1050 Unit 6 Flashcards
What are viruses?
Submicroscopic pathogens that can cause many human diseases
Describe structure of a virus
- core of DNA or RNA packaged into protein coat or capsid
- rely on host cell for replication and survival
What are basic steps of virus life cycle?
① attachment of the virus to receptor on host on surface
② penetration or entry of the virus in the host through endocytosis or other mechanisms
③degradation of the viral nucleic acid
④transcription to produce additional viral nucleic acid
⑤ translation of viral nucleic acid to produce Viral proteins
⑥ assembly of the viral components to produce intact virons
⑦ budding off the host, cell membrane or host cell lysis results in…
⑧ release of viral progeny
What provides the first line of defense against viral pathogens?
“Barrier”
- skin and mucous membrane
What are two non specific defenses against viruses?
- Type I IFN
-NK cells
What are virus infected cells stimulated to produce ?
IFN alpha and beta following recognition of viral RNA by foll-like receptors
What is the function of IFNs pertaining to viruses?
Inhibit viral replication by inducing transcription of several genes that code for proteins w/ antiviral activity
What do IFN alpha and beta enhance, explain?
Enhance activities of NK cells which binds to virus infected cells and release cytotoxic proteins such as perforin and granzymes
What happens when cytotoxic proteins are released? (Perforin and granzymes)
- Cause cells to die and release virus
- these are now accessible to antibody molecules
What occurs when innate defenses do not work?
Specific humoral and cell-mediated defenses
Are activated
What are virus specific antibodies produced by? What do they do?
- B-cells
- plasma cells
- attack free virus particles in several ways
What plays a key role in preventing viral infection through neutralization? And how?
Antibodies → involves production of antibodies that are specific for a component of the virus that binds to a receptor on host cell membrane
What happens when neutralizing antibodies bind to virus?
They prevent if from attaching to and penetrating the host cell
How does Secretory IgA play an important role in neutralization?
They neutralize viruses in mucosal surfaces in the respiratory and digestive tract. (Usually entry way of pathogens)
What are the Roles of IgM and IgG?
① bind to viruses in the blood stream and inhibit dissemination of infection
② activate complement
-IgG → promote phagocytosis of virus through their ospinozing activity and promote destruction of viruses through antibody - dependent cellular cytotoxity
- lgM →inactivate viral particles by agglutinating them
When can antibodies not attack a virus?
When the virus has already penetrated host
What is required to eliminate intracellular virus?
Cell mediated immunity
What cells play a key role in elimination of intracellular virus?
- Th1 cells
-CTLS (cytotoxic T lymphocytes)
What does Th1 produce and what is the function of this component?
-IFN-g→ induces an anti- viral state in infected cells
-IL -2→ assists in development of effector CTLs
What do CD8 and CTLs do
Programmed to expand in number and attack the virus-infected cells
How does CD8 + CTLS recognize the viral infected host?
- The T cell receptor (TLR) on CTL must bind to a viral antigen complexed with class I MHC on surface of infected cell
-CD8 is a co-receptor here
When molecular interaction stimulate granules in the CTL, what is released and what is its role?
Perforin→ produces pores in the membrane of the infected host cell and granzymes enter the pores
What happens when granzymes enter the pores of an Infected host cell?
Activates apoptosis in the host cell, interrupting the viral replication cycle and resulting in release of assembled infectious virons
What can free virons can be bound by?
Antibodies
Describe the CTL response
-powerful
- involves series of cell divisions that can produce up to 50,000 times the original number of cells in a period of 1 to 3 weeks
What are the 5 ways that viruses can “escape” the host cell defense?
①mutations result in production of new viral
→ influenza viruses undergo frequent genetic changes
②viruses block action of immune response
→ HSV can bind C3b
③ suppression of the immune response
→CMV reduces MHC I expression
④ immune function altered
→ ebb stimulates polyclonal b-cell activation
⑤ latent state is established
→VZV remains latent in nerve cells
When viruses rapidly divide agents undergo genetic mutations, what do these mutations result in?
- Production of new viral antigens which are not recognized by initial immune response to virus
How do CMV and HIV suppress adaptive immune system?
Reducing expression of class I MHC molecules on the surface of virus-infected cells. Making them recognized by CTLs
How does rubeola suppress adaptive immune response?
Cause decreased expression of class II MHC, resulting in reduced Th cell activity
Describe epstein-barr virus (EBV)
- Cause polyclonal activation in B lymphocytes
- inhibit immune responses by producing a protein that can suppress Th1 cells because of its similarity to IL-10
What does HIV suppress?
Function of CD4 Th cells
Describe serological testing of viral infection
-monitors course of infection
- detects past infection
- assessing immune status
Describe molecular testing in viral infection
- Enhanced our ability to detect active infection
- essential in guiding anti viral therapy
What does the presence of virus-specific IgM antibodies in patient serum indicate?
Current or recent Infection
What does the presence of viral-specific IgG antibodies in patient serum indicate?
- Current or past infection
What does virus specific IgM antibody in newborn indicate?
Congenital infection because IgM is actively made during fatal life
What does virus-specific IgG antibodies in newborns indicate?
Nothing, IgG antibodies in infants serum are mainly maternal antibodies that have crossed the placenta
What is the family and type of hepatitis A?
- RNA
-picornaviridae
What is the family and type of hepatitis B?
- DNA
-hepadnaviridae
What is the family and type of hepatitis C?
- RNA
- flaviviridae
What is the family and type of hepatitis D?
- RNA genus
-deltavirus
What is the family and type of hepatitis E?
- RNA
-hepeviridae
How is hepatitis A transmitted?
- Fecal-oral
- direct contact w/ infected individual
-blood transfusion (rare)
How is hepatitis B transmitted?
- Perinatal (mom to baby)
- sexual (semen and vaginal secretion)
- parenteral ( blood contact, IV drugs, tattoo)
- saliva
How is hepatitis C transmitted?
- Parental
- sexually
-perinatal
How is hepatitis D transmitted?
- Most parenteral
- sexually
- perinatal
-HBV infection required
How is hepatitis E transmitted?
- Fecal-oral
-blood transfusion
Which class of hepatitis does not progress to a chronic stage?
Hepatitis A
What are complications of hepatitis A?
-low risk of fulminate
- liver disease
What are complications of hepatitis B?
- 10%-90% develop chronic hepatitis with increased risk for liver cirrhosis and hepatocellular carcinoma
What are complications of hepatitis C?
