Cottone's Practical Infection Control in Dentistry 3rd Edition PDF

Cottone’s Practical Infection Control in Dentistry THIRD EDITION Cottone’s Practical Infection Control in Dentistry THIRD EDITION John A. Molinari, PhD Professor and Chairman Department of Biomedical Sciences University of Detroit Mercy School of Dentistry Detroit, Michigan Jennifer A. Harte,...

Cottone’s Practical Infection Control in Dentistry THIRD EDITION Cottone’s Practical Infection Control in Dentistry THIRD EDITION John A. Molinari, PhD Professor and Chairman Department of Biomedical Sciences University of Detroit Mercy School of Dentistry Detroit, Michigan Jennifer A. Harte, DDS, MS Director, Professional Services USAF Dental Evaluation and Consultation Service Great Lakes, Illinois Acquisitions Editor: Barrett Koger Managing Editor: Matt Hauber / Laura Horowitz Marketing Manager: Allison M. Noplock Associate Production Manager: Kevin Johnson Designer: Teresa Mallon Compositor: Maryland Composition Third Edition Copyright © 2010, 1996, 1991 Lippincott Williams & Wilkins, a Wolters Kluwer business. 351 West Camden Street Baltimore, MD 21201 530 Walnut Street Philadelphia, PA 19106 Printed in China All rights reserved. This book is protected by copyright. No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews. Materials appearing in this book prepared by individuals as part of their official duties as U.S. government employees are not covered by the above-mentioned copyright. To request permission, please contact Lippincott Williams & Wilkins at 530 Walnut Street, Philadelphia, PA 19106, via email at [email protected], or via website at lww.com (products and services). 9 8 7 6 5 4 3 2 1 Library of Congress Cataloging-in-Publication Data Molinari, John A. Cottone’s practical infection control in dentistry / John A. Molinari, Jennifer A. Harte. —3rd ed. p. ; cm. Rev. ed. of: Practical infection control in dentistry / James A. Cottone. 2nd ed. 1996. Includes bibliographical references and index. ISBN 978-0-7817-6532-9 1. Dental offices—Sanitation. 2. Cross infection—Prevention. 3. Asepsis and antisepsis. I. Harte, Jennifer A. II. Cottone, James A. III. Cottone, James A. Practical infection control in dentistry. IV. Title. V. Title: Practical infection control in dentistry. [DNLM: 1. Dentistry. 2. Infection Control—methods. WU 29 M722c 2010] RK52.C685 2010 617.6’01—dc22 2008021812 DISCLAIMER Care has been taken to confirm the accuracy of the information present and to describe generally accepted practices. However, the authors, editors, and publisher are not responsible for errors or omissions or for any consequences from application of the information in this book and make no warranty, expressed or implied, with respect to the currency, completeness, or accuracy of the contents of the publication. Application of this information in a particular situation remains the professional responsibility of the practitioner; the clinical treatments described and recommended may not be considered absolute and universal recommendations. The authors, editors, and publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accordance with the current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any change in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new or infrequently employed drug. Some drugs and medical devices presented in this publication have Food and Drug Administration (FDA) clearance for limited use in restricted research settings. It is the responsibility of the health care provider to ascertain the FDA status of each drug or device planned for use in their clinical practice. To purchase additional copies of this book, call our customer service department at (800) 638-3030 or fax orders to (301) 223-2320. International customers should call (301) 223-2300. Visit Lippincott Williams & Wilkins on the Internet: http://www.lww.com. Lippincott Williams & Wilkins customer service representatives are available from 8:30 am to 6:00 pm, EST. Acknowledgments John dedicates this book to his wife, Gail, their children, and his parents, Ignazio and Clare Molinari. Their love, encouragement, and continued support were invaluable throughout preparation of this book. John also would like to thank Carol Grennan for her assistance in preparation of the manuscript. Jennifer dedicates this text to the memory of her mother, Shirley Brukner Harte. Jennifer would like to thank the following individuals for their encouragement, support, and friendship over the years: John A. Molinari, William J. Davis, Stephen F. Robison, and William G. Kohn. Last, but certainly not least, both authors want to acknowledge Dr. James A. Cottone, for whom this book has been re-named. As the amount of scientific and clinical knowledge about hepatitis B, HIV/AIDS, and healthcare occupational infectious disease risks expanded rapidly in the 1980s, Jim worked tirelessly to spearhead efforts in educating the dental profession in the principles and practices of infection control. His efforts in presenting leading edge information in seminars and numerous publications were major factors leading to the acceptance, utilization, and current success of standard infection control practices. v Preface to the Third Edition Infection control education and practices have continued to evolve since the second edition of Practical Infection Control in Dentistry. In addition to numerous technological advances in equipment and other available products, dental professionals have demonstrated a willingness to respond to scientific and clinical evidence delineating occupational infectious disease risks. The routine application of former universal, and now standard, precautions has provided increased safety for all healthcare providers and their patients alike. As was mentioned in the Preface for the second edition, the routine use of effective infection control practices in dentistry actually led the way in addressing a number of infectious disease challenges confronting the health professions. This was illustrated by the profession’s rapid acceptance of the hepatitis B vaccine in the early to mid-1980s before other healthcare workers adopted this preventive measure. Dental healthcare professionals should be rightly proud of their infection control progress. Along with recognition of documented success in reducing the potential for many occupational infectious diseases must come the realization that emerging infectious diseases should also be considered when teaching and evaluating infection control precautions. The third edition of this book has been extensively modified from the previous editions to reflect many of these challenging issues for infection control. This should become initially apparent to the reader as one reviews the list of chapter titles. Included are expanded discussions on infectious diseases such as tuberculosis and influenza, which are transmitted by respiratory droplets and aerosols. The most current information and healthcare recommendations regarding the microbiology of airborne infectious diseases and their prevention are provided. In addition to updated chapters which present scientific and clinical knowledge about viral hepatitis, human immunodeficiency virus infection, and acquired immunodeficiency syndrome, readers will also find a separate chapter dealing with dental unit