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Zoom conference, Friday 31 January 2020, 1pm (Paris time)
Participants: Billy Karesh (Chair
– President OIE Wildlife Working Group), Casey Barton Behravesh (Centers for
Disease Control, USA), Peter Ben Embarek (WHO), Etienne Bonbon (FAO), Stephane
de La Rocque (WHO), Keith Hamilton (OIE), Hiroshi Kida (Hokkaido University),
Jean-Claude Manuguerra (Institut Pasteur, Paris), Stefano Messori (OIE),
Misheck Mulumba (OIE Scientific Commission for Animal Diseases), Malik Peiris
(Hong Kong University), Dirk Pfeiffer (Hong Kong University), Primal Silva
(Canadian Food Inspection Agency), Changchun Tu (Changchun Veterinary Research
Institute) Sophie VonDobschuetz (FAO), Linfa Wang (Duke University, Singapore),
Zheng Zengren (OIE Scientific Commission for Animal Diseases)
The purpose of the call was to
discuss what is known about the role of animals in the emergence of Coronavirus
Disease 2019, COVID-19 (caused by the SARS-CoV-2 virus (otherwise known as the
COVID virus)) and to make preliminary recommendations relating to
investigations at the human-animal ecosystems interface.
1. Review of current knowledge base
Many important questions remain
unanswered about the animal origin of the COVID-19 virus. Although an animal
source is probable, the scarcity of information leaves significant knowledge
gaps, which leaves the door open for speculation and rumours. The lack of
evidence also leads to, and in some ways necessitates, several assumptions
being made.
From what is known, the COVID-19
virus isolated from humans shares 96% homology with beta coronaviruses isolated
from multiple species of bats in the genus Rhinolophus (Yunnan, 2013). SARSCoV
isolated from humans shared 92% homology with SARS-like viruses that were
circulating in bats. 90% of the SARS-like viruses from bats have been isolated
from the Rhinolophus genus. The comparatively strong genetic sequence homology
between the COVID-19 virus and beta coronavirus isolated from bats suggests
that ancestors of the COVID-19 virus were circulating in bats in the
Rhinolophus genus. Bats belonging to the Rhinolophus genus are widely
distributed across Asia, the Middle East, Africa and Europe.
There is evidence that the
transmission of SARS-CoV from an animal reservoir to humans involved an
intermediate host (civets were implicated as an intermediate host for
SARS-CoV). Owing to similarities between SARS-CoV and the COVID-19 virus,
including the circumstances around their emergence, and considering the absence
of other plausible theories an alternative assumption is being made that the
transmission route of the COVID-19 virus to humans involved an intermediate
animal host which has yet to be identified as opposed to direct bat to human
transmission. The epidemiology of MERS shows how the role of an intermediate
host can be more significant at the human animal interface than the original
animal source of the virus. Thus, it is important to investigate the
involvement of an intermediate host and to identify it.
Human epidemiological data links
a high proportion of first- and second-generation human cases of COVID-19 to
the Huanan Seafood Wholesale Market in Wuhan. An assumption is made that the
COVID-19 virus was introduced to humans who visited or worked in the market. In
the absence of detailed epidemiological data, several hypotheses exist for the
introduction of the COVID-19 virus from animals to humans at the market.
These include that 1. the virus
was introduced to the human population from an animal source at the market and
2. that a human introduced the COVID-19 virus to the market (following exposure
to the virus outside the market) and the virus was then amplified in animals
which then infected humans.
There is only preliminary and
incomplete information from investigations into the animal source at the
market. This is understandable considering the importance and urgency of focussing
on the public health response to contain the disease. However, information from
these investigations is critical because it may hold the key to preventing
further introductions of the virus into the human population, and it may also
provide useful insights to reduce the risk of future spill over events from
animals to humans.
In the absence of detailed
information, the following assumptions are made. That a spill over event from
animals to humans occurred at the Huanan Seafood Wholesale Market. The fact
that wildlife was being sold at a seafood market indicates a possible route of
introduction by wild species being brought into the market.
