Disease

A malfunction of the body’s system. A failure of the homeostatic control.

Types of Disease

Infectious Disease

Caused by microbes that invade the body and upset its homeostasis.

Pathogens

Microbes which cause disease.

Modes of Infection

Hygiene

• Sanitary Cordon – stop the spread of the infection
• Quarantine – isolate infected persons
• Sterilisation of contaminated materials – stop the spread of infection
• Pasteurisation – 1863 Louis Pasteur
• Antiseptics – 1865 Lister
• Water/food treatment
• Pest control

Medicine

Reporting on disease: Symptoms, spread, incubation, and attempted remedies.
Vaccination/Immunisation – stimulating the body’s natural defence system
Antibiotics are only useful against bacteria and fungi, which have a metabolism. They do not affect viruses. Most bacterial antibiotics are inhibitors of protein synthesis blocking the 70S ribosome.
Anti viral drugs

Use the link below to open a map showing the spread of the Black death across Europe between 1347 and 1350

Internet Link

• Black Death was the bubonic plague caused by the bacterium Yersinia pestis.
  Transmission is through direct contact with contaminated rodents or their fleas that may bite humans and from the contaminated blood and sputum of infected humans.
  The effects are high fever, aching arms and legs, vomiting and coughing blood, swelling of lymph nodes in the neck, arm pits and groin to form black buboes (hence "the black death"). These burst and soon after the patient dies.
• Between 1347 and 1351, one-third of Europe was dead. Whole villages disappeared and towns were devastated. This was the major pandemic of the medieval period.
• The plague continued to break out during the next two hundred years.
• The first responses to the cause of the plague were irrational or superstitious - miasma from the ground, strangers, foreigners, lepers, God's vengeance!
• People (chroniclers, poets and authors, and physicians) started to write about what might have caused the plague and how the plague affected the population.
  
• In Italy in the 1350s there were efforts to improve public sanitation.
  
• Finally, by the sixteenth century ideas of contagion developed.
  
• That microbes were responsible for infection was not established until 1876 by Robert Koch
  
• Today the disease is limited to Southern Africa and South East Asia. Treatment using the antibiotic streptomycin is effective if started early. Complications (e.g. meningitis) need additional treatment.