waterlines and infection control. A substantial portion of this book addresses the most recent infection control recommendations for dentistry published by the Centers for Disease Control and Prevention in December 2003. The evidence-based approach used in the development of those guidelines has also been incorporated into the content for the third edition. Sections citing scientific and clinical evidence have been expanded to reinforce the rationale for specific infection control practices and protocols. Information found within chapters is presented in a manner which reflects a conscious effort by the authors to increase the profession’s understanding of both the “why” and the “what” of infection control guidelines. We hope you find this third edition of Cottone’s Practical Infection Control in Dentistry to be a valuable textbook for infection control courses taught in schools and an important resource for dental care providers as you continue to refine your long-standing infection control commitment and efforts. Additional Resources The third edition of Cottone’s Practical Infection Control in Dentistry includes additional resources for both instructors and students that are available on the book’s companion website at http://thePoint.lww.com/Molinari3e. Instructors Approved adopting instructors will be given access to the following additional resources: *PowerPoint presentations, with review questions *Brownstone Test Generator *Image bank *WebCT and Blackboard Ready Cartridge The PowerPoint presentations and Test Generator questions were created by David Cohen. Students Purchasers of the text can access the searchable full text online by going to the Cottone’s Practical Infection Control in Dentistry website at http://thePoint.lww.com. See the inside front cover for more details, including the passcode you will need to gain access to the website. vii Preface to the First Edition Until recently the basic sources for infection control information for the dental practitioner were: 1. Advice from older practitioners whose knowledge was usually minimal or outdated. 2. Dental supply personnel who lack formal education in this area and could be biased towards their own products. 3. A trained assistant whose knowledge was variable depending on his or her experience. 4. A trained hygienist, who usually was the most knowledgeable but was discouraged once out in practice with statements such as “we don’t do it that way here.” 5. Miscellaneous articles and research reports in the literature, many of which perpetuate myths or sometimes are even misleading or wrong in their results and advice as they may have been authored by individuals who thought they knew the basics of something as “simple” as infection control. In the past, few dental education institutions included sufficient classroom and clinical teaching of infection control. The basic information was usually discussed in microbiology or in a clinical introduction. Most schools prepared and sterilized the students’ instruments for them, resulting in students graduating with little real experience in sterilization or other infection control procedues. The new graduate then embarked on a “doit-yourself” project to develop some type of infection control system for their office. This system consisted of a blend of instrument disinfection, instrument sterilization, and household cleaning procedures adapted for the dental office, again depending on the quality of his or her staff. Recent information regarding the transmission of hepatitis and herpes, and the emergence of Human Immunodeficiency Virus (HIV) infection and AIDS, along with the impact of standards from governmental agencies such as the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), have led to an increased interest in infection control in general and as it relates to dentistry in particular. This interest is warranted because of the lack of traditional infection control procedures in dentistry over the years. In some instances, these events have led to the development of infection control protocols that are overly detailed and elaborate, incorporating every conceivable barrier, product, and procedure. Infection control procedures have gone too far in many facilities. There are some basic procedures that need to be followed. The GOAL of good infection control in dentistry is to treat every patient as though he or she is infected with an incurable disease (universal precautions). The method to implement this goal is to develop one infection control protocol for use in the dental operatory that is simple and effective for use with all patients, including hepatitis B carriers, HIV antibody positive, and diagnosed AIDS patients. If appropriate measures are taken, infection control will then occur as a routine component of dental practice. In order to assist in the development of one infection control protocol for all patients, this textbook has been divided into the following major areas: 1. Patient Assessment 2. Personal Protection 3. Sterilization and Chemical Disinfection 4. Environmental Surface and Equipment Disinfection 5. Aseptic Technique Each of these areas is explored thoroughly in the chapters that follow, with a discussion of medical and legal considerations and today’s minimum requirements in infection control at the end of the text. This volume contains much information about infection control protocols and procedures. Although the authors, contributors and publisher have taken meticulous care to ensure the accuracy of the product formulations and manufacturer recommendations, the law ix x ■ PREFACE TO THE FIRST EDITION requires the reader to consult information about changes in formulation and methods of product use printed in the package insert before using any product. The reader then can be certain that new data has not led to altered instructions. Additionally, the area of infection control is changing daily with new products and techniques. The reader will need to become an evaluator of these advances. The use of this text as part of the reader’s infection control education and training programs is encouraged because good infection control is a philosophy, not a series of “cookbook” steps. Practical infection control in dentistry is making a needed permanent change in the dental profession as we know it. Contributors NANCY ANDREWS, RDH, BS VIRGINIA A. MERCHANT, DMD, MS Consultant Costa Mesa, California Professor Department of Biomedical Sciences University of Detroit Mercy School of Dentistry Detroit, Michigan ROSS ANDREWS, AIA Principal Ross Andrews & Associates, Architects Costa Mesa, California HELENE BEDNARSH, RDH, MPH, BS Director HIV Dental Ombudsperson Program Boston Public Health Commission Boston, Massachusetts EVELYN CUNY, MS, RDA Assistant Professor Department of Pathology & Medicine University of the Pacific Arthur A. Dugoni School of Dentistry San Francisco, California LOUIS G. DEPAOLA, DDS, MS Professor Department of Diagnostic Science & Pathology Dental School University of Maryland Baltimore Baltimore, Maryland KATHY J. EKLUND, RDH, MHP SHANNON E. MILLS, DDS Vice President Professional Relations Northeast Delta Dental Concord, New Hampshire GAIL E. MOLINARI , DDS, MS, MS Associate Professor and Chairperson Department of Pediatric Dentistry University of Detroit Mercy School of Dentistry