Horizon scanning for emergence of new viruses in animal and public health

Drivers in action: Horizon scanning for

emergence of new viruses in animal

health and public health

Dr Paul Gale

APHA, Weybridge, UK

Overview of this talk

• Define “horizon-scanning”

• Complex scenarios and combinations of events

• Spidergrams revisited

• Identifying “Unknowns”

• The Internet and approaches in other fields

• Closing thoughts: it’s all about getting the right experts talking

Horizon scanning for viruses

• What’s the next virus?

– Public health, Animal health, or both

• Is that virus even in the text books?

• Schmallenberg virus, November 2011

• What are its routes and from where?

• But was it in South Africa in 2006 – a weak signal missed?

Horizon scanning for viruses against a background of

change

• The world is changing – Political

– Economic

– Deforestation

– Fragmentation of landscape

– Globalisation

– Farming practice – intensity, breeds, feed

– Wildlife behaviour

– Climate

• The virus is changing – RNA viruses mutate rapidly and many are segmented

– Single amino acid changes in envelope protein affects vector specificity

Horizon scanning for emergence of new viruses - looking

for change

• Present - Short term – Disease monitoring

• Future – Medium to long term – Understanding the drivers and pathways

– Combinations of events

– How the world is likely to change – new routes, hosts and interactions

• Internet – Find out what people are doing – chat rooms, twitter

Prediction is difficult because of

complex scenarios for zoonotic and epizootic viruses

• Complex scenarios

– Anti-inflammatory drug give increase in rabies cases

• Drug use in cattle

• Vultures eat cattle carcasses and die from drug

• Cattle carcasses pile up

• Feral dogs increase

□ Dog bites and rabies cases increase

– WNV and swimming pools

• Increase in number of houses with swimming pools in boom

• House repossessions in economic crash

• Stagnant swimming pools become mosquito breeding sites

• Increase in vector for WNV

• Obvious afterwards

• Why didn’t I think of that? – before it happened

• How can we go about generating these complex scenarios?

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South Georgia Glacier changes since 1950

Retreat Advance

Map provided by

Prof. Alan Rodger

Developing complex scenarios comes through

talking to experts in different fields

Glacier

Land – rat free

Land – rat infested Impact – ground nesting birds

Constructing spidergrams: Examples of factors

• Zoological – Increase in rodents

– Decline in amphibians

– Increase in mosquitoes

– Increase in insectivorous birds

– Fall in wildlife biodiversity

– Fall in dragonfly abundance

– Increase in ecotoparasites (ticks)

– Increase in insects

– Collapse of a scavenger species

• Farming practice and husbandry – Change in breeds

– Intensity of farming

– Expansion of livestock farming into new habitats

– Mixing of sheep and cattle

– Failure of livestock carcass disposal

• Sustainability – More households with livestock

– Wood taken from copses for burning

– More allotments

• Environmental and climatic – Flooding

– Warmer soil temperature

• Land use – Loss of ponds and marshes

– Fragmentation of landscapes

– Deforestation

Ecological □ Increase in feral dogs

□ Increase in vector breeding sites

□ Exposure of pigs to bat

Socio-economic /Anthropogenic

□ Generation of stagnant water bodies

(swimming pools, poor plumbing, temporary

water storage)

□ Increase in wind turbines

□ Veterinary drugs and pesticides

□ Increased globalisation and transport

□ Failure of drinking water treatment and

sewage treatment

□ Failure of power supplies

□ Property maintenance

□ Eating more vegetables

Generation of 1,000s of complex scenarios

• Start with one from anthropogenic or environmental

• By systematically taking one from each category and

combining with one from the next category and so on…….

• Will most be meaningless?

• Will some give insights?

