update issued on January 27.
The experts at Imperial College also say the recent decision of WHO not to declare this outbreak a global health emergency was no pointer to the severity of the outbreak.
“Despite the recent decision of the WHO Emergency Committee to not declare this a Public Health Emergency of International Concern at this time, this epidemic represents a clear and ongoing global health threat,” it said.
The virus’ incubation period is 1-14 days, according to Chinese officials. Worse is the fact that it is contagious even during the incubation period. The WHO, on the other hand, in a situational update says the incubation period could be 2-10 days.
As far as the risk assessment is concerned, the UN health body said it is very high in China, high at the regional level and high at the global level.
The health body said air transmission through droplets, contact and fomites can’t be ruled out. Therefore, people must avoid contact with people suffering from acute respiratory infections and do frequent hand-washing especially after contact will ill people.
What about India?
After France and the US, the Indian government has also decided to evacuate its citizens from Wuhan, the epicentre of the outbreak of the novel coronavirus.
This was decided at a meeting chaired by the cabinet secretary to review the preparedness amid the outbreak scare. So far, 12 samples have been tested for the virus from various parts of India by the National Institute of Virology (NIV), Pune, according to a government communique. All of them have tested negative.
Meanwhile, the sample of a 29-yr-old woman, who hails from Saran district in Bihar, has been sent to NIV.
“She is a student who had very briefly stayed in Wuhan before landing at Kolkata airport. She showed no symptoms immediately after landing on January 23. However, on the night of January 25, she displayed mild fever, chest pain and cough. Thereafter, she was brought to Patna and is not being kept at an isolation ward at Patna Medical College and Hospital. We are waiting for results from NIV,” a senior health department official told Down To Earth.
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