Detroit, Michigan KATHLEEN NEVEU , RDA, RDH, MS Dental Hygiene Clinic Coordinator Department of Periodontology & Dental Hygiene University of Detroit Mercy School of Dentistry Detroit, Michigan GÉZA T. TERÉZHALMY, DDS, MA Endowed Professor in Clinical Dentistry The UTHSCSA Dental School San Antonio, Texas Associate Professor and Director of Infection Control and Occupational Health The Forsyth Institute Boston, Massachusetts VALLI I. MEEKS, DDS, MS Assistant Professor Department of Diagnostic Sciences & Pathology Dental School University of Maryland Baltimore Baltimore, Maryland xi Reviewers BARBARA C ROWLEY, MED, CDA MARTHA MCCASLIN, CDA, BSBM Department Chair (Retired) Dental Studies Department Pima Community College Tucson, Arizona Program Director Department of Dental Assisting Dona Ana Community College Las Cruces, New Mexico CONNIE GROSSMAN, RDH, MED R. HUNTER RACKLEY JR ., RDH, BSDH, MHE Chairperson, Allied Health Profession Columbus State Community College Columbus, Ohio Assistant Professor Department of Periodontics and Allied Dental Programs Indiana University School of Dentistry Indianapolis, Indiana KATHLEEN HARLAN, RDH, MS Assistant Professor Department of Dental Hygiene Ferris State University Big Rapids, Michigan xiii Contents PART I MICROBIOLOGICAL RATIONALE FOR PRACTICAL INFECTION CONTROL IN DENTISTRY 1 13. How to Choose and Use Environmental Surface Disinfectants John A. Molinari and Jennifer A. Harte 185 14. Asepsis Considerations of Office Design and Equipment Selection Nancy Andrews and Ross Andrews 194 1. Historical Perspectives and Principles of Infection Control Helene Bednarsh and John A. Molinari 3 2. Viral Hepatitis and Hepatitis Vaccines John A. Molinari and Jennifer A. Harte 13 3. Human Immunodeficiency Virus, Acquired Immunodeficiency Syndrome, and Related Infections Louis G. DePaola and Valli I. Meeks 32 15. Management of Occupational Exposures to Blood 4. Tuberculosis and Other Respiratory Infections Géza T. Terézhalmy and John A. Molinari 45 16. Instrument Processing and Recirculation 5. Dental Unit Water and Air Quality Challenges Shannon Mills 63 17. Role for Single-Use Disposable Items PART II PERSONAL PROTECTION 77 6. The Concept and Application of Standard Precautions Helene Bednarsh, Kathy Eklund, and John A. Molinari 79 7. Immunizations for Dental Healthcare Personnel John A. Molinari and Géza T. Terézhalmy 89 8. Personal Protective Equipment John A. Molinari and Jennifer A. Harte 101 PART III ANTISEPSIS, STERILIZATION, AND DISINFECTION 121 9. Antisepsis and Hand Hygiene Nancy Andrews, Eve Cuny, John A. Molinari, and Jennifer A. Harte 123 10. Antimicrobial Preprocedural Mouth Rinses Gail Molinari 141 11. Sterilization Procedures and Monitoring Jennifer A. Harte and John A. Molinari 148 12. Environmental Surface Infection Control: Disposable Barriers and Chemical Disinfection John A. Molinari and Jennifer A. Harte 171 PART IV INFECTION CONTROL PROCEDURES AND PROTOCOLS 207 and Other Body Fluids Jennifer A. Harte and John A. Molinari 209 Jennifer A. Harte and John A. Molinari 221 Jennifer A. Harte and John A. Molinari 232 18. Infection Control in Dental Radiography Jennifer A. Harte and John A. Molinari 237 19. Infection Control in the Dental Laboratory Virginia A. Merchant 246 20. Medical Waste Management Kathy Neveu, Jennifer A. Harte, and John A. Molinari 261 PART V ADDITIONAL RESOURCES 269 21. Evaluation of a Practical Dental Infection Control Program Jennifer A. Harte 271 22. Centers for Disease Control and Prevention Guidelines for Infection Control in Dental HealthCare Settings—2003 283 23. Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard 294 Appendix: Answers to the Review Questions 309 Glossary 311 Index 321 Color Insert follows page 206 xv Cottone’s Practical Infection Control in Dentistry THIRD EDITION P A R T I Microbiological Rationale for Practical Infection Control in Dentistry 1 C H A P T E R 1 Historical Perspectives and Principles of Infection Control Helene Bednarsh John A. Molinari LEARNING OBJECTIVES After completion of this chapter individuals should be able to: 1. List representative infectious diseases encountered in dental medicine. 2. Describe direct, indirect, and airborne modes of microbial transmission. 3. Describe representative historical milestones in the investigation of infectious diseases and their control in healthcare facilities. 4. Understand the rationale for effective and practical infection control precautions. 5. Describe the rationale for minimizing the potential for microbial cross-contamination and cross-infection in dental healthcare settings. 3 4 PART I ■ MICROBIOLOGICAL RATIONALE FOR PRACTICAL INFECTION CONTROL IN DENTISTRY KEY TERMS Airborne transmission: a means of spreading infection in which airborne droplet nuclei are inhaled by the susceptible host. Asepsis: prevention from contamination with microorganisms. Includes sterile conditions on tissues, on materials, and in rooms, as obtained by excluding, removing, or killing organisms. Aseptic technique: a procedure that breaks the cycle of cross-infection and ideally eliminates cross-contamination. Cross-contamination: passage of microorganisms from one person or inanimate object to another. Cross-infection: passage of microorganisms from one person to another. Dental healthcare personnel (DHCP): refers to all paid and unpaid personnel in the dental healthcare setting who might be occupationally exposed to infectious materials, including body substances and contaminated supplies, equipment, environmental surfaces, water, or air. DHCP include dentists, dental hygienists, dental assistants, dental laboratory technicians (in-office and commercial), students and trainees, contractual personnel, and other persons not directly involved in patient care but potentially exposed to infectious agents (e.g., administrative, clerical, housekeeping, maintenance, or volunteer personnel). Direct contact transmission: physical transfer of microorganisms between a susceptible host and an infected or colonized person. Healthcare-associated infection: any infection associated with a medical or surgical intervention. The term “healthcare-associated” replaces “nosocomial,” which is limited to adverse infectious outcomes occurring in hospitals. Iatrogenic: induced inadvertently by healthcare personnel (HCP) or by medical treatment or diagnostic procedures. Used especially in reference to an infectious disease or other complication of medical treatment. Indirect contact transmission: contact of a susceptible host with a contaminated, intermediate object, usually inanimate. ental healthcare personnel (DHCP) routinely are at an increased risk of cross-infection while providing treatment for their patients. This occupational potential for disease transmission becomes evident initially when one realizes that most human microbial pathogens have been isolated from oral secretions, and many of these can cause serious diseases in clinical D Infection control: policies and procedures used to prevent or reduce the potential for disease transmission. Nosocomial infection: describes an infection acquired in a hospital as a result of medical care; now referred to as healthcare-associated infection (see definition for healthcare-associated infection). Opportunistic infection: infection caused by normally nonpathogenic