QUICK REVIEW HEPATITIS

HEPATITIS A DISEASE: HEPATITIS A CHARACTERISTICS: enterovirus classified in the picornavirus family Naked nucleocapsid virus with a single- stranded, positive-polarity RNA. Transmission—fecally contaminated water or food such as oysters grown in polluted water and eaten raw. Pathogenesis—The virus replicates in the GI tract and then spreads to the liver during a brief viremic period. Laboratory Diagnosis: The detection of IgM antibody is the most important test Treatment: No antiviral therapy is available.

HEPATITIS B Diseases—Hepatitis B; implicated as a cause of hepatocellular carcinoma. Characteristics: hepadnavirus family. Enveloped virus with incomplete circular double-stranded DNA. Important antigens surface antigen (HBsAg): protein in the envelope which is important for laboratory diagnosis and immunization. core antigen (HBcAg): located in the core (nucleocapsid) e antigen (HBeAg): located in the core is an important indicator of transmissibility.

Profiles to know + core antibody and surface antigen * current infection + core antibody by itself * window period + core antibody and surface antibody * had past infection but now immune +surface antigen alone * just been vaccinated less than 2weeks ago +surface antibody alone * vaccination

Meaning What we expect in acute hepatitis B( what would the markers be)? S Ag, E Ag, HBV DNA and core IgM What if the pt is in the window period? Core IgM What if had Hep B, but have recovered from it? Core Ab IgG and surface Ab IgG What if pt was vaccinated( what is the only thing you should have)? Surface Ab IgG What if you have at the end of 6 months S Ag, core IgM, with everything else negative? Means you are healthy carrier What if you have after 6 months surface Ag, E Ag, HBV DNA and core Ab IgM? Infective carrier

Transmission 1. IV(90%) 2. BLOOD 3. SEXUAL 4. VERTICAL Note: disease is acute and occasionally severe and chronic 10% HBV vaccine is the first vaccine to prevent a human cancer.

HEPATITIS C Disease: Hepatitis C; associated with hepatocellular carcinoma. HCV is the most prevalent blood-borne pathogen in the United States. Characteristics—member of the flavivirus family.Enveloped virus with one piece of single- stranded, positive-polarity RNA Transmission—Most transmission is via blood. Sexual transmission Laboratory Diagnosis—Serologic testing detects antibody to HCV. Treatment—Alpha interferon plus ribavirin mitigates chronic hepatitis but does not eradicate the carrier state.

HEPATITIS D Disease: Hepatitis D virus (HDV) causes hepatitis D (hepatitis delta). Important Properties & Replicative Cycle: unusual in that it is a defective virus HDV can replicate only in cells also infected with HBV, because HDV uses the surface antigen of HBV (HBsAg) as its envelope protein. Transmission—Transmitted by blood, sexually, and from mother to child. Laboratory Diagnosis—Serologic testing detects either delta antigen or antibody to delta antigen. Treatment—Alpha interferon mitigates symptoms but does not eradicate the carrier state.

HEPATITIS E major cause of enterically transmitted hepatitis. common cause of water-borne epidemics of hepatitis in Asia, Africa, India, and Mexico uncommon in the United States. nonenveloped, single-stranded RNA virus tentatively classified as a member of the calicivirus family. Clinically the disease resembles hepatitis A, with the exception of a high mortality rate in pregnant women. Pregnant women who acquire HEV have a 20% fatality rate (compared to 0.5% for the rest of the population). India, a country where HEV is endemic.

HUMAN IMMUNODEFICIENCY VIRUS Disease—Acquired immunodeficiency syndrome (AIDS). Characteristics—Enveloped virus with two copies (diploid) of a single-stranded, positive- polarity RNA genome. RNA-dependent DNA polymerase (reverse transcriptase) makes a DNA copy of the genome, which integrates into host cell DNA.

