One Health Flashcards
What triggers the immune response?
Antigens (fond on the outside of viruses/ bacteria/ parasites..)
What cell types makes you feel unwell after infection?
Effector T lymphocytes (dangerous when in your system at high levels for a long period of time) as they create inflamation and tissue damage
Name some types of vaccines
live attenuated/ subunit/ killed/ inactive/ nucleic acid
Give some examples of viruses with current vaccination programmes.
polio / covid/ rabis / mpox/ hpv/ ebola/ sars
What is the aim of prophylactic vaccination? When is this vaccine applied?
to prevent infection through developing immunity within an individual (occurs before infection)
What is the aim of therapeutic vaccination? When is this vaccine applied?
it accelerates immune response in an individual (used for individual’s which are or have been infected)
What is in a vaccine?
Waer/ Active ingredient (small amount of harmless bacteria or virus )/ preservative and stability (allows for storage and incresed shelf-life ) // residual traces (substances used in vaccine manufacturing ) / adjuvants (substance which enhances the bodys responce)
Why might some individuals not be able to get vaccinated ?
immunosuppressed / allergies / pregnant /
What is herd immunity ?
When a large proportion of a population is vaccinated , making it much harder for diseases to spread (breaks the chain of transmission)
What is the R0 number ?
The reproduction number , explains how likely the disease is going to spread around a population
What are some viruses which are currently trying to be eradicated by vaccines?
Polio , measles and rubella.
How do replicating vaccinations work?
Live, attenuated (weakened virus or bacterium is used to replicate a natural infection triggering an immune response, therefore an individual gains memory and adaptative immune cells.
How do non-replicating vaccines work?
(inactive/ subunit vaccines) stimulate an immune response using inactivated (killed pathogens) // subunit (specific parts of the pathogen e.g. proteins/ antigens..)
Give some examples of replicating vaccines, and what does the vaccine use?
Measles, Mumps and rubella (live attenuated ) // elobla (uses replicating viral vectors- transports genetic info )
Give some examples of non-replicating vaccines an what they use.
influenza( subunit , protein) // Hepatitis B (Virus-like particle) // SARS-CoV-2 (non-replicating viral vectors) or nucleic acid
What are some advantages of replicating (living) viral vaccines?
produces antibodies and t cell responses / stimulates mucosal immunity / single vaccine may be enough
What are some disadvantages of replicating (living) viral vaccines?
may be pathogenic and cause disease/ cell culture may not be possible/ cannot be applied to individuals who are immunosuppressant
What are some advantages of non-replicating (non-living) viral vaccines?
No risk of infection/ often a very fast response
What are some disadvantages of non-replicating (non-living) viral vaccines?
less immunogenic - less effective at producing cytotoxic T cells/ requires adjuvants / requires boosters / might not stimulate mucosal response
What does immunogenic tell you?
How much of the vaccine is needed to craete the same level of immune response (production of T, B cells and antibodies)
Give an example of a disease which has been eradicated by vaccines
Smallpox 1980. using a replicating , living viral vaccine
What characteristics of smallpox made it ‘easy’ to eradicate using a vaccine?
Has distinctive symptoms (rash, fever, headache..) // transmitted through droplets but only human-human. //long-lived immunity
What is meant by one health?
An approach to balance and optimise the health of people, animals and ecosystem.
Give some examples of global challenges which one health can be related to.
zoonoses (pathogens transmitted from animals to people)// food security (global warming and the effect on food production)// Biodiveristy (environmental health and water quality )
What was foot and mouth disease ?
A zoonoses disease which overtook Tanzania , affecting food security, one health aims to understand the origin and restricting movement and therefore transmittion
What is Nipah virus and what was done to mitigate its issues?
zoontonic disease, which leave individuals with fevers, transmitted through frit bats which feed on mango plantations humans use.// Mango plants can be covered to prevent transmission
What are some examples of rabis management?
PEP (post-exposure prophylaxis) delivered after individuals are bitten /// mass dog vaccinations//
What are some issues with the one health approach?
