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08 - Pathology: Diagnosis of Viral Diseases

Terms

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Viruses are measured according to this unit
nanometers
2 virus stages
1. Virion = dormant, transmissible

2. Infectious = active, intracellular stage
Definitive diagnostic test for Rabies
Brain biopsy and isolation of infectious virus
Explain Standard Culture of Virus
Mammalian Cells are in tubes. The specimen is inoculated onto cell layers. It is examined daily for CPE. May take WEEKS to detect any viral growth
Explain Rapid Culture of Virus
Mammalian cells are on a coverslip in a small vial. Specimen is added to cells and CENTRIFUGED. Cell layers are fixed after 24-48 hours and stained with IMMUNOFLUORESCENCE for specific viral proteins
Term used to describe virus-induced cellular changes that are visible by light microscopy
Cytopathic Effect
Adenovirus:
-cells infected have an affinity for __1__.
-infected cells become __2__ and the cell sheet __3__.
-__4__ inclusions within the __5__

1. haemotoxylin
2. rounded
3. disintegrates
4. Basophilic
5. Nucleus
Many enveloped viruses possess a ______ protein in their envelopes
fusion
2 functions of Fusion proteins
1. fusion of virion to the host cell membrane allowing entry of viral genome into cytoplasm

2. Multi-nucleate cells = Syncytia
Measles diagnostic features
1. very large Syncytia
2. Eosinophilic inclusions in nuclei
RSV diagnostic features
1. Large Syncytia
2. pale Eosinophilic Inclusions in CYTOPLASM
Mumps diagnostic features
1. Large Syncytia
2. Pale EOSINOPHILIC inclusion in CYTOPLASM
3. Hemagglutinin --> causes haemadsorption when RBC's are added to infected cells
What differentiates between RSV and Mumps
With Mumps, infected cells will agglutinate RBC's due to presence of Hemagglutinin in PM
All Herpesviruses replicate in the _______
nucleus
Herpesvirus inclusion characteristics
Eosinophilic IntraNUCLEAR inclusions
This typifies infection with HSV-1
prominent foci, or plaques, of rounded cells
Other manifestations of Herpesvirus infection
Giant cells = MNGC's
CMV:
-replicates only in __1__ cells.
-growth-rate: __2__
-Foci size: __3__
-Inclusion characteristics: 4
1. fibroblasts
2. slow
3. small and discrete
4. Eosinophilic "owl-eye" in nuclei
Looking at Pathology of viruses necessitates?
getting a tissue sample from the patient
Tests that can detect viruses that are in the Latent stage
PCR

Antibody
Tests that can detect specific viral proteins in specimens
Enzyme Immunoassays

Immunofluorescence
Example of Antigen that can be detected in the serum
HBsAg
Detection of most VIRAL ANTIGENS requires collecting a sufficient number of.....
infected cells from the patient
Detection of Viral Nucleic Acid allows you to detect presence of viruses before...
host Ab response can be detected
Virus that is commonly detected by it Viral Nucleic Acid
HIV
Detection of viral nucleic acid allows you to _____ the amount of viral replication associated with disease
Quantitate
3 methods of virus-specific antibody
1. Immunofluorescence
2. Enzyme Immunoassays
3. Western Blot
Detection of this virus specific Ab tells you the patient may be immune
IgG
Are Rhinoviruses and Coronavirus usually associated with Pneumonia?
NO
Complications of Rhino/Corona
Sinusitis

Otitis Media
Pathology of SARS is diffuse __1__ damage with __2__ and __3__
1. alveolar
2. edema
3. hyaline membranes
Clinical Features of Influenza
Rapid onset of HIGH FEVER, CHILLS, myalgia, BAD Headache

progresses to DRY COUGH
Pathology of Influenza (3)
-Necrosis
-Desquamation of Ciliated Epithelium
-Inflammation
Secondary Bacteria causing Pneumonia from Influenza
H. influenza
S. pneumonia
S. aureus
Composition of the Influenza vaccine
A - H1N1
A - H3N2
B from hong kong
# of Parainfluenza types
4
Parainfluenza causes _____
Croup
Parainfluenza causes __1__ with a __2__ in children
1. Acute Pneumonitis
2. barking cough

*no vaccine
RSV most commonly happens during this time of year
Winter months
RSV:
-causes __1__ infections in adults
-causes __2__ in children
1. mild
2. ACUTE LOWER RESPIRATORY DISEASE
Diagnosis of RSV (2)
1. cultured
2. direct detection of Ag by Enzyme Immunoassay or IF
Pathognomic for RSV
MNGC's with Mononuclear cell infiltration
Types of Adenovirus infections (4)
1. Respiratory
2. Eye
3. GI
4. UTI's
Adenovirus can cause a rapidly fatal _________ in Immunocompromised hosts
Hemorrhagic Pneumonia
Is there an Adenovirus vaccine?
Yes, available to certain pops
Pathology of Adenovirus (3)
1. Necrosis
2. HEMORRHAGE
3. Inflammation
Histology characteristic of Adenovirus
Smudge cells
Hantavirus clinical features
Abrupt Fever, Cough, Headache, Myalgia

Followed by RAPIDLY developing RESPIRATORY FAILURE
Are there vaccines or antiviral drugs for Hantavirus?
Nope
Diagnosis of Hantavirus
CLINICAL - all others take too long and patient may be dead by that time
Pathology of Hantavirus
1. Interstitial Pneumonitis
2. Congestion
3. Edema
4. Mononuclear infiltration
Histologic cell of Hantavirus
Immunoblast = large activated cells with a high nuclear:cytoplasmic ratio

What virus
Adenovirus
-infected cell becomes rounded
-cell sheet disintegrates
-dark basophilic inclusions withing the nuclei

What virus?
Measles
-syncytia
-eosinophilic influsions in nuclei

What virus?
RSV
-large sycytia
-nuclei do not contain inclusions
-pale eosinophilic inclusions in cytoplasm

What virus
Mumps
-syncytia
-RBC hemagglutination

WHat virus
CMV = "owl eyes"

What virus?
SARS
-diffuse alveolar damage
-edema
-hyaline membranes

What virus
SARS = virus in cytoplasm of pneumocytes

What virus?
Adenovirus

What virus?
Hantavirus
-Immunoblasts = large activated cells with prominent nucleoli and high N:C ratio

Deck Info

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