It is likely that many different
animal species were present in the market. Sampling investigations would likely
have taken place several days (at least one incubation period) after
animalhuman exposure had occurred, by which time the source animals may no
longer have been present in the market. It is known that samples were taken
from several species of animal and that none of these samples tested positive,
however information about the number of samples and species sampled is not
available. However, several environmental (swab) samples did test positive and
virus was isolated from environmental sample(s). It is not clear exactly how
animals were incriminated from the positive environmental samples (apart from
knowing that the swabs were taken from areas adjacent to where animals had been
kept). The fact that the COVID-19 virus was easily isolated from environmental
specimens taken at the Huanan Seafood Wholesale Market suggests that
survivability of the virus in the environment is good and/or that viral load in
the environment was high. In general, the COVID-19 virus and other SARS-like
viruses appear to be stable; this has implications for contamination of and
persistence in the environment and on fomites. Available information also
suggests that it is relatively easy to culture and isolate the COVID-19 virus
from specimens and that the virus grows well in Vero cells.
It is critical that important
epidemiological and virological information which may explain the emergence and
transmission of the COVID-19 virus from animals to humans is collected and
preserved.
The opportunity to understand
this event must not be lost. General immediate recommendations:
• The
Advisory Group offers technical collaboration to support investigations into
the animal source.
• Multisectoral
one health collaboration including animal health, public health, wildlife
experts should be encouraged.
• Immediate
sharing of information from field investigations so far (including positive and
negative results) should be encouraged.
2. Research priorities (broad
categories):
SURVEILLANCE AND RISK ASSESSMENT
Strategic objective: To develop a
better understanding of the key determinants of COVID-19 virus infection and
transmission dynamics in animals (including at ecosystem level) and to humans
to inform research, surveillance, and control.
Suggestions:
o Identify
the animal reservoir and intermediate host through surveillance/investigation
strategies which consider:
▪ Evidence that ancestors of the COVID-19 virus
circulate in bats from Rhinolophus genus.
▪ The absence of information about an intermediate
host, which could be any number of animal species (including wildlife,
pests/vermin, domestic animals (companion or livestock), stray/feral animals).
▪ In the absence of specific information, studies
into the role of animals may need to consider a broad range of animal types and
species. Where possible and appropriate, scientific information
(epidemiological, virological, genetic etc.) may guide and support targeting of
the investigations.
▪ Broad serological surveillance is more likely to
detect the COVID-19 virus in animals than virological surveillance alone
(virological surveillance is too narrow). Serological studies can guide more
specific targeted virological surveillance.
▪ Targeting surveillance to selected locations may
improve likelihood of detection e.g. markets/farms where wildlife and other
animal species (including domestic animals/livestock) are gathered
(particularly markets with a link to the Huanan Seafood Wholesale Market).
Sampling locations may include other points identified along the supply chain
to and from the market. Investigation around markets should also consider that,
many markets have already been closed to support control efforts.
▪ Other types of animal (free ranging, feral, vermin)
found in proximity to markets (and other relevant locations) should also be
considered in investigations.
▪ Strategies could include testing archived animal
samples (serum, faeces etc.) collected from recent surveillance projects.
▪ Positive environmental samples could be tested for
genetic material belonging to animal species (using metagenomics or DNA bar
coding techniques (DNA bar coding may be more efficient than sequencing the
whole genome)). This approach may guide investigations to identify the source
of environmental contamination.
▪ Rhinolophus group has extensive range, concerted research in China
has found >50 SARSlike CoV’s. Using biodiversity and host-phylogenetic
diversity data sets to model targeting of sampling to increase likelihood of
identifying range of reservoirs across Asia, Middle East and Europe.
o Transmission pathways
▪ Investigate potential transmission pathways from animal reservoirs to
intermediate hosts to humans.
▪ Evaluate the role of intermediate hosts in amplifying the virus.
▪ Investigate routes and duration of viral shedding from potential
hosts.
▪ Investigate viral persistence under a variety of environmental
conditions.
▪ Testing of farmed wildlife, wildlife markets and wild animals of
species other than bats that could be intermediate hosts to identify potential
CoVs and possible transmission pathways to humans.