microorganisms in a host whose resistance has been decreased or compromised. Spatter: visible drops of liquid or body fluid that are expelled forcibly into the air and settle out quickly, as distinguished from particles of an aerosol, which remain airborne indefinitely. Standard precautions: universal precautions were based on the concept that all blood and body fluids that might be contaminated with blood should be treated as infectious because patients with bloodborne infections can be asymptomatic or unaware they are infected. The relevance of universal precautions to other aspects of disease transmission was recognized and, in 1996, the Centers for Disease Control and Prevention (CDC) expanded the concept and changed the term to standard precautions. Standard precautions integrate and expand the elements of universal precautions into a standard of care designed to protect healthcare personnel (HCP) and patients from pathogens that can be spread by blood or any other body fluid, excretion, or secretion. Standard precautions apply to contact with (a) blood; (b) all body fluids, secretions, and excretions (except sweat), regardless of whether they contain blood; (c) nonintact skin; and (d) mucous membranes. Saliva has always been considered a potentially infectious material in dental infection control; thus, no operational difference exists in clinical dental practice between universal precautions and standard precautions. Universal precautions: set of practices and procedures based on the concept that all blood and all body fluids that might be contaminated with blood should be treated as infectious. (Also see standard precautions) personnel via cross-infection from patients (Table 1-1). As a result of repeated exposure to the microorganisms present in blood and saliva, the incidence of certain infectious diseases was shown in the 1970s and early 1980s to be significantly higher among dental professionals than observed for the general population. Hepatitis B, hepatitis C, tuberculosis, herpes simplex virus infections, influenza, CHAPTER 1 ■ HISTORICAL PERSPECTIVES AND PRINCIPLES OF INFECTION CONTROL 5 Table 1-1 Representative Infectious Disease Risks in Dentistry Disease Etiologic Agent Incubation Period Bacterial Staphylococcal infections Tuberculosis Streptococcal infections Pneumococcal infections Legionellosis Staphylococcus aureus Mycobacterium tuberculosis Streptococcus pyogenes Streptococcus pneumoniae Legionella pneumophila 4–10 days up to 6 months 1–3 days 1–3 days 2–10 days Viral Influenza Common cold Recurrent herpetic lesion Rubella Hepatitis B Hepatitis C Delta hepatitis (hepatitis D) Infectious mononucleosis Hand-foot-and-mouth disease Herpangina Acquired immunodeficiency syndrome (AIDS) Influenza viruses Rhinoviruses (most common) Herpes simplex, types 1 and 2 Rubella virus Hepatitis B virus Hepatitis C virus Hepatitis D virus Epstein-Barr virus Primarily coxsackievirus A16 Coxsackieviruses group A Human immunodeficiency virus (HIV) 1–4 days few days up to 2 weeks 9–11 days 6 weeks to 6 months weeks to months weeks to months 4–7 weeks 2 days to 3 weeks 5 days months to years days to weeks Candidiasis Trichophyton, Microsporum, Epidermophyton, and Candida genera Candida albicans days to weeks Miscellaneous Infections of fingers, hands, and eyes from dental plaque and calculus Variety of microorganisms 1–8 days Fungal Dermatomycoses (superficial skin infections) and a variety of dermatological bacterial and mycotic diseases were well recognized. These and other occupational infections continue to serve as the rationale for increased understanding of modes of disease transmission and infection control procedures by dental care providers. As a result, DHCP are required to use appropriate infection control measures during patient care to reduce, as much as possible, potential risks of disease transmission to patients and themselves. The general routes for transmission of microbial agents in dental medicine are as follows: 1. Direct contact with infectious lesions or infected saliva or blood 2. Indirect contact via transfer of microorganisms from a contaminated intermediate object 3. Spatter of blood, saliva, or nasopharyngeal secretions directly onto broken or intact skin or mucosa 4. Aerosolization, the microorganisms airborne transmission of Part of the problem was that many practitioners and auxiliaries previously failed to comprehend or appreciate the infection potential presented by saliva and blood during treatment. Neglecting to implement effective precautions and procedures also places others, including the practitioner’s family and other patients, at an increased risk of disease. These dangers often were dismissed because much of the spatter coming from the patient’s mouth is not readily noticed. Organic debris may be transparent or translucent and dries as a clear film on skin, clothing, and other surfaces. A novel demonstration was first developed by Crawford in the 1970s using the premise “if saliva were red.” He had practitioners dip their fingers into red poster paint before starting their normal clinical treatment. The paint subsequently was deposited on the various surfaces of the operatory as treatment progressed. This demonstrated the cross-contamination that occurred from the practitioner’s “saliva-covered” fingers. This study was expanded by Glass, Cottone, and Leuke at the University of Texas Dental School at San Antonio by coating the surface of a dental (rubber) dam placed on a mannequin with the same type of poster paint as used by Crawford. A Class II operative preparation then was performed on a lower second molar by a dentist using a high-speed handpiece with air and water coolant. The practitioner and dental assistant were 6 PART I ■ MICROBIOLOGICAL RATIONALE FOR PRACTICAL INFECTION CONTROL IN DENTISTRY attired properly, using barrier precautions during the procedure. During treatment, dyed “saliva” was visible as spatter (Fig. I-1) that heavily contaminated the face, hair, protective eye wear, mask, chest, arms, and clothing of the dentist by the end of the procedure (Fig. I-2). In addition, the assistant and high-volume evacuator became laden with intraoral exudate (Fig. I-3). The use of a fluorescent light more graphically demonstrated the spatter (Fig. I-4). These figures dramatically show what occurs on a daily basis in the dental operatory and illustrate the challenge of infection control in dentistry. Routine examinations and dental prophylaxis procedures also substantially expose the dental professional and patient to potentially infectious fluids. When Molinari, York, and others used red dye and water to simulate patient saliva at the University of Detroit Mercy, cross-contamination by the simulated saliva was evident as the gloved hands of the clinician became noticeably contaminated during the intraoral examination. As a result, secretions were transferred to the patient’s chart when notations were written (Fig. I-5). Before the oral cavity was reentered, the gloved hands were washed. They were contaminated immediately, however, when the clinician continued the examination. When other procedures were started, such as periodontal probing and scaling and root planning, saliva also contaminated the instrument tray, instruments, and other equipment (Figs. I-6 to I-10). The unit