What is an endemic
= A disease that is present within a population and constantly maintained at a baseline level within a geographical area.
Eg TB in UK badger population
What is an epidemic
= The rapid spread of a disease within a geographical area or population. Not worldwide
What is a pandemic
= The rapid spread of a disease across a large region (continents or worldwide).
E.g. Bovine Spongiform Encephalopathy (BSE), H1N1 Swine Flu
What is globalisation and factors
= The process by which the world is becoming increasingly connected as a result of increased trade and cultural exchange
- International communication, trade and partnerships
- Global exchange of people and goods
- 30-40 million flights moved over 4 billion passengers per year globally pre-COVID
- Driven by growing world population and increased demand for animal protein
- Cause ecosystems to interact at a local and global level
What is the impact of globalisation and animal health
- Interaction between ecosystems:
~ Emergence of new pathogens at intersection between habitats: humans, domestic animals (poor biosecurity), wildlife
~ Greater animal-animal and animal-human interface leading to zoonotic disease and contagious disease spread - Global movement of people, animals and goods
~ Spread of disease over long distances/greater range
e.g. travel on wind
person takes dogs from romania, if quarantine = low risk but can still transmit - Pathogens may encounter new environments favourable for growth:
~ High density of naïve populations
~ Adequate vectors
~ This will greater increase spread (possible epidemic)
Urbanisation
- Up to 90% population growth expected in cities of developing countries
- Rural pathogens (wildlife, livestock) adapt to urban areas
- cattle in amazon - cut trees, room due to urbanisation
- Impact of urbanisation on drivers of EIDs (emerging infectious diseases)
~ Increased population density
~ Increased migration
~ Increased trade
~ Change in sanitation/biosecurity - stagnent water moved = spread protozoa
Lassa fever - about and stats
= An acute viral haemorrhagic virus
- endemic
- Virus transmitted via
~ food contaminated with excrement from infected rats
~ direct contact between humans (contagious zoonotic disease)
- 4 in 5 infected show no symptoms
- 1 in 5 results in serious disease with virus affecting liver spleen and kidneys
- 1% mortality within 2 weeks of infection
Lassa fever - globalisation
- seasonal outbreak dec-mar
- disease endemic to region so outbreak expected
- Redding et al 2016 paper = Created a model to determine the impact of global change on the spread and prevalence of Lassa fever from 2012 to 2070
- Study highlights need to look at more than one disease – decrease in one pathogen may cause increase in another
Lassa Fever - The Impact of Urbanisation and Abiotic Factors
- 4 variables
1. Land use change: savannah and grasslands to agricultural crops
2. Expected changes in human mobility patterns: assumed decreased movement in these areas due to increased wealth as a consequence of land change
increase agriculture = increased wealth = stay
3. Human population: increasing
4. Climate change: hotter and wetter
future prediction double lasa spillovers per year (400,000)
Lassa fever- results from redding paper what can we dtermine from findings - land use
- Land use change: only slightly above 200,000 spill over events presently
~ Minimal impact on Lassa fever emergence
~ Rat is a common household and agriculture rodent pest so both environments support the host.
~ No expected change in rat populations
Lassa fever- results from redding paper what can we dtermine from findings - mobility
- Mobility (movement of individuals): slightly less than present value of spillover events
~ Expected to decline in infected areas due to increased wealth, hence negative impact on spread.
~ Reduced human-host contact and human-human contact
~ assumes no increase in population size
Lassa fever- results from redding paper what can we dtermine from findings - demographic change
- Demographic changes:
~ The single biggest impact on disease emergence
~ Increased population = increased host-human and human-human contact (mode of transmission important) more rats/cats and more contact as less space
~ increase no. niaeve individuals = no immune response
~ increase population density = more rat-human contact, more humans to be infected
Lassa fever- results from redding paper what can we dtermine from findings - climate change
- A significantly positive impact on disease emergence
- Wetter, humid conditions provide a more suitable habitat for host (rat)
Deforestation and How can deforestation affect the (re)emergence of infectious diseases?
- Removal of woodland/forests
- Commodities such as palm oil, soy, beef and wood.
