KS4 Infections

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KS4 Human Infection & Response Learning Objectives

3.1.1 Communicable (infectious) diseases
(References to Semmelweis not included).

Students should:

  • Be able to explain how diseases caused by viruses, bacteria, protists and fungi are spread in animals and plants.
  • Know that Pathogens are microorganisms that cause infectious disease.
  • Know that Pathogens may be viruses, bacteria, protists or fungi.
  • Know that Pathogens may infect plants or animals and can be spread by direct contact, by water or by air.
  • Know that bacteria and viruses may reproduce rapidly inside the body.
  • Know that bacteria may produce poisons (toxins) that damage tissues and make us feel ill.
  • Know that viruses live and reproduce inside cells, causing cell damage.
  • Be able to explain how the spread of diseases can be reduced or prevented, including:
    - simple hygiene measures
    - destroying vectors
    - isolation of infected individuals
    - vaccination.

3.1.2 Viral diseases: details on measles and HIV

Students should:

  • Know that Measles is a viral disease showing symptoms of fever and a red skin rash.
  • Know that Measles is a serious illness that can be fatal if complications arise and for this reason most young children are vaccinated against measles.
  • Know that the measles virus is spread by inhalation of droplets from sneezes and coughs.
  • Know that HIV initially causes a flu-like illness
  • Know that unless successfully controlled with antiretroviral drugs the virus enters the lymph nodes and attacks the body’s immune cells.
  • Know that late stage HIV, or AIDS, occurs when the body’s immune system becomes so badly damaged it can no longer deal with other infections or cancers.
  • Know that HIV is spread by sexual contact or exchange of body fluids such as blood which occurs when drug users share needles.

3.1.3 Bacterial diseases: details on salmonella and gonorrhoea

Students should:

  • Know that Salmonella food poisoning is spread by bacteria ingested in food, or on food prepared in unhygienic conditions.
  • Know that in the UK, poultry are vaccinated against Salmonella to control the spread.
  • Know that fever, abdominal cramps, vomiting and diarrhoea are caused by the bacteria and the toxins they secrete.
  • Know that Gonorrhoea is a sexually transmitted disease (STD) with symptoms of a thick yellow or green discharge from the vagina or penis and pain on urinating.
  • Know that gonorrhoea is caused by a bacterium and was easily treated with the antibiotic penicillin until many resistant strains appeared.
  • Know that gonorrhoea is spread by sexual contact and that the spread can be controlled by treatment with antibiotics or the use of a barrier method of contraception such as a condom.

3.1.5 Protist diseases: details on malaria

Students should:

  • Know that the pathogens that cause malaria are protists.
  • Know that the malarial protist has a life cycle that includes the mosquito.
  • Know that malaria causes recurrent episodes of fever and can be fatal.
  • Know that the spread of malaria is controlled by preventing the vectors, mosquitos, from breeding and by using mosquito nets to avoid being bitten.

3.1.6 Human defence systems

Students should:

  • Be able to describe the nonspecific defence systems of the human body against pathogens, including the ways that the human body defends itself against the entry of pathogens, including:
    - The skin is a barrier and produces antimicrobial secretions.
    - The nose traps particles which may contain pathogens.
    - The trachea and bronchi secrete mucus which traps pathogens and cilia waft the mucus to the back of the throat where it is swallowed.
    - The stomach produces acid which kills the majority of pathogens which enter via the mouth.
  • Know that if a pathogen enters the body the immune system tries to destroy the pathogen using white blood cells that help to defend against pathogens by:
    - Phagocytosis
    - antibody production
    - antitoxin production.

3.1.7 Vaccination

Students should:

  • Know that Vaccination involves introducing small quantities of dead or inactive forms of a pathogen into the body to stimulate the white blood cells to produce antibodies.
  • Know that if the same pathogen re-enters the body the white blood cells respond quickly to produce the correct antibodies, preventing infection.
    (Students do not need to know details of vaccination schedules and side effects associated with specific vaccines)
  • Be able to explain how the spread of pathogens can be reduced by immunising a large proportion of the population.
  • Be able to evaluate the global use of vaccination in the prevention of disease.

3.1.8 Antibiotics and painkillers

Students should:

  • Be able to explain the use of antibiotics and other medicines in treating disease.
  • Know that antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body.
  • Know that it is important that specific bacteria should be treated by specific antibiotics.
  • Know that the use of antibiotics has greatly reduced deaths from infectious bacterial diseases.
  • Know that the emergence of strains resistant to antibiotics is of great concern.
  • Know that antibiotics cannot kill viral pathogens.
  • Know that painkillers and other medicines are used to treat the symptoms of disease but do not kill pathogens.
  • Know that it is difficult to develop drugs that kill viruses without also damaging the body’s tissues.

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