- 85% develop chronic infection with increased risk of cirrhosis, hepatocellular carcinoma or autoimmune manifestations
What are complications of hepatitis D?
- Increased risk of developing fulminate hepatitis, cirrhosis, or hepatocellular carcinoma
What are complications of hepatitis E?
- Fulminate liver failure in pregnant women
What are the markers for hepatitis A?
-IgM anti-HAV
- total anti-HAV
-HAV RNA
What are markers for hepatitis B?
-HBsAg
-HBeAg
-IgM anti-HBc
-total anti-HBc
- anti-HBe
-anti-HBs
-HBV DNA
What are the markers for hepatitis C?
- Anti-HCV
-HCV RNA
What are the markers for hepatitis D?
-IgM-anti-HDV
-IgG-anti-HDV
-HDV RNA
What are the markers for hepatitis E?
-IgM anti-HEV
-IgG anti-HEV
-HEV RNA
What does the IgM anti-HAV indicate?
- Acute hepatitis A
What does total anti-HAV indicate?
Immunity to hepatitis A
What does theHAV RNA marker indicate?
Detection of HAV in clinical, food, or water samples
What does the HBsAg marker indicate?
_Active hepatitis B infection
What does the HbeAg marker indicate?
Active hepatitis B infection with high degree of infectivity
What does the IgM anti-HBc marker indicate?
Current or recent acute hepatitis B
What does the total anti-HBc marker indicate?
Current or past hepatitis B infection
What does the anti-HBe marker indicate?
Recovery from hepatitis B
What does the anti-HBs marker indicate?
Immunity to hepatitis B
What does the HBV DNA marker indicate?
-acute, atypical, or occult hepatitis B
-viral load made used to monitor effectiveness of therapy
- used to determine HCV genotype.
What does the anti-HCV marker indicate?
-current or past hepatitis C infection
What does the HCV RNA marker indicate?
-current hepatitis C infection
- viral load may be used to monitor effectiveness of therapy
-used to determine HCV genotype
What does the IgM- anti-HDV marker indicate?
Acute or chronic hepatitis D
What does the IgG- anti-HDV marker indicate?
Recovery from hepatitis D or chronic hepatitis D
What does the HDV RNA marker indicate?
Active HDV infection
-viral load may be used to monitor effectiveness of therapy
What does the IgM anti-HEV marker indicate?
Current hepatitis E infection
What does the IgG anti-HEV marker indicate?
Current or past hepatitis E infection
What does the HEV RNA marker indicate?
Current hepatitis E infection
What is the general meaning of hepatitis?
Inflammation of liver
What happens if hepatitis progresses?
Can lead to…
- liver enlargement and tenderness
- jaundice
- dark urine
-light feces
.
What is typical by found in the initial laboratory testing?
- Elevations in bilimban and in liver enzymes
- most notably alanine Aminotransferase (ALT)
Describe genotypes of hepatitis A
-two genotypes
- both can be detected with same serological assays
What is the incubation period for hepatitis A?
- Average of 28 days
Describe symptoms of hepatitis A
- Flu-like symptoms
- children are asymptomatic
-typically resolves itself in 2 months
Describe treatment of hepatitis A
Mainly supportive
- bed rest
- nutritional support
- medication for fever, nausea, and diaherra
- rare → hepatic necrosis and death (mainly in patients with other ailments of liver)
Describe HAV antigens
- Shed in feces of infected individuals during incubation period and early acute stage
- usually decline to low levels shortly after symptoms appear
- not clinically useful indicator of disease
Describe testing of hepatitis A
- Serological testing is critical for diagnosis
- most commonly detected by EIAs and CLIAs
- routinely diagnosed in symptomatic patients by demonstrating IgM-anti-HAV (declines in 6 months)
-total HAV antibodies also detect IgM but predominately IgG and persists for life
What is the primary marker of hepatitis A in acute phase?
IgM anti-HAV but can cause false negatives results during early phase of infection
Describe molecular testing of hepatitis A
-most common format of these methods is reverse-transcriptase polymerase chain reaction RT-PCR
- can also be used to test food or water suspected of transmitting disease
How do you prevent infection in unimmunized that has been exposed to hepatitis A
- Administer prophylactic of hepatitis A vaccine or injections of immune globulin
- must be administered within 2 weeks of exposure
Describe genotypes of hepatitis E
-4 genotypes
- 1 and 2 are primarily associated with consumption of fecal matter in water
→ common in Africa, Asia, the Middle East, and Mexico
→ outbreaks are common after natural disasters
- 3 and 4 are primarily associated with consumption of infected pork
→ Europe, North America, china, Taiwan, and Japan
→ primary hosts are pigs, deer and wild boars or direct contact with infected animal
- have symptoms that make genotypes undistinguishable
Which hepatitis virus is “silent”?
Hepatitis E
What is the incubation period for hepatitis E?
2 to 10 weeks
What is the recovery period for hepatitis E?
4 to k weeks
What are severe consequences of hepatitis E?
_ Neurological syndromes
- renal injury
- pancreatitis
- hematological abnormalities
Describe chronic stage of hepatitis E
-HEV3 can result in chronic infection in immune compromised individuals
- can progress to liver fibrosis, cirrhosis, and liver failure
What measures are taken to prevent infection ot hepatitis E
- Provision of clean drinking water
-improvement of sanitation conditions - avoidance of undercooked meat, especially pork (HEV3)
Describe testing of hepatitis E
- Diagnosis relies on to detect antibodies to the virus and molecular methods to detect HEV nucleiC acid
- identified by sensitive EIAs that use recombinant and synthetic HEV antigens
- rapid immunochromatographic assays have also been developed.
- antibody test can detect all four genotypes
Acute infection of hepatitis E is indicated how?
- Presence of IgM anti-HEV
- remains elevated for 8 weeks
- becomes undetectable at 32 weeks
When do HEV- specific IgG bodies peak?
About 4 weeks after symptoms develop and persist for several years
When is molecular testing for HEV RNA recommended for patients with hepatitis E?
-in immunecompromised person because they often yield a false negative
What is the gold standard for diagnosis of acute HEV infection?
Quantitation of HEV nucleic acid can be performed by qPCR
What testing is used to detect acute hepatitis E in a resource-limited settings?
-loop-mediated isothermal amplification assay (LAMP)
- can be performed on blood or stool samples
- no expensive equipment
When does HEV RNA become undetectable?
