B3 : Infection and response

• Diseases are spread through contaminated food and water, the air, and physical contact
• Pathogen

  
  

  microorganism that enters the body and causes disease
• Virus

  
  

  Have regular shapes

  Only replicate inside organism

  Can cause disease in any living thing
• Fungi

  
  

  Single or multicellular

  Hyphae - thread like structures -- can penetrate human skin