MLT 115 Exam#6

the major structural protein (core) of the human immunodeficiency virus type 1 (HIV) encoded by the gag gene is:

gp41 & gp 120

the serology marker HBsAg for hepatitis B virus (HBV) infection in early asymptomatic) infection is:

Positive

In the late (tertiary) stage of syphilis, a clinical finding is:

Presence of gummas.

which of the following is a term for nontreponemal antibodies produced by an infected patient against components of their own or other mammalian cells?

Reagin antibodies.

a representative characteristic of hepatitis D is:

Requires HBV as a helper.

immunocompetent patient patients infected with T. pallidum produce:

Specific antibodies against T. pallidum Nonspecific antibodies against the protein antigen group common to pathogenic spirochetes. Reagin antibodies. All the above.

. Discuss treponemal methods of laboratory diagnosis.

These are used as confirmatory tests after a positive RPR or VDRL. Fluorescent Treponema pallidum-absorbed (FTA-abs) is the most common. -It is the most sensitive method for the detection of primary syphilis. It uses killed suspension of T. pallidum spirochetes as the antigen -MHA TP -TP-PA

another name for hepatitis B infection is:

Long incubation hepatitis.

an associated characteristic of hepatitis A is:

Should receive immune globulin intramuscularly after exposure

The FTA-ABS test is:

Treponemal method

the human immunodeficiency virus (HIV) attaches itself to receptor sites by means of:

p24 antigen

What diagnostic laboratory methods are available for HIV?

- Anti-HIV by EIA is the first line test. They are very sensitive, specific and rapid test methods. They must be confirmed by Western Blot. -The Western Blot is capable of recognizing three major HIV proteins - p24, p41 and p120/160. -If the EIA is positive and the Western Blot is positive for p24 and/or p41, it confirms HIV infection. However, these tests are expensive and miss diagnosis in the lengthy window between infection and sero-conversion. - There is an EIA method for detecting uncomplexed p24 antigen. -It can be performed on blood or CSF. -A positive result is evidence of infection before seroconversion. - The test has low sensitivity and may be negative in patients with high levels of p24. -HIV-PCR detects HIV-1 by DNA amplification. - - It is ultrasensitive and can detect as little as 100 molecules of viral nucleic acid. -Can be used as a confirmatory test or to monitor effectiveness of anti-viral drugs.

What are the symptoms of primary syphilis?

- The development of a characteristic chancre at the point of initial inoculation. The chancre becomes a papule and erodes to form an ulcer with a clean base and indurated edge. It is relatively painless. They are commonly found on the genitalia but can be found on the throat, lips and hands. The chancre persists for 1-5 weeks without treatment.

VDRL- Venereal Disease Research Laboratory

- is the recommended test when a patient suspected of syphilis has a negative darkfield or when atypical lesions are present. -It detects reagin antibodies. Patient's heat inactivated serum is mixed with a buffered saline suspension of cardiolipin-lecithin-cholesterol antigen. - The serum-antigen mixture is examined microscopically for flocculation.

Explain Hepatitis B laboratory diagnosis

-HBsAg by EIA - presence of HBsAg indicates active HBV infection either acute or chronic -Anti-HBs by EIA - determines immunity - Anti-HBc by EIA - may provide additional advantage since it would identify patients recently recovered from a HBV infection who may still be infective. Always detection of patients in the "anti-core window" -Vaccinated individuals are Anti-HBc negative; Anti-HBs positive -Nucleic acid testing by PCR may be useful if EIA results are questionable. Good for following treatment in chronically infected patients.

What is Hepatitis C? Include virus description, epidemiology and symptoms in your answer

-HCV was originally referred to as "non-A, non-B" hepatitis. It is a single-stranded RNA virus thought to be a flavivirus or togavirus. It is a major cause of chronic liver disease worldwide. Approximately 50-70% of cases evolve into chronic hepatitis; 20% progress to cirrhosis with increased risk of hepatocellular carcinoma. Disease resembles HBV infection with elevated ALT but is generally mildly symptomatic.

How is HIV transmitted?

-HIV has been isolated from blood, semen, vaginal secretions, saliva, tears, breast milk, CSF, amniotic fluid and urine. -Only blood, semen, vaginal secretions and breast milk have been implicated in transmission due to the high number of lymphocytes/macrophages present in those fluids. -Infants born to HIV+ women have a 20-30% risk of infection.

What cells are targeted in HIV infection?