Interdisciplinary issues (different langue’s and trust issues) // driven by top-down initiatives therefore reduces community involvement
What makes a disease easy to eradicate it by a vrius?
a seasonal disease. easily diagnosed/ has no animal reservoir / distinctive symptoms
Why are RNA genome viruses hard to combat ?
RNA genome, is good at mutating therefore the immune system must adapt to prevent widespread infection
What is a viral vector?
An unrelated harmless virus is modified to deliver genetic material for the target virus
At what age is the HPV vaccination given in the UK?
12-13 years old
Explain the structure of Mpox.
there is a linear double -stranded DNA // brick-shaped virus// has surface tubules // // has inter tandem repeaters (ITR) allowing the virus to fold within itself therefore DNA polymerase works much faster in a circle
Explain the replication cycle of Mpox.
- Binding// 2. Fusion and entry // 3. Nucleocapsid release// 4. Transcription // 5. Translation // 6. Replication // 7. Lysis or budding // 8. Release
Where is Mpox genetic information replicated ?
cytoplasm
What are the two classifications of Mpox, what does this mean?
Clade I - More fatal as it inhibits the immune response of the virus creating a greater infection (faitality rate = 3.6%) is endemic to Central Africa // Clade II = less fatal at fatality rate 0.03%, is endemic to western African
What was a trigger of increased efforts to eradicate Mpox?
Initially was found in West and Central Africa, with little treatment // 2003 huge outbreak in America due to illegal import of exotic animals, triggering a response from the WHO// The shift from Mpox being an exotic disease to reaching more ‘westernised’ countries.
How is Mpox transmitted ?
a zoonotic ( first spread from animals to people) // can be directly (bites/ scratches) or indirectly (blood / bodily fluids)
What are some symptoms of Mpox?
generic symptoms (coughing/ neck and back pains/ fever / swollen lymph nodes) It is a respiratory did ease
Give some ways Mpox can be diagnosed.
electron microscope-> visualises // real-time quantitive PCR -> indicated the level of infection // Gene sequencing -> understands evolution and origin of disease(if it has been in animals)
What are some methods for treating Mpox?
Anti-viral drugs = stop replication of the virus // monoclonal antibodies = bind to virus preventing it from entering the cell preventing replication// vaccination= specifically live-attenuated
What is the difference between surveillance and monitoring?
Both collect and analyse data however monitoring is usually more descriptive and often doesn’t create an outcome
What are the main 3 types of surviellence?
- active (requesting information of notifiable disease )// 2. passive (regular reporting of observed cases, without seeking out the information)// 3. Syndromic (reports based on symptoms, without knowing the cause e.g. monitoring search bases)
What are some issues with attempts to monitor wildlife diseases?
Observing can be difficult due to remoteness/ scavengers/topography
Give some examples of procedures used to test for:
1. Pathogens
2. Nucleic Acids
3. Antibodies
- pathogen -> culture
- nucleic acids-> PCR
- antibodies-> ELISA
Give some examples of diseases which can be classed as re-emerging.
E-bola/ dengue fever and yellow fever
What is molecular epidemiology and why is it useful?
Tracking the spread of infection using genetic data// helpful as understanding mutations can allow us to identify how diseases are evolving.
What are the two main origins of diseases?
- co-evolution-> pathogen is transmitted from ancestors // 2. cross-species -> pathogen is recently introduced from another species
Give some examples of impacts caused by disease?
- HUMAN - deaths // 2. LIVESTSOCK- economic loss/ peoples livelihood/ zoonotic diseases risk human health// 3. WILDLIFE- threatens endangered species/ may act as resoviours /
What are some modes of transmission ?
DIRECT - cut/ bodily fluids / sexually transmitted infection// INDIRECT - food borne/ environmental contamination/ vector born … HORIZONTAL - between individuals or species// VERTICLE- mother to offspring via pregnancy , labour or breastfeeding
What are some public health measures taken to reduce infection?
