The chain of infection is a way of gathering the information needed to interrupt or prevent an epidemic. Each of the links in the chain must be favorable to the organism for the epidemic to continue.

1. Identification of Infectious Disease
Processes
Lecturer:
Dr. Yasser Al-Geshani
Infection Control Manager 48MMC
Infection Control Program
1st Lecture

2. Chain of infection:
Risk factors transmitting infection
Infectious disease process
Identification of Infectious Disease Processes

3. Infectious agent
Reservoir
Portal of exit
Mode of transmission
Portal of entry
Host
Chain of Infection
H1N1

4. Portal of exit
Chain of Infection
H1N1

5. • Bacteria
• Viruses
• Fungi
• Parasites
• Prions
Chain of Infection – Infectious agent
Infectious agent

6. 1- Duration of exposure
Length of time the person
is exposed to the organism
Chain of Infection – Infectious agent
Virulence
Ability to invade tissues & create disease

7. 2- Infectious dose:
Number of organism required
to cause a disease
Chain of Infection – Infectious agent
Virulence
Ability to invade tissues & create disease

8. 3- Infectivity :
Ability to enter tissues
Chain of Infection – Infectious agent
Ability to invade tissues & create disease
Virulence

9. Chain of Infection – Infectious agent
4- Pathogenicity:
Ability to cause disease
Virulence
Ability to invade tissues & create disease

10. Humans
Animals
Insect
Food
Environment
•Staph. Aureus
•Strept. Pneumonia
•C. diffcile
•Avian Flu
•Swine flu
•Malaria - Plasmodium
•Dengue fever –Flavivirus
•West Nile disease
•Sallmonella
•Aspergillus
•Legionella
Chain of Infection – Reservoir

11. Chain of Infection – Reservoir
Human Reservoir
•Clinical cases
•Carrier
•Subclinical cases

12. Chain of Infection – Reservoir
Types of Carriers
•Convalescent Carrier
•Chronic Carrier
Intermittent Carrier

13. Chain of Infection – Portals of Exit & Entry
•Respiratory
•Gastrointestinal
•Skin/mucous membranes
•Trans Placental
•Blood

14. Chain of Infection – Portal of Entry
Patient care activities:
•Catheter Insertion
•Intubation
•Surgery

15. Chain of Infection – Transmission
• Droplet
• Contact (Direct, Indirect )
• Air-borne
• Common Vehicle ( Active & Passive )
• Vectors ( External & Internal )

16. • Physiologic factors
• Environmental factors
• Occupational factors
• Surgical / invasive procedures
Chain of Infection – Susceptible Host

17. Infectious Disease Processes
• Infection
• Colonization
• Contamination

18. Infectious Disease Processes
Infection
• Tissue Invasion
• Multiplication
• Disease process
• Endogenous Infection
• Opportunistic infection

19. Infectious Disease Processes
Colonization
Bacteria on a body surface without
causing disease
Multiplication ???

20. Infectious Disease Processes
Contamination
Tissue: Superficial wound contamination
Food : Dangerous infection, E. Coli Outbreak
Environment : Healthcare associated infection

21. Important Definitions
Incubation Period
Time an organism invades a host until the first
sign of infection occur
Period of communicability
Period during which infectious agent can be
transmitted

22. Thank
you for
not
asking!!!
Any Questions???

23. How to decrease
risk of disease
transmission?
2nd Lecture

24. How to decrease risk of transmission ?
• Establish IPC Polices and Procedures
• Monitor compliance whit P&P
• Monitor high-risk patient care procedures
• Feed back to concerned staff
Surveillance

25. • Proper patient placement
• What is meant by cohorting ?
• When to use cohorting ?
How to decrease risk of transmission ?
Isolation

26. • Patient and family education.
• Staffing Ratio.
• Environmental practices.
• Dietary practice.
How to decrease risk of transmission ?

27. Any question