Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

M2 | Microbiolgy > Bacterial & Viral Lymphadenitis > Flashcards

Bacterial & Viral Lymphadenitis Flashcards

1
Q

Important properties of Epstein–Barr Virus (EBV)

A
  • Structurally similar to herpesviruses but antigenically different
  • Antigens :
    1. Viral Capsid Antigen (VCA): most important (diagnosis )

2- Early antigens (EA): produced before viral DNA synthesis (diagnosis)

3- Epstein-Barr nuclear antigen (EBNA): located in nucleus bound to chromosomes (diagnosis).

4- Lymphocyte-determined Membrane Antigen

5- Viral Membrane Antigen :
Neutralizing activity is directed against it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is EBV is transmitted ?

A
  1. Exchange of saliva (e.g., during kissing)

2. Blood transmission (very rare)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How are the Nonspecific heterophil antibodies are found ?

A
  • Heterophil antibodies: are detected by tests using antigens different from antigens that induced them.
  • They agglutinate sheep or horse red blood cells in laboratory
  • Heterophil antibodies disappear within 6 months after recovery.
  • They are not specific for EBV (seen in hepatitis B & serum sickness.)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

EBV infection modifies cell membrane constituent such that it becomes______ & induces______

A

Antigenic - heterophil antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where does EBV infection occur & infects which cells ?

A

Infection occurs in epithelial cells of oropharynx infects lymphoid cells (B lymphocytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How EBV remain latent ?

A

EBV remains latent within B lymphocytes (EBV DNA is in nucleus not integrated into cellular DNA)

  • Cytotoxic T lymphocytes react against infected B cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

IgM to VCA pathogenesis ?

A

IgM to VCA: first immune response ——> diagnosing acute infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

IgG to VCA pathogenesis?

A

IgG to VCA: persists for life ——-> past infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the life immunity in EBV

A

Lifetime immunity against infectious mononucleosis is due to antibody to viral membrane antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Clinical findings of EBV

A
  1. Infectious mononucleosis is characterized by
    * fever
    * sore throat
    * lymphadenopathy & splenomegaly
  2. Hepatitis is frequent
  3. Encephalitis occurs in some patients
  4. X- linked lymphoproliferative syndrome:
    * inherited immunodeficiency in children
    * severe, fatal, progressive form of infectious mononucleosis
  5. hairy leukoplakia
    * whitish, nonmalignant lesion with an irregular “hairy” surface on the lateral side of the tongue
    * in immunocompromised individuals
    * e.g. AIDS patients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which diseases are associated with EBV ?

A
  1. Several cancers
    * Burkitt’s lymphoma, Hodgkin’s lymphoma and nasopharyngeal carcinoma) is associated with EBV infection
  2. Post-transplant lymphoproliferative disorder (e.g. B-cell lymphoma) is EBV-associated disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

State the Diagnostic tests for EBV

A
  1. Hematologic approach:
  2. Immunologic approach; two types of serologic tests
  3. Isolation EBV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the Hematologic approach?

A
  • Absolute lymphocytosis with 30% abnormal lymphocytes
  • Atypical lymphs are enlarged, have expanded nucleus & abundant, often vacuolated cytoplasm
  • They are cytotoxic T cells reacting against the EBV-infected B cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Mention the types of serologic tests in EBV

A
  1. Heterophil antibody test:
  • Useful for early diagnosis of infectious mononucleosis because it is positive by week 2 of illness
  • Antibody titer declines after recovery not useful for detection of past infection
  1. EBV-specific antibody tests (difficult cases )
    - IgM VCA antibody detect ——> early illness
    - IgG VCA antibody detect —-> past infection
    - Antibodies to EA & EBNA can be useful diagnostically
    - Monospot test is used to detect heterophil antibody (more sensitive & specific & less expensive)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

IgM VCA Ab detect ?

A

detect early illness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

IgG VCA Ab detect ?

A

detect past infection

17
Q

Which test is more specific and inexpensive?

A

Monospot test

18
Q

Important properties of dengue virus

A
  • Single stranded RNA positive-strand virus

* have 4 serotypes

19
Q

Which organism/s transmit dengue virus ?

