• Agent of disease
    • Being the carriers/vectors of disturbing , destroying or causative agents
      • vectors being
        • any other species which carry the disease with in themselves
          • insects
      • causative agents
        • non - cellular life
          • Viral Infection , virology
        • cellular life
          • Bacterial Infection , microbiology
          • Parasitic Infection , parasitology
          • Fungal Infection , mycology
  • Entry of either vectors or causative agents
    • Mode of transmission of either vectors or causative agents
      • water borne disease
      • air borne diseases
      • food borne diseases
        • Minerals and nutrition
    • contact with other hosts
      • physical contact or sexual contact