light handle also was adjusted frequently throughout the session and showed obvious contamination from the clinician’s hands (Fig. I-11). When the clinician repositioned her eye wear during the polishing procedure, oral fluids were transferred subsequently to her face, glasses, and mask (Fig. I-12). Finally, the “patient” showed dramatic evidence of the ease of oral fluid spread and the resultant accumulation of contamination at the conclusion of the appointment (Fig. I-13). The documented exposure of practitioners, auxiliaries, and patients to a variety of bacterial, viral, and other microbial pathogens led to the development of a series of infection control protocols by the American Dental Association (ADA), Centers for Disease Control and Prevention (CDC), and, most recently, the Occupational Safety and Health Administration (OSHA). While the accomplishments from these recommendations are noteworthy, it is important to remember that the foundation principles and practices of asepsis were discovered and evolved long before the 20th century. It took many centuries of observation and investigation for scientists and clinicians to conclude that a vast array of microbial organisms were etiologies of most infectious diseases. Appreciation of major historical events and the chronology of infection control practices allow us to place current principles and recommendations into perspective. The timeline included in this chapter also reinforces a basic premise of infection control compliance, that is, we need to understand how far we have come in order to ascertain where we are in the control of infectious diseases, so that we may investigate and develop effective approaches to address emerging issues (Table 1-2). As a result of these and other numerous epidemiological, scientific, and clinical accomplishments, all patient care providers and their patients are far safer at the beginning of the 21st century than they were at the dawn of the previous century (Table 1-3). When infection control recommendations are reviewed, a distinction must be made between sterilization and disinfection. Sterilization is defined as the destruction of all microbial forms. The limiting factor and the requirement for sterilization is the destruction of bacterial and mycotic spores. Disinfection properly refers only to inhibition or destruction of some but not all microbial pathogens. The term often is applied to the use of chemical agents and procedures that cannot destroy microbial endospores and certain pathogenic microorganisms, such as Mycobacterium tuberculosis. Cleaning simply refers to the removal of visible organic and inorganic contaminants from a surface. The use of chemical disinfectants in certain instances is warranted because it is neither possible nor necessary to sterilize all items and surfaces contaminated during dental treatment. The application of aseptic technique principles are at the heart of the healthcare professional’s efforts to reduce cross-infection by ideally eliminating crosscontamination. With stringent application of fundamental principles, the wide range of occupational, healthcareassociated (i.e., nosocomial), iatrogenic and opportunistic infections can be dramatically reduced. When the red-dye studies are viewed, one is tempted to institute every precaution available with no regard for the efficacy of various modes of transmission. Accumulated data has reinforced the CDC conclusion that hepatitis B virus is the most infectious occupational bloodborne pathogen. Thus hepatitis B is an excellent prototype when designing infection control procedures in dentistry. The principal transmission modes for this virus in order of efficiency are listed in Table 1-4. When the efficiency of various modes of transmission is coupled with available products and techniques available today, the practitioner can make rational decisions as to which products and techniques are needed to formulate an appropriate, but not excessive, infection control program. Concern about asepsis in the dental office has increased in recent years because of the danger of disease transmission, although anxiety has been almost inversely proportional to the degree of transmissibility (Table 1-5). The need for accurate objective information on infection control procedures is greater than ever. Demonstration of visible patient spatter on the hands, face, and clothes of the treatment provider, as well as on numerous surfaces in the treatment area, substantiates the need for an effective infection control program in the dental office. Routine examination and prophylaxis (text continues on page 11) CHAPTER 1 ■ HISTORICAL PERSPECTIVES AND PRINCIPLES OF INFECTION CONTROL 7 Table 1-2 Infectious Disease and Infection Control Timeline 1546 Fracastoro—first reports of disease transmission by contagion. 1675 van Leeuwenhoek—first described bacteria and protozoa (animalcules) under microscope; built first simple microscope. 1750 Pringle—observed relationship of putrefaction to disease; performed studies with agents he called antiseptics. 1790s Jenner—introduction of smallpox vaccine as effective method of preventing disease epidemics. 1827 Alcock—emphasized disinfectant properties of hypochlorite. 1840–70s Nightingale—emphasized importance of sanitation; used statistics, surveillance, and data collection. 1843 Holmes—first to apply clinical epidemiologic methods to examine causal relationship between disease and practices of healthcare professionals. Demonstrated contagiousness of childbed fever (puerperal sepsis) from doctors and nurses. 1860s Semmelweis—instituted hospital procedures to reduce mortality from puerperal septicemia; emphasized role of hand hygiene in prevention of cross-infection. 1860s Lister—“Father of clean and decent surgery”; introduced aseptic technique for surgery and care of wounds; introduced phenols (carbolic acid). 1860–80s Pasteur—established microbiology as a science; developed process of pasteurization. 1870–80s Koch—isolated and demonstrated infectivity of anthrax bacillus; discovered Mycobacterium tuberculosis; formulated Koch’s postulates for infectious disease investigation; examined effects of numerous disinfectants against bacteria. 1877 First isolation guidelines. 1890 Introduction of rubber gloves for use during surgery. 1929 Penicillin discovered by Sir Arthur Fleming. 1944 Public Health Service Act passed by Congress; included regulation of biologic products and control of communicable disease. 1949 First occupational case of serum hepatitis (later termed hepatitis B) reported in a healthcare worker. Infection developed following needlestick exposure to contaminated blood. 1952 First version of ADA infection control guidelines published in Accepted Dental Remedies; focus was on the use of chemical agents for disinfection and emphasized precleaning and heat sterilization. 1963 First published description of microbial contamination of dental unit waterlines; high levels of microbial contamination isolated in water samples taken from handpiece and syringe lines. 1970 OSHA created by Congress. 1970 EPA created; takes over pesticides program from FDA. 1973 General infection control recommendations released by the CDC. 1976 ADA Council on Dental Therapeutics publishes first consensus report delineating the role of the dentist and other dental personnel in preventing the transmission of type B hepatitis through dental practice. 