A

A. aegypti mosquito bite

  • jungle cycle : monkeys as reservoir & Aedes species as vectors
20
Q

Who is the reservoir in dengue fever ?

21
Q

Clinical findings of classic dengue / breakbone fever

A
  • Sudden influenza like syndrome: fever, malaise, cough & headache
  • Severe pains in muscles joints (breakbone)
  • Enlarged lymph nodes & maculopapular rash & leukopenia
22
Q

Clinical features of Dengue Hemorrhagic Fever (severe)

A
  • Initial picture is same as classic dengue, hemorrhage, into gastrointestinal tract & skin
  • Hemorrhagic shock syndrome
23
Q

Why hemorrhagic shock syndrome takes place ?

A

is due to production of of cross reacting antibody in second dengue infection

24
Q

How patients recover from dengue hemorrhagic fever ?

A

recovers by one of four serotypes & antibody against that serotype is produced

25
What happens when patients get infected again with another serotype ( 2ndry ) ?
occurs & large amounts of cross - reacting antibody to first serotype are produced * anamnestic * heterotypic response
26
What are the 2 hypothesis abt Dengue Hemorrhagic Fever?
1. Immune complexes : of virus & antibodies formed —-> activate complement ——-> increased vascular permeability & thrombocytopenia 2 . Antibodies increase entry of virus into monocytes & macrophages, with consequent liberation of large amount of cytokines * In either scenario, shock & hemorrhage result
27
Laboratory diagnosis of dengue virus
1 Cell culture: Isolation of virus 2. Serologic tests: - IgM antibody in acute sera - Fourfold or greater rise in antibody titer in convalescent sera. 3. Polymerase chain reaction (PCR) assay: detects virus in blood
28
Important features of Bartonella henselae
* Small, pleomorphic gram-negative rod | * Fastidious organism & will not grow on routine blood agar
29
How B. henselae is transmitted?
1. Cat scratches or bites (main mode; oral flora of cats) 2. Bite of cat fleas or exposure to cat urine or feces 3. Person-to-person transmission (not significant)
30
Cat scratch disease symptoms?
fever & tender, enlarged lymph nodes on same side as scratch
31
Clinical findings in immunocompromised (AIDS) individuals ?
1. Bacillary angiomatosis (raised, cherry-red vascular lesions in skin & visceral organs) 2. Bacillary peliosis (peliosis hepatis) is similar to bacillary angiomatosis but lesions occur primarily in liver & spleen
32
How to diagnose the cat scratch disease ?
* Antibodies detected in patient’s serum * Culture on artificial media * 5 days or longer to grow * But its not usually dine
33
Diagnosis of B.henselae
Pleomorphic rods in biopsy tissue using Warthin-Starry silver stain
34
Important properties of Francisella tularensis
Small, pleomorphic gram-negative rod
35
Mode of Transmission in Francisella tularensis
* Reservoir : wild animals (rabbits, deer & rodents ) * Humans are accidental “dead-end” hosts who acquire infection by bitten by ticks (Dermacentor) or by skin contact with animal * Rarely, organism is ingested in infected meat, causing gastrointestinal tularemia or inhaled causing pneumonia
36
Pathogenesis of F.tularensis
* It enters through skin, forming ulcer. * It localizes to cells of reticuloendothelial system ——-> granulomas * Caseation necrosis & abscesses. * Symptoms are caused primarily by endotoxin
37
Clinical finding of F.tularensis
1. Presentation vary from sudden onset of influenza like syndrome to prolonged onset of low-grade fever & adenopathy 2. “Ulceroglandular” type: site of entry ulcerates & regional lymph nodes are swollen & painful 3. Less frequent forms of tularemia: * glandular ( lymph node enlargement) * oculoglandular * typhoidal * gastrointestinal * pulmonary 4.Life long immunity
38
How culture for F.tularensis is made ?
* Rarely done (high risk to laboratory workers of infection by inhalation) * Cysteine- containing medium is used
39
What other diagnosis methods for F.tularensis ?
1. Agglutination test: serum samples in acute & convalescent phase 2. Fluorescent-antibody staining of infected tissue

M2 | Microbiolgy (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions