---

There is only one serotype.

It causes chickenpox (Primary infection) and shingles (recurrence infection)

 

Transmission

Direct person to person.

Through respiratory route from VZV infected patient either with chickenpox or shingles although the risk of transmission from patient with shingles in areas where it is covered by cloths is low.

Virus particles can be found from respiratory secretions or vesicular fluids.

Incubation period- 8-20 days

Attack rate- over 80 % .

 

---

Clinical presentation

---

 

Chickenpox

Malaise and fever is common during the prodromal period.

First maculopapular rash appear on the trunk followed by vesicular rash.

The vesicle  at the beginning  are watery then they become pusy.

The rash could be itchy.

Secondary bacterial infection with staph aureaus is common.

 

Complications in adult patients

Ø      Pneumonitis

Ø      Encephalitis

 

Complications in Pregnant women

Ø      Missed abortion

Ø      Congenital abnormality

Ø      Pneumonitis especially in the third trimester

 

Neonates with congenital VZV infection

Ø      Congenital defects- limbs

Ø      Skin- scars

Ø      Vesicular rash

 

Immunocompromised patients

Ø      Pneumonitis

Ø      Hepatitis and

Ø      Disseminated infection

 

Shingles

It is a reactivation of VZV infection.

It is characterised by

ü      Paresthesia before developing skin lesions

ü      Vesicular rash along the dermatomal line

ü      Post herpetic neuralgia

It is much more common in the elderly and immunocompromised patients.

 

Ophthalmic shingles

Ø      Corneal ulceration

 

Other rare complications

Ø      Bell’s palsy

Ø      Encephalitis

Ø      Acute retinal necrosis

 

 

---

Investigation

---

 

Depending on the presentations.

VZV antibody

 

Chickenpox                                                      +                        +

Shingles                                                            _                        +

 

Diagnostic tests

Vesicular lesions

Swabs for IF and virus isolation.

PCR can also be used to detect VZV.

No vesicular lesions

Serum for VZV IgM- VZV IgM indicates recent infection however it is not useful in patient who present with shingles as it is reactivation, as opposed to primary infection.

 

Neonates

Vesicular lesion

ü      IF and virus isolation

EDTA blood for PCR

Serum for VZV IgM.

 

Immunocompromised patients

Ø      Vesicular lesions

Ø      swabs for IF and virus isolation

Ø      blood for VZV DNA PCR

 

Screening

Before vaccination

Serum for VZV IgG- those who are negative can be considered to be susceptible to infection.

 

Before transplant

Serum for VZV IgG-  VZV IgG can be taken as evidence not to have previous exposure.

 

Pregnant women

Test for VZV IgG can be carried out after or before exposure to chickenpox if there is no history of chickenpox .

 

Screening of pregnant women after exposure to Chickenpox (shingles) PDF file

 

---

Treatment 

---

 

Valacyclovir (acyclovir) should be used to treat patients at risk of severe infection. Infection contracted from household contact, adult  and immunocompromised patients have a high chance to develop severe illness.

Treatment should be considered for pregnant women especially after 6 months of pregnancy as there is good evidence that the drug is not associated with serious adverse effect on fetuses and pregnant women.

Treatment should be considered for patient with shingles presented within 48 hours.

Hospital care

Intravenous treatment is indicated for patients with pneumonitis or severe infections.

All neonates developing chickenpox should be treated with intravenous therapy.

---

Prevention 

---

 

Occupational health

Vaccination of health care workers is advised to reduce transmission of chickenpox.

Community care by GP and midwife

Post-exposure prophylaxis

Give VZV immunoglobulin (VZIG) to susceptible pregnant women and neonates if they are exposed to Varicella Zoster.

The immunoglobulin should be given intramuscularly within 7 days of exposure and not after 10 days.

 

Hospital care

 Immunocompromised patient can be given either VZIG or acyclovir after exposure to VZV. The immunoglobulin should be given within 4 days, and not considered to be effective if given after 7 days.

To prevent infection,  acyclovir should be started at 8 days from the day of exposure and should be continued for 2 weeks.

---

---