1976 Congress passes amendments to the Medical Device Act; ensures safety and effectiveness of medical devices. 1976 Outbreak of pneumonia (later called Legionnaire’s disease) occurs at Philadelphia hotel during an American Legion convention; 221 cases reported and 34 fatalities. 1978 First ADA report on infection control for dental offices published in the Journal of the American Dental Association: • suggested procedures for reducing contamination and cross-contamination • all instruments, burs, mirrors, bands, and other devices used in intraoral treatment should be routinely sterilized • initial consideration to waterline contamination and possible solutions suggested (continued) 8 PART I ■ MICROBIOLOGICAL RATIONALE FOR PRACTICAL INFECTION CONTROL IN DENTISTRY Table 1-2 Infectious Disease and Infection Control Timeline (continued) 1981 ADA Council on Dental Materials, Instruments, and Equipment publishes report to assist dentists in selecting and using devices and equipment for acceptable, effective, and controlled methods for the sterilization of instruments. 1981 First case reports of what is now known as AIDS but referred to as GRID reported by the CDC. 1982 CDC releases occupational infection control guidelines for HCW; guidelines included recommendations for dental HCW: (a) wear gloves, mask, and protective eyewear; and (b) sterilize instruments. 1982 Plasma-derived hepatitis B vaccine (Heptavax-B) becomes commercially available. 1983 HCW unions petition OSHA for emergency standard to make employers pay for HBV vaccine. 1983 Voluntary OSHA guidelines released for HCW receipt of hepatitis B vaccine. 1983–84 HIV identified. 1984 First case report of occupational HIV infection of a HCW; transmission occurred via accidental needlestick from an AIDS patient to a nurse in Africa. 1985 ADA Councils publish first comprehensive dental infection control guidelines; central recommendation was a shift from selective precautions to routine use of universal infection control precautions. 1986 CDC publishes first comprehensive dental infection control guidelines; central recommendation was a shift from selective precautions to routine use of universal infection control precautions. 1987 Last reported case of HBV transmission in a dental care setting, from an oral surgeon to 4 patients in New Hampshire; prior to this time, 20 clusters involving 300 patients reported; 9 of these clusters involved a dentist/oral surgeon. 1987 Recombinant HBV vaccine (Recombivax HB) becomes available in the United States; soon thereafter, Engerix B becomes available in many other countries for HBV vaccination. 1987 CDC reinforces universal precautions as basis for routine infection control. Agency emphasizes that blood, saliva, and gingival fluid in dentistry should be considered infectious; universal precaution recommendations also are published for HIV- and HBV-infected healthcare workers. 1987 OSHA publishes advance notice of rule-making for HCW infection control regulations. 1987 FDA approves AZT, first drug approved for treatment of AIDS. 1987 No further reports of HBV transmission from dentists to patients; outbreaks still reported from physicians to patients. 1988 OSHA releases draft of occupational exposure to bloodborne pathogens standard for review and comment. 1988 CDC releases Guidelines for Prevention of Transmission of HIV and HBV to Healthcare and Public-Safety workers. 1989 HCV identified; first form of NANBH identified; HCV believed to be major cause of hepatitis cases associated with blood transfusions. 1990 First case report of HIV transmission from a HCW to a patient (HIV-infected dentist). 1990 Americans with Disabilities Act passed, with implementation to occur in phases. 1990 First generation anti-HCV serologic blood test developed. 1990 OSHA revises enforcement procedures for draft of bloodborne pathogens standard. 1990 Reports of multiple drug-resistant Mycobacterium tuberculosis continue to increase. 1991 FDA sends Dear Colleague letter to dentists concerning sterilization of dental handpieces. 1991 FDA publishes initial recommendations for people with latex hypersensitivity. 1991 CDC releases infection control guidelines for HBV- and HIV-infected HCW; these include: (a) adherence to universal precautions; (b) acknowledgment that HIV is transmitted much less readily than HBV; and (c) recommendations for establishment of review panels in healthcare facilities. CHAPTER 1 ■ HISTORICAL PERSPECTIVES AND PRINCIPLES OF INFECTION CONTROL 9 Table 1-2 Infectious Disease and Infection Control Timeline (continued) 1991 OSHA Bloodborne Pathogens Standard becomes U.S. law. 1991 Reports of occupational dental injuries demonstrate downward trend from 12/year to 3–4/year. 1992 EPA regulations for tracking and management of medical waste standard become effective. 1992 CDC publishes report titled Management of Persons Exposed to Multidrug-Resistant Tuberculosis. 1992 OSHA petitioned by healthcare unions for workplace standard on TB control. 1992 HBV incidence continues to decline; down to 9% in general dentists and 20% in oral surgeons. 1993 CDC publishes updated dental infection control guidelines; included are TB precautions and recommendations for dental unit waterline infection control. 1993 CDC reports 55% decrease in rate of HBV infection. 1994 CDC finalizes guidelines on TB, guidelines for preventing transmission of Mycobacterium tuberculosis in healthcare facilities; occupational risk for dental healthcare workers generally considered to be low in most dental settings. 1995 ADA publishes statement on dental waterlines; suggestion of microbial target level for year 2000. 1995 CDC reports AZT reduces HIV infection risk by 79% in HCW when used as PEP. 1995–96 HIV protease inhibitors receive FDA approval; major successes of combination antiretroviral chemotherapeutic regimens in controlling HIV replication in infected patients. 1996 ADA Councils on Scientific Affairs and Dental Practice publish latest infection control recommendations for the dental office and the dental laboratory. 1996 CDC introduces standard precautions as the method of choice for infection control. 1996 CDC revises HIV PEP guidelines for occupational exposures to include use of reverse transcriptors and protease inhibitors in either mono or combination therapy. 1996 President signs Safe Drinking Water Act to improve U.S. water processing systems and water quality. 1997 FDA publishes latex policy statement requirement for manufacturers in product labeling; “hypoallergenic” label deemed inappropriate and misleading; regulations to go into effect in 1998. 1997 French Health Ministry issues findings of epidemiological investigation concerning HIV-infected orthopedic surgeon who transmitted HIV to patient during surgery. 1997 CDC releases Immunization of Healthcare Workers; Recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Hospital Infection Control Practices Advisory Committee (HICPAC). 1998 CDC publishes recommendations for prevention and control of HCV infection and HCV-related chronic disease. 1998 FDA mandated latex regulations for manufacturers becomes effective. 