communicable diseases Flashcards
(18 cards)
communicable disease definition
an infectious transmittable disease caused by a pathogen
communicable period definition
time when infectious agent transfers directly or indirectly from infected person to another person etc
viral pathogens
HIV/AIDS, influenza, TMV
bacterial pathogens
bacterial meningitis, cholera, tuberculosis, ring rot
protists (single celled eukaryotic organism) pathogens
malaria, late blight
fungi pathogens
athlete’s foot, ringworm, black sigatoka
ways harmful organisms can spread/enter body
- indirect contact (air, dirty water, food)
- direct contact (cuts, mouth, nose etc)
- blood transfusions
- placenta
- vectors
how does a viral infection occur
1 - viral particle attaches to receptor sits of proteins on cell’s plasma membrane
2 - host cell engulfs virus by endocytosis
3 - digestion of capsid releases viral dna which is replicated in host cell nucleus using viral enzymes
4 - viral proteins synthesised in cytoplasm and uses host enzymes to form new viral particles which are then released
what is a virus
consists of DNA or RNA as genetic material enclosed by protein coat called capsid. may be surrounded by outer lipid membrane called envelope, infect all organisms
what vector causes malaria
female anopheles mosquito
symptoms of malaria
headache, shivering, pain, fever
how is malaria transmitted
plasmodium parasites reproduce sexually to form sporozoites inside mosquito which go to salivary glands, when the mosquito bites, the sporozoites are injected into victim.
in the victim, sporozoites travel to liver and multiply asexually in liver cells causing them to burst, parasite released into blood which infect RBCs.
pathogen burst open RBCs
strategies to control malaria
reduce mosquito numbers (oil on water surface, insecticide, drain bodies of water), insect repellent, long clothing, mosquito nets, antimalarial drugs before infection
difficulties in controlling malaria
many strains of plasmodium so resistance, no 100% effective vaccine, mosquitos resistant to insecticides, mosquitoes breed fast
how does antibiotic resistant bacteria evolve
selection pressure of antibiotic, mutations in bacteria cause genetic variation, natural selection, resistant survive and reproduce via binary fission and pass resistant alleles to offspring
physical barriers that help plants defend against disease
waxy cuticle on leaves, bark on trees, cellulose cell walls, lignified cell walls
sources of medicine
penicillin from fungus
morphine from poppy seed heads
aspirin from willow bark
daffodils for alzheimer drug
how is medicine personalised
use genetic information by screening individuals genomes to predict responses to drugs and prescribe most effective