-blood → 3 weeks after symptom onset
-stool→ 5 weeks after symptom onset
-therefore, a negative result forHEV RNA does not exclude possibility of recent infection
What is the major cause of morbidity and mortality throughout the world?
Hepatitis B
Where is hepatitis B prevalent?
- Far east
- parts of Middle East
- sub Saharan Africa
- Amazon areas
What measures have been taken to prevent hepatitis B infection?
- Screening for blood donors
-treating plasma-derived products to inactivate hepatitis B - implementing affection infection control measure
- immunizations
Describe the vaccine for hepatitis B
- Consists of recombinant hepatitis B surface antigen (HBsAg) produced from genetically engineered beast or mammalian cells
- can also be administered to those who have been exposed along with hepatitis B immune globulin (HBIG)
What is hepatitis B immune globulin (HBIG )?
-preparation derived from donor plasma with high concentrations of antibodies to HBV that provides temporary protection
What is the incubation period for hepatitis B?
30 to 180 days
Describe symptoms of hepatitis B
-90% of newborns are asymptomatic
-acute hepatitis symptoms observed in 10% in ages 1-5
- 1/3 and adults adolescents
- last several weeks to several months
- 1% develop fulminant liver disease with hepatic necrosis
When do most HBV infected people recover?
6 mouths and develop immunity
Describe chronic infection of hepatitis B
-virus persists in the body for 6 month or more
-occurs in majority of infected Infants
- 1/3 of infected children
- 10% of infected adults
- more likely to develop in people who cere immune compromised and who have HIV
-results in inflammation and damage to liver and makespatient at high risk (for developing cirrhosis or hepatocellular carcinoma
What is the treatment for a chronic infection of hepatitis B?
- Antiviral drugs to reduce liver inflammation and the risk of developing liver complications
-therapies consist of nucleoside analogues that inhibit the polymerase Enzyme needed for viral replication and IFN alpha (which enhances the immure response against the vines)
Describe genotypes for hepatitis B?
_8 genotypes
-A-H are named
- identified by nucleotide sequence differences in their genomes
- can be identified by same serological assays
Describe structure of intact HBV viron
- 42 nm sphere
- has nucleu capsid core surrounded by an outer envelope of lipoprotein
- core contains circular partially stranded DNA
→ a DNA dependent DNA polymeraseenzyme
→ two proteins
→→hepatitis is core antigen
→→hepatitis Be antigen (HBeAg)
Describe the protein Found on the outer envelope of hepatitis B
- Hepatitis B surface antigen (HBsAg)
- produced in excess and is found in noninfectious spherical and tabular particles that lack viral DNA and circulate freely in the blood
How are serological markers used in reference to hepatitis b?
- Differential diagnosis of HIV infection
- monitoring course of infection in patients
- assessing immunity to virus
- screening blood productsfor infectivity
What is the first marker to appear in hepatitis B?
-HBsAg →protein on outer envelope of virus
-active infection
-detectable at 2-10 weeks after exposure
-levels peak at acute stage.
- serum becomes undetectable at 4 to 6 mouth after the onset of symptoms in acute infection
-remains elevated for 6 months or more in chronic infection
When will HBeAg appear in hepatitis B?
- Protein in core of HBV
- Appears shortly after HBsAg
- disappears right before HBsAg
-marker is present during periods of active replication of the virus and indicates a high degree of infectivity.
Why is the hepatitis B core antigen not detectable in serum?
The viral envelope masks it
Once host develops immune response, what marker/ antibody would appear first in hepatitis B
-IgM anti-HBc
- appears 1 to 2 weeks after ,HBsAg during acute infection and persists in high titer for 4 to 6 months, then gradually declines
-useful in detecting infection when HBsAg is undetectable
- used in addition to HBsAg for screening donor blood
Describe IgG antibodies to the core antigen in hepatitis B
-produced before lgM anti-HBc disappears and persists for a lifetime
When does anti-HBs appear in hepatitis B?-
- Appears during recovery period of acute infection
- a few weeks after HBsAg disappears
- antibody persist for years and provide protection
- not produced during chronic infection
Describe serological testing of hepatitis B
- Most commonly detected by EIAs and CLIAs
- typically automated
- excellent specificity and sensitivity
- false positives and false negatives can occur
- positive results should be repeated with same sample and confirmed with assay such as HBsAg neutralization test or molecular test that detects HBV DNA
Describe molecular testing of hepatitis B
- Detect HBV DNA in serum or plasma
- based on target amplification by traditional or qPCR or branched DNA signal amplification
When can HBV DNA be detected in serum?
- 21 days before HBsAg
- can be used to detect early acute infection
Besides detecting early infection, what else is HBV DNA used for?
- Evaluate effectiveness of antiviral therapy in patients w/ chronic hepatitis B
- success til treatment is indicated by a 1-log(v10) reduction in HBV DNA levels by 6 months
What does hepatitis D consist of?
- Circular RNA genome and a single structural protein called hepatitis delta antigen within its core
- surrounded by viral envelope that is of HBV origin and contains the HBsAg
Describe genotypes of hepatitis D
-3 genotypes
-1 is most common (world wide)
- 2 is in Japan and Taiwan
-3 South America
Where is hepatitis D highly prevalent?
Mediterranean Europe, Middle East, amazon basin, central Africa and parts of Asia
What are two ways a hepatitis D infection can occurs
①HDV transmitted simultaneously as a co-infection with HBV
② can be contracted as a superinfection of individuals who are already chronic HIV carriers
What do 70% of people with a superinfection develop ?
_ Develop chronic liver disease with accelerated progression to cirrhosis and liver failure
Describe treatment of a chronic infection of hepatitis D
_ Combination of IFN alpha and antiviral drugs
Describe GENERAL testing for hepatitis D
-testing for HDV should be performed in all patients HBsAg positive
- involves detection of HDV antibodies or HDV RNA
-antibodies detected by immunoassays employing hepatitis D antigen
Describe presence of IgM anti-HDV
-appearance may be delayed
-may persist for only short period of time
- may be missed
- can persist in chronic infection
Describe serological testing in hepatitis D
-used to help distinguish HBV and HDV co-infections from HBV and HDV superinfections.
- co-infection→positive for IgM anti-HBC
- superinfections → positive for IgG anti-HBc
Describe molecular testing for hepatitis D
- Detect HDV RNA (present in all hepatitis D)
→ routinely used to confirm a positive HDV antibody screening
→ serum HDV RNA is performed by sensitive real time PCR (RT-PCR) assays - assays also provide quantitative results that can be used to monitor the response of patients to antiviral therapy
What is the most common blood borne infection in the United States?
Hepatitis C
What is the leading cause of chronic liver infection In the U.S.?
Hepatitis C
What are some characteristics of HCV?
- Enveloped
- single stranded
Describe genotypes of hepatitis C
-7 genotypes
-1-7 names
-numerous subtypes for each
-1 most common
-1-3 predominant in North America, Europe and Japan
- 3-6 south and Southeast Asia
-4,5, and 7 parts of Africa
-important to know what typeto determine most effective treatment
Why is it difficult to design a vaccine for hepatitis C?
-the variability of HCV
- ability to undergo rapid mutations within host
What is the incubation period of hepatitis C?
7 weeks (2 weeks to 6 month range
Describe symptoms of hepatitis C
- Symptoms of acute hepatitis
- 80% asymptomatic which leads to chronic infection
-70% of patients develop chronic infection - 50% of these individuals develop cirrhosis (occurs slowly over 25-30 years )
- increased risk of hepatocellular carcinoma
What may develop when a patient has a chronic infection of hepatitis C
- Cirrhosis
- hepatocellular carcinoma
- glomerulonephritis
-vasculitis - other autoimmune manifestations
- neuropathy
-ophthalmological symptoms - dermatological symptoms
Describe treatment of of hepatitis C
- Clearance may occur or spontaneously
- may require antiviral drugs
- standard treatment involve A combination of pegylated IFN alpha and ribavirin
→this treatment most success in genotype 2 and 3
→ was numerous side effects - direct-acting antiviral drugs (DAAs) and host-targeted agents (HTA) that inhibit specific steps of viral replication cycle
Describe serological testing of hepatitis C
-anti-HCV IgG is most commonly detected by sensitive EIAs or CLIAs that use recombinant and synthetic antigens
- antigens developed from conserved domains of capsid core protein and nonstructural proteins NS3, NS4, and NS5
-rapid immunoblot assay can be used for POCT
- positive results must be confirmed
→ CDC recommends nucleic acid test for HCV RNA confirmation
→→ if NAT is non reactive this suggests past HCV infection or false positive test
When do HCV antibodies become detectable?
8-10 weeks
Can remain positive for a lifetime
What could cause a false positive in hepatitis C testing?
- Cross reactivity in personswith other viral infections or autoimmune disorder
- to distinguish between a true positive and a false positive, HCV antibody testing can be repeated with different assays from initial tests.
Describe molecular testing of qualitative assays for hepatitis C
- Assays for HCV RNA can be qualitative or quantitative
- qualitative distinguish between presence or absence of HCV RNA in a clinical sample
→ used to confirm infection in HCV antibody positive patients
→ detect -infectionin antibody patients
→ screen blood and organ donors
→ detect perinatal infections - qualitative RT-PCR and transcription mediated amplification (TMA) are available
→ become positive within 1-3 weeks after infection
Describe molecular testing of quantitative assays for hepatitis C
- Performed by RT-PCR, qPCR, or bDNA amplification
- used to monitor the amount of HCV RNA or the “viral load” before, during, and after antiviral therapy
→ goal is to achieve a sustained virological response (SVR)
→→ patient test negative continuously for 12 or 24 weeks after therapy
Describe genotyping testing in hepatitis C
-to determine genotype and subset
- performed by PCR amplification and sequencing of the target gene
- reference method because it provides precise information regarding genomic variability of virus in patients during course of disease
Describe structure of herpes virus
- Large complex DNA viruses that are surrounded by a protein capsid, an amorphous tegument, and outer envelope
What are the 8 types of herpes?
①HSV-1
②HSV-2
③VZV
④EBV
⑤CMV
⑥HHV-6
⑦HHV-7
⑧HHV-8
What are some diseases caused de EBV
-mononucleosis (IM)
-lymphoproliferative disorders
- several malignancies
How can EBV be transmitted?
- Mostly through intimate contact with salivary secretion
- blood transfusion
- bone marrow and organ transplants
- sexual contact
- perinatal exposure
Describe EBV infection rate
-in poor sanitation, lower socioeconomic groups → early childhood
- industrialize nation wl higher hygiene standards → adolescents or adults
- 100 % of population has had it by .age 40
What are the steps in an Initial infection of EBV?
‘① occurs.in orophanynx where the virus infects epithelial cells and B lymphocytes
② EBV binds to beta1 interns on surface of epithelial cells, which take up the virus by endocytosis
③ inside epithelial cells, EBV enters a lytic cycle until acute infection is resolved
④ virons spread to adjacent structures, including the salivary glands and tonsils
⑤EBV infects B lymphocytes and spread through lymphoreticular system
⑥EBV enters B cells by binding to surface CD21
⑦ virus infected B cells become polycionally activated, proliferating and secreting antibodies
→EBV - specific antibodies, heterophile antibodies and autoantibodies
What are characteristics of the lytic cycle of EBV
_ Rival replication
- lysis of host cells
- and release of infections viron
What cells keep the initial infection of EBV in check?
- NK cells
- specific CTLs
Describe latent state of EBV
- EBV can persist in the body indefinitely in small percentage of memory bars
-EBV nucleiC acid exists as episomal DNA outside of chromosomes in this case viral replication does not occur
What does periodic reactivation of EBV results in?
- Re-entry of the virus into the lytic cycle, with viral shedding into saliva and genital secretions
Describe antigens that are in the early stages of EBV
- Produced during the initial stages of viral replication
-known as early antigens - these antigens are further classified into two groups
Based on location
→EA-D: has diffuse distribution in nucleus and cytoplasm
→EA-R: restricted to cytoplasm only
Describe antigens in late stage of EBV
_ - Appear during the period of the lytic cycle following viral DNA synthesis
- they include viral capsid antigens (VCAs) in proton capsid and membrane antigens in envelope
What antigens are present in the latent stage of EBV
-EBV nuclear antigens
→EBNA-1 through EBNA-6
-latent membrane proteins
→LMP-1, LMP-2A, LMP-2B
Describe symptoms in EBV
-infants and young children are generally asymptomatic or mild
- primary infection in adults and adolescents commonly results in IM
→ more than half of patients with IM with three classic symptoms:sever, lymphadenopathy and sore throat (last 2 to 4 weeks)
- fatigue, myalgias, and need for sleep persists for months
What are characteristics of laboratory findings in patient with IM?
