Chickenpox is highly contagious disease characterized by fever, malaise, aches and appearance of vesicular rash within 24 hours. It is also called as varicella.
Magnitude of problem
It is worldwide in distribution and occurs in both epidemic and endemic forms.
* Agent factor
The causative agent of chickenpox is Varicella-Zoster (V-Z) virus which is also called as “human (alpha) herpes virus 3” * Source of infection
The source or reservoir of infection is a case of chickenpox. The virus is present in the nose and throat secretions and lesions of the skin, mucous membrane and blood * Period of infectivity
The case is infectious for a period of about 1 week, 1 to 2 days before and 4 to 5 days after the appearance of rash.
* Host factor
* Age: No age is exempted but it mostly occurs in children under 10 years. * Sex: Both sexes are prone to the disease
* Immunity: One attack gives durable immunity, second attack is rare. Maternal bodies protect children up to few months.
* Environmental factor
It shows seasonal trend in India, i.e. first six months of year. Overcrowding favors transmission Mode of transmission
The infection spreads through droplet infection i.e sneezing, talking, kissing. It is also spread by means of articles such as cups and spoons recently contaminated by the patient. Pathophysiology
Virus gains entry through the mucosa of the upper respiratory tract, followed by viraemia and circulation through blood, and then becomes localized in the skin. The virus produces swelling of the epithelial cells, ballooning, degeneration and accumulation of tissue fluid resulting in vesicle formation. Sign and symptoms
* A red, itchy rash, initially resembling insect bites, on face, scalp, chest and back * Small, liquid-filled blisters that break open and crust over * Fever
* Abdominal pain or loss of appetite
* Mild headache