Communicable diseases Chapter 12 Flashcards
what are all the types of pathogens
bacteria, viruses, protista and fungi
how do viruses attack and damage the host tissues
viral genetic material is inserted into the host DNA of the host cell, then when the host cell multiplies more viral genetic material is created, which then bursts out the cell
how do some protoctista attack and damage the host tissues
take over cells and break them open by digesting and using the cell contents as they reproduce
how do fungi attack and damage the host tissues
digest living cells and destroy them or produce toxins
how do bacteria damage the host tissues
by producing toxins
what is ring rot
a bacterial disease of potatoes, tomatoes and aubergines, damages leaves, tubers and fruit, once it infects a field, the field cannot be used for two years, NO CURE
what is tobacco mosaic virus
virus that infects tobacco plants, tomatoes, peppers, cucumbers, petunias and delphiniums, damages fruit, flowers and leaves, stunts growth and reduces yield and lead to almost total crop loss, resistant strains have been produced
what is potato blight
protist, the hyphae penetrate host cells, destroying leaves, tubers and fruit, no cure but resistant strains
what is black sigatoka
fungi,banana disease which attacks leaves, hyphae penetrate and digest the cells, can cause a 50% reduction yield, resistant strains produced
what is TB
a bacterial disease that damages and destroys lung tissue and suppresses the immune system
what is bacterial meningitis
a bacterial infection of the meninges of the brain which can spread to the rest of the body and cause septicaemia. 10% of those infected will die, vaccines against certain types have been developed and antibiotics can cure it
what is HIV/AIDS
virus, HIV targets T helper cells in the immune system of the body, gradually destroys someone’s immune system so they are more open to other infections, spreads via bodily fluids, no vaccine or cure but can be treated using anti-retroviral drugs
what is influenza
viral infection of the ciliated epithelial cells in the gas exchange system, kills them leading to easier infection, spread via respiratory droplets in the air, no cure
what is malaria
spread by bite of infected mosquitoes, the protoctista reproduces inside the female mosquito, it invades the red blood cells, liver and brain, the disease recurs making people weak to infection, no vaccine and limited cures
what is ring worm
a fungal disease affecting dogs, cats, cattle and humans, antifungal creams can cure it
what is athlete’s foot
a human fungal disease that digests the warm moist skin in between the toes, creams can cure it
what are examples of direct transmission in animals
direct contact, inoculation (e.g. animal bite), and ingestion
what are examples of indirect transmission in animals
fomites (inanimate objects), droplet infection, vectors, transmission between humans and animals
factors affecting the transmission of communicable diseases between humans
overcrowding, malnutrition, compromised immune system, poor disposal of waste, climate change, culture and infrastructure, socioeconomic factors
what are examples of indirect transmission in plants
soil contamination and vectors
factors affecting the transmission of communicable diseases in plants
planting varieties of crop that are susceptible to disease, overcrowding, malnutrition, damp and warm conditions increases spread of pathogens and spores, climate change
what do plants produce in response to a pathogen
a polysaccharide called callose
what does callose do?
act as a barrier to prevent pathogens entering plant cells around the site of the infection
plant defensive chemicals examples
insect repellents and insecticides, antibacterial compounds including antibiotics, antifungal compounds, anti-oomycetes, general toxins
non-specific defences in humans, first line of defence
skin, mucous membranes, lysozymes and expulsive reflexes
what substances do platelets excrete in response to a damaged blood vessel
thromboplastin which triggers a cascade of reactions resulting in the formation of a blood clot
serotonin which makes the blood vessels contract, reducing the blood supply
in an inflammatory response, what chemicals do mast cells produce
histamines and cytokines