4.1 Communicable Disease, Disease Prevention And The Immune System (Disease Examples) Flashcards
Give key information about tuberculosis (TB)
- disease of humansa, badgers, cows, pigs + deer
- damages lungs + supresses immune system
- cured by antibiotics
- prevented via vaccination + improved living conditions
How is tuberculosis transmitted and how does it then affect the organism?
- Bacteria transmitted in droplets
- Encased in tubercle, release when sneezing/coughing
- Inhaeled by individual
- Bacteria are dormant
- If immunosupressed bacteria activate/replicate + spread
- Bacteria destory alveoli leading to fibrosis/scaring, reducing diffusion due to less SA
- Sufferers breathoess due to less SA for gaseous exchange - less oxygenation of blood + coughing up blood
When is contraction and infection of Tuberculosis more likely?
- with a weakened immune system (e.g. HIV)
- poor ventilation
- overcrowding
- poor diet
- homeless
- living/working areas common to the infection (Asia/Africa)
List ways Tuberculosis can be transmitted
- in air through coughing + sneezing and spreading to uninfectd animals
- small chance of human infection from milk + meat
- more common in developing world
Why has Tuberculosis not been eradicated?
- drug/anatibiotic resistance
- vaccine not 100% effective
- no vaccine for mutant strains
- can be symptomless/ dormant in body
- lack of education about TB
- overcrowding (in poorly ventialted accomodation)
- developing countires can’t afford treatment/drugs/vaccines
- malnutrition
- untreated milk + uncooked meat
- breakdown of treatment programme due to war/unrest
- migration of carriers/refugees/tourists
Give key information about Ring Rot
- affects potatoes, tomatoes, aubergines
- causes damage to leaves, tubers + fruits
- in potato, bacteria infect xylem + phloem, so less water reaches leaves + spreads to stem and tubers
- no cure
Give key information about HIV/AIDS
HIV: Human immunodeficiency virus (retrovirus)
AIDS: Acquired immunodeficiency syndrome
- infects T helper cells of bodies immune system
- destroys immune system so individual suffers ‘opportunistic infections’ e.g. TB + pneumonioa
- passed in bodily fluids (shared needles, unprotected sex, unscreened blood transfusions, during birth, breat feeding)
- no vaccine or cure
- anti-retroviral drugs slow progress of HIV
How does HIV infect individuals?
- has protein receprots to target + infect T helper cells
- viral RNA + reverse transcriptase inserted
- makes DNA copy of viral RNA
- DNA copy placed in nucelus to code for more viral RNA + viral proteins
- number of T helper cells decrease + phagocytes can’t destroy pathogen as virus is within cells
Why is HIV difficult to prevent?
- no cure + vaccine
- high mutation rate
- can’t be treated with antibiotics
- symptomless carriers + long incubation period
- transmitted easily by bodily fluids
- people reluctant to test for HIV
Why is HIV more common in Africa + Asia?
- poverty
- less education on disease transmission
- sexual attitudes/promiscuity
- religious/culural reasons
- denial/ superstitious beliefs
- less medical facilities + hospitals
- less blood screening/testing of people
- more infected mothers breast feed
- more cases of rape
- more intravenous drug abuse
Give key information about Influemza (flu)
- virus of mammals (humans + pigs) + birds
- caused by family of viruses called Orthomyxoviruses
- affects ciliated epithelial cells of respiratory system
- epithelial cells killed, leading to secondary infections
- can be fatal to young + old people + people with chronic illnesses
- three main strains - A,B,C
- regularly mutates causing changes of surface antiugens
- major changes can lead to epidemics, pandemics
- no cure due to regular mutation
- flu vaccine given to vulnerable group annually
How do new mutations of the influenza virus make it difficult to develop vaccinations?
- mutations change antigens on surface
- memory cells from 1st infection no longer effective
- no antibodies for new antigen
- so disease contracted again
- not killed by antibiotics as not a bacteria
How is the risk of flu being managed?
National vaccinmation for vulnerable high risk groups:
- over 65 years
- weak immune system (HIV)
- infants (immune system not mature)
- pregnant women
Open access to vaccination at supermarkets
Research to find most common type of flu virus each year
Give key information about Tobacco Mosaic Virus (TMV)
- infects tobacco plants, tomatoes, peppers, cucumbers, petunias + delphiniums
- causes leaf, flowers + fruit damage + causes yellow mosaic pattern
- protein rod surrounding single stranded RNA (coding for 3 proteins)
- stunts growth of plants + reduces yield for farmers/growers
- resistant crop strains exist
- no cure
Give key information about Malaria
- caused by plasmodium (protoctista)
- vector is female mosquitoes, found in high numbers in tropical areas where climate is suitable + countries are poor
- plasmodium infect erythrocytes, liver cells + the brain
- no cure + vaccie
- inecticides kill vector + remove standing water are preventive measures
