Magnitude of problem It is worldwide in distribution and occurs in both epidemic and endemic forms. Epidemiological factors * 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.
* General feeling of unease and discomfort (malaise) or irritability * A dry cough * Headache Incubation period The incubation period is usually 14 to 16 days but may vary from 7 to 21 days. Complications * Skin infection * Pneumonia * Otitis media * Myocarditis * Encephalitis * Reye’s syndrome Diagnosis * Examination of vesicle fluid under microscope * Blood tests Treatment There is no specific treatment for chickenpox. Treatment mainly consists of easing the symptoms as there is no actual cure to the condition. Some treatments are however available for relieving the symptoms.
It is important to maintain good hygiene and daily cleaning of skin with warm water to avoid secondary bacterial infections. Anti itching creams can be used to relieve the symptoms of chickenpox. Prevention and control Following are the preventive and control measures:- * Isolation of the patient * Disinfection of oronasal discharge and solid articles * Terminal disinfection of room. * Passive immunization with normal human immunoglobulin (VZIG) * Active immunization with line alternated varicella vaccination * Other airborne illness control measures.