The city of Wuhan in China is the focus of global attention due to an outbreak of
a febrile respiratory illness due to a coronavirus 2019-nCoV. In December 2019, there
was an outbreak of pneumonia of unknown cause in Wuhan, Hubei province in China, with
an epidemiological link to the Huanan Seafood Wholesale Market where there was also
sale of live animals. Notification of the WHO on 31 Dec 2019 by the Chinese Health
Authorities has prompted health authorities in Hong Kong, Macau, and Taiwan to step
up border surveillance, and generated concern and fears that it could mark the emergence
of a novel and serious threat to public health (WHO, 2020a, Parr, 2020).
The Chinese health authorities have taken prompt public health measures including
intensive surveillance, epidemiological investigations, and closure of the market
on 1 Jan 2020. SARS-CoV, MERS-CoV, avian influenza, influenza and other common respiratory
viruses were ruled out. The Chinese scientists were able to isolate a 2019-nCoV from
a patient within a short time on 7 Jan 2020 and perform genome sequencing of the 2019-nCoV.
The genetic sequence of the 2019-nCoV has become available to the WHO on 12 Jan 2020
and this has facilitated the laboratories in different countries to produce specific
diagnostic PCR tests for detecting the novel infection (WHO, 2020b). The 2019-nCoV
is a β CoV of group 2B with at least 70% similarity in genetic sequence to SARS-CoV
and has been named 2019-nCoV by the WHO.
SARS is a zoonosis caused by SARS-CoV, which first emerged in China in 2002 before
spreading to 29 countries/regions in 2003 through a travel-related global outbreak
with 8,098 cases with a case fatality rate of 9.6%. Nosocomial transmission of SARS-CoV
was common while the primary reservoir was putatively bats, although unproven as the
actual source and the intermediary source was civet cats in the wet markets in Guangdong
(Hui and Zumla, 2019). MERS is a novel lethal zoonotic disease of humans endemic to
the Middle East, caused by MERS-CoV. Humans are thought to acquire MERS-CoV infection
though contact with camels or camel products with a case fatality rate close to 35%
while nosocomial transmission is also a hallmark (Azhar et al., 2019). The recent
outbreak of clusters of viral pneumonia due to a 2019-nCoV in the Wuhan market poses
significant threats to international health and may be related to sale of bush meat
derived from wild or captive sources at the seafood market.
As of 10 Jan 2020, 41 patients have been diagnosed to have infection by the 2019-nCoV
animals. The onset of illness of the 41 cases ranges from 8 December 2019 to 2 January
2020. Symptoms include fever (>90% cases), malaise, dry cough (80%), shortness of
breath (20%) and respiratory distress (15%). The vital signs were stable in most of
the cases while leucopenia and lymphopenia were common. Among the 41 cases, six patients
have been discharged, seven patients are in critical care and one died, while the
remaining patients are in stable condition. The fatal case involved a 61 year-old
man with an abdominal tumour and cirrhosis who was admitted to a hospital due to respiratory
failure and severe pneumonia. The diagnoses included severe pneumonia, acute respiratory
distress syndrome, septic shock and multi-organ failure. The 2019-nCoV infection in
Wuhan appears clinically milder than SARS or MERS overall in terms of severity, case
fatality rate and transmissibility, which increases the risk of cases remaining undetected.
There is currently no clear evidence of human to human transmission. At present, 739
close contacts including 419 healthcare workers are being quarantined and monitored
for any development of symptoms (WHO, 2020b, Center for Health Protection and HKSAR,
2020). No new cases have been detected in Wuhan since 3 January 2020. However the
first case outside China was reported on 13th January 2020 in a Chinese tourist in
Thailand with no epidemiological linkage to the Huanan Seafood Wholesale Market.
The Chinese Health Authorities have carried out very appropriate and prompt response
measures including active case finding, and retrospective investigations of the current
cluster of patients which have been completed; The Huanan Seafood Wholesale Market
has been temporarily closed to carry out investigation, environmental sanitation and
disinfection; Public risk communication activities have been carried out to improve
public awareness and adoption of self-protection measures. Technical guidance on novel
coronavirus has been developed and will continue to be updated as additional information
becomes available.
However, many questions about the new coronavirus remain. While it appears to be transmitted
to humans via animals, the specific animals and other reservoirs need to be identified,
the transmission route, the incubation period and characteristics of the susceptible
population and survival rates. At present, there is however very limited clinical
information of the 2019-nCoV infection and data are missing in regard to the age range,
animal source of the virus, incubation period, epidemic curve, viral kinetics, transmission
route, pathogenesis, autopsy findings and any treatment response to antivirals among
the severe cases. Once there is any clue to the source of animals being responsible
for this outbreak, global public health authorities should examine the trading route
and source of movement of animals or products taken from the wild or captive conditions
from other parts to Wuhan and consider appropriate trading restrictions or other control
measures to limit. The rapid identification and containment of a novel coronavirus
virus in a short period of time is a re-assuring and a commendable achievement by
China’s public health authorities and reflects the increasing global capacity to detect,
identify, define and contain new outbreaks. The latest analysis show that the Wuhan
CoV cluster with the SARS CoV.10 (Novel coronavirus - China (01): (HU) WHO, phylogenetic
tree Archive Number: 20200112.6885385).
This outbreak brings back memories of the novel coronavirus outbreak in China, the
severe acute respiratory syndrome (SARS) in China in 2003, caused by a novel SARS-CoV-coronavirus
(World Health Organization, 2019a). SARS-CoV rapidly spread from southern China in
2003 and infected more than 3000 people, killing 774 by 2004, and then disappeared
– never to be seen again.
However, The Middle East Respiratory Syndrome (MERS) Coronavirus (MERS-CoV) (World
Health Organization, 2019b), a lethal zoonotic pathogen that was first identified
in humans in the Kingdom of Saudi Arabia (KSA) in 2012 continues to emerge and re-emerge
through intermittent sporadic cases, community clusters and nosocomial outbreaks.
Between 2012 and December 2019, a total of 2465 laboratory-confirmed cases of MERS-CoV
infection, including 850 deaths (34.4% mortality) were reported from 27 countries
to WHO, the majority of which were reported by KSA (2073 cases, 772 deaths. Whilst
several important aspects of MERS-CoV epidemiology, virology, mode of transmission,
pathogenesis, diagnosis, clinical features, have been defined, there remain many unanswered
questions, including source, transmission and epidemic potential. The Wuhan outbreak
is a stark reminder of the continuing threat of zoonotic diseases to global health
security. More significant and better targeted investments are required for a more
concerted and collaborative global effort, learning from experiences from all geographical
regions, through a ‘ONE-HUMAN-ENIVRONMENTAL-ANIMAL-HEALTH’ global consortium to reduce
the global threat of zoonotic diseases (Zumla et al., 2016). Sharing experience and
learning from all geographical regions and across disciplines will be key to sustaining
and further developing the progress being made.
Author declarations
All authors have a specialist interest in emerging and re-emerging pathogens. FN,
RK, OD, GI, TDMc, CD and AZ are members of the Pan-African Network on Emerging and
Re-emerging Infections (PANDORA-ID-NET) funded by the European and Developing Countries
Clinical Trials Partnership the EU Horizon 2020 Framework Programme for Research and
Innovation. AZ is a National Institutes of Health Research senior investigator. All
authors declare no conflicts of interest.