One Health Quiz 2

What are the 4 interactions between living beings and their (x/x)?

mutualism (+/+)

commensalism (+/0)

predation (+/-)

competition (-/-)

Pathogenic microoragnisms

Microorganisms that can cause disease upon colonization of host

Obligate pathogens

microorganism which must infect host to survive and multiply

Facultative pathogens

microorganisms which can infect and multiply in host but also capable of multiplying in the environment

Opportunistic pathogen

microorganism that does not usually cause disease but may become pathogenic under certain conditions

Communicable diseases

diseases that can be spread directly or indirectly from one animal to another

Infectious diseases

diseases caused by pathogens

What are the 5 ways of transmission?

food borne

water borne

air borne

vector borne

fomites

What is a zoonosis?

pathogen that is shared by both humans and non-human animals and can be transmitted from animals to humans

What % of existing human infectious diseases are zoonotic?

60

What % of emerging infectious diseases of humans have animal origin?

75

How does the case of Trichostrongylus tenuis and red grouse demonstrate the role of parasites in the ecosystem?

Trichostrongylus tenuis regulates red grouse so that grasslands have time to recover

When do pathogens become a problem and give an example of case study for each?

When they threaten
our existence (black plague killed almost 50% of europe’s population)

our food production system and economic income (rinderpest in africa caused losses and deaths)

existence of other animal species (christmas island’s rats were first disease-mediated extinction in history)

What was disease thought to be caused by in early times?

imbalance of spirits, bad omens, curse

Now we know that diseases are caused by a wide range of causes, from ______ to _______

genetic/metabolic disorders

tiny bugs

Emerging infectious disease

disease that is newly recognized or newly evolved or has occurred previously but shows an increase in incidence or expansion in geographical, host or vector range

Re-emerging infectious diseases

disease that appears after it has been eradicated or on a significant decline

_____ new human diseases appear every year. ___ are of animal origin

5

3

The WHO’s global surveillance system currently picks up ____ public health threat signals every month

7000

What is the relationship between species richness and hosts?

taxonomic groups with more host species generally hold more potentially zoonotic pathogens

Where in the world is there the largest number of zoonotic pathogens?

tropics

What orders contain the most host species?

rodentia

chiroptera

soricomorpha

primates

carnivora

artiodactyla

What are the 5 reasons for reemergence of diseases and give examples if applicable?

changes in pathogen characteristics (mutation, drifting)

change in environment (lack of biodiversity, climate change, deforestation)

change in population dynamic of host range (population growth, urbanization, hunting/farming practices, trade/travels)

lack in application of control measures

lack of surveillance

Dilution effect

Higher the diversity, lower the risk of being infected because less likely for pathogen to infect correct host

Amplification effect

Higher the diversity, higher the risk of infection because some pathogens can infect different host species

What is an example of a disease impacted by biodiversity loss?

lyme disease

What is an example of a disease impacted by climate change and how?

dengue virus

increased vector abundance and feeding activity

Increased geographical range

Increased human activties during warmer times

What is an example of a disease impacted by land use change, parasites, public health?

adaption of plamodium knowlesi from macaques to humans

How does an abundance of generalist animal species affect risk of infection to humans in agricultural landscapes?

increases risk by increasing abundance of multi-host parasites

What is spillover?

interspecies transmission where pathogen transmitted from reservoir to novel species producing disease

Is spillover always zoonotic?

no

How does canine distemper in Africa demonstrate spillover?

spread from domestic dogs to wild dogs

some local populations of wild dogs went extinct

transmitted to lions

How does bornean felids demonstrate spillover?

test for 4 viruses that usually affect domestic cats

How does rinderpest in serengeti demonstrate impacts on ecosystem? Is it zoonotic?

disease regulated wildebeest population and ecosystem

decrease in wildebeest=grass grows=easier bushfires

not zoonotic but caused death from famine

What was the first pathogen eradicated due to vaccinations?

rinderpest

What happened during the Nipah virus outbreak in Malaysia in 1998?

transmitted by flying foxes

pigs would eat under fruit trees where bats were and become infected

poor biosecurity

pigs transmitted virus to farmers

How do you deal with an african swine fever outbreak?

no vaccine or treatment

eliminate all infected and suspected pigs

What factors does implementation of isolation/culling measure depend on?

characteristics of pathogen

animal species and their value

social and cultural context

economics and politics

Do you have to vaccinate every animal in the herd for effective disease transmission?

no, herd immunity means that you only have to vaccinate enough to reduce transmission

How does conflict and war affect disease management?

deterioration of health systems

pause of vaccination campaigns

migration to safe places and bringing disease along

How does inequity affect disease manegement?

poverty and hunger

unaffordable health care

access to vaccines and treatments

displacement

Why does antimicrobial reisistance occur?

bacteria, viruses, fungi, parasites change over time and no longer respond to medicines making infections harder to treat and increasing disease risk

What is the name of the main group of pathogens considered of high concern due to their increasing resistance to antibiotics?

