communicable diseases- plant/animal diseases, transmission and non-specific immune response Flashcards
(39 cards)
what is a communicable disease?
an illness from a pathogen
how are bacteria classified?
- by their shapes
- by their cell walls which is determined by gram staining.Gram positive bacteria are blue/black and gram negative bacteria are red. The type of cell wall affects the reaction to antibiotics.
what is the basic structure of a virus?
genetic material (DNA or RNA) surrounded by a protein
why do viruses invade living cells?
the reproduce rapidly and evolve by adapting to their host
why are some protists parasitic?
because they use people or animals as their host organism. Protists are eukaryotic organisms and uni-cellular.
what are fungi?
multi-cellular eukaryotic organisms.
what adaptation of fungi allows them to spread rapidly?
when they reproduce, many tiny spores are produced which can spread huge distances.
how are symptoms made from virus?
viral genetic material inserts into the hosts DNA allowing it to reproduce and burst out the cell. Destroying it and infecting other cells.
how are symptoms made from protists?
protists also burst cells but they don’t affect the DNA. They just digest and use cell contents as they reproduce.
how are symptoms made from fungi?
Fungi digest living cells and destroy them. Some fungi produce toxins.
how are symptoms made from bacteria?
toxins can damage host cells by breaking down cell membranes, inactivate enzymes or interfere with genetic material making them unable to divide.
describe ring rot disease
bacterial disease of potatoes, tomatoes caused by gram positive bacterium. Damages leaves, tubers and there is no cure.
Describe TMV
viral disease that infects tobacco plants. Damages leaves, flowers and fruit. Stunted growth means lower yield. Resistant crop strains are available but there is no cure.
Describe potato blight
caused by protists which invade cells, destroy leaves, tubers and fruits. No cure but there are resistant strains.
Describe black Sigatoka
a banana disease caused by fungi which destroy leaves. Hyphae penetrates and digests cells. Resistant strains are being developed and fungicide (kills fungi) treatment can control the spread but there is no cure
Describe tuberculosis
Bacterial disease in animals and humans. Damages lung tissue and suppresses the immune system. TB can be cured with antibiotics and prevented with vaccines and improving living standards.
Describe black meningitis
Bacterial disease that infects the meninges (protective membrane) of the brain which can cause blood poisoning and rapid death. Symptom: rash. Antibiotics can cure the disease when taken early and there is a vaccine.
Describe HIV/AIDS
virus (RNA) that targets t helper cells in the immune system. It gradually destroys the immune system causing people to develop TB, cancer or AIDS. It is transmitted through exchange of bodily fluids e.g unprotected sex, shared needles and from mother to baby during pregnancy. There is no vaccine and no cure but anti-retroviral drugs slow the progress of the disease.
Describe influenza(flu)
a viral infection of ciliated epithelial cells in the gas exchange system. It kills them leaving them vulnerable to secondary infection. It mutates regularly. There are no antibodies and no cure but there is a vaccine.
Describe malaria
caused by protist, Plasmodium and spread by mosquitoes. The two hosts are: humans and mosquitoes. The reproduce in side mosquitoes and invade red blood cells, liver and the brain in humans. There is no vaccine and limited cures but you can prevent it by controlling the vector e.g using insecticides, removing standing water where they breed and using mosquito nets.
Describe ring worm
fungal disease causing crusty grey infectious areas of the skin. It is itchy and can be treated with anti fungal creams.
Describe athletes foot
a fungal disease which is a type of ring worm that grows and digests the warm moist skin between the toes. It is itchy and can be cured with anti fungal cream.
Direct transmission is directly transferred from one individual to another. Describe the three ways of direct transmission.
- Direct contact: Kissing, exchange of bodily fluids, direct skin to skin contact (athletes foot and ring worm)
- inoculation: through a break in the skin, animal bite, sharing needles
- ingestion: ingesting contaminated food or drink
Describe the three ways of indirect transmission
- Fomites: inmate objects such as bedding and socks can transfer pathogens (athletes foot)
- Droplet infection: coughing, sneezing (TB, flu)
- vectors: animals or water
