keeping people healthy week 2 Flashcards
Describe meiosis
DNA replication is followed by two rounds of cell division to produce four potential daughter cells, each with half the chromosomes
Describe fertilisation
male and female gametes fuse during fertilisation, creating a fertilised cell with a completet set of chromosomes (22 somatic pairs, 1 sex pair)
What are the three ways in which Down syndrome can be caused?
trisomy 21 - most common
translocation - extra piece of chromosome 21 attaches itself to another chromosome
Mosaicism - only some cells have an extra copy
Describe the physical appearance of Down syndrome
reduced muscle tone and floppiness small nose and flat nasal bridge small mouth and protruding tongue eyes slant upwards and outwards flat back of the head big space between 1st and 2nd toes broad palms and short fingers single transverse palmar crease below average weight and length at birth
What are other common effects of Down Syndrome?
delayed development and low IQ early onset dementia ASD and ADHD GI problems hearing and vision problems Thyroid problems
Describe screening for Down Syndrome
The combined test (blood tests plus nuchal translucency ultrasound scan 11-14 weeks)
Or later just blood tests - less accurate
hCG remains higher later in pregnancy
Pappalysin 1 - pregnancy associated plasma protein is lower in Down Syndrome
What is vaccination?
induced immunity using a vaccine
what is immunisation?
encompasses both vaccines and passive immunity
What is an antigen?
a live or inactivated substance capable of producing an immune response
What are the aims of vaccines?
to save lives, protect against disability and improve health
What is selective vaccination used for?
to protect those at high risk
What is mass vaccination used for?
to eradicate or eliminate disease
When might selective vaccination be used?
travel
occupational risk
high risk groups
outbreak control
what is eradication?
wipe disease completely - small pox
What is elimination?
disease to disappear from one WHO region - POLio
What is containment?
when disease no longer constitutes a “significant health problem”
What is the purpose of having intervals between vaccines?
to allow immune response to develop
to avoid immune interference
What is primary vaccination failure?
an individual fails to make an adequate immune response to the initial vaccination
What is secondary vaccination failure?
an individual makes an adequate immune response initially but immunity waves over time ( most inactivated vaccines)
What can be done to prevent secondary vaccination failure?
boosters
What is the difference between adverse effects in live and inactivated vaccines?
live - adverse effects fall with more doses
inactive - adverse effects rise with more doses
What are some contraindications to live vaccines?
primary immunodeficiency chemotherapy haematopoeitic stem cell transplant organ transplant systemic corticosteroid use HIV
Describe live vaccines
attenuated strains which replicate in the host
acts like natural infection
strong, long lasting immunity
MMR, BCG, yellow fever
Describe inactive vaccines
suspension of whole intact killed organisms - pertussis, rabies ,, hepA
acellular or sub-unit vaccines Hib, diptheria
What are the advantages of live vaccines?
long lasting strong response can revert to virulence in pregnancy/immunosuppressed poor stability
What are the advantages of inactivated vaccines?
stable constituents clearly defined unable to cause infection needs several doses adjuvent needed shorter lasting
What is heard immunity?
for a disease there is a certain level of immunity in the population which protects the whole population because the pathogen stops spreading in the community
disease can be eradicated even when some people are still susceptible
What is R?
the effective reproductive number - the secondary infections produced by a typical infected person
What is R0?
The basic reproductive number - the number of secondary infections produced by a typical infection in a totally susceptible population
What does it mean in R
no sustained transmission
What does it mean if R>1?1
Epidemic possible
What does cvt mean?
1-(1/R0)
What is passive immunity?
immunity from pre-formed components in order to provide protection at or time around the time of exposure to specific pathogen
provides immediate but temporary protection
What are the pros of antibody preparations?
rapid
preventive
can be those in those who can’t take vaccines
What are the cons of antibody preparations?
expensive
potential adverse effects
limited evidence base for some
no lasting immunity
What indicates there is the need for a vaccine programme?
disease incidence age distribution trends complications mortality
What is the mechanism for vaccine policy
recommendation policy decisions licensing of vaccine purchase of vaccine control of vaccine
What is vaccine surveillance?
the ongoing, systematic collection, recording, analysis,, interpretation and dissemination of data
What is the criteria for severe acute malnutrition?
below 3 SDs below median weight or height, visible and severe wasting, or presence of nutritional oedema
What is moderate malnutrition?
weight loss and 2-3 SDs below median for weight and height
What are some problems caused by obesity?
medical
social - isolation, depression
economic - health care cost, ill health leading to absence from work
medical - diabetes, ischaemic heart disease
body image
difficulty socialising
stigma
What is meant by obesogenic environment?
readily available high calorie foods
increase labour saving devices
increase in passive and motorised transport
decreased participation in leisure pursuits
What can be done to shift the population to the left with regards to obesity?
food restrictions, public transport
what can be done to target outliers in obesity?
liposuction
what can be done to squeeze the distribution of obesity?
tackle inequality
What are protective factors for risk taking behaviour in adolescence?
self esteem
close relationship with parents
perceived control over life
What are some risk factors for risk behaviour in adolescents?
peer pressure low parental monitoring lower socio-economic class lack of future aspiration depression
