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