Varicella Zoster

Varicella Zoster DR.T.V.RAO MD

Varicella Zoster and Chickenpox

Varicella-zoster virus (VZV) causes chickenpox and herpes zoster (shingles). Chickenpox follows initial exposure to the virus and is typically a relatively mild, self-limited childhood illness with a characteristic exanthem, but can become disseminated in immunocompromised children. Reactivation of the dormant virus results in the characteristic painful dermatomal rash of herpes zoster, which is often followed by pain in the distribution of the rash (postherpetic neuralgia).

Varicella Zoster

( Herpes Virus)DNA Virus

Varicella - Chicken pox. Contagious Disease Mainly infects Children Generalized Vesicular eruptions on Skin and Mucous membranesSevere manifestations in Adults and Immune compromised.

Shingles (Herpes Zoster )

Rash Limited to Distribution of Single

Sensory Ganglion In Adults and immune compromised Sporadic

Zoster. Associated with Immune compromised. Manifest with severe pain Vesicles on trunk , head, neck Trigeminal Neuralgia

HERPES VARICELLA ZOSTER HVZ

Causes chicken pox -fever + characteristic rash variable incubation period 14-21 days usually mild in children and more severe in adults complications

◦ secondary infection - uncommon◦ varicella pneumonia◦ secondary bacterial pneumonia S aureus & pneumococci◦ post-infetious encephalitis◦ generalized varicella (in immunocompromised patients)◦ congenital and neonatal varicella

Herpes Zoster Primary Contact - Chicken Pox Reactivation - Zoster (Partially Immune )

Herpes zoster (shingles) The most common presentation is the shingles vesicular rash, which most commonly affects a thoracic dermatome

After a prodromal illness of pain and paraesthesia's, erythematous macules and papules develop and progress to vesicles within 24 hours

The vesicles eventually crust and resolve Pain and sensory loss are the usual symptoms Motor weakness also occurs and is frequently missed on examination Cases of actual monoplegia due to VZV brachial plexus neuritis have been reported

Zoster multiplex Shingles may appear in multiple dermatomes, both contiguous and noncontiguous, on either side of the body

Immunocompromised individuals are more susceptible Terminology depends on the number of involved dermatomes and on whether the condition is unilateral or bilateral (eg, zoster duplex unilateralis refers to the involvement of 2 unilateral dermatomes)

Cases of zoster simultaneously occurring in 7 noncontiguous dermatomes have been reported

Properties of Virus. Like Herpes Virus Icosahedrons shape ds DNA

VZV virons are spherical and 180–200 nm in diameter. Their lipid envelope encloses the 100 nm nucleocapsid of 162 hexameric and pentameric capsomeres arranged in an icosahedral form. Its DNA is a single, linear, double-stranded molecule, 125,000 nt long.

Progress of events in Varicella Zoster Infection

Culturing virus Grows in Human embryonic Tissue Produce inclusion bodies No difference in virus In Chicken pox and zoster infection

Pathogenesis and Pathology

Varicella virus enter through URT/Conjunctiva.

Lymph nodes Viremia Liver and spleenSecondary viremiaInfects Mononuclear Cells Rash Vesicle formation

Risk Factors Chickenpox

Exposure to the virus if you have not had chickenpox nor received the vaccine Being under 10 years of age Time of year: late winter and early spring is the most common time that the virus is spread

Shingles Age (most common in people over 60) Stress

Weakened immune system (for example, people with HIV/AIDS, or those taking drugs to suppress the immune system due to autoimmune diseases or organ transplants)

Having had chickenpox before age 1

Herpes Zoster Skin Lesions Inflammation of Sensory Nerves and Ganglia Single Ganglion Dorsal root Ganglion

Entry of Varicella Zoster virus

Skin lesions showing different stages

Clinical Findings. Varicella, Incubation 10-20 days Fever, Malaise Rash Trunk –Face –Limbs – Buccal and Pharyngeal mucosa Lesions at all stages Macules, Papules, Vesicles, Crusts,May last 5 days, Hundreds of eruptions.