Anthropogenic

Increase in wind turbines

Farming practice and husbandry

Change in breeds Ecological

Increase in feral

dogs

Anthropogenic

Veterinary drugs and pesticides

(Diclofenac)

Farming practice and husbandry

Failure of livestock carcass disposal

Zoological

Collapse of a scavenger species

Ecological

Increase in feral

dogs

Some do make sense

Use your knowledge and expertise - Or randomly select? • Zoological

– Increase in rodents
















– More allotments





– Deforestation




Anthropogenic/ Socio-economic



water storage)





sewage treatment




Constructing a spidergram



Increase in feral dogs

Dog bites and rabies


Branches and extensions • Zoological

















– More allotments





– Deforestation







water storage)





sewage treatment




□ Increase in rubbish/landfills






Dog bites and rabies Increase in insects

Increase in insectivorous birds

West Nile virus host

Increase in

Ecotoparasites

(ticks and fleas) Hantavirus

Increase in rubbish/landfills

Increase in rodents

Combinations • Zoological










– Increase in seagulls








– More allotments


– Warmer temperature



– Deforestation







water storage)





sewage treatment




□ Increase in rubbish/landfills






Dog bites and rabies Increase in insects

Increase in insectivorous birds

West Nile virus host

Increase in

Ecotoparasites

(ticks and fleas) Hantavirus

Increase in rubbish/landfills

Increase in rodents

Flooding

Warmer

temperature

Overview of European Science Foundation-funded

workshop to test spidergrams (July 2010)

• All participants very positive

• Spidergram approach provides a framework for how different factors could interact, irrespective of the virus

• Enables the testing of combinations not previously considered but which would be tested in nature

• Spidergrams generate discussion points and new angles – It gets people talking

• Use of spidergrams for developing case-control questionnaires

Nipah virus

• Fatal encephalitis in humans (pig farmers) in Malaysia, India and Bangladesh

• Pigs infected by Pteropus fruit bats

– Deforestation

– Pigs exposed to bat saliva on partially eaten fruit

– Level of containment of pigs important

• Pigs infect humans

• The spidergram for Nipah virus suggested how emergence could be linked to temperature through a range of seemingly unrelated factors including migration, deforestation and war

– Looking for climate change impact on NiV

Migration

*Level of

containment

War Host

behaviour

Poverty

Deforestation

Temperature Nipah Virus

*Level of containment of pigs/biocontrol

Spidergram for Nipah Virus

(Drought?)

Effect of … on Mig LC Temp War HB Pov Def

Migration + NA +? + ++ +

Level of

containment NA NA NA + NA

Temperature ++ + + + + ++

War + + NA + + +

Host behaviour NA + NA NA+ + NA

Poverty + ++ NA + + +

Deforestation ++ + + + + +

Effect of pairwise linkages with respect to Nipah virus. For each pair the

factor listed in the left hand column is the primary driver in the linkage, and

the factor in top row is the factor that may be affected

Some of these links are not obvious…….

with missing information

Acid rain

Wild bird behaviour

Environmental & Climatic

Zoological

Outcome

Missing information……., the calcium link

Making sense of it …….., filling in the detail

Acid rain

Wild bird behaviour

Environmental & Climatic

Zoological

Increase in contacts

between backyard

poultry and wild birds?

Feed, faeces, egg shells?

Outcome

Decline in snails/Calcium Zoological

Calcium foraging

Could spidergrams shift the focus

to identify what we don’t know?

• Known-knowns – Need to break out of this box: Ask a stupid question

• Known-unknowns – Specified well-defined data gaps

• Viraemia levels in dogs exposed to EBOV

– Ideal for “further work required” type recommendations

• Unknown-knowns – Acid rain affects wild bird behaviour

• Known: acid rain/calcium in physical chemistry books

• Unknown to me, need to think outside the veterinary microbiology box

• Important – bridging species for H5N1 transmission to BYD poultry?

