Focus on Hepatitis Relates to Chapter 44 Nursing

Focus on Hepatitis (Relates to Chapter 44, “Nursing Management: Liver, Pancreas, and Biliary Tract Problems” in the textbook) Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis n Inflammation n Viral n of the liver hepatitis Most common cause Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis n Types of infectious viral hepatitis A n. B n. C n. D n. E n. G n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis n Other possible causes Drugs (alcohol) n Chemicals n Autoimmune liver disease n Bacteria (rarely) n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis n 61, 000 cases of hepatitis A occur annually in the United States n 10 million cases of hepatitis A occur worldwide n Nearly universal during childhood in developing countries Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis n Nearly 400 million people infected with hepatitis B n 50% to 75% active vial replication n 73, 000 new cases of hepatitis B annually in United States n Incidence decreased due to HBV vaccine Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis n Approximately 170 million people are infected with the hepatitis C virus (HCV) n Estimated 30, 000 new cases diagnosed annually Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis n 8000 to 10, 000 people in the United States die each year from complications of end-stage liver disease secondary to HCV n Approximately 30% to 40% of HIV-infected patients also have HCV Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Causes A, B, C, D, E, and G virus n Cytomegalovirus n Epstein-Barr virus n Herpes virus n Coxsackievirus n Rubella virus n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis A virus (HAV) RNA virus n Transmitted fecal–oral route, parenteral (rarely) n Frequently occurs in small outbreaks n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis A virus (HAV) Found in feces 2 or more weeks before the onset of symptoms and up to 1 week after the onset of jaundice n Present in blood briefly n No chronic carrier state n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Serologic Events in HAV Infection Fig. 44 -2 Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis n A virus (HAV) Anti-HAV immunoglobulin M (Ig. M) Appears in the serum as the stool becomes negative for the virus n Detection of Ig. M anti-HAV indicates acute hepatitis n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis n A virus (HAV) Anti-HAV immunoglobulin G (Ig. G) Ig. G anti-HAV: Indicator of past infection n Presence of Ig. G antibody provides lifelong immunity n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis B virus (HBV) DNA virus n Transmission of HBV n Perinatally by mothers infected n Percutaneously (IV drug use) n Horizontally by mucosal exposure to infectious blood, blood products, or other body fluids n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis n B virus (HBV) Transmission occurs when infected blood or other body fluids enter the body of a person who is not immune to the virus Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis B virus (HBV) Sexually transmitted disease n Can live on a dry surface for 7 days n Kissing/sharing food items may spread the virus via saliva n More infectious than HIV n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Serologic Events in HBV Infection Fig. 44 -3 Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis B virus (HBV) n Complex structure with three antigens n n Surface antigen (HBs. Ag) Core antigen (HBc. Ag) E antigen (HBe. Ag) Each antigen—a corresponding antibody may develop in response to acute viral hepatitis B Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis n B virus Presence of hepatitis B surface antibodies n n Indicates immunity from HBV vaccine Past HBV infection With chronic infection, liver enzyme values may be normal or ↑ n 15% to 25% of chronically infected persons die from chronic liver disease n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis C virus (HCV) n n n RNA virus Transmitted percutaneously Risk factors n IV drug use § Most common mode of transmission in United States and Canada n Blood transfusions § Transmission <1 per 1 million blood transfusions Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis n C virus (HCV) Risk factors (cont’d) High-risk sexual behavior n Hemodialysis n Occupational exposure n Perinatal transmission n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis C virus (HCV) Up to 10% of patients with HCV cannot identify a source n Additional data needed regarding risk of body piercings, tattooing, and intranasal drug use in transmission of HCV n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis D virus (HDV) Also called delta virus n Defective single-stranded RNA virus n Cannot survive on its own n Requires the helper function of HBV to replicate n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis n D virus (HDV) (cont’d) HBV-HDV co-infection ↑ Risk of fulminant hepatitis n More severe acute disease n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis E virus (HEV) RNA virus n Transmitted fecal–oral route n Most common mode of transmission is drinking contaminated water n Occurs primarily in developing countries n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis G virus (HGV) RNA virus n Poorly characterized parenterally and sexually transmitted virus n Found in some blood donors n Can be transmitted by blood transfusion n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Etiology n Hepatitis G virus (HGV) (cont’d) Coexists with other hepatitis viruses and HIV n Does not appear to cause liver damage n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Pathophysiology of