Herpes virus:
Get to know Herpes virus, its classification, types, usual sites of infection, sites of latency, the diseases caused by herpes virus and their routes of transmission. Also do you know what is herpes B virus?
Herpes virus is a double stranded DNA enveloped virus.
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Structure of Herpes Virus |
Properties of herpes virus:
- Virion: Spherical
- Genome: Double stranded linear DNA
- Capsid: Icosahedral
- Replication: Occurs within the nucleus and form intranuclear inclusions.
- Envelop: The only virus that develops envelop (lipoprotein envelop) from the nuclear membrane by budding.
- Enzyme: No viral polymerase enzyme. Uses host cell RNA polymerase.
- Serotype: Single.
- Size: large, 120-200 nm diameter. Second in size to poxvirus.
- Latent infection: Noted for their ability to cause latent infection. In such cases, the acute infection is followed by a period of asymptomatic period during which the virus is in acquiescent (latent) stage. When the patient is exposed to an inciting agent or immunosuppression occurs then reactivation of virus replication and disease can occur. ( Acute disease > asymptomatic period > latent state)
- Sensitivity: Ether sensitive.
- Giant cell: All produce giant cells.
Classification and disease of herpes:
There are 8 types of herpes virus and they belong to 3 subgroups according to the type of cell they mainly infect and their site of latency:
The diseases and routes of transmission of Herpes Virus:
Sub group
|
Type
|
Usual site of
infection
|
Site of latency
|
α subgroup
|
Herpes simplex
virus 1 (HSV 1)
|
Epithelial cells
|
Cranial sensory
ganglia
|
Herpes simplex
virus 2 (HSV 2)
|
"
|
Lumbar or sacral
ganglia
|
|
Human herpes virus
3 ( Varicella Zoster Virus)
|
"
|
Cranial or thoracic
sensory ganglia
|
|
Lymphotropic β
subgroup virus
|
Human herpes virus
5 ( Cytomegalo virus)
|
Variety of cells
|
Variety of cells
|
Human herpes virus
6
|
"
|
"
|
|
Human herpes virus
7
|
"
|
"
|
|
γ subgroup
|
Human herpes virus
4 (Epstein-Barr virus)
|
Lymphoid cells
(mainly
B lymphocytes)
|
Lymphoid cells mainly
lymphocytes
|
Human herpes virus
8
|
Vascular endothelial
cells
|
Uncertain
|
The diseases and routes of transmission of Herpes Virus:
Herpes Virus
|
Disease (Primary
infection)
|
Disease (Recurrent
infection)
|
Routes of transmission
|
HHV 1
(Herpes Simplex
Virus 1)
|
Gingivostomatitis
|
|
|
HHV 2
(Herpes Simplex
Virus 2)
|
|
Genital herpes
|
|
HHV 3
( Varicella
Zoster Virus)
|
Varicella (Chicken
pox) – in children
|
Zoster (Shingles) – in
adults.
|
|
HHV 4
(Epstein-Barr
Virus)
|
|
None
|
|
HHV 5
(Cytomegalo
Virus)
|
|
Asymptomatic shedding
|
|
HHV 6
|
|
||
HHV 7
|
Nonpathogenic and may
even be helpful against HIV (Human Immunodeficiency virus)
|
What is herpes simiae?
It is an Old World monkey virus that resembles HSV 1 and can cause fatal neurologic disease in animal handlers, usually resulting from animal bite. It is also called Herpes simian B virus, Macacine herpesvirus 1 (formerly Cercopithecine herpesvirus 1, CHV-1), Herpes B virus.
Diseases caused by HSV 1 and HSV 2:
Site of infection
|
Herpes Simplex Virus 1
|
Herpes Simplex Virus 2
|
Skin
|
Vesicular lesion above the waist
|
Vesicular lesion below the waist
|
Mouth
|
Gingivostomatits
|
Rare
|
Eye
|
Keratoconjunctivitis
|
Rare
|
CNS
|
Encephalitis (temporal lobe)
|
Meningitis
|
Neonate
|
Rare
|
Skin lesion and disseminated
infection
|
Dissemination to viscera in
immunocompromised patients
|
Yes
|
Rare
|
To know more about HSV 1 and HSV2 read:
Varicella zoster virus (VZV):
Disease caused by VZV: Varicella (chicken pox) is the primary disease.
Zoster (shingles) is the recurrent form.
Properties of VZV:
- VZV is structurally and morphologically identical to other herpes virus but its antigenicity is different
- It has a single serotype
- Humans are the natural host
- Transmission by respiratory droplet and direct contact
- Infect mucosa of urinary tract via blood to the skin
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Stages of Chicken Pox |
- Incubation Peroid: 14-21 days
- Rash: Papulovesicular rash that appears in crops
on the trunk and spread to head and extremities.
The rash evolves from papules to vesicle, pustules and finally crust. Itching is common when vesicle are present - Complication: Varicella pneumonia, encephalitis, Reye’s syndrome (Encephalitis with liver degeneration)
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Shingles |
- Painful vesicle along the course of a sensory nerve of the head or trunk
- Pain can last for weeks and post-zoster neuralgia (post-herpatic neuralgia) can be debilitating.
- In immunocompromised: Life threatening disseminated infection such as pneumonia can occur.
To know more about Varicella Zoster Virus and Chicken Pox / Shingles read:
That's all for today!
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got to know much by this post ..
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genital herpes treatments
Try a zinc gluconate topical on the HSV-2 lesions. It will heal the skin naturally and stop the itching.
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