one health Flashcards
understand the terminology
incidence, prevalence, case fatality rate and mortality
incidence- incidence rate of 1 per 100,000
prevelence- current prevalence is 100 per 100,000 or 0.1%
case fatality rate- 50% will die from this infection
5 causes of infectious diseases
1) virus
2) bacteria
3) parasites
4) fungi
5) prions, transmissible cancers
4 modes of transmission?
vertical (parent to offspring)
horizontal (individual to individual)
indirect (vector born, food borne, contamination)
direct
what is a multi host pathogen and give an example?
able to infect more than one species e.g. influenza virus
difference between reservoirs and carriers of a infection
reservoirs = shows clinical signs of infection
carriers- shows no sign of infection
what are the three factors affecting infection outcome in the epidemiological triad?
1) host (level of susceptibility eg breed)
2) pathogen (virulence)
3) environments (temperature)
^ affects other 2 factors
explain the emergence of ‘Venezuelan encephalitis’ by pathogen evolution
virus in horses/humans required a single point mutation in the virus’ envelope gene
what is the R0 number of measules
r0= 10-15 (very high)
requires almost 100% vaccination to prevent spread of infection
explain the four types of disease surveillance?
1) active surveillance (best)= actually look for evidence of disease (with 24-72 hours depending on urgency)
e.g. bovine tuberculosis
-more regulatory surveys
2) targeted surveillance=
directed at individuals who have a risk of a disease allows for early detection
-more citizen science
3) passive surveillance= regular reporting of observed cases but no active search
-more general surveillance
4) syndromic surveillance= looks for a rise of people reporting types of symptoms e.g. school reception.
-risk of mis-diagnosis
what is the definition of molecular epidemiology?
tracking the spread of infections using genetic data. (DNA, RNA, whole genome)
what are the two hypothesis of where our own pathogens come from?
1) CO-EVOLUTION- pathogens inherited from our ancestors
2) CROSS-SPECIES TRANSMISSION-
(data supports this one)
what are the zoonotic diseases originated from bats, camels and apes/monkeys?
bats- SARs
camels_ Mers
apes/monkeys - Zika
(great apes as the source of major human diseases e.g. malaria and HIV)
define one health
health of humans is connected the health of animals and the environment.
explain the five different levels of eradication and give an example
control= achievable
reduction of a disease, incidence and prevalence. happens at a local level.
e.g. diarrhoea
elimination of disease= achievable
reduction of incidence in a defined geographical area e.g. tetanus
elimination of infections= achievable
reduction of incidence and infection caused by a specific agent in a defined geographical area
e.g. measules
reduction or eradication= hard but manageable. occurs as a worldwide incidence. infection caused by a specific agent. intervention methods are no longer needed.
e.g. smallpox
extinction- impossible.
e.g. none
understand the lifecycle of the one health tropical disease ‘toxocara’ (dog roundworm)
-when was it discovered
-where was larvae detected in children
it’s a control method.
occurs in eggs as worms in dog and cat that pass to faeces. can be transmitted from mother to foetus.
-discovered 1950.
- toxocara larvae detected in ocular granulomata in children with suspected retinoblastoma.