ESCAPE

How is AMR a global threat?

threatens progress in healthcare, food production, life expectancy

disrupts balance of microbial community in soil and aquatic systems

How does AMR develop?

whenever there is high number of bacteria, few of them are resistant to antibiotics

antibiotics kill both bad and good bacteria

resistant bacteria can now grow and multiply without competition

some bacteria transfer resistance to other bacteria

What is intrinsic resistance?

innate ability of bacteria to resist antibiotics

What are the two ways of acquired resistance in bacteria?

vertical gene transfer

horizontal gene transfer

What is vertical gene transfer?

genome replication and cell division to produce two new bacteria

What are the three methods of horizontal gene transfer and explain them?

conjugation- AMR bacteria uses pilus to transfer AMR genes to recipient cell

transformation- AMR bacteria dies and transmit genes to other bacteria

transduction- viruses kill AMR bacteria and absorb DNA and infect other bacteria so AMR genes transducted

How is the bacteria changed when they develop AMR?

impermeable cell wall protein to limit uptake of drug

modification of drug target

pumps to increase active efflux of drug

inactivation of drug

What are the 4 drivers of AMR?

inappropriate use of antibiotics in human medicine

inappropriate use of antibiotics in veterinary medicine

lack of hygiene and infection prevent and control strategies

political conflicts, equity, human mobility

_____ of all medically important antibiotics continue to be sold for use in livestock production

two thirds

How can antibiotics in livestock spread to humans?

food borne

manure

environmental

occupational

What are the three systems involved in the One Health approach against AMR?

environmental subsystems

environmental metadata

human subsystems

What are limitations to the one health approach against AMR?

number of sites recruited to compile data limited

sites have access to human data only

AMR data from animal and environment are limited

focus on farm animals

What are the roles of AFCD?

outbreak

trade

inspection

importation/exportation

welfare

diagnostic and surveillance

What are the 6 common species of stray animals in HK and what disease do each of them transmit?

dog- rabies

wild birds- avian influenza

wild pigs- african swine fever

cattle- lumpy skin disease

monkeys- herpes B, monkeypox

bats- coronovirus

Why are stray dogs an issue with disease?

most likely to be unvaccinated

pack behavior- may attack people

rabies

AFCD has statutory responsibility to do what regarding stray dogs?

manage population to prevent rabies outbreaks

reduce nuisance

safeguard public health 

What kind of animals does rabies infect?

all mammals

Rabies belong to what
order

family

genus

mononegavirales

rhabdobiridae

lyssavirus

What two continents have the highest risk of human mortality from rabies?

africa

asia

Around 99% of human cases of rabies are due to bites from ___

infected dogs

Is the main animal reservoir for rabies the same worldwide?

no, differ between continents

What are the modes of transmission for rabies?

direct bite

non-bite exposures

rarely, inhalation or transplantation of inflicted organ

What are the two forms of rabies?

furious

paralytic

What must a test include to rule out rabies in an animal?

tissue from at least two locations in brain, preferably brain stem and cerebellum

How did HK achieve rabies eradication?

legislation

enforcement

monitoring, surveillance, research

education & publicity

What are the legislation related to rabies?

duty to report rabies

vaccinations

control of animal imports

prohibits slaughter of dogs and cats

manage stray animals

How was enforcement administered in regard to rabies?

compulsory vaccination and licensing of dogs

control of stray dogs

investigating animal bite incidents

control of animal trading

import control and quarantine

anti-smuggling

When are dogs required to get vaccinated for rabies and how often after that?

5 months

every 3 years

____% of stray dogs have to be vaccinated for group protection against rabies

80

When is world rabies day?

sep 28

What migration route is HK located on?

east asian-australasian flyway

Avian influenza is of what

family

genus

orthomyxoviridae

alphainfluenzavirus

How many influenza genera and how many strains in birds are there?

7

16

What is highly pathogenic avian influenza?

intravenous pathogenicity index greater than 1.2

caused by groups H5 and H7

What are the modes of transmission of avian influenza?

direct contact

indirect contact through fomites and environment

What are methods to test for avian influenza?

PCR

necropsy

immunuoperoxidase test on frozen tissue

virus isolation

What are the three steps of the cephalic index?

dolichocephalic

mesocephalic

brachycephalic

What dermatological problems are seen in brachycephalic dogs?

skin fold dermatitis

otitis externa

primary secretory otitis media

Why are brachycephalic breeds prone to skin fold dermatitis?

hot and humid environment inside folds=ideal place for fungi and bacteria

debris accumulation + commensal overgrowth + toxin production + inflammation

What is otitis externa?

inflammation of ear canal

What are signs of otitis externa?

head shaking

ear scratching

discharge

malador

What breeds are prone to otitis externa?

french bulldogs

pugs

boxers

What are predisposing factors to otitis externa?

pendulous ears

narrow ear canals

hairy ear canals

swimming

manipulation of ears

What are primary factors of otitis externa?

allergy

parasites

foreign body

growth

hormonal

autoimmune

keratinization abnormalities

What are secondary factors in otitis externa?

bacteria

yeast

What are perpetuating factors of otitis externa?

chronic changes going along the otitis

What is the standard treatment for otitis externa?

ear cleaner

ear drops

oral prednisolene

pain killers

What physical changes happen with primary secretory otitis media?

decreased nasopharynx width

increased mucus production

What age dogs does primary secretory otitis media primarily affect?

middle aged

What are signs of primary secretory otitis media?

aural pruritus

neck pain

abnormal vocalization

reduced hearing

secondary otitis externa

neurological signs

lethargy

What breed is chiari-like malformation usually seen in?

king charles cocker spaniel

What are signs of chiari-like malformation?

rubbing face

abnormal pain sensation

abnormal vocalization

body shaking

neurological signs

air guitar pseudo pruritus