12.3 - Transmission Of Communicable Diseases Flashcards
What are the two main types of transmission of communicable diseases between animals ?
Direct and indirect
What are the 3 main types of direct transmission in animals ?
- Inoculation
- Direct contact
- Ingestion
What happens in ingestion in the direct transmission of animal pathogens ?
- taking in contaminated food or drink
- transferring pathogens to the mouth from the hands
- eg. Diarrhoeas diseases & Amoebic dysentery
What are the 3 ways pathogens can be spread via inoculation ?
- through a break in the skin for eg. During sex ( HIV/AIDS)
- from an animal bite for eg. Rabies
- through a puncture wound or through Sharing needles eg. Septicaemia
What are the 3 ways pathogens can be spread via direct contact ?
- kissing or any contact with the body fluids of another person for eg. Bacterial meningitis, STD
- direct skin to skin contact for eg.ring worm, athletes foot
- microorganisms fro, faeces transmitted on the hands for eg. Diarroheoel diseases
What is indirect transmission ?
Where the pathogen travels from one individual to another indirectly
What are the 3 main types of indirect transmission of pathogens between animals ?
- Formites
- Vectors
- Droplet infection
What is formite ?
- where an inanimate object such as socks,bedding or cosmetics can transfer pathogens
- eg. Athletes foot & gas gangrene
What occurs during a droplet infection ?
- minute droplets of saliva or mucus are expelled from the mouth during talking , coughing or sneezing
- if the droplets contain pathogens when healthy individuals breathe the drops in they may become infected
- eg, influenza & tuberculosis
What are the most common types of vector to spread diseases between animals ?
- Mosquito- malaria
- dogs,foxes and bats carrying rabies
- fleas carrying plague
What is a non animal example of a vector ?
Water which can transit diarrhoeal diseases
What disease can be transmitted between sheep and humans ?
Brucellosis
What are some factors which can increase the risk of transmission of diseases between animals ?
- overcrowded living and working conditions
- poor nutrition
- a compromised immune system eg. HIV/AIDS
- poor disposal of waste , providing breading sites for vectors
- climate change = can introduce new vectors and new diseases for eg. Increased temp promote the spread of malaria as or mosquito species is able to survive over a wider area
- culture and infrastructure - in many countries traditional medical practises can increase transmission
- socioeconomic factors - eg. Lack of trained health workers and insufficient public warning when there is an outbreak of disease can also affect transmission rates
Can plant pathogens be transmitted directly ?
Yes if a part of a healthy plant comes into direct contact with a part of an infected plant
What are some plant pathogens which can be transmitted directly ?
Ring rot , TMV , black Sigatoka, potato blight
What are the two main types of indirect transmission of pathogens in plants ?
Soil contamination
Vectors
What is soil contamination ?
- infected plants often leave pathogens or reproductive spores from protoctista or fungi in the soil
- this can infect the next crop
- some pathogens or their spores can also survive the composting process so the contaminated compost can infect plants it is spread on
- eg. TMV, ring rot bacteria
What are the 4 main types of vectors which can spread plant pathogens ?
- Wind
- Water
- Animals
- Humans
How is wind a vector ?
bacteria, viruses and fungal or oomycete spores may be carried on the wind
Explain how water is a vector ?
- spores swim in the surface film of waters on leaves
- raindrop splashes carry pathogens and spores etc.
- eg. Potato blight which swim over films of water on the leaves
Explain how animals are vectors ?
- insects and birds carry pathogens and spores from one plant to another as they feed
- insects such as aphids inoculate pathogens directly into plant tissues
Explain how humans are vectors ?
pathogens and spores are transmitted by hands, clothing, fomites, farming practices and by transporting plants and crops around the world
What are some factors affecting the spread of communicable diseases between plants ?
- plant varieties of crops that are susceptible to disease
- over crowding increases the likelihood of contact
- poor mineral nutrition reduces resistance of plants
- damp,warm conditions increase the survival and spread of pathogens and spores
- climate change - increased rainfall & wind promote the spread of diseases
- changing conditions allow animal vectors to spread to new areas , drier conditions may reduce the spread of disease