Skin lesions of chickenpox

Chicken pox lesions in the buccal cavity

Herpes Zoster involving a Nerve segment

Other Complications. Encephalitis, Mother to Child transmission Varicella Pneumonia. Fatal Complications.

Events in Varicella Zoster Infection

Immune compromised

HIV / AIDS Malignancies. Organ transplantations Corticosteroid usage Leukaemia's.

HERPES VARICELLA ZOSTER HVZ

Causes chicken pox -fever + characteristic rash variable incubation period 14-21 days usually mild in children and more severe in adults complications

◦ secondary infection - uncommon◦ varicella pneumonia◦ seconday bacterial pneumonia S aureus & pneumococci◦ post-infetious encephalitis◦ generalised varicella (in immunocompromised patients)◦ congenital and neonatal varicella

Pain and hyperesthesia

Pain and hyperesthesia

Ramsay-Hunt syndrome This syndrome occurs when the geniculate ganglion is involved. The clinical presentation includes the following:

A peripheral facial palsy Pain in the ear and face Vesicles in the external ear canal (not always present) Additional auditory and vestibular symptoms in some case

Keratitis (herpes ophthalmicus)

Caused by reactivation of VZV infection in the ophthalmic division of the trigeminal nerve.

The presentation may include conjunctivitis or corneal ulcers

Complications include blindness Vesicles do not have to be present Rarely, the virus migrates along the intracranial branches of the trigeminal nerve, causing thrombotic cerebrovasculopathy with severe headache and hemiplegia

Laboratory Diagnosis. Smears --Scrapings from Lesions Demonstration of Multi nucleated giant cells

Tzanck smearsDNA DemonstrationCell cultures,Fluorescent –antibodyELISA PCR

Treatment Specific treatment is indicated mainly in Immunodeficient and elderly subjects and also in complicated with Varicella pneumonia ,encephalitis,and disseminated zoster Acyclovir and Famiciclovir.

Antiviral Medications Antiviral medications decrease the duration of symptoms and the likelihood of post herpetic neuralgia, especially when initiated within 2 days of the onset of rash. Oral acyclovir may be prescribed in otherwise healthy patients who have typical cases. Compared with oral acyclovir, other medications (eg, valacyclovir, penciclovir, famciclovir) may decrease the duration of the patient's pain.

Varicella zoster Immune globulins

Varicella zoster immune globulin (VariZIG) is indicated for administration to high-risk individuals within 10 days (ideally within 4 days) of chickenpox (VZV) exposure.[4] High- risk groups include the following:

Immunocompromised children and adults New-borns of mothers with varicella shortly before or after delivery Premature infants Infants less than younger than 1 year of age Adults without evidence of immunity Pregnant women

Epidemiology

Communicable Disease World wide prevalence Common in < 10 year olds. Zoster in Adults Droplet spread is common

Prevention of Chickenpox

Susceptible populationchildren

adults living in close proximity

Do nothing

Immunizelive attenuated

vaccine

Protect if contact with patient with chickenpoxand at risk of severe disease Zoster Immune Globulin (ZIG)

Recent advances in research

The introduction of DNA analysis techniques has shown some complications of varicella-zoster to be more common than previously thought. For example, sporadic meningoencephalitis (ME) caused by varicella-zoster was regarded as rare disease, mostly related to primary varicella, and occurring mainly in children or immunocompromised people.

Approval of Vaccine by FDA In 2006, the United States Food and Drug Administration approved Zostavax for the prevention of shingles. Zostavax is a more concentrated formulation of the Varivax vaccine, designed to elicit an immune response in older adults whose immunity to VZV wanes with advancing age. A systematic review by the Cochrane Library shows that Zostavax reduces the incidence of shingles by almost 50%

Vaccine availableA live modified Varicella virus lyophilised vaccine which can be stored at low temp is available for protectionChildren 1 -12 years given single dose.>12 years 2 doses 2 -6 weeks apartHigh titre serum from convalescing from herpes zoster protect Immunocompromised children.But not useful for treatment

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