Hepatitis n Acute n infection Liver damage mediated by Cytotoxic cytokines n Natural killer cells n n Liver cell damage results in hepatic cell necrosis Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Pathophysiology of Hepatitis n Acute infection (cont’d) n n n Proliferation and enlargement of Kupffer cells Inflammation of the periportal areas may interrupt bile flow Cholestasis may occur Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Pathophysiology of Hepatitis n Widespread inflammation of the liver tissue n Pathophysiologic changes in the various types of viral hepatitis are similar Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Pathophysiology of Hepatitis n Liver cells can regenerate with time and if no complications occur, resume their normal appearance and function Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Pathophysiology of Hepatitis n Antigen–antibody complexes n Systemic effects of this activation include Rash n Angioedema n Arthritis n Fever n Malaise n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Pathophysiology of Hepatitis n Systemic effects (cont’d) Fever n Malaise n Cryoglobulinemia n § Abnormal proteins in blood Glomerulonephritis n Vasculitis n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n 30% of patients with HBV are asymptomatic n 80% of patients with acute HCV will be asymptomatic Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n Acute phase Lasts from 1 to 4 months n May be icteric (symptomatic) or anicteric n During incubation, symptoms include n Malaise n Anorexia n Fatigue n Nausea n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n Acute n phase (cont’d) Symptoms (cont’d) Nausea n Occasional vomiting n Abdominal discomfort n Headache n Low-grade fever n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n Acute phase (cont’d) n Symptoms (cont’d) n n Arthralgias Skin rashes Physical exam may reveal hepatomegaly, lymphadenopathy and splenomegaly Maximal infectivity period for hepatitis A Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n Jaundice n Results when bilirubin diffuses into tissues n Urine darkens due to excess bilirubin being excreted n If bilirubin cannot flow out of liver, stool will be light or clay-colored Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Severe Jaundice Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n Pruritus n can accompany jaundice Accumulation of bile salts beneath the skin n When jaundice occurs, fever subsides n Liver usually enlarged and tender Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n Convalescent phase Begins as jaundice is disappearing n Lasts weeks to months n Major complaints n Malaise n Easy fatigability n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n Almost all cases of hepatitis A resolve n Absence of jaundice does not mean recovery Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n General n considerations Not all patients with hepatitis virus have jaundice n Termed anicteric hepatitis Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n General n considerations Hepatitis A virus Acute onset n Mild, flu-like manifestations n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n General n considerations Hepatitis B virus Insidious onset n Symptoms more severe n Fewer GI symptoms n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Clinical Manifestations n General n considerations Hepatitis C virus Majority of cases are asymptomatic or mild n High rate of persistence n Leads to chronic liver disease n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Complications n Most patients with acute viral hepatitis recover completely with no complications n Overall mortality rate <1% Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Complications n Fulminant hepatic failure n Chronic hepatitis n Cirrhosis n Hepatocellular carcinoma Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Complications n Fulminant hepatitis n n n Results in severe impairment or necrosis of liver cells and potential liver failure Develops in small percentage of patients Occurs because of n n Complications of hepatitis B Toxic reactions to drugs and congenital metabolic disorders Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Diagnostic Studies n Hepatitis C Several tests available n Antibodies to HCV are not protective n May be indicator of chronic disease n Anti-HCV antibody test by immunoassay n n If positive § Confirmatory testing must be done Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Diagnostic Studies n Hepatitis C (cont’d) n n HCV recombinant immunoblot assay may be used if false positive HCV antibody test HCV RNA polymerase chain reaction performed n n Document viremia if antibody positive To detect active disease Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Diagnostic Studies n Hepatitis C (cont’d) n n Six genotypes and 50 subtypes of HCV Genotyping: Important role in managing infection n n One of the strongest predictors of response to therapy and influences duration of treatment Should be determined before drug therapy started Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Diagnostic Studies n History n Physical assessment findings Hepatic tenderness n Hepatomegaly n Splenomegaly n Palpable liver n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Diagnostic Studies n Aspartate aminotransferase (AST) n Alanine aminotransferase (ALT) n -Glutamyl transpeptidase (GGT) n Alkaline phosphatase Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Diagnostic Studies n Serum proteins n Serum bilirubin n Urinary urobilinogen Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Diagnostic Studies Prothrombin time n Biopsy n n If diagnosis is in doubt Chronic