VACCINATION

IMMUNITY PassiveActive Production of antibodies is stimulated Long-lasting Antibodies are introduced into the body Short-lived as these aren’t replaced once they break down

Vaccinations Are prepared antigens from pathogens Stimulate the body to produce memory cells, so that you can mount a secondary response if you come into contact with the pathogen

Preparation of vaccines Killed pathogens with the antigen intact eg cholera Weakened (attenuated) pathogens with their antigens intact eg polio Purified antigens eg hepatitis B

Success of Vaccination programmes Availability – there needs to be enough to immunise the population Few side-effects Availability of storage Enough trained staff to administer the vaccine safely

Need to vaccinate the majority of the population to ensure herd immunity - so that the transmission of the pathogen through the population is interrupted

Problems: Some individuals don’t mount a response Disease may develop before the antibodies are produced Antigenic variability may occur eg flu May be too many viral strains eg cold Some pathogens may be difficult for the immune system to reach eg cholera Some individuals may object to vaccinations eg MMR

Cholera, sometimes known as Asiatic cholera or epidemic cholera, is an infectious gastroenteritis caused by enterotoxin-producing strains of the bacterium Vibrio cholerae.[1][2] Transmission to humans occurs through ingesting food or water that is contaminated with cholera vibrios. The major reservoir for cholera was long assumed to be humans themselves, but considerable evidence exists that aquatic environments can serve as reservoirs of the bacteria.gastroenteritis enterotoxin bacteriumVibrio cholerae[1][2]

bacterium that produces cholera toxin, an enterotoxin, whose action on the mucosal epithelium lining of the small intestine is responsible for the disease's infamous characteristic, exhaustive diarrhea.[1] In its most severe forms, cholera is one of the most rapidly fatal illnesses known, and a healthy person's blood pressure may drop to hypotensive levels within an hour of the onset of symptoms; infected patients may die within three hours if medical treatment is not provided.[1] In a common scenario, the disease progresses from the first liquid stool to shock in 4 to 12 hours, with death following in 18 hours to several days, unless oral rehydration therapy is provided.[3][4]cholera toxin enterotoxinmucosal epitheliumsmall intestinediarrhea[1] blood pressurehypotensive[1]stoolshockoral rehydration therapy[3][4]

Now read page 112 – 113 of your text book and answer Q1-3 on page 113. Do Q3 and 4 page 116