Transmission—Transfer of body fluids, eg, blood and semen. Also transplacental and perinatal transmission. Pathogenesis—Two receptors are required for HIV to enter cells. One receptor is CD4 protein found primarily on helper T cells. HIV infects and kills helper T cells, which predisposes to opportunistic infections. The other receptor for HIV is a chemokine receptor such as CCR5 or CXCR4 The NEF protein is an important virulence factor. It reduces class I MHC protein synthesis, thereby reducing the ability of cytotoxic T cells to kill HIV- infected cells. Cytotoxic T cells are the main host defense against HIV.

A pregnant southeast Asian immigrant presents for prenatal care. Her past medical history is significant for a severe illness 3 years ago characterized by fatigue, nausea, anorexia, vomiting, jaundice, joint pains, and generalized skin lesions that slowly disappeared. She has felt well recently. Which of the following laboratory tests should be ordered to investigate the patient's past illness? A. Hepatitis B surface antigen (HBsAg) B. IgG cytomegalovirus (CMV) antibody levels C. IgM antibody to HBsAg D. IgM antibody to hepatitis B core antigen E. Quantitation of hepatitis A virus (HAV) IgM antibody

After passing his physical exam, a 19-year-old army recruit gives urine and blood samples for further testing. Serum analysis yields elevated ALT, HBsAg, Anti-HBc, HBeAg, and bilirubin. All other values are normal. Which of the following is the hepatitis B status of this recruit? A. Asymptomatic carrier B. Chronic active carrier C. Fulminant hepatitis B D. Recovered from acute self-limited HBV E. Vaccinated against HBV

Delta hepatitis only occurs in patients who also have either acute or chronic infection with hepatitis B virus. The delta agent is a. An incomplete hepatitis B virus b. Related to hepatitis A virus c. A hepatitis B mutant d. An incomplete RNA virus

Hepatitis E, a recently characterized hepatitis virus, is best described by which of the following statements? a. It is not a threat to the blood supply b. It is a major cause of blood-borne hepatitis c. It is prevalent in North America d. It is a single-stranded DNA virus e. The disease resembles hepatitis C

A nurse develops clinical symptoms consistent with hepatitis. She recalls sticking herself with a needle approximately 4 months before after drawing blood from a patient. Serologic tests for HBsAg, antibodies to HBsAg, and hepatitis A virus (HAV) are all negative; however, she is positive for IgM core antibody. The nurse a. Does not have hepatitis B b. Has hepatitis A c. Is in the late stages of hepatitis B infection d. Is in the “window” (after the disappearance of HBsAg and before the appearance of anti-HBsAg) e. Has hepatitis C

Hepatitis D virus (delta agent) is a defective virus that can replicate only in cells already infected with which of the following viruses? a. Hepatitis A virus b. Epstein-Barr virus c. Hepatitis G virus d. Hepatitis B virus e. HIV

A hospital worker is found to have hepatitis B surface antigen. Subsequent tests reveal the presence of e antigen as well. The worker most likely a. Is infective and has active hepatitis b. Is infective but does not have active hepatitis c. Is not infective d. Is evincing a biologic false-positive test for hepatitis e. Has both hepatitis B and C

Which one of the following groups of people may be at increased risk for HIV infection? a. Members of a household in which there is a person who is HIV-positive b. Receptionists at a hospital c. Factory workers whose coworkers are HIV- positive d. Foreign service employees who are hospitalized in Zaire for bleeding ulcers e. Homosexual females

A 22 year old surgical resident underwent several screening tests. His hepatitis B serologies are: HBsAg (-), anti-HBsAb (+), anti- HBcAb (-), HBeAg (-). These results show that he: a. is recovering from Hepatitis B infection b. has chronic Hepatitis B infection. c. was vaccinated and is now immune

A 32 year old male presents to the emergency department with progressive fatigue, malaise and lymphadenopathy. When tested for HIV infection, his blood samples are positive for viral protein p24. The protein detected in this patient is a product of which of the following viral genes? Pol Env Gag Nef Rev