The Dental Learning Network

Infection Control - 12 hrs

Chapter Two - Etiology and Transmission of TB, HIV, CJD, and Hepatitis B,C

Chapter 1: Introduction

Chapter 2: Etiology and Transmission of TB, HIV, CJD, and Hepatitis B,C
Introduction
Tuberculosis
AIDS
Creutzfeldt-Jakob
Disease (CJD)
Hepatitis

Chapter 3: Personnel and Personal Protective Attire

Chapter 4: Surfaces and Waste Disposal

Chapter 5: Chemical Disinfectants

Chapter 6: Steps in Instrument Processing

Chapter 7: Methods of Sterilization

Chapter 8: The Dental Laboratory

Chapter 9: Waterlines

Chapter 10: Ethical and Legal Considerations Regarding AIDS and HIV

Chapter 11: Summary Checklists

Bibliography and Suggested Reading List

Appendices

Internet Resources

Endnotes

Post Examination

Exit to Menu



Introduction

Preventing Transmission of Bloodborne Pathogens
Bloodborne viruses such as hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV):

  • Are transmissible in health care settings
  • Can produce chronic infection
  • Are often carried by persons unaware of their infection


Average Risk of Bloodborne Virus Transmission after Needlestick
Source
 Risk
HBV

HBsAg+ and HBeAg+



HBsAg+ and HBeAg-

22.0%-31.0% clinical hepatitis; 37%-62% serological evidence of HBV infection

1.0%-6.0% clinical hepatitis; 23%-37% serological evidence of HBV infection
HCV 1.8% (0%-7% range)
HIV 0.3% (0.2%-0.5% range)


The average risk of transmission after a single needlestick from an infected patient by type of bloodborne virus is shown. Risk varies greatly by type of virus.

For instance, the risk of HBV transmission after a percutaneous exposure (e.g., needlestick) to HBV-infected blood varies from 1% - 62%, depending on the hepatitis B e-antigen (HBeAg) status of the source patient. If the source patient's blood is positive for HBeAg (a marker of increased infectivity), the risk of transmission can be as high as 62%. If the patient's blood is hepatitis B surface antigen (HBsAg) positive but HBeAg negative, the risk varies from 1% - 37%.

The average risk of HCV transmission after a percutaneous exposure to HCV-infected blood is 1.8%.

The average risk of HIV infection after a percutaneous exposure to HIV-infected blood is 0.3%. To put this in perspective, 1 in 3 needlesticks from an HBeAg+ source patient would result in infection compared to only 1 in 300 needlesticks from an HIV-infected patient.

Continue on to Tuberculosis