Active immunity #
- result of infection/naturally/artificially/vaccination
- body manufactures its own antibodies
- stimulated by memory cells
- most effective/rapid response (second infection) persists for a long time
Passive immunity #
- antibodies from another individual
- give immediate protection
- protects for short time (about a week)
Natural
- natural active
- natural infection by pathogen/antigen
- natural passive
- antibodies from mother to foetus/across placenta
- antibodies in colostrums/breast milk to baby
Artificial
- artificial active
- injection of pathogens/antigens into the body
- artificial passive
- ready-made antibodies injected into the body
How vaccination give protection against diseases #
- vaccination- injection/administration of an antigen
- causes production of antibodies (against the antigen)
- vaccination is artificial immunity
- booster injection may be used for longer lasting/more effective protection
- response due to B and T cells memory cells survive for a long period
- memory cells are B cells
- memory cells enable a rapid response
- antibody brings about destruction of antigen/organism carrying it
- effective against infectious diseases 9e.g. small pox/diphtheria/polio/measles/whooping cough) – vaccinate children in national/international campaigns
Describe why vaccination managed to eradicate small pox but not malaria #
Small pox #
- varilosa virus stable
- (harmless) strain of (live) vaccine effective
- vaccine could be kept for a long time (6 months)
- infected people were easy to identify
- ring vaccination was possible
- political stability during that time
Malaria #
- no vaccine/no effective vaccine against the protozoan
- resistance of Plasmodium to drugs
- resistance of vector/mosquitoes to DDT/dieldrin/insecticide
- difficulty of mosquito control
- expensive to expand the programs.
- civil wars disrupt the programs.
Measles #
- caused by an RNA virus
- viruses are intracellular pathogens
- antigenic concealment have a short time in the blood
- major changes in the epilate as a result of mutation
- poor response to vaccine (children do not respond well to one dose of vaccine)
- deficiency immune system
- or protein energy malnutrition
- need several boosters which are expensive
- high birth rates and flighting populations make it difficult for boosters
- follow up cases and trace contacts also impossible
- refugees and immigrants from reservoirs of the infection
- it is highly infectious resulting in the whole population requiring vaccination which is highly expensive
- the virus is of hiring attenuated virus can be virulent
Tuberculosis #
- some strains of TB bacteria resistant to drugs;
- the AIDS pandemic;
- poor housing and rising homelessness in inner cities in the developed world;
- the breakdown of TB control programes particularly in the USA;
- partial treatment for TB increases the chance of drug resistance in Mycobacterium;
- attacks many of the poorest and socially disadvantaged because it is spread by airborne droplets;
- so people who are overcrowded are particularly at risk;
- those with low immunity particularly because of malnutrition or being HVI+ are also vulnerable;
- transmission is easily achieved but the bacteria may remain in the lung, or in the lymphoid tissue for years until they become active;
Cholera #
- cholerae in intestine;
- out of reach of immune system;
- antigenic concealment;
- antibodies broken down in intestine;
- antibodies are proteins;
- ref to pH and effect on structure or shape; e.g. in the stomach
- denaturation;
- vaccine stimulates antibodies in, blood / lymph;
- not in gut;
- oral vaccine needed;
- mutation;
- different strain idea;
- AVP; e.g. not required in developed countries
- developing countries cannot afford to develop vaccines
- no / limited, demand
- cholera can be treated with ORT
- can be treated with antibiotics