- Absolute lymphocytosis of greater than 50% of the total leukaustes and atleast 20% atypical lymphocytes
- a typical lymphocytes are predominantly activated cytotoxic T calls that are responding to the viral infection
What is a heterophile antibody
- Antibody capable of reacting with similar antigens from two or more unrelated species
-IM association →IgM antibodies are produced because polyclonal B cell activation and capable of reacting with horse RBC, sheep RBC, and bovine RBC - produced in 40% of patient with IM in the first week
-by 3rd week, 80 to 90% of patients - disappear by 3rd month after onset of symptoms
Describe testing for ,detection of heterophile antibodies
-monospot→rapid slide agglutination method
→ serum premixed with guinea pig ,kidney antigen still capable of agglutinating horse RBC
→ No longer used
- rapid agglutination tests or immunochromeographic assess using purified bovine RBC extract as antigen
What causes false positives testing for IM?
- Lymphoma
- viral hepatitis
-malaria - autoimmune disease
- error in interpretation
What can help to diagnose IM when patients test negative for heterophile antigens?
-testing for EBV specific antibodies
- by indirect immunofluorence assays (IFAs)
- using EBV- infected cans, blot techniques, encyme-linked immune sorbet assay (ELISA) or CLIA using recombinant or synthetic EBV proteins or flow cytometric microbead immunoassays
- all have high sensitivity but IFAhas the higher level of specificity (gold standard of serological methods)
Describe markers found in IM
- Most useful →IgM anti-VCA for acute infection
→ appears at onset and disappears by 3 months
-IgG anti-VCA
→ present at onset of symptoms but persist for life
→ indicates past infection
-EA-D antibodies present in acute infection - positive for anti-EA-D and IgM anti-VCA and absence of anti-EBNA indicates primary acute infection
Describe chronic active EBV infection
- Severe, life threatening symptoms rAssociated with IM
- symptoms persist or recur for 6 or more months
-EBV can integrate its DNA into the genome of cells it infects and transform them into cancer cells - can cause lymphoproliferative disorders in the immunOcompromised
→ results from inability of immunosuppressed patients to control EBV infection, leading to massive polyclonal expansion of EBV infected B cells and illness with high mortality rate
How can EBV malignancy be diagnosed?
- Serological method→ test for EBV antibodies
-molecular method → to detect EBV DNA
Describe molecular testing in EBV
- May be more reliable than serological methods in immunocomprosmised patients
- quantitative PCR is useful in monitoring viral load in transplant patients, high EBV viral load indicates need to decrease immunosuppressive treatment and administer antiviral therapy
How is CMV transmitted?
- Close, prolonged contact with infections body secretions
- solid organ transplant
- perinatal exposure
- isolated in saliva, urine, stool, vaginal and cervical secretions, semen, breast milk, and blood
Describe an acute infection of CMV
- Asymptomatic in healthy individuals
- some people experience IM- like symptoms (fatigue, myalgia and fever)
Describe more severe CMV disease
- Immunocompromised patients
- mostly involves gastrointestinal tract, CNS, and hematological abnormalities
What cells does the CMV virus persist in a latent state?
- Monocytes
- dendritic cells
- myeloid progenitor cells
- peripheral blood leukocytes
- may be reactivated later in life.
What are clinical consequences for immunocompromised patients infected with CMV
- More serious, especially inorgan-transplant recipients and patients with HIV/AIDS
- infections resulting from reactivation of CMV in recipient or transmission from donor
CMV infections of a previously unexposed recipient is associated with what? Explain it.
- With increased risk for allograft failure or graft-versus-host disease (GVHD)
- poses risk for variety of syndromes such as fever and leukemia, hepatitis, pneumonia, GI complications, CNS dysfunction and retinitis
CMV remains a major opportunistic pathogen in what kind of patients
- With low CD4 t-cell counts
What are ways to prevent or treat CMV?
- Serological testingperformed to identify CMV positive donors
-is CMV infection has been established in a transplant patient, immunosuppressive treatment shoudbe reduced to lowest dose possible
-variety of antiviral drugs used to treat CMV infection
What is the most common cause of congenital infections?
CMV
What virus has significantly higher risks in pregnancy?
- CMV
- transmission can occur through placenta, by passage of infected birth canal or by postnatal contact w/ breast milk
CMV Symptoms of infant?
- Platelet dysfunction
- CNS involvement
- 10% of asymptomatic infants develop sensorineural hearing loss
Describe testing for immunocompromised and neonates for CMV
- Assays for direct detection of virus such as viral culture, identification of CMV antigens and molecular tests forCMV DNA are necessary to detect current CMV infection
What type of testing is best for detecting past exposures to CMV
Serological
Describe isolation of virus in culture of CMV
- Isolation of virus in culture is traditional method of direct viral detection
→ human fibroblast cell lines are inoculated w/ CMV- infected specimens, most commonly urine, respiratory secretionsor anti coagulant whole blood
→ presence of virus is indicated by characteristic cytopathic effects (CPEs) that produce enlarged rounded refractile cells
→ limited because CPEs do not appear for a few days to several weeks - centrifugation enhanced method
→ reduced time of detection
→ infected cells grown on coverslips sin shell vial
→ incubated w/ fluorescent-labeled monoclonal antibodies
What are testing methods of direct identification of CMV serological testing?
- Isolation of virus in culture
- CMV antigenemia assay
Describe CMV antigenemia testing
-uses immunocytochemical or immunofluroscent staining to detect CMV protein, pp65, in infected leukocytes from peripheral blood or cerebral spinal fluid
- can be completed in 2-4 hours
Describe molecular testing in CMV
- Detect CMV DNA or mRNA
-RT-PCR most widely used method because sensitive, simple to perform, and can provide quantitative results - identification of CMV/ CMV DNA in amniotic fluid at 20th week is gold standard for confirming fetal infection
- quantitative PCR is used to monitor effectiveness of antiviral treatment in immunocompromised host
How do you detect past and possible future (risks) infections of CMV
- Serological → EIAs
- assay for CMV IgG are most useful at documenting past infection and determine if individual is at higher risk for future infections
- low-avidity IgG antibodies indicate recent infection
- high avidity IgG antibodies past exposure
Why are assays for IgM CMV limited?
-potential for false-negative results in newborn and immunocompromised
- potential for false positives in presence of rheumatoid factor
- cannot indicate primary infection because it persists up to 18 months
What two distinct diseases are caused by VZV
- Chick pox
- shingles (herpes zoster)
How is VZV transmitted?