▪ Investigate the possibility for transmission from humans to animals
(domestic animals).
o Host range
▪ Investigate the possible animal host range of the COVID-19 virus
(including use of field (serology) and laboratory studies). o Dynamics of
wildlife trade
▪ Better understand the dynamics of wildlife trade e.g. origin of
different wildlife species in markets, diversity of species, husbandry/production
practices, contact/mixing of groups, supply chains etc.
o Possible role of livestock
▪ As well as assessing the possible role of other types of animal
(wildlife, stray animals), it will be important to consider the possible role
of livestock, including the possibility for them to become infected by humans.
o Possible role of companion animals in
epidemiology of human disease
▪ Assess the potential role of
pets and companion animals in the epidemiology of the disease in countries
affected with human cases. Consider investigations/sampling of pets of humans
suspected or confirmed with disease.
DIAGNOSTICS
Strategic objective: To develop
diagnostic tools (for use in animal species) that provide consistent optimal
results in any setting.
Suggestions:
o Serology
▪ A fit for purpose serology test
for use in different species would be a powerful tool in surveillance for the
COVID-19 virus in animals (the utility of serology was demonstrated in SARS-CoV
and Hendra virus investigations).
▪ Adapt and validate current
serology test for antibodies to the COVID-19 virus used in humans to animal
systems.
▪ Consider developing laboratory
and field serology kits for animal investigations.
▪ Assess cross reactivity between
the COVID-19 virus and other SARS-like viruses.
▪ Recombinant protein techniques
can play a role in developing serological techniques. o RT-PCR
▪ RT-PCR platforms for the
COVID19 virus have been developed and disseminated for use in humans. ▪ RT-PCR
platforms for the COVID-19 virus need to be adapted to animal systems.
▪ RT-PCR tools need to be adapted
to be fit for purpose e.g. For initial screening of animal surveillance
samples, sensitivity will be more important than specificity, therefore for RT-PCR
screening tools, primers which span the whole subgroup of SARS-like viruses
could be used (with SARS as a positive control). RT-PCR which are more specific
to the COVID-19 virus could be used to differentiate viruses when samples are
positive on screening.
o Other tests
▪ Virus neutralisation, pseudo
particle VN, and other tests may also be useful for detection in animal
samples.
PREVENTION AND CONTROL
INTERVENTIONS
Strategic objective: To
guide targeted and effective evidence-based interventions.
Suggestions: In addition to the priorities listed under
Surveillance and Risk Assessment above:
o Collect baseline data to inform prevention
and control strategies
Conduct studies to develop a
better understanding of the dynamics around illegal wildlife capture,
transport, and trading, and current prevention strategies, considering:
• Social science around criminal behaviour.
• Social/marketing studies on consumer demand.
• Existing international standards, agreements, legislation, and
guidance around wildlife trade, markets etc.
• Relevant stakeholders – NGOs, IOs, national government, public,
criminals, traders.
• Coordination between law enforcement, veterinary services, market
inspectors/regulators.
• Effectiveness of various interventions e.g. law enforcement,
legislation, prosecution, risk communication, incentivisation of legal
practices, certification.
• Use of innovation and technology in criminal
surveillance/prosecution – cameras, drones, identification of animals.
• The management of wet markets in China, particularly in Wuhan.
Identify high-risk practices and
behaviours (for spill over events) along the food/wildlife supply chain.
o Assess drivers of high-risk practices
▪ Social and economic drivers of legal and illegal activities.
▪ Value chains leading to human animal/wildlife/environmental
exposure
o Develop strategies to reduce risk of spill
over events
▪ Research to determine the most effective risk communication
strategies which avoid stigmatisation and other unintended consequences.
▪ Research to determine the most effective social and behavioural
change (SBC) practices to improve hygiene practices at wet markets.
▪ Research to determine most effective SBC practices to implement
realistic and feasible strategies to encourage a high level of compliance at
wet markets.
▪ Research to determine the strategy to strictly manage the wild
animal farming and to stop the illegal transportation and trading as well as
smuggling.
o Information from laboratory studies
▪ In the absence of field data, animal laboratory studies could help
to inform prevention and control strategies e.g. animal models.
