communicable diseases Flashcards
what is a pathogen
a pathogen is an organism that causes disease.
what are the 4 types of pathogen
bacteria
fungi
viruses
Protoctista
how do bacterial pathogens cause damage
their presence can cause damage by releasing waste products and toxins that are toxic to the host.
how do fungal pathogens cause damage
Fungus lives in the skin of the animal, and where its hyphae, which forms a mycelium, grow under the skin surface. The fungus can send out specialised reproductive hyphae, which grow to the surface of the skin to release spores. This causes redness and irritation. In plants, the fungus often lives in the vascular tissue, where it can gain nutrients. The hyphae release extracellular enzymes, such as cellulases, to digest the surrounding tissue, which causes decay.
How do viruses cause damage
Viruses invade cells and take over the genetic machinery and other organelles of the cell. They then cause the cell to manufacture more copies of the virus. The host cell eventually bursts, releasing many new viruses which will infect healthy cells.
How do protocista cause damage
These organisms usually cause harm by entering host cells and feeding on contents as they grow. The malarial parasite plasmodium has immature forms that feed on haemoglobin inside red blood cells.
What is the organism that causes tuberculosis
Bacteria- mycobacterium tuberculosis
What organism causes the disease- bacterial meningitis
Bacteria- neisseria meningitis or sprepococous pneumonia
What organism causes the disease; ring rot
Bacterium- clavibacter mischiganesis subsp.
What organism causes the disease HIV/AIDS
Virus- human immunodeficiency virus
What type of organism causes influenza
Virus- from family orthomyxoviridae- flu viruses
What type of organism causes tobacco mosaic virus
Tobacco mosaic virus- virus
What type of organism causes the disease black Sigatoka
Fungus- mycosphaerella fijiensis
What organism causes the disease of ringworm in cattle
Fungus- trichophyton verrucosum
What type of organism causes the disease of athletes foot in humans
Fungus- trichophyton rubrum
What type of organism causes the disease of malaria in humans
Protoctistan- plasmodium falciarum, p.vivax, p.ovale, p.malariae
Give 3 forms of direct transport
Direct physical contact, Such as touching a person who is infected or touching contaminated surfaces that harbour pathogens. For example HIV(virus), bacterial meningitis(bacteria), ringworm(fungus) and athletes foot.(fungus)
Facecal- oral transmission, usually by eating food or drinking water contaminated by the pathogen. For example cholera, food poisoning.
Droplet infection- in which the pathogen is carried within tiny. Water droplets in the air. For example, influenza(virus) and tuberculosis( bacteria)
Transmission by spores- which are resistant stage of the pathogen. These can be carried in the air or remain in the soil. For example, anthrax or tetanus.
What are the social factors that affect transmission
Overcrowding
Poor ventilation
Poor health
Poor diet
Homelessness
Living or working with people who have migrated from areas where disease is more common
What is a mean of indirect transmission in plants
Pathogen often occur as a result of an insect attack, spores or bacteria will become attached to the burrowing insect, such as a beetle, which attacks an infected plant. When that beetle attacks another plant, the pathogen is transmitted to the uninfected plant. The beetle lis acting as a vector. For example, the fungus that causes Dutch elm disease is carried by the beetle scolytus multistriatus