VBDs Flashcards
What is a vector?What is a vector?
vector - an agent which carries an infectious agent between hosts
Describe the impact of vector borne disease on plants?
- vector borne diseases profoundly affect agricultural productivity
- annual loses in crop quality and yield associated are measured in the billions of dollars
- threat to food security
- casava - 5th most common crop in the world - very good staple crop if your water supply is unsire
- Casava mosaic virus and casava brown streak virus threaten thee food seccurity of 135 mil people in ceentral and east africa
describe the impact of vector borne disease on animals?
- sleeping disease carried by the tze-tze fly
- bluetongue virus affects sheep and costs around 3bil dollars per year
- vector-borne diseases can also affect wild populations -Rift valley fever is a viral zoonosis that can primarily affect animals but can also infect humans
How many diseases in humans are vector borne?
> 17% of all infectious diseases in humans
What are some neglected VBDs in humans and what is their impact?
- include negtected diseases
- chagas disease causes greatest burden of any parasitic disease in the Americas
- in 2017 Onchoceciasis caused vision loss in 1.15 million people
What is mechanical transmission?
mechanical transmission - for example when a fly has a pathogen on it and then it sits on somebody’s food and mechanically implants the pathogen on the food; the flye never gets infected, the fly just moves the infections between hosts
What is non-circulative transmission?
non-circulative - basically mechanical transmission but in plants
What is biological transmission?
biological transmission - the vector actually is infected with the pathogen
What is an extrinsic incubation period?
extrinsic incubation period - period in which the pathogen spends time in the vector either getting to the right places or completing the required developmental stages in given tissues
What is an important thing about VBds?
TRUTH ABOUT VBD: only a small proportion of your susceptibles will be infected and even a smaller proportion will be infectious
What is a gonotrophic cycle?
Gonotrophic cycle - thee mosquito eats blood and then they have to develop that blood meal into eggs aand lay those egss
Why is malaria so complicated to study?
malaria gets very complicated because while the pathogen needs to undergo its own cycle the vector still continues with their own life cycle and laying eggs and stuff like that
Draw out the model for vector borne diseases?
see notes
What is the equation that describes R0 for VBDs?
see notes
What is vector capacity?
vectorial capacity - estimation of a vector population’s potential to transmit