• Unknown-unknowns – Ebola virus outbreak

• Role of mobile phones and better transport recruiting relatives to funeral of a case

– Unknown-unknown is really the outcome of change in a world of combinations of events

– Spidergrams can help

Using the Internet - H5N1 transmission through frozen duck meat to backyard chickens

• Germany in 2007 (Harder et al. 2009) – Risk of presence of HPAIV in meat destined for human consumption had

been estimated to be low (Harder et al. 2009)

• But had anyone thought about duck meat being fed to poultry? • Internet chat rooms on feeding meat to poultry

• “Can chickens eat meat or not?” (2009) – “my chickens get all food scraps”

– “I would only give them unprocessed meat

– Mine get meat but nothing too greasy” – Unknown-known

H5N1 asymptomatic

infections in ducks

Frozen duck meat in

food chain Raw duck meat scraps

fed to chickens

Aug 2007 December 2007 Frozen food

Human

Human

Horizon scanning: Overlaying known pathways

to new scenarios

Brain

Tradition

kuru

Mortuary cannibalism

Amplification

Cattle

Cattle

Horizon scanning: Overlaying known pathways

to new scenarios

Brain

Rendering

BSE

MBM, farming practice

So we’re now looking for a “virus” with a particular

combination of properties to fit to a new scenario:- 1. More thermo-stable TSE strain

2. Highly infectious to cows through oral route

Amplification

Spotting a bad idea: the right combination

of experts

• BSE epidemic in UK in the 1980/90s

• New disease, but …. – Renderer (thermal conditions of rendering and efficiency)

– Expert on thermostability of TSEs

– Epidemiologist on transmission of TSEs through cannibalism (kuru)

• Oral route

• Brains

– Cattle feed production manager/farming practice expert (recycling of cattle brain into MBM feed)

• Did this group ever get together in the early 1980s?

“If you’ve done your job properly as a

horizon scanner, nobody knows you’ve

done it” (Fiona Lickorish)

We need help to make sense out of nonsense

How do other fields get help?

A FEW MILLION VIRTUAL MONKEYS ARE CLOSE

TO RE-CREATING THE COMPLETE WORKS OF

SHAKESPEARE BY RANDOMLY MASHING KEYS ON

VIRTUAL TYPEWRITERS.

A running total of how well they are doing shows

that the re-creation is 99.990% complete

Online game Foldit helps anti-Aids drug quest (www.bbx.co.uk 20 Sep 2011)

The game, called Foldit, allows players to create new shapes of

proteins by randomly folding digital molecules

on their computer srceens

Virtual monkeys write Shakespeare (www.bbc.co.uk 26 Sep 2011)

Can we think up an “on-line game” to generate

complex scenarios?

Human intuition vs automated methods

Humans are good are spatial reasoning

http://www.bbx.co.uk/

http://www.bbc.co.uk/

Closing thoughts

• Trying to make sense out of nonsense, order out of disorder • Right combinations of people

– Broad range of disciplines

• Keep talking to experts in different fields – Critical mass of scientists needed

• Spidergrams give a starting point in producing random links – Combinations of events

• Missing information is a problem – filling in the detail • Internet is a huge database

– Text mining – discussion fora, social networking sites – Possibility of automation to generate complex scenarios – And identify change

• Could set up a web-forum with a universal set of factors for spidergram generation

Can YOU think up an “on-line game” to generate complex

scenarios?

Thank You

Some key points from workshops

• Long term MEGA trends, e.g., climatic. • “If you’re not making people uncomfortable you’re not

doing your job” (Fiona Lickorish) • Five “i”s (Ozcan Saritas)

– Intelligence, imagination, integration, interpretation (vision to action) and intervention

– This is what the spidergrams try to do

• Amplifying weak signals – Problem getting heard – index case of a new virus – What’s its trajectory?

• What’s changed, e.g. mobile phones, transport in Ebola virus

• Wild cards (e.g. swine flu 2009, Ebola virus outbreak 2013) • Non-linearity – people not good at this, good at pattern

recognition – How many clicks are we away from a disaster? – Can spidergrams take us further up the chain?

• Give us a bit more warning

Horizon scanning for emergence of new viruses in animal and public health

Food

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