Chicken Pox (Varicella)

Introduction

  Chickenpox or varicella, is a highly contagious disease, caused by Varicella Zoster (V-Z) virus. It is characterized by vesicular rash which may be accompanied by fever and malaise.

Epidemiological Factors :

   Agent : The causative agent of chickenpox V-Z virus is also called “Human Herpes Virus 3”

   Source of Infection : Usually a case of chickenpox. The virus is present in the oro-pharayngeal secretions, skin lesion and mucosa. Rarely the source of infection may be a patient with Herpes Zoster. Chickenpox is transmitted from person to person by droplet infection.

    Period of Communicability : It is estimated to range from 1-2 days before the appearance of rash and 4-5 days thereafter.

Host Factors :

   Age : Chickenpox occurs primarily among children under 10 years of age.

   Immunity : One attack gives durable immunity. Second attacks are rare. Infants are protected by maternal antibodies during the first few months of life.

   Environmental Factors : Chickenpox shows a seasonal trend in India, the disease occurring mostly during the first six months of the year.

   Incubation period : Usually up to 14-16 days, although exteremes as wide as 7 to 21 days have been reported.

Clinical Features :
 
  The clinical course may be divided in two stages

1. Pre-eruptive stage
2. Eruptive stage

1.  Pre-eruptive stage : Onset is sudden with mild or moderate grade fever, pain in the back, shivering and malaise. This stage is very brief, lasting about 24 hours. In adults, prodromal illness is more severe and may last for 2-3 days, before rash comes out.
2. Eruptive stage : In children, rash is often the first sign and it comes on the day the fever starts, The distinctive features of the rash are

1. Centripetal distribution : The rash is symmetrical, it comes on the trunk where it is abundant, then comes on the face, arms, legs, where it is less abundant. Mucosal surfaces are generally involved i.e. buccal, pharyngeal surfaces are involved.
2. Rapid evolution : The rash advances quickly through the stages of macule, papule, vesicle and scars. The vesicles are filled with clear fluid and looking like dew drops on the skin. They are superficial in site and surrounded by an area of inflammation. Scabbing begins 4-7 days after the rash appears.
3. Pleomorphism : A characteristic feature of rash in chickenpox is its pelomorphism i.e. all stages of rash (Macule, Papule, Vesicle and Crust) may be seen simultaneously at one time in the same area.       
4. Fever : The fever does not run high but shows exacerbation with each fresh crop of eruption.

Diagnosis :
 
  The most rapid and sensitive means of diagnosis is examination of vesicle fluid under electron microsope, which shows round particles and may be used for the cultivation of the virus. Scrapings of floor of vesicle show multinucleated giant cells coloured by Giemsa stain.

Complication :
 
  In most cases chicken pox is mild, self limiting disease. Complication of chickenpox include Haemorrhages, Encephalitis, acute cerebellar ataxia and Ray’s syndrome. Maternal varicella during pregnancy may cause foetal wastage and birth defects.

Treatment

Prevention

1. Administration of Immunoglobulins
2. Vaccine

1. Varicella Zoster Immunoglobulin (VZIG) : VZIG is given within 72 hours of exposure for prevention. A dose of 1.25 to 5 ml is given intramuscular to modify or prevent the disease.
2. Vaccine : No serious attempt was made in the past to develop a vaccine against chickenpox, probably because the disease, in general, was not considered a health priority. Now a live attenuated vaccine (OKA Strain) is available. A general reaction to the vaccine, mainly rash may occur which is usually vesicular.

Homoeopathy Prevention

• Identification of cases and notification
• Health education
• Community awareness for immunisation