Infectious Diseases Flashcards
What is a disease?
a disease is an illness or disorder of the body or mind which leads to poor health, each disease has a set of signs and symptoms
What is the difference between an infectious and non-infectious disease?
an infectious disease is one caused by a pathogen and are communicable, a non-infectious disease is not, eg. lung cancer, sickle cell anaemia
What is the pathogen of cholera?
vibrio cholerae
What is the pathogen of malaria?
plasmodium (falsiparum, vivax, ovale, malariae)
What is the pathogen of tuberculosis?
myobacterium tuberculosis, m. bovis
What is the pathogen of HIV/AIDS?
human immunodeficiency virus
What is the pathogen of measles?
morbillivirus
What is the pathogen of smallpox?
variola
How is cholera transmitted?
contaminated food and water
How is malaria transmitted?
vector - female anopheles mosquito
How is tuberculosis transmitted?
airborne droplets (m. tuberculosis), undercooked meat/unpasteurised milk (m. bovis)
How is measles transmitted?
airborne droplets
How is HIV/AIDS transmitted?
exchange of bodily fluids eg. blood, semen, vaginal fluids, breast milk, placenta
How is cholera prevented?
sewage treatment, clean water, vaccination in endemic places
What biological, social, and economic factors need to be considered in the control and prevention of infectious diseases?
dense populations, overcrowding, poor sanitation, lack of education, poor healthcare, lack of funding
How is malaria prevented?
reduce mosquitos with insecticides, oil, drainage, fish which feed on larvae, bacterium bacillus thuringiensis
reduce chances of being bitten by sleeping under bed nets and covering at dusk
profylactic drugs such as chloroquine or mefloquine before, during, and after a visit to endemic areas
How is tuberculosis prevented?
BCG vaccine , testing cattle, pasteurising milk, cooking meat
How is HIV/AIDS prevented?
blood donations screened and heat-treated, babies and mothers drug treated, condoms, femidoms, dental dams, education programs, education programmes, encourage not sharing needles between intravenous drug users
What factors influence the global distribution of malaria?
hot, humid areas near the equator as there are more mosquitos present
What factors influence the global distribution of tuberculosis?
all countries, predominantly densely populated and developing places
What factors influence the global distribution of HIV/AIDS?
95% in less developed countries, mostly sub-saharan africa
What is the worldwide importance of malaria?
increase in drug resistant forms, increase in proportion of cases caused by p. falciparum, difficulty developing vaccine, increase in number of epidemics due to climatic changes, migration for economic and political reasons, modern techniques in gene sequencing, development of vaccines, international will to remove disease
What is the worldwide importance of tuberculosis?
endemic in whole population, increase in drug-resistant forms
What is the worldwide importance of HIV/AIDS?
exponential spread of virus since 1980s, no cure, reversed economic growth, risk to public health
How does penicillin act on bacteria?
by targeting:
- synthesis of bacterial cell walls
- activity of proteins in cell surface membrane
- bacterial enzyme action
- bacterial DNA synthesis
- bacterial protein synthesis
Why don’t antibiotics affect viruses?
they do not have cells or cell walls and therefore antibiotics cannot target their features
How do bacteria become resistance to antibiotics?
evolution by natural selection, vertical transmission, horizontal transmission
What is mutation?
a change in DNA nucleotide sequence/gene resulting in new variant
What is selection?
variation in bacteria caused by mutation of a gene may result in antibiotic resistance, this bacteria can reproduce with less competition, so the genes for resistance are passed on to the next generation, over time resulting in a new antibiotic resistant strain of the species
What are the consequences of antibiotic resistance?
increase in strains of resistant bacteria, race to find new antibiotics, resistance spreads quickly, multiple resistance, problem for doctors, long hospital stays and death,
What can be done to reduce the impact of antibiotic resistance?
- prescription
- avoid over/unnecessary use
- narrow spectrum antibiotics
- finish course
- don’t keep at home
- different types of antibiotics prescribed for same disease
- avoid preventative antibiotics in farming
How is measles prevented?
vaccine, cover mouth and nose
How is cholera treated/controlled?
ready access to oral rehydration therapy, monitoring programmes, antibiotics in severe cases
How is malaria treated/controlled?
improve diagnosis, improve supply of effective drugs, use drugs in combination, promoting methods to prevent transmission, dipstick tests, plasmodium genome has been sequenced making it easier to develop a vaccine, anti-malarial drugs
How is tuberculosis treated/controlled?
contact tracing/testing, isolation, drugs
How is HIV/AIDS treated/controlled?
contact tracing, screening blood, needle exchange programmes, encouraging high risk groups to be tested, antiretroviral drugs, HIV-positive mothers advised not to breast feed in high income countries
