Herpes Virus

HSV-1, HSV-2,   

Clinical Features:

HS Encephalitis (>90 % due to HSV -1, 10% due to HSV-2)Majority infection due to reactivation 

If left untreated, infection spreads to both the temporal lobe, causing hemorrhagic necrosis, and death (case-fatality-rate: 15-30%)

Dx: CSF PCR (95% sensitive, 100% specific) (no role of CSF viral culture or serological assays); PCR remains positive for unto 7 days after initiation of treatment ; False negative can occur early on in the disease process 

A Novel Potential Therapy for HSV Editorial NEJM 2014

           

Varicella-zoster virus, 

CMV

Pathogenesis: Like other herpesviruses, CMV demonstrates icosahedral symmetry, replicates in the cell nucleus, and can cause either a lytic and productive or a latent infection. 
Once infected, an individual generally carries CMV for life. The infection usually remains silent. CMV reactivation syndromes develop more frequently, however, when T lymphocyte–mediated immunity is compromised—for example, after organ transplantation, with lymphoid neoplasms and certain acquired immunodeficiencies (in particular, HIV infection), or during critical illness in intensive care units

Characteristics: CMV can be distinguished from other herpesviruses by certain biologic properties, such as host range and type of cytopathology.

Manifestations:

• Congenital CMV
• Perinatal CMV
• CMV Mononucleosis Syndrome
• CMV infection in immunocompromised individuals
•     Fetus
•     Organ Transplant Recipient
•     Hematopoetic Transplant Recipient
•     Person with AIDS

Diagnosis CDC

    Active Infection:  PCR or viral culture of CMV from urine, saliva, throat swab specimens or other body tissues CDC    CMV IgM is not solely indicative of primary infection. CMV IgM is detectable when a person 

• 1) is newly infected, 
• 2) has been infected in the past but recently re-exposed to CMV,
• 3) is undergoing reactivation of CMV infection that was acquired in the past, or 
• 4) has a false-positive test result. 

    
Prevention 
Treatment
References: 
Cytomegalovirus (CMV) and Congenital CMV Infection CDC

EBV

Has Tropism to B Lymphocytes and such cells remain immortalized
Usually EBV goes into latent stage as soon as they enter the cells 
Viral Antigen (3 classes based on phase of virus life cycle when they are expressed)

1. Latent Phase Antigen: EBNA (EB Nuclear Antigen 1, 2 3A -3C, LP) and LMPs (Latent Membrane Proteins) i.e Latent phase where antigen is embedded in nucleus.. hence, Nuclear Antigen
2. Onset of Productive Viral Replication: Early Antigen. i.e early stage hence Early Antigen
3. Productive Viral Replication: Late Antigen (structural component of viral capsid i.e Viral capsid Antigen and envelop i.e glycoproteins) i.e. viral full blown replication .. hence capsid is present ... hence, VCA

Common Lab Repots of EBV tests include the following tests: Here is an example of past infection: 

Latent Phase: EBV Ab Nuclear Ag,IgG(IV) > 600.0 H U/mL (0.0-21.9)

Onset of Viral Replication: EBV Ab Early [D] Ag,IgG(IV) <5.0 U/mL (0.0-10.9)

Productive Viral Replication: EBV Ab VCA, IgG(IV) >750.0 H U/mL (0.0-21.9)

EBV Ab VCA, IgM(IV) 13.6 U/mL (0.0-43.9)

Herpesviruses 6 and 7, and 

Herpesvirus 8 (Kaposi sarcoma-associated herpesvirus i.e KSHV)

HPV

Parvo (simplest DNA virus that requires host or other viruses for replication)

Parvovirus B 19 (has tropism to RBC progenitor cells)
Pathogenesis of Human Infections: Pathogenesis of diseases caused by B19 parvovirus (ebook)

Fifth Disease
TAC (Transient Aplastic Crisis)
PRCA (Pure Red Blood Cell Aplasia)
Hydrops Fetalis

Lab tests: 

Antigen detection:
Antibody detection:
Virus Detection: 

PCR (most sensitive tests)
Probe hybridization of fixed tissues
In site hybridization of fixed tissues

Pox (2 sub-families; Overall Human Infections is Rare)    

Causing Infection in Insects

Causing Infection in Humans (4 Genres; Most human infections caused by first two genres viruses)

Orthopoxvirus: Variola (small pox) 

Parapoxvirus; 

Yatapoxvirus and

Molluscipoxvirus (Molluscum contagious; skin nodules, mostly benign)

MMR 
    Measles : Viral Exanthem 
        DDx: Rubeallo (Sixth Disease); Chicken Pox, Small Pox.             
Paramyxovirus and Rubella Virus
Picarnovirus (Enterovirus and Rhinovirus groups)
Parechovirus
Reovirus

Adenoviruses
Hepatitis Viruses
Reoviruses, Rotaviruses, and Caliciviruses
Arthropod-Borne and Rodent-Borne Viral Diseases
Orthomyxoviruses (Influenza Viruses)
Coronaviruses
Rabies, Slow Virus Infections, and Prion Diseases
Human Cancer Viruses