- Mostly through inhalation of infected respiratory secretions and/or aerosols from skin lesions
Transplacental transmission to fetus can occur
Describe varicella
- Primary infection with VZV
- highly contagious illness characterized by a blister-like rash with severe itching and fever
- majority in childhood.
What are symptoms of varicella
- vesicular lessons appear on face and trunk and spread to other areas
- usually mild and self-limiting in healthy children
- may produce secondary bacterial infection caused by scratching of lesions
- primary infections tend to be more severe
-immunocompromised →extensive slanrash, neurological conditions,pneumonia, hepatitis, and nephritis
Describe primary infection of VZV
-thought to travel from San leasions and blood to sensory neurons where it deposits DNA and lifelong latent state established.
Describe shingles
-Reactivation resulting in eruption of painful vesicular rash
- rash can persist for week to months
→ more severe in immunocompromised, elderly, and pregnant women
- complications → postnerpatic neuralgia (Extremely painful), herpes ophthalmicus ( causes blindness), pneumonia
Describe testing of varicella and herpes zoster
-usually based on identify vesicular lesions
- definitive diagnosis based on identifying VZV or its products in skin lesions, vesicular fluids or tissue
- microscopic detection of Tzanck cells (giant, multi-nucleated) in stained smears allow for rapid identification of virus. No longer used
→ can not distinguish between VZV and HSV
-qPCR for VZV DNA is method of choice!
→ also useful in monitoring response in immunocompromised patient to antiviral drugs
What can PCR be tested on to detect VZV ?
- Vesicular fluid. Scabs, sweat, San swabs, throat swabs, cerospinal fluid, blood, saliva, and tissues from biopsies/autopsies
Why is testing for VZV IgM is not performed routinely?
_ May not be .detectable until convalescent stage
- cannot distinguish between primary and reactivated infection
- They may not be free of IgG antibodies when serum is processed for testing
How is immunity determined for VZV
- Serology most useful
- most detect Total VZV antibody which consists primarily of IgG
- most sensitive and reliable → fluorescent test called fluorescent antibody to membrane antigen (FAMA) that detects antibody to the envelope glycoproteins of the virus
→ requires live virus infected cells and not suitable for large-scale routine testing - most common → ELISA (no vival culture needed)
→ false positive can occur because can detect low levers of centibilly that do not confer long ‘ term protection
How is immunity determined for VZV
- Serology most useful
- most detect Total VZV antibody which consists primarily of IgG
- most sensitive and reliable → fluorescent test called fluorescent antibody to membrane antigen (FAMA) that detects antibody to the envelope glycoproteins of the virus
→ requires live virus infected cells and not suitable for large-scale routine testing - most common → ELISA (no vival culture needed)
→ false positive can occur because can detect low levers of centibilly that do not confer long term protection to variety
What are characteristics of rubella virus?
- Single-stranded enveloped RNA
- genus → rubivirus
- family → togavividae
-replicates in upper respiratory tract and cervical lymph nodes
How is rubella transmitted?
- Respiratory droplets
- transplacental
What virus causes German measles?
- Rubella virus
- mainly in children but can occur in Unvaccinated adults
What is the incubation period for rubella virus?
12 to 23 days
What are symptoms of rubella vines?
-erythematous
-maculopopular rash (resolves in 3 to 5 days)
- low grade fever
- malaise
- swollen glands
-upper respiratory infection
- 50% of infected individuals are asymptomatic
Describe treatment of rubella virus
- Usually resolves itself with no complication
- no specific treatment is available
Describe the effect rubella virus has on pregnant
-Severe consequences including miscarriage, still birth and congenital rubella syndrome (CRS)
- chance of severe consequences Occurring increases when infection occurs during first trimester
- vaccines are availa to children and infants that will prevent future infections in pregnant women
What can occur when an infant is born with CRS?
- May have several abnormalities
- deafness
- eye defects → cataracts and glaucoma
- cardiac abnormalities
- mental retardation
- liver and spleen damage
-motor disability
Describe general testing of rubella virus
- Important in German measles because symptoms mimic other viral infection
- culture of virus
- demonstration of viral RNA
- detection of virus-specific antibodies
- viral nucleic acid can be identified by RT-PCR (MOST COMMON)
-viral proteins can he detected by IFA or EIA
Describe molecular methods in testing for rubella virus
-RT-PCR most widely used
- can be used to detect rubella RNA in variety Of clinical samples.
Describe serological testing of rubella vines
- Most common means of confirming diagnosis
-most common today → ELISA
→ used to detect IgM rubella antibodies.
-used to screen for immunity to rubella (IgG) - low avidity antibodies indicate recent infection
What can simutaneously detect mumps, measles, varicella and rubella
- Automated chemo luminescence assays
-multiplex bead immunoassays
How is primary rubella infection indicated?
- Either by presence of rubella specific lgM antibodies
-Or by a four fold or greater rise in rubella - specific IgG antibody titer - time of collection is
Important because IgM antibodies don’t appear until 5 days after onset of rash and IgG may not be detectable for 8 days
Explain reasonings for false negative and false positive in rubella
False negative → if sample is obtained to early
False positive → IgM antibodies can persist
In low levels for years
False positive → parvovirus infection, enterovirus infection, heterophil antibodies, or rheumatoid factor.
Describe characteristics of rubeola vines
- Single stranded RNA vines
- genus → morbillivirus
- family → paramyxovividae
- highly contagious
How is rubeola virus transmitted?
- Direct contact with aerosolized droplets from respirators secretions of infected individual
What occurs after the initial infection of rubeola virus of epithelial cells of upper respiratory tract?
- Rubeola virus is disseminated through the blood To multiple sites in the body such as the San, lymph nodes and liver
What disease does the rubeola virus cause?
Measles
What is the incubation period for rubeola virus?
10 - 12 days
What are symptoms of the rubeola virus?
During prodromal period
- Fever
- cough
- coryza (runny nose)
- conjunctivitis
After prodromal period
-Koplik spots appear on inner cheek or lips
→ white gray lesions against red background
→ rash after 14 days
-erythematous
- maculopapular eruption beginning on hairline
What complications can result from rubeola?
- Diarrhea
- otitis media
- croup
-bronchitis - pneumonia
-encephalitis - subacute sclerosing panencephalitis (SSPE)
How does rubeola affect pregnancy?