hepatitis Sonograms (Fibroscan) n Determining degree of liver scarring Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n No specific treatment or therapy for acute viral hepatitis n Most patients can be managed at home n Emphasis on resting the body and receiving adequate nutrients Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n Drug therapy n n No specific drug therapies Support therapy n Antiemetics § § Dimenhydrinate (Dramamine) Trimethobenzamide (Tigan) Phenothiazines should not be used If requires sedative or hypnotic, diphenhydramine (Benadryl) or chloral hydrate may be used Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n Drug n therapy for chronic hepatitis B Focused on ↓ Viral load n ↓ Liver enzyme levels n ↓ Rate of disease progression n ↓ Rate of drug-resistant HBV n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n Long-term goals n n Prevention of cirrhosis and liver cancer Not all patients respond to current therapeutic regimens Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n Drug n therapy for chronic hepatitis B α-Interferon Multiple effects on viral replication cycle n Must be administered subcutaneously n Side effects: Flu like symptoms, depression, hair thinning, diarrhea, insomnia n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n Drug therapy for chronic hepatitis B (cont’d) n Nucleoside analogs n n n When active viral replication exists Inhibit viral DNA synthesis Lamivudine (Epivir) § Taken for 1 year n Adefovir (Hepsera) Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n Drug therapy for chronic hepatitis C Directed at eradicating virus n Reducing viral load n Decreasing progression of disease n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n Drug therapy for chronic hepatitis C (cont’d) n Treatment n n Pegylated α-interferon with ribavirin (Rebetol, Copegus) Ribavirin side effects: Anemia, anorexia, cough, rash, pruritus, dyspnea, insomnia, teratogenicity Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care Prevention n Hepatitis A vaccine Preexposure prophylaxis n IM in deltoid n n Immune globulin (IG) Pre/post exposure n Temporary passive immunity n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care Prevention n Hepatitis B n Immunization Most effective method n Part of routine vaccination schedules for newborns, adolescents, and adults in major risk groups n Recombivax HB, Engerix-B n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care n Hepatitis B n Immunization (cont’d) n n Recombinant DNA using HBs. Ag Promotes synthesis of specific antibodies against hepatitis B Series of three IM injections given at 0– 1– 6 month intervals More than 95% effective Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care Prevention n Hepatitis B immune globulin (HBIG) Used for postexposure with vaccine n Contain antibodies to HBV n Should be given within 24 hours of exposure n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care Prevention n Hepatitis C No vaccine to prevent HCV n CDC does not recommend IG or antiviral agents for postexposure prophylaxis n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Collaborative Care Nutritional therapy n No special diet n Vitamins (B-complex and vitamin K) n Low-fat n Adequate calories Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing assessment n Past health history Hemophilia n Exposure to infected persons n Ingestion of contaminated food or water n Past blood transfusion (before 1992) n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing assessment n Medications (use and misuse) Acetaminophen n Phenytoin n Halothane n Methyldopa n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing assessment n IV drug and alcohol abuse n Weight loss n Dark urine n Fatigue n Right upper quadrant pain n Pruritus Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing assessment n Low-grade fever n Jaundice n Abnormal laboratory values Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing diagnoses n Imbalanced nutrition: Less than body requirements n Activity intolerance n Ineffective therapeutic regimen management Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management n Overall goals: Planning Relief of discomfort n Resumption of normal activities n Return to normal liver function without complications n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing implementation n Health promotion n Hepatitis A and B Education n Vaccination n Good hygiene practices n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing implementation n Health promotion n Hepatitis C Education n Infection control precautions n Modification of high-risk behavior n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing implementation n Acute intervention Rest n Jaundice n Assess degree of jaundice n Small, frequent meals n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing implementation n Ambulatory and home care Dietary teaching n Assessment for complications n Regular follow-up for at least 1 year after diagnosis n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Nursing implementation n Ambulatory and home care Avoid alcohol n Medication education n α-Interferon administered subcutaneously n Side effects n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Evaluation n Expected outcomes Adequate nutritional intake n Increased tolerance for activity n Verbalization of understanding of follow-up care n Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.

Hepatitis Nursing Management Evaluation n Expected outcomes n Able to explain methods of transmission and methods of preventing transmission to others Copyright © 2007, 2004, 2000, Mosby, Inc. , an affiliate of Elsevier Inc. All Rights Reserved.