Topic 10 Flashcards
Define the term infectious disease
A disease caused by a pathogen which can be transmitted
Define the term non infectious diease [2]
- A disease that cannot be transmitted by direct contact between individuals (lung cancer, sickle cell anaemia)
State the binomial name and pathogen type for cholera [2]
- Vibrio cholerae
- bacterium
State the binomial names and pathogen type for malaria [5]
- Plasmodium ovale
- Plasmodium falciparum
- Plasmodium malariae
- Plasmodium vivax
- Protoctist
State the binomial names and pathogen type for tuberculosis [3]
- Myocbacterium tuberculosis
- Mycobacterium bovis
- bacerium
State the pathogen type for HIV/AIDS
Virus
What does HIV stand for?
Human immunodeficiency virus
What does AIDS stand for?
Acquired immunodeficiency syndrome
What causes HIV/AIDS? [4]
- The HIV virus is transmitted by direct contact with blood, semen, rectal fluids, vaginal fluids and breast milk
- Attachment proteins bind to complementary CD4 receptor on Th cells
- HIV particles replicate inside Th cells, killing or damaging them
- AIDS develops when there are too few Th cells for the immune system
How is HIV/AIDS treated?
Taking a combo of antiretroviral drugs prevents HIV replication. PEP can prevent infection after exposure
What causes tuberculosis? [4]
- Transmitted by droplet infection
- trigger inflammatory response by infecting phagocytes in lungs
- Infected phagocytes are sealed in waxy coated tubercules so bacteria remain dormant. Primary TB has no symptoms
- If another factor weakens the immune system, bacteria become active. Secondary TB destroys lung tissue
Outline primary treatment of TB
Patients take a combination of antibiotics for several months
How is cholera transmitted? [2]
- Fecal/oral transmission
- Ingesting contaminated food or water
How is cholera treated? [2]
- Rehydration (fluid and electrolytes)
- Antibiotics
Why might incidence and prevalence of communicable diseases change over time? [4]
- Development of vaccines
- Development of treatments (antibiotics)
- Random mutations cause antigen variability in pathogens. Memory cells no longer complementary
- Random mutations result in treatment resistant strains
How can spread of HIV be prevented? [6]
- Take PEP or PrEP
- Multi drug treatment
- Use clean needles
- Screen blood donations
- Education on safe sex and the disease
- Use of condoms
How can spread of TB be prevented? [4]
- Combination of drugs and vaccines
- Cover mouth and nose when coughing and sneezing
- Quarantine
- Improved sanitation
How can transmission of cholera be prevented? [2]
- Education on water sanitation
- Education on contamination of water supply
Outline the mode of transmission and infection of the plasmodium spp parasite [2]
- Female mosquitos act as vectors when it transfers saliva to another organism during feeding
- Parasite reproduces asexually in red blood cells in liver causing lysis
How is endemic malaria controlled? [3]
- Preventing mosquito bites
- controlling mosquito numbers
- drug treatment
Biological, economic and social factors in preventing infectious disease [4]
- Spread faster in densely populated and poorly sanitised areas
- Countries with good healthcare and good education often have less disease
- Social stigma (HIV discrimination)
- Patronage of developed countries (vaccine programs considered suspicious)
Pattern of malaria
Generally tropical countries (warm and humid to allow plasmodium to survive). Tend to lack education and healthcare for prevention methods
Pattern of TB
Common in developing countries where people live in poorly sanitised cramped conditions
HIV/AIDS pattern
Common in developing nations. Lack of access to education in prevention. Lack of healthcare means people go undiagnosed
How does penicillin act as an antibiotic? [2]
- Penicillin inhibits the syntheses of the pepdigoglycan wall in bacteria, preventing new cell walls forming. The cell bursts
- This class of antibiotic is bactericidal. They work by preventing cell wall synthesis or disrupting protein synthesis
Why do antibiotics have no effect on viruses
Work by targeting machinery found in bacteria (prokaryotic cells). Viruses dont have this machinery, meaning they have no effect
Why is it important antibiotics do not effect eukaryotes?
Humans are eukaryotic. If antibiotics affected eukaryotic cells they could potentially kill the recipient
How does antibiotic resistance occur? [2]
- Spontaneous mutation of bacterial plasmids can occur which may lead to improved tolerance to an antibiotic. These cells are able to survive long enough to divide, increasing the prevalence of the mutation and making the population more resistant to a particular antibiotic.
- Resistance can be spread ‘horizontally’ - the movement of genetic material between unicellular and/or multicellular organisms (conjugation) other than by the ‘vertical’ transmission of DNA from parent to offspring via reproduction.
How can we mitigate bacterial resistance? [8]
- Complete full course of antibiotics
- Don’t overuse antibiotics
- dont use antibiotics in animal feed
- reduce contamination in hospitals
- aseptic techniques in hospitals
- Isolation of infected patients
- emphasis on hygiene
- reduce use of antibacterial hand gel