-HIV targets the protein receptor on CD4 T-helper lymphocytes and any B-lymphocytes expressing CD4. It also targets glial cells in the brain and Chromaffin cells in the stomach.

How many sero-types of HIV are there? How are they different?

-HIV-1 and HIV-2 - HIV-2 has a slightly different envelop and slightly different core proteins than HIV-1. -HIV-1 is responsible for the AIDS epidemic. HIV-2 is transmitted through heterosexual contact and is most prevalent in West Africa. The periods of infection may be longer in HIV-2.

What is the treatment for Hepatitis C?

-Harvoni -Alpha interferon is the drug of choice. Relapse is seen in 40-90% of patients. Treatment is difficult due to varying genotypes of the virus. Those with end-stage chronic HCV may be candidates for liver transplantation but re-infection of the allograft is common.

What are the signs of secondary syphilis?

-It begins approximately 2-8 weeks after the appearance of the primary chancre. It is characterized by a generalized illness beginning with headache, sore throat, low-grade fever and, occasionally a nasal discharge. - The WBC is elevated with a lymphocytosis. Lymphadenopathy develops and lesions of the skin and mucous membranes containing organisms appear. -This is highly contagious. -Macular lesions are common. - A rash of the genitalia and often prominent rash on the palms and soles appears. -Condylomata lata (flat resembling warts) may appear around the anus and/or vagina. -Approximately 1/3 have asymptomatic central nervous system involvement and 2% develop syphilitic meningitis. -Usually resolves itself in 2-6 weeks without treatment.

Who is at risk for Hepatitis C?

-Patients who have received multiple blood transfusions, IV drug users, healthcare workers (needle sticks), sexual/household contacts, dialysis patients, those living in close quarters with lowered socioeconomic status, prisoners, and a few documented cases of mother to infant transmission

HIV is a retrovirus. Describe characteristics of a retrovirus including HIV replication.

-Reverse transcriptase enables the virus to convert viral RNA to DNA. This reverses the normal process of transcription where DNA is converted to RNA. The virus attaches and penetrates target cells, losing its protein coat and exposing the RNA core. Reverse transcriptase converts viral RNA to proviral DNA. The proviral DNA is integrated into the genetic makeup of the host cell. New virus particles are produced as the result of transcriptase and translation. Once the virus is integrated into the host cell DNA, the potential for viral production always exists and the viral infection of new cells can continue.

RPR - Rapid Plasma Reagin

-Same specificity as the VDRL but more sensitive. It also detects reagin antibodies. -Can be performed on unheated serum or plasma. -Serum is mixed with an antigen suspension of a carbon particle (or charcoal) cardiolipin antigen. - If antibody is present, flocculation occurs with the agglutination of the carbon particles of antigen. -Flocculation appears as black clumps against the white background of a plastic-coated card. Cards are examined macroscopically. -It is a primary screening test and must be confirmed by a treponemal method.

What are the signs of tertiary syphilis?

-Tertiary syphilis develops 3-10 years after primary infection. At least 15% will develop late benign syphilis characterized by the presence of destructive granulomas. -The skeletal system is often affected but treponemes are rarely seen. -10% develop cardiovascular manifestations particularly syphilitic aneurysm usually of the aortic arch. -8% have CNS involvement (seizures or stroke) or develop general paresis, personality changes, dementia and delusional states. - May develop a broad-based gait. - Impotence and bladder dysfunction. - CSF should be examined in all syphilis patients of unknown duration or who have had syphilis more than one year.

Discuss non-treponemal methods of diagnosis.

-VDRL- Venereal Disease Research Laboratory -RPR - Rapid Plasma Reagin

In the RPR procedure, a false -positive reaction can result from all the following except:

-infectious mononucleosis -Leprosy -Rheumatoid arthritis -Except: Streptococcal pharyngitis

the infected blood. T. pallidum does not appear to survive at 4C (39C) for longer than:

3 days

The primary incubation period for syphilis (T. Pallidum) is usually about:

3 weeks

Anti-HBs is:

A serologic marker of recovery and immunity

AIDS is a(n)

Acquired T-cell disorder

Anti-HBc is:

An indicator of recent HBV infection may be only serology marker during the window phase.

the specific diagnostic test for hepatitis C is

Anti-HCV

Discuss Hepatitis C diagnosis and testing.

