1. Disease Transmission
Good morning.

2. Objectives Review disease transmission Discuss standard precautions
Describe and demonstrate transmission-based precautions
The objectives of this talk are to review the basics of disease transmission, briefly discuss standard precautions, and describe and demonstrate transmission-based precautions. This will be a fairly brief presentation, so that we have enough time to conduct a group activity that will help highlight implementation of transmission-based precautions.

3. Modes of Disease Transmission
Direct contact
Indirect contact
Droplet
Airborne
To start, listed on this slide are the main modes of disease transmission which include direct contact, indirect contact, droplet, and 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
During direct contact transmission microbes are directly transferred from an infected person to another person. Examples of direct contact transmission include having contact with blood or other body fluids from another person or when a healthcare worker has ungloved contact with a scabies-infested patient. Another example of direct contact transmission is if a healthcare worker were to have ungloved contact with wounds or mucous membranes from a patient.

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
During indirect contact transmission, microbes are transferred through a contaminated intermediate object. Perhaps the best example of this is when healthcare personnel are not performing adequate hand hygiene between patients. The hands of the healthcare personnel can serve as the contaminated intermediate object in spreading infectious agents from patient to patient. Other examples of indirect contact transmission include sharing medical equipment without cleaning or disinfecting between patients and having defective medical equipment that allow for inadequate disinfection or sterilization. In both of these examples, the medical equipment may become contaminated and serve as the intermediate object in spreading infectious agents from patient to patient.

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
During droplet transmission, respiratory droplets carrying infectious pathogens can lead to disease transmission. Respiratory droplets are generated during coughing, sneezing, talking, and even certain medical procedures such as suctioning. Droplets are traditionally defined as being greater than 5 micrometers and historically, the area of defined risk has been a distance within 3 feet around the infected patient. However, the maximum distance for droplet transmission is currently unresolved and a distance of 3 feet around the patient is best viewed as an example of what is meant by “a short distance from a patient” and should not be used as the sole criterion for deciding when a mask should be donned to protect from droplet exposure. Examples of diseases that are transmitted through droplet transmission include influenza and pertussis.

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
During airborne transmission, there is dissemination of droplet nuclei containing infectious agents. These droplet nuclei can be dispersed over long distances and face to face contact is not required for disease transmission to occur. Special ventilation systems are required to prevent airboren transmission from occurring. Examples of diseases that can be transmitted via airborne transmission are measles and SARS.

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
Standard Precautions are a group of infection prevention practices intended to be applied to the care of ALL patients in all healthcare settings, regardless of the suspected or confirmed presence of an infectious agent. Implementation of Standard Precautions constitutes the primary strategy for the prevention of healthcare-associated transmission of infectious agents among patients and healthcare personnel. Standard Precautions are based on the principle that all blood, body fluids, secretions, excretions except sweat, nonintact skin, and mucous membranes may contain transmissible infectious agents.

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
Standard Precautions are applied during patient care based on the nature of the interaction between the healthcare worker and the patient and are dependent on the anticipated blood, body fluid, or pathogen exposure that is expected during that interaction. This means that for some interactions , such as performing venipuncture, only gloves may be needed; during other interactions, such as intubation) use of gloves, gown, and face shield or mask and goggles is necessary. Standard Precautions are intended to protect both the healthcare worker and the 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
Education and training on the principles and rationale for recommended practices are critical elements of Standard Precautions because they facilitate appropriate decision-making and promote adherence when healthcare workers are faced with new circumstances. Key elements that are a focus of standard precautions include hand hygiene, respiratory hygiene/cough etiquette, the use of appropriate personal protective equipment, safe injection practices, and 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
We have now covered the main modes of disease transmission and some basic information on standard precautions. We will now focus on transmission-based precautions and keep in mind that these precautions are based on the mode of transmission for a particular infectious agent.
Transmission-based precautions are used when the route of transmission is not completely interrupted using standard precautions alone. Therefore, transmission-based precautions are always used in addition to standard precautions. Categories of transmission-based precautions include contact, droplet, and airborne precautions and we will cover each of these in more detail.

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
Here is some basic information regarding contact precautions. Contact precautions are intended to prevent the spread of infectious agents that are transmitted by direct or indirect contact. These precautions are 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
To implement contact precautions, single-patient rooms are preferred. If this is not possible and multi-patient rooms have to be used, at least 3 feet of separation is recommended between patient beds. Healthcare personnel should wear gown and gloves for all patient interactions. This PPE, the gown and gloves, should be donned upon entry and discarded before exiting the patients 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
On this slide, there is some basic information regarding droplet precautions. As the name implies, droplet precautions are intended to prevent the spread of infectious agents that are transmitted by respiratory secretions or mucous membrane contact. Remember the droplets do not travel far and special ventilation systems are not required to implement droplet precautions.

