Varicella Zoster Virus (VZV).
Sub-family : alphaherpesviridae.
Genus : varicelloriuses.
Species : Human herpesvirus 3.
Double stranded DNA virus.
Heat sensitive.
Varicella Zoster Virus (VZV) causes infections of Varicella Zoster (Varicella/Chickenpox) and Herpes Zoster (Shingles).
In the first infection Varicella ➡ then the next infection becomes Herpes Zoster.
Cases of Varicella in tropical countries generally occur in children, whereas cases of Shingles often occur in adulthood. This disease can be prevented by vaccination.
Pathogenesis.
Varicella Zoster Virus infection is transmitted through :
- Air from coughing / sneezing.
- Direct contact with fluids from vesicles.
Lifecycle of the Varicella Zoster Virus.
Viral infection begins with replication of respiratory tract mucosal epithelial cells atas local replication followed by spread to tonsils and regional lymphoid tissue ➡ infected T cells will carry the virus to the replication site in the skin ➡ spread from the bloodstream to the skin ➡ appear lesions on the skin (skin Varicella Zoster Virus) will enter the latent phase in the sensory ganglia ➡ if reactivation occurs, the spread will occur dermatomally (Herpes Zoster).
Clinical manifestations.
- The incubation period for Varicella Zoster Virus is between 10-21 days.
- Mild prodromal symptoms appear 1-2 days before the rash appears.
Prodromal symptoms that appear include :
- Fever.
- Malaise.
- Nausea.
- Muscle ache.
- Decreased appetite.
- Headache.
- In children the initial symptoms are rashes.
- Rashes generally arise from the head to the body and extremities.
- Most concentrations are generally in the body bagit.
- Lesions appear varied and their phases vary.
- A reddish, small lump.
- Pustul.
- Vesicles.
- Itchy crust.
- Lesions can occur in the mucosal area of the eye, mouth and upper respiratory tract.
Diagnosis.
- Physical examination.
- Clinical manifestations.
Supporting examinations, such as :
- Tzanck test : a smear was made which was stained with Giemsa.
- Polymerase Chain Reaction (PCR).
- Direct Fluorescent Antibody (DFA).
- Samples were taken from vesicle fluid.
Positive Varicella : if found many nucleated datia cells.
- An enzyme immunoassay is used to detect an increase in IgG titer.
Treatment.
Varicella therapy is limited to symptomatic therapy, in the form of :
- Antipyretics (acetaminophen).
- Analgesic.
- Antipruritis.
- Sedative.
- Can be given antibiotics if secondary therapy is found.
- Patients must keep bathing to avoid secondary infections.
Prevention.
This disease can be prevented by vaccinating and avoiding contact with Varicella infection patients. The available vaccines are Varivax and Varilix, which are live attenuated vaccines and derivatives of Oka strains.
Vaccination Indications :
- There is no accurate data about the history of the disease or serological evidence of Varicella infection.
- Medical personnel and families in contact with immunocompromised patients.
- High-risk individuals infected with Varicella Zoster Virus.
- Have plans to become pregnant in the future.
- Living in a house with children.
- Planning on traveling abroad.
Contraindications :
- History of vaccine component allergies.
- Pregnant/planning a pregnancy within the next 1 month.
- Substantial suppression of cellular immunity.
- Tuberculosis.
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