1999 OSHA initiates drafting of legislation to reduce needlesticks among HCW. 2000 President signs Needlestick Safety and Prevention Act into law. This legislation calls for modifications to the federal OSHA Bloodborne Pathogens Standard: (a) to clarify the need for employers to evaluate and consider implementing safer sharps devices as they become available; and (b) to involve employees in identifying and choosing appropriate safety devices. 2000 CDC begins drafting updated dental infection control recommendations. 2001 OSHA releases new compliance directive for updated Bloodborne Pathogens Standard. 2001 CDC publishes updated guidelines and recommendcations for management of occupational exposures to HBV, HCV, and HIV and recommendations for PEP. (continued) 10 PART I ■ MICROBIOLOGICAL RATIONALE FOR PRACTICAL INFECTION CONTROL IN DENTISTRY Table 1-2 Infectious Disease and Infection Control Timeline (continued) 2002 CDC releases recommendations for hand hygiene in healthcare settings: Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. 2003 CDC releases Guidelines for Infection Control in Dental Health-Care Settings—2003; comprehensive update, includes other relevant guidelines and additional information; emphasis on standard precautions. 2005 CDC updates HIV PEP. 2007 CDC updates guidelines for isolation precautions regarding prevention of transmission of infectious agents in healthcare settings. ADA, American Dental Association; AIDS, acquired immunodeficiency syndrome; AZT, azidothymidine; CDC, Centers for Disease Control and Prevention; EPA, Environmental Protection Agency; FDA, Food and Drug Administration; GRID, gay-related immune deficiency; HBV, hepatitis B virus; HCV, hepatitis C virus; HCW, healthcare workers; HIV, human immunodeficiency virus; NANBH, non-A, non-B hepatitis; OSHA, Occupational Safety and Health Administration; PEP, postexposure prophylaxis; TB, tuberculosis. Table 1-3 Representative 20th Century Accomplishments in Infection Control • Recognition of relationship between microbial pathogens and risk of occupational transmission of infectious disease: bloodborne, airborne, wound, acute, chronic infections • Development and refinement of efficient aseptic techniques: hand-washing procedures, classes of antiseptics, infection-control cleaning procedures • Conversion from chemical immersion to heat sterilization procedures for instrument reprocessing • Adaptation to use of personal protective barriers during patient care: gloves, face masks, eyewear, clinic coats, and gowns • Receipt of hepatitis B vaccine and other vaccines recommended for health professionals • Application of universal precautions against bloodborne disease as infection control standard for patient treatment • Adaptation of safer procedures to minimize accidental exposures to contaminated sharp items • Development and use of newer technologies to prevent microbial cross-contamination and facilitate better infection control: sterilizers; personal and equipment barriers; automated instrument cleaning equipment; reusable, heat-stable dental instrumentation; single-use disposable needles; technical advancements in promoting dental unit water asepsis • Provision of routine care to patients with increasing variety of immune system compromise • Discovery and development of antimicrobial antibiotics to treat clinical infections Adapted from Molinari JA. Dental infection control at the year 2000: Accomplishment recognized. J Am Dent Assoc 1999;130:1291–1298. Copyright © 1999 American Dental Association. All rights reserved. Reproduced by permission. Table 1-4 Bloodborne Disease Transmission Efficiency 1. Direct or percutaneous inoculation by a contaminated needle or sharp object 2. Nonneedle percutaneous inoculation (scratches, burns, dermatitis; i.e., nonintact skin, especially on the hands) 3. Infectious blood or serum onto mucosal surfaces (intraoral, nasal, and ocular mucosa) 4. Other potentially infectious secretions (saliva) onto mucosal surfaces 5. Indirect transfer of potentially infectious blood via environmental surfaces (spatter) 6. Aerosol transfer of infectious blood (theoretical) Adapted from Bond W. Modes of transmission of infectious diseases. From Proceedings of the National Symposium on Infection Control in Dentistry. Chicago, Illinois: May 13, 1986. U.S. Department of Health and Human Services. CHAPTER 1 ■ HISTORICAL PERSPECTIVES AND PRINCIPLES OF INFECTION CONTROL 11 Table 1-5 Infectious Agents of Concern to Healthcare Workers Transmissibility Influenza Herpes Simplex Virus Rubella virus Varicella-Zoster virus Hepatitis A virus Hepatitis B virus Hepatitis C virus Cytomegalovirus Human immunodeficiency virus Prions expose the dental professional and patient to potentially infectious fluids. Recognition of the varying degrees of infection potential by microbial-laden secretions initially led to formulation of guidelines aimed at minimizing hepatitis B virus transmission. Similar protocols and procedures have been recommended regarding the routine treatment of patients with hepatitis C, human immunodeficiency virus, and acquired immune deficiency syndrome. Each of these guidelines mandates the use of the same appropriate infection control procedures in the care of all patients. In 1996, in an effort to prevent any potential infectious problems that might arise as a result of possible confusion between universal precautions (directed at bloodborne pathogens) and body substance isolation precautions (directed at other moist body substances), the CDC developed and published new guidelines for isolation procedures in hospitals. These guidelines incorporated the major features of universal and body substance isolation precautions into standard precautions. Since that time the use of standard precautions has replaced the use of both of its individual components. Just as with universal precautions, standard precautions should be used in the treatment of every patient regardless of their infection status. In the application of infection control principles, the images of “red saliva” should come to mind during any treatment procedure and serve as reinforcement for the routine use of effective, practical infection control procedures. Anxiety ↑ ↓ SELECTED READINGS ADA Councils on Dental Materials, Instruments, and Equipment; Dental Practice; and Dental Therapeutics. Infection control recommendations of the dental office and the dental laboratory. J Am Dent Assoc 1992;Suppl:1–8. ADA Councils on Dental Therapeutics. Guidelines for infection control in the dental office and the commercial dental laboratory. J Am Dent Assoc 1985;110:969–972. ADA Councils on Dental Therapeutics. Infection control in the dental office. J Am Dent Assoc 1978;97:673–677. CDC. Guidelines for infection control in dental healthcare settings. MMWR 2003;52:1–66. CDC. Guidelines for prevention of transmission of HIV and HBV to health-care and public safety workers. MMWR 1989;38(S-6):1–37. CDC. Provisional PHS interagency recommendations for screening donated blood and plasma for antibody to the virus causing AIDS. MMWR 1985;34:1. CDC. Recommendations for preventing transmission of infection with human T lymphotropic virus type III/ lymphadenopathy associated virus in the work place. MMWR 1985;34:682–686, 691–695. CDC. Recommendations for prevention of HIV transmission in health-care settings. MMWR 1987;36:1S-18S. Critical Thinking 1. Explain the historical data which showed hand washing to be a fundamental infection control precaution. CDC. Recommended infection control practices for dentistry. MMWR 1993;41(RR-8):1–12. CDC. Update: Universal precautions of prevention of transmission of HIV, HBV, and other bloodborne pathogens in health-care settings. MMWR 1988;37:377. 