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
To implement droplet precautions, single patient rooms are preferred, as was the case with contact precautions. However, if this is not feasible and multi-patient rooms must be used, at least 3 feet of separation is recommended between patient beds and drawing the curtain between beds is also recommended. Healthcare personnel should wear a mask upon entering the patients room and discard this PPE before exiting the room. Patients under droplet precautions that are being transferred out of the room, perhaps for imaging or other procedures, should wear a mask if they are able to tolerate it and follow respiratory hygiene and cough etiquette. Wearing a mask will not be possible for all patients under droplet precautions.

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
Last but not least, here is some basic information on airborne precautions. Airborne precautions prevent the transmission of infectious agents that are able to remain infectious in the air over long distances. An airborne infection isolation room, or AIIR, is the preferred placement for patients under airborne precautions. These rooms are single-patient rooms and have special ventilations systems installed.
AIIRs are monitored for negative pressure relative to the surrounding area, 12 air exchanges per hour for new construction and renovation and 6 air exchanges per hour for existing facilities. Air is exhausted directly to the outside or recirculated through HEPA filtration before return
Also important for airborne precautions is that healthcare personnel should don a fit-tested N95 mask before entry into the isolation room.

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
However, if an AIIR is not feasible, the following options should be done to reduce the likelihood that airborne transmission occurs. Mask the patient if they can tolerate it, place the patient in a private room, and provide N95 or a higher level respirator for staff. This should be done until the patient can be transferred to a facility with an AIIR or returns home. Healthcare personnel should don a mask or respirator upon entry depending on the patient’s infection and the disease-specific recommendations.

18. Reference:
Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings 2007 (CDC)

19. Example: Key to abbreviations: see page 94
If you have not used Appendix A from the 2007 CDC Isolation guidelines before, it will take you a few minutes to orient yourself. Here is an example from page 112 of the guidelines. Depending on the type of infection with Group A Streptococcus, you can read the type of precautions necessary in the second column. For major skin wounds, both droplet and contact precautions are recommended. For pharyngitis in infants, Droplet precautions are recommended. For pneumonia, droplet precautions are recommended.
How long should the patient with pneumonia remain in droplet precautions? Look in the column under “Duration.” “U24” means until 24 hours of effective therapy. A list of abbreviations is found on page 94.
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
Now it is time for the group exercise. There will be # of groups. Each group will use Appendix A for guidance and this document is located in your books directly following my presentation slides. To conduct this exercise, each group has been assigned a particular disease as noted by the disease card on your table. Using appendix A as reference, please complete the table found on the disease card that is affiliated with your disease. The table asks for information pertaining to the type of precautions that should be used, the type of personal protective equipment that is needed, any special considerations for room placement, and when to discontinue the precautions.

21. Group Exercise (2) Use completed table to set up patient’s room
Demonstrate how to set up PPE / hand hygiene
Classroom discussion
After completing the table, use that information to set up the patients room. Pick one person from your group to demonstrate how to don and doff the PPE that corresponds with the appropriate precautions required by your disease.
When all groups have finished, we will go around the room and have the groups report on the information for their disease.

22. Norovirus Precautions Personal protective equipment Room placement
Discontinuation of precautions
Instructor: Ask the norovirus team to present.

23. Norovirus
Precautions
Standard precautions; Contact precautions for institutional outbreaks
Personal protective equipment
Contact precautions: gowns, gloves (masks)
Room placement
“cohort to separate airspaces and toilet facilities may help interrupt transmission during outbreaks”
Discontinuation of precautions
Norovirus is found on page 100 of Appendix A.
Standard precautions are required for norovirus.
However, the notes section suggests contact precautions for diapered or incontinent patients or for control of institutional outbreaks. The notes also mention use of masks for cleaning up areas heavily contaminated with vomitus or feces.
Appendix A does not offer any guidelines on duration of precautions, so it might be reasonable to continue precautions until ill persons were recovered and your housekeeping has had a chance to do deep cleaning of the isolation room.

24. Influenza Precautions Personal protective equipment Room placement
Discontinuation of precautions
Instructor: Ask the influenza team to present.

25. Influenza
Precautions
droplet
Personal protective equipment
don mask upon entering room … patient to wear mask (if tolerated) when out of room
Room placement
Private or cohort with spatial separation of >=3 feet.
Discontinuation of precautions
5 days; duration of illness for immunocompromised patients
Influenza is found on page 103.
D stands for ‘droplet precautions.’
The notes section says that gown and gloves may be important in pediatric settings.
Room placement should be private. Patients can be cohorted if necessary with at least 3 feet of spatial separation between beds.
Precautions should be extended for 5 days after onset, unless the patient is immunocompromosed. If the individual is immunocompromised he or she should be in isolation for the duration of illness.