Improved hygiene / isolation/ social distancing / drugs/ antibiotics/ vaccination
What is epidemiology?
Study of distribution of a disease and how to control it at a whole population level
What is morbidity ?
Frequency of disease within a population measured by incidence and prevalance
What is meant by incidence ?
The number of new cases per unit
What is meant by prevalence?
The proportion of a population that has a disease at a given moment
What is seroprevalence?
Proportion of serum samples reacting positively, therefore containing antibodies
What is the R0 number?
The average number of secondary infections caused by a single infected host (in a population which is susceptible
What is the 5 stages of eradication?
- CONTROL // 2. ELIMINATION/ 3. REDUCTION AND ERRADICATION// 4. EXTINCTION
What should be considered with eradication models?
economic cost, social, biological and political impacts of the disease
Give an example of a disease which has been eradicated through delivered efforts.
smallpox, using vaccinations
What is toxocara?
A zoonotic disease, found in cats and dog faeces , it is a worm which causes the disease spreading to the eyes, liver an lungs… it creates generic symptoms making it hard to identify
What are some problems which we are faced with when attempting to control Toxocara?
has multiple modes of transmission/ multiple sources of infection/ varies in exposure levels and has generic symptoms so hard to define
What is taenia soliium (pork tapeworm)
A parasitic infection caused by worms often found in pig feaces which is found in many African countries making it a neglected disease
How is toxocara managed?
It is in the control stage, as infection can be prevented through improved hygiene and education on picking up pet faeces
What is guinea worm?
A zoonotic infection with revivors in dogs and bamboos/ obtained through drinking water containing the worm / can only be removed via physically removing the worm.
What was the 3 step criteria of eradicating a disease?
- INTERRUPTION OF TRANSMISSION - there was no indigenous cases over a month// 2. PRE-CERTIFICATION- 0 indigenous cases found through active surveillance for at least 3 years // 3. CERTIFICATION - ICT visits the country to ensure it has been eradicated
What are some methods of erradicartion?
mapping / surveillance/ stop contamination/ education
What are some virulence factors of Vibrio cholera ?
rapidly proliferates inside the intestine , producing cholera toxins which prevent water uptake = dehydration// survives without oxygen (facultative anaerobic) // have pilus and flagella
What is the role of the environemnt in the spread of cholera?
V .cholera is usually in aquatic environments// different environments promote the development of cholera// climate change is associated with increased cholera due to increase algae and therefore increased copepods( host of V cholera)
What methods can be used to predict future cholera outbreaks?
Satellite remote sensing - monitors and predicts outbreaks (can be direct - identifying visual characteristics or indirect - identifying properties)//
What are some methods used to mitigate cholera outbreaks?
education/ improved water quality/ improve sanitation and hygine
What are some symptoms of cholera?
watery diarrhoea / leg cramp/ dehydration/ vomiting / poor skin elasticity
How does CT infect an individual?
- Cholera toxin is released by Vibrio cholera , CT B subunit binds intestine cell wall//2. Alpha subunit is taken into the cell via endocytosis // 3. Alpha subunit moves into ER // 4. A subunit separates with alpha - 1 binding to GM1 protein creating the overproduction of cAMP// 5. chlorine ions channels are therefore opens and as a result chloride ions are released leading to fluid imbalance and dehydration via diarrhea
Which scientists were involved in findings around cholera?
John snow - found transmission source// Pacinit - first isolated V cholera// Koch discovered cholera causing organism // 1885 first vaccination created
What are some remerging diseases?
cholera/ influenza/ malaria /TB
Give a way to represent how big the largest virus can be
The size of a bacterium
Why is Tanzania vulnerable to zoonotic diseases?
Tanzania is home to the largest livestock populations in Africa
Give an example of a zoonotic disease which has affected Tanzania.
Foot and mouth
Give some examples of land-use changes and specific disease outbreaks they have created
irrigated-based agriculture-> Japanese encephalts // Deforestation-> plasmoidium kowlesi // Agricultural pratices -> Nipah virus// Forest fragmentation-> Lyme disease