12 PART I ■ MICROBIOLOGICAL RATIONALE FOR PRACTICAL INFECTION CONTROL IN DENTISTRY Crawford JJ. Suggested guidelines for asepsis in the dental office environment, special supplement. N C Dent J 1980;63:4. Glass BJ, Cottone JA, Leuke P. Contamination in dental radiology. Annual Meeting of the American Academy of Dental Radiology, Las Vegas, NV, 1987. Department of Labor, Occupational Safety, and Health Administration. Enforcement procedures for the occupational exposure to bloodborne pathogens, CPL2-2.69. November 27, 2001. Molinari JA. Dental infection control in the year 2000. Accomplishment recognized. J Am Dent Assoc 1999;130:1291–1298. Department of Labor, Occupational Safety, and Health Administration. Occupational exposure to bloodborne pathogens; final rule. Fed Reg 1991;56:64004–64182. Environmental Protection Agency. Standards for the tracking and management of medical waste: interim final rule and request for comments. Fed Reg 1989;54:12371. Garner JS. Guideline for isolation precautions in hospitals. The Hospital Infection Control Practices Advisory Committee. Infect Control Hosp Epidemiol 1996;17:53–80. Molinari JA. Infection control. Its evolution to the current standard precautions. J Am Dent Assoc 2003;134:569–574. Molinari JA, Bednarsh H. Infectious disease and infection control timeline. Compend Contin Ed Dent 1998;19:640–650. Molinari JA, Harte JA. Dental services. In: APIC Text of Infection Control and Epidemiology 2nd ed. Washington, DC: APIC; 2005:51-1–51-23. Molinari JA, York J. Cross-contamination visualization. J Calif Dent Assoc 1987;15:12–16. C H A P T E R 2 Viral Hepatitis and Hepatitis Vaccines John A. Molinari Jennifer A. Harte LEARNING OBJECTIVES After completion of this chapter individuals should be able to: 1 Define hepatitis and its symptomatology. 2 Distinguish between the various viruses associated with hepatitis. 3 Describe the general features of hepatitis A, hepatitis B, hepatitis C, hepatitis D, and hepatitis E, including the etiology, transmission, diagnosis, sequelae, and prophylaxis. 4 List and discuss the serologic markers used in the diagnosis of various forms of viral hepatitis. 5 Describe the implications of the carrier states for hepatitis B and hepatitis C. 6 List the risk factors associated with the different hepatitis viruses. 7 Comprehend the occupational considerations for viral hepatitis and transmission risks for healthcare workers. 8 Understand the chemotherapeutic approaches for management of persons infected with hepatitis viruses. 9 Describe the types and efficacy of available hepatitis A and hepatitis B vaccines. 13 14 PART I ■ MICROBIOLOGICAL RATIONALE FOR PRACTICAL INFECTION CONTROL IN DENTISTRY KEY TERMS Anicteric: not associated with jaundice. Antibody: a protein found in the blood that is produced in response to foreign substances (e.g., bacteria or viruses) invading the body. Antibodies protect the body from disease by binding to these organisms and destroying them. Antigen: a foreign substance, usually protein or carbohydrate substance (as a toxin or enzyme) capable of stimulating an immune response, usually the production of antibodies. Carrier: an individual harboring a disease agent who may transmit the infection without demonstrating apparent symptoms. Chronic: of long duration. Cirrhosis: chronic liver disease characterized by progressive destruction and regeneration of liver cells and increased connective tissue formation. Fulminant: occurring suddenly, rapidly, and with great intensity. INTRODUCTION Two diseases have been primary occupational concerns over the past few decades for healthcare personnel (HCP): viral hepatitis and acquired immune deficiency syndrome (AIDS). Prior to the late 1970s, many dentists, hygienists, assistants, and dental lab technicians learned about viral hepatitis in school, but because there were only limited epidemiological studies and little infection control data available, people generally accepted the risk with little worry. Unfortunately, several dental professionals were infected, with some subsequently manifesting disease sequelae ranging from development of an infectious carrier state to cirrhosis, hepatocellular carcinoma, and even death. Viral hepatitis can have a short- or long-term incubation interval, depending on the etiologic agent involved. The possibility of prolonged symptomatic and asymptomatic sequelae to primary infection also exists. Fortunately, as much more is understood regarding modes of transmission, diagnosis, and prevention, approaches about viral etiologies, sensitive assays have been developed and effective vaccines have been produced against most of the major viral etiologies. This chapter examines the challenge that viral hepatitis continues to pose for the dental profession and places this challenge in proper perspective. Gamma globulin: generally any serum protein exhibiting antibody activity. Hepatitis: an inflammation of the liver; the most common cause is infection with one of the five hepatitis viruses; hepatitis can also be caused by other viruses, bacteria, parasites, and toxic reactions to drugs, alcohol, and chemicals. Icteric: related to or marked by jaundice. Inflammation: a fundamental immunological and pathologic process which occurs following any injury to tissue, such as that following the establishment and multiplication of microorganisms. Jaundice: a yellowish staining of the skin, mucous membranes, and sclera with bilirubin and other bile pigments. Subclinical: a state in which the individual either does not experience all of the characteristic symptoms of a particular disease, or the manifestations are less severe. Viremia: the presence of viruses in the blood. VIRAL HEPATITIS: THE MAJOR BLOODBORNE CHALLENGE Hepatitis, or inflammation of the liver, can be caused by several viruses and a variety of other nonmicrobial etiologies. It can be caused by various disease states and drug reactions. It is therefore important for dental healthcare personnel (DHCP) to remember at the outset that a patient history of hepatitis does not automatically signify a case of viral hepatitis. While several different viruses can induce hepatic symptoms and abnormalities, currently at least seven distinct viruses have been identified as major causes of viral hepatitis, with manifestations ranging from acute to chronic disease. Table 2-1 lists these and other viruses that can cause hepatitis. Currently, at least six viruses are believed to account for the overwhelming majority of viral hepatitis infections (Table 2-2). While there are additional hepatitis viruses which could be added here, the following will discuss the five most extensively studied, the infections they cause, and the occupational implications for health professionals. Hepatitis conditions in general are classically divided into prodromal, icteric, and convalescent phases. During the prodromal stage, nonspecific respiratory and/or gastrointestinal symptoms can develop. These can include malaise, loss of appetite, headaches, nausea, and flu-like CHAPT