26. Clostridium difficile (C. diff)
Precautions
Personal protective equipment
Room placement
Discontinuation of precautions
Instructor: Ask the CDI table to present

27. Clostridium difficile (C. diff)
Precautions
contact
Personal protective equipment
wear gown and gloves for ALL patient interactions; don PPE upon entry and discard before exiting room
Room placement
Private or cohort
Discontinuation of precautions
Duration of illness
Clostridium difficile begins on page 99. Contact precautions (“C’) are recommended for the duration of illness (‘DI’).
So, you will set your room up with gowns and gloves on the outside. Gowns and gloves should be donned before entry. Then, they should be removed and discarded in the room and hand hygiene should be performed before leaving.
The notes encourage use of hypochlorite solution for cleaning ‘if transmission continues’ and use of soap and water for hand hygiene.

28. Streptococcus pneumoniae (single patient)
Precautions
Personal protective equipment
Room placement
Discontinuation of precautions

29. Streptococcus pneumoniae (single patient)
Precautions
standard
Personal protective equipment
Only for anticipated contact with secretions or excretions or blood or body fluids …
Room placement
Private room and cohorting are not necessary
Discontinuation of precautions
Standard precautions are NEVER discontinued
Streptococcus pneumoniae is listed in two different places. It is listed with causes of meningitis on Page 105, and it is listed as pneumococcal pneumonia on page Either way, standard precautions are recommended. AND standard precautions are always in place for everybody, so they are never discontinued.
Private room and cohorting are not necessary.

30. Streptococcus pneumoniae (outbreak)
Precautions
Personal protective equipment
Room placement
Discontinuation of precautions

31. Streptococcus pneumoniae (outbreak)
Precautions
droplet
Personal protective equipment
don mask upon entering room … patient to wear mask (if tolerated) when out of room
Room placement
Private or cohort
Discontinuation of precautions
(while there is transmission in the facility)
While Streptococcus pneumoniae is listed under meningitis and pneumoniae, streptoccoccus outbreaks are referenced only under pneumococcal pneumonia. Pneumococcal meningitis is pretty rare, so you won’t usually get outbreaks of (exclusively) pneumococcal meningitis. Pneumococcus is spread by the respiratory route, so if you get an outbreak, it is going to be an outbreak of pneumonia.
Droplet precautions are recommended. No duration for precautions is listed in the guidelines. Presumably droplet precautions are maintained until the outbreak is over and no further transmission is identified.

32. Pulmonary Tuberculosis
Precautions
Personal protective equipment
Room placement
Discontinuation of precautions
Instructor: Ask the tuberculosis team to present.

33. Pulmonary Tuberculosis
Precautions
Airborne
Personal protective equipment
Fit-tested N95 mask
Room placement
Negative pressure room
Discontinuation of precautions
When patient is on effective therapy, is clinically improving and has 3 consecutive negative smears for TB
It is very important to understand precautions for pulmonary tuberculosis. The patient should be placed in airborne precautions. That means that the patient is placed in a negative airflow room. The healthcare worker should wear a fit-tested N95 mask.
Duration of isolation for TB is until the patient is clinically improving on effective therapy and has 3 negative smears for TB.

34. Scabies Precautions Personal protective equipment Room placement
Discontinuation of precautions
Instructor: ask scabies team to present

35. Scabies Contact precautions Gloves and gown. Private or cohort
Personal protective equipment
Gloves and gown.
Room placement
Private or cohort
Discontinuation of precautions
24 hours after completion of effective therapy
Scabies is found on page 110
Contact precautions are required.
That means that you will set up your room with gloves and gown outside and don your protective garb before going in. You will remove before exiting and practice hand hygiene.
Precautions can be discontinued ‘U24’ meaning 24 hours after effective therapy is completed.

36. RSV (Respiratory Syncytial Virus)
Precautions
Personal protective equipment
Room placement
Discontinuation of precautions
Instructor: Ask the RSV team to present

37. RSV (Respiratory Syncytial Virus)
Precautions
Infants, children and immunocompromised adults: contact precautions
Personal protective equipment
For contact precautions, don gowns and gloves before entry; discard before leaving and practice hand hygiene
Room placement
Private or cohort
Discontinuation of precautions
Duration of illness
RSV is found on page 109, just below ‘respiratory infectious disease, acute (if not covered elsewhere)’
Contact precautions means to practice hand hygiene; don gowns and gloves before entering the room; then remove protective garb before leaving and practice hand hygiene.
Room placement for contact precautions is private room or cohort.
Precautions should be continued through the end of the illness.