Anti-HCV and HCV PCR. Problem with Anti-HCV is the long window period between infection and antibody production (sero-conversion). Anti-HCV IgM and IgM is by ELISA or EIA. HCV-PCR can be used to monitor treatment and donor blood testing.

the most common clinical response to hepatitis is:

Asymptomatic infection Subclinical infection

the HIV infectious process begin when the protein on the viral envelope binds to the protein receptor------ on the surface of a target cell

CD4

Direct examination of the treponemes is most often performed by

Darkfield microscopy

In the primary stage of syphilis, a clinical finding is:

Development of a chancre.

In the latent stage of syphilis, a clinical finding is:

Diagnosis only by serology methods

HBsAg is:

Initially detectable marker found in serum during the incubation period of HBV infection.

the of transmission of hepatis E is:

Fecal -oral

the mode of transmission of hepatitis A is:

Fecal-oral

HBeAg is:

Found in the serum of some patients who are ABsAg positive, marker for level of virus infectivity.

in the secondary stage of syphilis, a clinical finding is:

Generalized illness followed by macular lesions in most patients.

What are the Hepatitis B serology markers? Describe each

HBsAg - antigen present on the outer surface. First detectable marker. Rise and fall in titer parallels rise and fall of ALT. HBeAg - Hepatitis B related antigen. Found in the serum of some patients who are HBsAg positive. Appears to be associated with the hepatitis core. Reliable marker for the presence of high levels of virus and a high degree of infectivity. Anti-HBc - antibody to the core antigen. During most infections, it forms a complex with HBsAg as part of the recovery process and the HBsAg in these complexes is usually undetectable. Indicator of recent infection. Period of time between the disappearance of HBsAg and the appearance of Anti-HBc is called the anti-core window. This window may last for a few weeks to a year. Anti-HBe and Anti-HBs - Both develop during convalescence and recovery from the HBV infection. Anti-HBe is the first evidence of the convalescent phase. Anti-HBs does not rise in acute disease; it is manifested in the convalescent phase and is a sign of recovery and immunity. Anti-HBs is the major protective antibody. Hepatitis B immune globulin has high levels of Anti-HBs.

in health care workers, the risk of contracting hepatitis C is-------the risk of contracting AIDS.

HIGHER THAN

which form of hepatitis does not bane a chronic form of the disease?

Hepatitis A

which of the following viruses is rarely implicated in transfusion associated hepatitis?

Hepatitis A

Discuss Hepatitis A prevention

Hepatitis A immune globulin should be administered intramuscularly to all close personal contacts. Vaccination is recommended for all individuals >12 months of age and for all people traveling to an area where Hepatitis A is endemic. Wash hands after using the restroom!!! Cook all vegetables.

What are primary hepatitis viruses?

Hepatitis A, B, C, D and E

the Australia antigen is now called:

Hepatitis B surface antigen (HBsAg)

. Discuss Hepatitis B prevention

Hepatitis B vaccine, administration of Hepatitis B immune globulin within 24 hours of exposure and again 25-30 days later. Elimination of high-risk blood donors. Routine screening of donated blood products - testing for Anti-HBc will detect almost 100% of HBsAg positive patients. Always practice universal precautions.

the most frequent malignancy observed in AIDS patient is:

Kaposi's sarcoma -It's a skin lesion.

the stage of syphilis that can be diagnosed only by serologic (laboratory) methods is the:

Latent phase.

Explain latent syphilis.

Latent syphilis is a noninfectious state and diagnosis can only be made from serological testing. During the first 2-4 years, 25% of the patients will relapse back to secondary syphilis and are infectious. Relapse after 4 years is rare. 1/3 are spontaneously cured; 1/3 will never develop further clinical manifestations of the disease; 1/3 will develop tertiary syphilis.

The RPR test is a:

Nontreponemal method

the mode of transmission of hepatitis B is:

Parenteral

the mode of transmission of Hepatitis C is:

Parenteral and non-parenteral.

Treponema pallidum (T. Pallidum) is the causative organism associated with the disease:

Syphilis

primary hepatitis viruses are given this name because they primarily attack:

The liver

How is Hepatitis A diagnosed in the laboratory?

Total antibody assay by EIA is the preferred method. IgM by radioactive immunoassay (RIA) or Hepatitis A antigen by RIA.

a representative characteristic of hepatitis C is:

Transmission by both parenteral and non-parenteral route

What is the causative agent of syphilis?

Treponema pallidum - a spirochete

The TP-PA test is a:

Treponemal method

What test is used to diagnose tertiary syphilis from cerebrospinal fluid (CSF)?

VDRL

In an established HIV infection, a patient will demonstrate

p24 antigen & HIV-I antibody -Patients with established infections will exhibit the p24 antigen and HIV-1 antibody