- Higher riskof premature labor
- spontaneous abortion
- low birth weight
Describe serological testing fo rubeola
-most practical and reliable in confirming diagnosis
- indicated by presences of rubeola-specific IgM antibodies or four-fold rise in rubeola specific IgG antibodies
-IgM capture ELISA method
-ELISA also use for detection of IgG antibodies
→ appear a few weeks after IgM appearance
→persist for life
→ indicates immunity to measles
What is associated with extremely high titer of rubeola antibodies?
SSPE
What could cause a false-negative result for rubeola î
Samples collected before 72 hours
Describe molecular methods used for rubeola?
- Detect rubeola RNA
- used in situation when serological testing is inconclusive
- also used to genotype
-RT-PCR
What are characteristics of the mumps virus?
- single stranded RNA virus
- genus → rubulavirus
-family→ paramyxovividae
Explain transmission of mumps
- respiratory droplets, saliva, and fomites and replicates in nasophangux and lymph nodes
What are formites?
Inanimate object/substances that can transmit infectious organisms
What is the incesation period of the mumps i
14 - 18 days
Where does the mumps virus spread?
-from blood to:
→ meninges of brain
→salivary glands
→ pancreas
→ testes
→ ovaries
What are symptoms of the mumps?
-inflammations of parotid gland
What is treatment for mumps.
- Only medications that alleviate symptoms
- resolves its self in 7-10 days
Describe diagnosis of mumps
- If parotitis is present, No laboratory testing required for diagnosis
Describe molecular methods of testing for mumps
RT-PCR is recommended for confirmationn
Describe serological testing for mumps
- Simple means of confirming diagnosis
- limitations
→EIAs and IFAs→ only measure IgG mumps virus antibodies - ELISA most commonly used
→ solid-phase IgM capture assays
What are characteristics of HTLV-1 and HTLV-2?
- Both have 3 structural genes
-infect T cells - viruses have RNA as their nucleic acid and reverse
Transcriptase
What do HTLVs infect?
-the prefer to infect CD4+ T lymphocytes
-CD8+ T cells
- dendritic cells
- macrophagesr
What are the 3 structural genes in HTLVs?
- Gag → which code for viral core proteins
-pol→ codes for rival enzymes - env→ encodes proteins in the viral envelope
Where is the px region found and what does it do?
-HTLVs
- encodes several regulatory proteins,Tax and Rex
What is the function of CTLs r
- Effectively, control proliferation or virus-infected cells
What does a HTLV-1 infection of CD4+ T cells do?
- Can increase production of inflammatory Cytokines
- impair production of Th1 cytokines necessary for cell-mediated immunity
-induce differentiation of T regulatory cells
How do Treg cells in HTLVs facilitate viral persistence?
Suppressing host’s immune response to the virus
How are HTLVs transmitted?
- Blood borne → transfusing or IV drugs
- sexual contact
- mother to child→ breast feeding
Where are HTLVs prevalent?
-HTLV-1 → Japan, Caribbean, south and Central Africa, Middle East, Romania, South America and papua new guinea.
-HTLV-2→ native Indian populations in Americas, a few Pygmy tribes in central Africa and IV abusers in North America and Europe
What disease does HTLV-1 cause?
- Adult t-cell leukemia/ lymphoma (ATLL)
→ acute, t-cell non-Hodgkin lymphoma, chronic, and, smoldering
→ characterized by monoclonal proliferation of mature T cells that express the surface markers CD3,CD4, and CD25 - HTLV- associated myelopathy/tropical spastic para paraparesis ‘(HAM/TSP)
What are the symptoms of HAM/TSP?
- Leg stiffness
- back pain
-urinary incontinence - inflammation of joints, muscle
Symptoms for HTLV-2
Most people are asymptomatic
Describe serological testing for the HTLVs
-tests used to detect HTLVs antibodies
-EIA, CLIA, and IFA
-particle agglutination test for confirmation
→ western blot assays most commonly used
Describe serological testing
- IgM (+)→ current or recent infection
-IgG(+) → past infection
Describe molecular testing
- Detect active infection
-Quantitative tests - guide antiviral therapy
What is the cause for inflammation of the liver in hepatitis?
- Radiation
- chemical toxins
- cirrhosis
- drugs
- hypothermia
- bacteria
- fungi
-parasites
Describe hepatitis A vaccine
Formalin- inactivated HAV
Describe “core window”
Period when neither hepatitis B surface antigen nor HBeAg can be detected in the serum of patient, only the anti-HBc.
Describe rubeola diagnosis
- Based on clinical presentation of confirmed by serology testing.
Where is toxoplasmosis vims found?
-feces of house cats and rodents
How is toxoplasmosis transmitted
- ingestion of oocytes (fecal contaminated of meat, raw milk
- transplacental
How to prevent toxoplasmosis?
- Avoid touching mucous membranes of mouth and eyes while handling raw meat
- wash hands after touching raw meat
- keep flies and cockroaches away from soul
- avoid direct contact when handing cat item box
What are symptoms of toxoplasmosis
- Usually asymptomatic
-if have symptoms, similar to mono
Describe treatments for toxoplasmosis
- None, spontaneous recovery
Describe congenital infection of toxoplasmosis
-most concern
-result in CNS malfunction and mortality of neonate
-75% have no symptoms at birth, disease is dormat,
And only discovered when neurological problems arise (blindness)
Describe testing for toxoplasmosis
- EIA
Describe torch testing
- Consist of antibodies to four organisms that cause congenital infectious transmitted from mother to fetus
→toxoplasmosis gondii - rubella
-CMV
-HSV
-o is for others → syphilis, hepatiTIS B, coxsackle virus,EBV,VZV, human parvoVIrus
Adenovirus is…
Respirating
Arbovirus is…
From SKin-mosquitos, ticks
Rotovirus is..
Garstointestinal (fecal oral route)
Describe HIV-1
- Cause of most HIV infections worldwide
- four groups: M, O, N, P
- nine subtypes in group M→A-K
How can HIV be transmitted?
- Sexual contact → most common
-blood - perinatal
What are characteristics of HIV ?
-retro virus
- contains a copies of ssRNA
-reverse transcriptase transcribes the viral RNA into DNA
- surrounded my a protein coat (capsid)
- outer envelope of glycoproteins embedded in a lipid
What is the marker for docking glycoprotein?
gp120
What is the marker for transmembrane glycoprotein?
gp41
What is the marker for matrix protein?
P 17
What is the marker for the capsid
p24
What is the protein product of the gag gene?
-p17
-p24
-p9
-p6
What are the protein product for the env gene?
