“As winter starts fading and summer begins to set in, cases of chickenpox start coming in. It is a highly contagious disease that spreads from person to person by direct contact or through the air from an infected person’s coughing or sneezing. Touching the fluid from a chickenpox blister can also spread the disease,’’ says Dr Monica Mahajan, consultant (intenal medicine) at Max Healthcare.

While Mahajan alone is receving around five cases of chickenpox every week at her clinic, Batra Hospital has received 50-60 such cases in the past fortnight. “This is the time when chickenpox cases peak in the city,’’ Dr Mahajan says.

Chickenpox is caused by the varicella zoster virus (VZV), also known as human herpes virus 3 (HHV-3), one of the eight herpes viruses known to affect humans. The infection first shows up as reddening of the eyes and then blisters appearing on the body and head which become increasingly itchy. Treatment is symptomatic. Sodium bicarbonate in baths or antihistamines ease itching and paracetamol reduces fever. In adults treatment with antiviral drugs, like acyclovir, is generally advised

Doctors advise a 10-21 day incubation period for those infected with chickenpox and caution against physical contact with patients. What mostly leads to quick spread of chickenpox is the fact that a person is infected two days before the symptoms appear.

“It is not necessary to have physical contact with the infected person for the disease to spread. Those infected can spread chickenpox before they know they have the disease,’’ says Dr Deepti Singh, Batra Hospital.

Doctors say more cases are reported from overcrowded areas or enclosed offices in the city as the spread of infection is faster there. “We get cases of children who went to school and spread the virus to everyone in the class. Infected children should not be going to school. Then, we also get executives coming to us who work in crowded offices and spread the virus through air,’’ says Dr Mahajan.

The good news, however, is that following primary infection, there is lifelong protective immunity from further episodes of chickenpox. But children, pregnant women and old people need to be extra cautious.