Biology Module 7 - Infectious Diseases Flashcards
What is a Vector
An organism that can transport or propagate a pathogen before implanting into an organism (by nature).
What is a Prion
Created from abnormal PrPC gene which causes protein to fold abnormally, leading to holes in the brain and eventual death.
What is a Virus (example)
Made of a protein coat (DNA/RNA), they require a host to replicate through transduction. (Influenza Type A)
What is bacteria (animal and plant example)
Unicellular etc, killed by antibiotics. E.g. E. Coli in animal intestines cause food poisoning. Black rot damages plant health)
What is a Protozoan (example)
Unicellular eukaryotic organism, produce asexually from binary fission. Most live in water with flagellum’s. Plasmodium causes malaria.
What is a fungi (animal and plant example)
Diverse group of eukaryotes, gain nutrients from decomposing matter, live on dead tissue or as parasites like living. Tinea on feet and white blister disease.
Macro-parasites (examples)
Multicellular eukaryote. 2 kinds; end parasites live inside hosts and extoparasites act as vectors carrying pathogens to infect the host. Tapeworms live in vertebrate intestines causing weight loss and pain.
Insects and mites (plant example)
Can damage be vectors to pathogens. Citrus leafer miner lays eggs in plant, larvae then mine in the leaf for nutrients, creating swivly tunnels.
Nematodes (plant example)
Common in soil and few act as pathogens. Root knot nematode affects tomatoes by attacking its roots to create lumps until the plant dies.
Phytoplasm (plant example)
Related to bacteria but doesn’t have a cell wall. Inhabit the phloem tissue, creating mottles and stealing nutrients on tomatoes and others.
Epidemic example
Equine Influenza / Horse flu in Australia 2007. Transmitted by nasal, horses were quarantined when moved and produced a vaccine.
Example of vector transmission
Malaria: The protozoan enters the mosquito after drinking, it develops in mosquito and is extracted as saliva when injecting into human.
Common symptoms of foodborne disease
Nausea, vomiting, stomach cramps and diarrhoea.
Example of bacteria food poisoning
Salmonella: found in animals, infection from eating undercooked food - term food poisoning comes from toxins released by bacteria.
Examples of viruses in food
Shellfish: from raw cool temperatures and hepatitis comes from shellfish; fatigue, stomach pain and yellowing skin - vaccine for travellers.
Examples of parasites in food
Trichinella spiralis: intestinal roundworm from consuming pork that’s undercooked. Symptoms are; eye swelling, aching muscles, takes 2-8 weeks to appear.
Pasteurs swan flasks
Disproves the theory of spontaneous generation. Uses meat broth to show how bacteria from the air comes to develop.
What’s needed for successful pathogen infiltration?
Enter the host. Multiply in their tissue. Resist hosts defence system. Damage the host.
Types of pathogens
Prion, virus, bacteria, protozoan, fungus and macroparasites.
Transmission routes for pathogens.
Airborne, waterborne, vector-borne, faeco-oral (resist harsh environments - e. Coli in stomach acid), soil-borne, sexual, bloodborne, vertical (mother to child).
Phytopthora Cinnamomi: Plant retaliation and effect.
Dangerous fungus, grows in warm damp soil on roots and spreads via spores. It blocks the nutrients getting to plants.
Plants use physical barriers (stomata, waxy cuticle) to prevent further damage. Chemically, enzymes can break pathogen or self destruct parts.
Tobacco mosaic virus effect and plant retaliation.
Infects tobacco and solanaceae family (tomatoes, peppers). Causes mottling or yellowing, disrupting chlorophyll which inhibits growth.
1st lines of defence
Skin, eyelashes and hair are physical barriers to prevent entry.
Tears, sweat, oil, stomach acid and mucus are chemical barriers to reduce pathogen activity.
2nd line of defence
Fever, vomiting, phagocytosis, lymph system and complement system attempt to reduce pathogens spread.
3rd line of defence
B / T cells. B cells form as plasma, with assistance of T cells they record new antigens and create antibodies specific to dealing with them. Memory B/T cells will then remember the pathogen and how to destroy it again.
Acquired resistance
Gained/developed as a result of vaccinations (artificial).
Natural resistance
Developed throughout our life time as we cross different pathogens.
Passive immunity
Gained antibodies temporarily, from placenta to foetus, breast milk and antibodies in certain vaccinations (hepatitis).
Example of passive acquired immunity
Immune serum globulin provides antibodies to protect against the pathogen. This is a passive acquisition since the memory of the pathogen is recorded for next time.
What is immunisation
Process of immune system making lymphocytes or antibodies to fight infection - can be natural or artificial.
What is innate immunity?
Nonspecific defence mechanism that occurs every time a pathogen enters. New or old the mechanisms always include the same physical/chemical barriers (1st/2nd(?) lines of defence).
