PREVENTION, TREATMENT & CONTROL: How can the spread of infectious…
PREVENTION, TREATMENT & CONTROL:
How can the spread of infectious diseases be controlled?
Factors affecting the spread of disease
diseases are more common in tropical climates
global warming/climate change causing many diseases to spread from tropics to spread further
melting of permafrost releasing pathogens that have been frozen e.g. anthrax outbreak in Siberia
poor living conditions, limited access to medical care, high degree of contact with animals, local cultural practices facilitate in spread of disease or make it harder for authorities to control
low resistance due to new pathogens (when pathogen crosses species border) creates epidemics. e.g. Flu epidemics
low resistance due poor living situation. overcrowded conditions, lack of clean water , proper sanitation or enough food e.g. Cholera epidemics
climates that enhance spread of diseases (tropics), high population densities, poverty (economic),conflict (leading to refugees),high levels of tourism and trade and global warming
how Virulent, robust (survival) and infectious a pathogen is. Characteristics, transmission, prevention or treatment and where they live.
increasing movement of of people due to tourism, trade ,migration and wars, the emergence of new diseases with capacity to infect enormous numbers of people due to low host resistance, possibility of bioterror attack deliberately releasing deadly pathogens, increasing numbers of antibiotic resistance.
Procedures to prevent the spread of disease
release antigens into body to teach the immune system to recognise it and fight it producing memory cells. Contains weakened pathogens.
release antibodies from an immune organism to fight the infection. Fast acting not long lasting and helpful for anyone who does not respond to immunisation or is immuno-deficient
difficult and costly to produce requiring huge amounts of donated blood. New development of monoclonal antibodies in the lab.
Public health campaigns
programs run by governments or public organisations to publicise health issues with the aim of reducing the incidence of disease by raising awareness and making people better informed
e.g. campaigns aimed at increasing vaccination rates 'no jab,no pay'.
herd immunity is created when a very high proportion of the population is vaccinated. it protects those who can't be vaccinated. decreases the spread of disease.
isolating diseased organisms
detaining anyone arriving at the border if suspected of carrying an infectious disease
system of measures taken by authorities to prevent people from bringing materials that could be carrying pest or diseases into a country (AQIS)
protects: farming industries, native plants and animals and health of human population
e.g. Riverland and Tasmania free of Fruit flies
chemicals used to kill pests that affect the health of humans, animals and plants. effectiveness is decreasing due to pesticide resistance
widely used to control vectors such as mosquitos
can be applied by spraying, irrigration water,baiting,dipping or drenching
causes environmental and health problems. e.g. leads to biological magnification affecting food chain and top predators and serious health problems in humans such as asthma.
household hygiene: keeping surfaces and utensils where microbes can proliferate clean.
hygeine in food preparation: wearing gloves, cooking thoroughly, storing at correct temperature
personal hygiene: handwashing, safe sex,avoid sharing things
community hygiene: water treatment, sewerage systems and treatment, rubbish collection and disposal, strict hygiene practices in health centres
improving purity of vaccines by using genetically modified bacteria to produce antigens in active vaccines
genetically engineering plants to produce vaccines that can be eaten
genetically modified cattle to produce antibodies for passive vaccines
genetically modified infertile mosquitoes released to reduce number of vectors
disease resistant animals and plants, increasing farming productivity, reducing pesticides
Effectiveness of pharmaceuticals
toxic to bacteria,killing them
'broad-spectrum' effective against a wide range of bacterial species. 'narrow-spectrum' effective against only a few species.
since mid-20th century (1940s), the use of antibiotics has hugely decreased the number of deaths due to bacterial infections and increase the average life expectancy.
the development of antibiotic resistance in bacteria-due to misuse and overuse, is now reducing their effectiveness.
superbugs: bacteria resistant to almost every available antibiotic. impossible to treat.
antibiotic resistance is an even greater problem in developing countries due to misuse of antibiotics by unskilled practitioners, poor conditions etc.
The World Health Organisation has launched a Global Action Plan on Antibiotic Resistance to limit the damage caused by this growing problem
treat viral infections by interfering with 'life' cycle by inhibiting their development, reducing their ability to bind to host cells or reproduce inside host cells, preventing it from leaving the host cells after it has multiplied and stimulating the host immune system
need to be taken soon after becoming infected to reduce symptoms and duration of a viral illness. making them useful during outbreaks to minimise spread.
antivirals have only been developed since 1980s, in response to the HIV AIDS epidemic.
harder to find compounds that are toxic to viruses but safe for human cells
finding new drugs is not easy and is also costly, time consuming and a risky investment as there is no guarantee that a new drug will actually be suitable for use in humans
new drugs taken for long-term chronic illnesses are more profitable than short-term antibiotics and antivirals
little incentive to develop new drugs however it is badly needed due to development of resistance.