HOST-PATHOGEN INTERACTION
Strategic objective: To improve understanding of virus-host
interactions and factors that impact on the interactions such as disease
pathogenesis, transmissibility, and immune responses to better inform infection
control.
Suggestions:
o Host pathogen studies
▪ Animal susceptibility - host range determination, receptor
specificity/distribution in different species etc.
▪ Cell line infections and animal experimental infections to
understand transmission and pathogenicity.
▪ Epidemiology of CoV in animal reservoirs, i.e. from bats to other
species (viral load, routes of transmission). o Behavioural risk
▪ Identify communities with high levels of exposure to bats and other
key wildlife; analyse their risk behaviours; test samples from wildlife and
people in these communities for serological evidence of the COVID-19 virus and
other CoV spill over.
▪ Inserting standardized key questions on wildlife exposure to be
used during interview with suspected cases.
SOCIO-ECONOMICS AND POLICY
Strategic objective: To improve
the effectiveness of detection, prevention and control measures through the
integration of social, economic and institutional analyses of the environment
affected.
Suggestions:
o Wildlife
trade
▪ Define what is meant by wildlife (i.e. farmed wildlife vs. domestic
animals/livestock etc.) in different contexts.
▪ Characterize the wildlife trade value chain globally and regionally
and how it is linked with China. ▪ Policy/social research to regulate wildlife
trading – innovation (cameras, drones etc.), collaboration with social
scientists, law enforcement/ behaviour/demographic patterns.
▪ Study of economic impact of removing wildlife from markets and
market closures.
▪ Analyses of the social impacts and economic analyses of different
degrees of limiting wildlife trade for food: 1) complete ban; 2) partial ban
(select species); 3) regulating and testing animals; 4) promoting only farmed
wildlife as a source of food.
o Wildlife capture vs. Production
▪ Scenario analysis of whether or not farming wildlife reduces the
risk of CoV emergence as compared to wild caught wildlife.
o Wildlife consumption
▪ Survey of public to assesses knowledge, attitudes, and practices
around wildlife consumption, geographic variation, and changing demographics.
o Domestic
animals
▪ Draw on research/risk
communication already existing in this area relating to other zoonotic diseases
(e.g. zoonotic influenza, Nipah, SARS, etc.) related to the breeding, keeping,
selling and consumption of livestock.
3. Additional general notes:
There is a need to learn lessons
from the introduction of the COVID-10 virus to the human population and from
similar past events. A similar event in the future is inevitable.
Research
There is a need to highlight the limitations of
research objectives in order to manage expectations on outcomes.
Risk mitigation strategies
It will be important to take a comprehensive long-term
approach to risk mitigation strategies which aim to reduce the risk of spill
over events. Risk mitigation strategies need to feasible and consider cultural
importance of certain high-risk practices. They need to adopt a
multidisciplinary approach (vets, economists, food hygienists, microbiologists,
social scientists, communication experts) and could include a package of risk
mitigation measures targeted to the right stakeholders. In risk communication
there is a need to be clear about the current uncertainties around the role of
animals in human outbreaks or animal species involved and it will be important
to manage expectations e.g. risk can be reduced but not eliminated.
For short
term, a key message is that the highest risk for COVID-19 virus infection is
human to human transmission; identifying animal hosts is only an additional measure
so that other (rare) spill over events can be reduced and similar human
outbreaks prevented in future. Risk communication can also build on material
developed for other risk mitigation strategies (Ebola and wildlife/bushmeat,
zoonotic avian influenza and live bird markets). The spectrum of people at risk
in different systems (field scientists, farmers, traders, consumers) needs to
be considered in risk communication and other risk mitigation strategies.
Interventions need to be targeted for maximal positive impact (e.g. HACCP) and
policies should avoid or manage unintended negative consequences (regulatory
impact assessment). Studies and guidance on wildlife trading and consumption
should be adapted to both the global and regional levels i.e. global coverage
whilst considering regional characteristics and specificities. Strategies
should be realistic and focus on risk reduction rather than elimination and
should take lessons from other successful policy initiatives which led to
behaviour change e.g. seat belts, smoking, diet.
Source :
OIE :
World Organization for Animal Health
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