- soil borne diseases enter air
- wildlife loose habitat
- human movement into areas with companion/livestock animals
(morand and Lajaunie 2021)
- as forest cover % decreases, the number of zoonotic outbreaks increases ~ 31.5% cover = around 75 outbreaks, 30.75 cover = 230 outbreaks
- as forest cover decreases no. vector borne disease outbreaks increases ~ 31.5% cover = 25 VBDO, 30.75% cover = 170 VBDO
- as palm oil area increases, zoonotic outbreak increases ~ 10 ha = 50 zoonotic outbreaks, 20 ha = 210 zoonotic outbreaks
- as palm il area increases, vector borne outbreaks increases ~ 10 ha = 25 VBDO, 20 ha = 155 VBDO
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Animal trade and disease emergance (3 types of animal trade)
- Illegal trade (exotic species)
~ Host species jumps (wet markets = live animals in close proximity, naïve populations)
~ Zoonotic infections, public health risk - Companion animal trade
~ Transboundary diseases = any disease that can cross geographical boundries
~ Pet passport scheme - subside disease and contain as much as possible
eradicating certain diseases in each country varies - companion not moved around as much
less research how disease spread and viral mutate for exotic animals - Livestock trade Eg BTV-8 and African Swine Fever
~ Spread across geographical areas
~ Naïve hosts
~ Potential rapid spread due to high population density
Illegal wildlife trade - species and no. of seizures
- no single species responsible for more than 5% of illegal wildlife trade seizures
- mamals most popular at 23% closely followed by reptiles with 21.3%
- no. seizures has steadily increased since 1999 w/ 3317 and up to 20,762 in 2017
Pathogen Prevalence within the Illegal Wildlife Trade
- rush et al 2021
- Systematic Review of Literature
- 82 research papers and case studies published from 1990 to 2020
- 126 events, 95 of which (75%) animals were live when seized
- Within those 126 seizures they detected ~ 240 total pathogens:
~ 85 viruses,
~ 87 bacteria,
~ 12 fungi,
~ 8 protozoans,
~ 40 endoparasites,
~ 8 ectoparasites - united states most prevelent with no. pathogens introduced through illegal wildlife trade - majority = viral
- france close behind with the majority = bacterial
- breeding of animals = close contact = increase risk disease spread/prevalence
Pathogen Prevalence within Taxa of the IWF
Rush, et al., 2021
- Birds: 44 different pathogens
- Mammals: 47 different pathogens
- Reptiles: 16 different pathogens
- Amphibians: 2 different pathogens
- Fish: 1 pathogen
- Invertebrates: 1 pathogen
Birds and mammals not necessarily greater risk, but perhaps more commonly traded and or seized, or more commonly published (systematic review).
- could be commonly published/traded = see more of particular pathogens
Current management strategies to minimise disease
- efficient vaccines
- antimicrobials
- theraputics
- understanding of biosecurity
- global legislation on animal movement and trade
- FAO and WHO animal health
- development of models to identify threats
- legislation in place for certain diseases
- communication systems for rapid exchange of data
- diagnostic tests = molecular biology (rapid detection)
- rapid detection of infections
Role of FAO and OIE
- 1994: FAO Emergency Prevention System EMPRES
~ Early warning, early detection and early response - 2004: FAO/OIE initiative: Global Framework for the Progressive Control of Transboundary Animal Diseases (GF-TADs) www.gf-tads.org
~ Key to eradication of Rinderpest 2011 - OIE strategic plan 2011-2015: Good governance of Veterinary Services
~ Performance of Veterinary Services pathway
~ Supports Vet services in establishing current level of performance
~ Disease surveillance, research and education, communication.
Future management
- Advanced technology to predict outbreaks
~ Computer models and communication routes
~ Without intervention from humans this will be ineffective - Involve the media –what is their role? - david attebourgh = education
- Decreased antimicrobial resistance and potential for new vaccines and therapeutics
- A holistic approach: One Health
~ Actively involve owners/keepers to motivate willingness
~ Intervention by authorities and vets
~ Link closely human and vet medicine
~ Cooperation between vets, biologists, socialists, authorities, physicians
~ Appropriate legislation
~ Financial resources
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Research for Evidence Based Practice and Systemic Reviews23
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Emerging Infectious Diseases31
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Climate Change12
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One Health22
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Genetics for Animal Health6
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Nutreogenomics and Antioxidants24
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Globalisation21
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Disease Management and Cost Effectiveness Analysis5
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Veterinary Epidemiology - Epidemiological studies29
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Measures of Association in Epidemiology16
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Concepts of infectious disease epidemiology15
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Survival Analysis7
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Confidence intervals for risk ratio and odds ratio3
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Antibiotic Resistance17
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Food Safety1