-gp120
-gp41
What are the protein products of pol?
-p66
-p51
-p31
-p10
What is the protein product for tat gene?
p14
What is the protein product of the rev gene?
p19
What is the protein product of nef gene?
p27
What is protein product of the vpr gene?
p15
What is the protein product of the vif gene?
p23
W what is the main target for replication of HIV?
CD4 Th
Describe steps of replication of HIV
① attachment of HIV to host cell to CD4 Th
② coreceptor(chemokines) required → promote fusion of HIV envelope with plasma cell membrane
③ reverse transcriptase converts viral RNA into complementary DNA (cDNA)
④cDNA is integrated into the host genome as a provirus
⑤ viral DNA is transcribed into viral RNA and proteins
⑥viral particles are assembled
⑦intact virons bud out of host cell membrane
What other cells can HIV infect?
- Langerhan cells
- monocytes
- macrophages
- microglial brain cells
Describe strains of HIV viruses
-infect t-cells→ t-tropic or x4
- infect t-cells and macrophages → m-tropic or R5
What is importance of CXCR4 chemokines receptor in HIV replication?
Required for HIV to enter T lymphocytes
W what is the importance of the CCR5 chemokines receptors of HIV replication?
Required for entry of HIV into macrophages
What are innate defenses for HIV
- Nk cells mediate cytolysis of HIV infected cells
- dendretic cElls stimulate release of cytolanos that have antiviral effects
L how can the initial viral replication of HIV in laboratory?
- Presence of increased levels of p24 antigen and viral RNA in hosts’ bloodstream
Describe the humoral antibody production immune response for HIV
- Antibodies are detected by 6 weeks after infection
- antibodies produced later may prevent HIV from infecting host cells and participate in ADCC
Describe cell-mediated immunity immune response of HIV
- T-cells produce cytokines with antiviral activity
-CTLs destroy HIV - infected host cells
What are symptoms of HIV
- Decline in immune system
Describe early stage of HIV….
- Rapid burst of viral replication before the development of hiv-specific immune response
- begins to disseminate to the lymphoid organs
–flu-like symptoms or IM- like symptoms - some develop neurological problems
- many are asymptomatic
) Describe latency stage of HIV
- Decrease in viremia as vines is cleared through circulation
-symptoms are subtle or absent
-CD4 will remain stable and then sudden rapid of decline
Describe final stage of HIV
- AIDS
- immunosuppression and low CD4 T cell count
-resurgence of viremia - life threatening infections and malignancies
- median of 10 years to have full blown AIDS
What are symptoms in infants that have HIV
- Failure to thrive
- persistent oral candidiasis
- hepatosplenomegaly
-lymphadenopathy - recurrent diaherra
- recurrent bacterial infections
HIV positive patients are broken down into what 5 categories
-0 → early HIV infection, positive lab result followed by negative HIV results within 6 months
-1-3 → based on peripheral blood CD4 t cell count
- unknown → information missing
Describe treatment of HIV
- ART→ antiretroviral therapy
-drugs that block various steps of HIV replication cycle
-nucleoside analog reverse transcriptase inhibitors - monnucloside relese reverse transcriptase inhibitors
- protease inhibitors
- integrate inhibitor
- fusion inhibits
-CCR5 antagonists - post attachment inhibitor
Describe prevention of HIV
- Screening blood/organ donors
- educating general public
- precautions for health care workers
- Describe laboratory testing for HIV
-Screening and diagnosis
→ previous/current algorithms and test methods
- monitoring for disease
→CD4 T cell count
→HIV viral load
→ drug resistance testing
- testing infant.
Desire previous CDC testing alogrithms
’ -screen for HIV-1 and HIV-2 antibodies. By ELISA or rapid EIA
- confin by repeating ELISA, follow by western blot
How to interpret western blot testin
- No bands-negative
- must have antibody against of the three bands
→ p24
→ gp41
→ gp120/160
Describe current CDC algorithms for testing
- HIV-1/2 antigen/antibody combination immunoassay →POSITIVE
→ HIV - 1/2 antibody differentiation immunoassay
→ indeterminate results →HIV-1 NAT
Steps of HIV - 1/2 antibody/ palantigen combination immunoassay
-Incubate patient serum with solid phase with hiv-1/2 antigens and p24 have been bound
-hiv-1/2 antibodies will bind to n antigens
-hik-p24 antigen will bind to anti-p24 on solid phase
- wash and add conjugatewith labeled anti-p24 and labeled hiv 1/2 antigens
- incubate, wash, and add trigger solution
- confirm wi rapid EIA
Beside western blot test
- Also known as immunoblotting
- uses antibodies to identify specific protein
- performed after gel electrophoresis has separated
Protein - separated proteins transferred onto nitrocellular or nylon membranes
What are talk positives of the wester blot
- serum collected to early
- contaminant of cells used in culture
DescribeCD4 T- cell enumeration
- Best indicator of immune function of HIV-infected people
- incubate peripheral blood with fluorescent- labeled anti-CD4, analyze results by flow cytometry
- it untreated, CD4/CD8 ratio is less than 1:1
-CD4 t-cell countof less than 200 microliters indicated AIDS
Describe quantitative viral road assays
- Measure amount of HIV RNA circulating in patient plasma
qPCR
-bDNA - detectable 11 days after interchange
- therapy with ART
What are 3 resistance testing for HIV ?
- Genotype resistance assays
- phenotype resistance assays
-tropism testing
Describe genotyping resistance assay
- HIV reverse transcriptase and protease genes from RNA are amplified by RT-PCR
- results reported as
→ resistance
→ possible resistanCE
→ no evidence of resistance
Describe phenotype resistance assay
- Determine HIV ability to grow in presence of antiretroviral drugs
-performed by specialized labs
Describe tropism testing
,- genotype or phenotypic assays performed to determine it patient has virus that will bind to CCR5 co-receptor and be responsive to CCR5 antagonist
Describe testing got children and pregnant women for HIV
- All pregnant women tested
-maternal antibodies in infant serum can complicate serological test results - molecular methods are for diagnosis
- qualifizatie HIV -I DNA OCR using infant peripheral blood mononuclear calls
- screolgica testing at 12-18 monTHS of age may be used to confirm diagnosis
Describe HIV escape of immune response
- Genetic mutation rapid, generating new viral mutants
- down regulate expression of MHC-1 molecules on infected cows
-can survive as latent provirus for prolonged period
-CD4 trolls are destroyed
