Disease Transmission

1. Disease Transmission

2. Objectives • Review disease transmission • Discuss standard precautions • Describe and demonstrate transmission-based precautions

3. Modes of Disease Transmission • Direct contact • Indirect contact • Droplet • Airborne

4. Direct Contact Transmission • Microbes directly transferred from an infected person to another person • Examples • Contact with blood or other body fluids • Ungloved contact with a scabies-infested patient • Ungloved contact with wounds or mucous membranes

5. Indirect Contact Transmission • Microbes transferred through contaminated intermediate object • Examples • Healthcare personnel not performing adequate hand hygiene between patients • Sharing medical equipment without cleaning or disinfection between patients • Defective medical equipment allowing for inadequate disinfection or sterilization

6. Droplet Transmission • Respiratory droplets carrying infectious pathogens • Generated during coughing, sneezing, talking, or certain medical procedures (e.g. suctioning) • Droplets traditionally defined as > 5 µm • Typically refers to distances within 3 feet of infected patient

7. Airborne Transmission • Dissemination of droplet nuclei containing infectious agents • Dispersed over long distances • Face-to-face contact not required • Special ventilation systems are required to prevent airborne transmission

8. Standard Precautions (1) • Group of infection prevention practices that apply to ALL patients • Based on principle that the following can contain transmissible infectious agents: • Blood and body fluids • Secretions • Excretions (except sweat) • Non-intact skin • Mucous membranes

9. Standard Precautions (2) • Applied during patient care based on nature of healthcare worker-patient interaction • Dependent on anticipated blood, body fluid, or pathogen exposure • Intended to protect both healthcare worker and patient

10. Standard Precautions (3) • Education and training are critical and include the following elements: • Hand hygiene • Respiratory hygiene/cough etiquette • Personal protective equipment (PPE) • Safe injection practices • Environmental considerations

11. Transmission-Based Precautions • Used when route of transmission is not completely interrupted using standard precautions alone • Always used in addition to standard precautions • Categories of precautions • Contact • Droplet • Airborne

12. Contact Precaution Basics • Intended to prevent spread of infectious agents transmitted by direct or indirect contact • Applied when excessive wound drainage, fecal incontinence, or other body discharges increase the potential for environmental contamination

13. Contact Precautions • Single-patient rooms are preferred • For multi-patient rooms, > 3 feet separation is recommended between beds • Healthcare personnel should wear gown and gloves for ALL patient interactions • PPE donned upon entry and discarded before exiting room

14. Droplet Precaution Basics • Intended to prevent spread of infectious agents transmitted by respiratory secretions or mucous membrane contact • Droplets do not travel far and do not require special ventilation systems

15. Droplet Precautions • Single-patient rooms are preferred • For multi-patient rooms, > 3 feet separation between beds and drawing the curtain is recommended • Healthcare personnel should wear mask upon entering room • Patients should wear mask (if tolerated) when transferred out of room • Follow respiratory hygiene/cough etiquette

16. Airborne Precaution Basics • Prevent transmission of infectious agents that remain infectious in air over long distances • An airborne infection isolation room (AIIR) for placement of patient • Single-patient room • Special ventilation system • Healthcare personnel should don a fit-tested N95 mask before entry

17. Airborne Precautions • Until AIIR can be instituted, the following should reduce likelihood of airborne transmission • Mask patient • Place patient in private room • Provide N95 or higher level respirator for staff

18. Reference: Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings 2007 (CDC) http://www.cdc.gov/hicpac/pdf/isolation/Isolation2007.pdf

19. Example: Key to abbreviations: see page 94

20. Group Exercise (1) • Use Appendix A for guidance • Each group has been assigned a disease • Please complete the table affiliated with your disease • Type of precautions • Type of PPE • Room placement • Discontinuation of precautions

21. Group Exercise (2) • Use completed table to set up patient’s room • Demonstrate how to set up PPE / hand hygiene • Classroom discussion

22. Norovirus

23. Norovirus

24. Influenza

25. Influenza

26. Clostridium difficile (C. diff)

27. Clostridium difficile (C. diff)

28. Streptococcus pneumoniae (single patient)

29. Streptococcus pneumoniae (single patient)

30. Streptococcus pneumoniae (outbreak)

31. Streptococcus pneumoniae (outbreak)

32. Pulmonary Tuberculosis

33. Pulmonary Tuberculosis

34. Scabies

35. Scabies

36. RSV(Respiratory Syncytial Virus)

37. RSV(Respiratory Syncytial Virus)