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7 Cards in this Set
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Facultative pathogens don’t require a host to live but obligate ones do. Respiratory pathogens are spread via aerosols generates by sneezing and coughing. BACTERIA: Mycobacterium Tuberculosis: TB Staphylococcus aureus: spots/boils/toxic shock syndrome |
VIRUSES Rhinovirus - common cold Influenza - flu Each pathogen has its own environmental niche. Eg - staphylococcus aureus in the nasal tract - influenza in primary bronchioles |
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TUBERCULOSIS: most commonly affects lungs, but can also effect lymph nodes, bones, and cause meningitis. Anyone can get TB but those most at risk are: - those in close contact with disease - live in areas where TB in endemic - weakened immune system - young or elderly - poor chronic health (more people get TB because they have diabetes than HIV) |
Combination of better lifestyle, antibiotics and BCG vaccine has reduced TB in the UK, but it still effects 1/3 of the worldwide population |
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WHAT HAPPENS WHEN INFECTED? 1) infection may resolve 2) over time, active TB develops 3) infection may be asymptomatic and bacteria are dormant. Can become active when you get older or if an event weakens the immune system (REACTIVATION) |
SYMPTOMS: - cough, with or without sputum for more than 3 weeks - coughing up blood - loss of appetite - tiredness |
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HOW TO TEST? Skin test: inject Tuberculin (which is extracted from M.TB) under the skin to see if BCG vaccine is required. 2 ways to do so: 1) HEAF: inject small amount using a device with 6 small needles. Examine after 7 days 2) MANTONX: inject using needle and syringe. Examine after 2 days. |
TREATMENT: combination of 3-4 antibiotics for 6 month period.
Problem is that people tend to start feeling better and stop using the antibiotics so bacteria develop resistance. |
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STAPHYLOCOCCUS AUREUS: can be transmitted directly or indirectly BOILS: SA gets into the skin and replicates, creating a chemical gradient of microbial molecules, which are detected by neutrophils which come to the site of infection. The SA produces a toxin which kills the neutrophils, creating pus in a sac. (So the infection is suppurative) |
TOXIC SHOCK SYNDROME: SA create a toxin, linked to tampon usage. Symptoms - high fever - red eyes - kidney and liver damage - vomiting and diarrhoea TREATMENT: fluids and antibiotics |
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VIRUSES: RHINOVIRUS: causes common cold. Each strain is antigenically distinct so can’t get immunity to all of them. Symptoms: snotty nose and sore throat |
Influenza causes a flu Symptoms: - head ache - high fever - vomiting |
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INFLUZENA A: bird flu passed over to humans since we come in close contact with animals more now than ever before. - ssRNA genome in 8 segments enclosed In a lipoprotein capsule that has 2 protruding proteins that are antigenically distinct in each strain: 1) Haemagglutinin 2) Neuraminidase |
H5N1 can now be transmitted human —> human since it has mutated. Can mutate in 2 ways 1) spontaneous mutation of RNA genome 2) reassortment: replication of viral genome where you get some of the human adapted strain and some of the pathogenic H5N1 to create a new strain that has a mix of characteristics. - so reassortment produces a hybrid strain Every 10-40 Years a new antigenically distinct strain emerges in the population and causes a pandemic. |
