Communicable Diseases

• What is a communicable disease?

  A disease caused by a pathogen
• How can communicable diseases be transmitted?

  They can be passed between animals or plants
• What is a pathogen?

  A disease-causing microorganism
• How do bacteria cause disease?

  They divide rapidly and produce harmful toxins
• How do viruses cause disease?

  They invade and reproduce inside body cells
• What are three ways pathogens can be spread?

  • By air (e.g., flu, tuberculosis)
  • By water (e.g., fungal spores)
  • By direct contact (e.g., STIs)
• What are four ways to reduce the spread of pathogens?

  • Hygiene (handwashing, disinfectants)
  • Quarantine infected individuals
  • Remove vectors (pesticides, habitat removal)
  • Vaccination
• Why is it important to prevent the spread of viral diseases?

  Many viral diseases have no cures
• What is measles?

  A serious viral disease causing blindness
• How is measles spread?

  By air through inhalation of droplets
• What is HIV/AIDS?

  HIV attacks the immune system
• How is HIV spread?

  Through direct sexual contact and bodily fluids
• How can the spread of HIV/AIDS be prevented?

  • Use of condoms
  • Blood screening for transfusions
  • Not sharing needles
  • Bottle-feeding by HIV-positive mothers
  • Antiretroviral drugs
• What is tobacco mosaic virus?

  A plant pathogen causing leaf discolouration
• How is tobacco mosaic virus spread?

  Contact between infected and healthy plants
• What is salmonella?

  A type of bacteria found in raw meat
• What are the symptoms of salmonella food poisoning?

  Fever, cramping, vomiting, and diarrhoea
• How can the spread of salmonella be limited?

  • Vaccinating animals for consumption
  • Keep raw and cooked meat separate
  • Disinfect hands after raw meat contact
  • Thoroughly cook meat
• What is gonorrhoea?

  A sexually transmitted bacterial infection
• What are the early symptoms of gonorrhoea?

  Yellow/green discharge and painful urination
• How can gonorrhoea be controlled?

  Using antibiotics and condoms
• What is rose black spot?

  A fungal disease affecting rose leaves
• How is rose black spot spread?

  By wind and water-borne fungal spores
• How can rose black spot fungus be treated?

  • Using fungicides
  • Destroying infected leaves
• What is malaria?

  A disease caused by protist pathogens
• How can the spread of malaria be reduced?

  Using insecticides and nets
• How does the skin prevent pathogens from entering the body?

  • Acts as a physical barrier
  • Scab formation after cuts
  • Antimicrobial secretions
  • Healthy skin flora compete with pathogens
• How does the respiratory system prevent pathogens from entering the body?

  • Nose traps pathogens with hairs and mucus
  • Trachea and bronchi have mucus and cilia
• How does the stomach prevent pathogens from infecting the body?

  • Secretes hydrochloric acid to kill pathogens
• How does phagocytosis protect us against disease?

  • White blood cells ingest and destroy pathogens
• How does antibody production protect us against disease?

  • Antibodies neutralize pathogens and mark them for destruction
• How does the nose prevent pathogens from entering the body?

  It has hairs and mucus that trap pathogens.
• What role do ciliated cells in the trachea and bronchi play?

  They move mucus to the mouth for swallowing.
• How does the stomach prevent pathogens from infecting the body?

  It secretes hydrochloric acid to kill pathogens.
• How does phagocytosis protect us against disease?

  Phagocytes ingest and destroy pathogens.
• How does antibody production protect us against disease?

  Antibodies bind to antigens, clumping pathogens.
• What happens during a second infection regarding antibodies?

  Memory cells produce antibodies rapidly.
• How do antitoxins protect us against disease?

  Antitoxins bind and neutralize toxins from pathogens.
• What is a vaccination?

  It contains a dead or inactivated pathogen.
• How do vaccinations help during a second infection?

  They enable rapid production of antibodies.