A mother was worried that her child’s playmate was suffering from chicken pox. She was worried that the child may acquire the infection. Chicken pox is a disease entity caused by Varicella zoster virus. It is a highly contagious illness. In case of a case occurring in the family, there are high chances of other members getting infected.
The epidemiology of Varicella infection has changed over the past 2 decades. Previously what was considered a childhood illness, is now affecting adults who have not been exposed previously.
It is a droplet infection. If someone harbouring the virus coughs or sneezes in the vicinity, it enters the body of affected person through droplets. After entry, it causes fever, body ache, cold, i.e. flu like symptoms. As the virus multiplies and spreads in body, these flu like symptoms are followed by vesicular eruptions on the body. These eruptions soon enlarge in size, become pustular, then dry up and shed. These skin lesions are troublesome as they cause intense itching. Secondary bacterial infection can develop over these lesions because of itching, causing boils at times. The virus may be cleared totally or it may become latent in the root ganglia of nerves. This latent virus can be reactivated later causing herpes zoster. Herpes zoster causes vesicular eruptions in distribution of a nerve or nerve root. The affection and inflammation of the nerve causes intense burning pain.
Some persons suffer from pain for months after due to the inflamed nerve (post herpetic neuralgia). In case of eye involvement (herpes opthalmicus), severe pain occurs in affected eye. One may develop herpes zoster without having chicken pox before, due to the virus being present in the body but not in a concentration producing the disease.
Complications occur due to spread of virus in other organs. Commonly pneumonia and infections of the brain or spinal cord occur.
In a healthy individual, chicken pox will subside spontaneously in a week or so. But in a person with low immunity as in AIDS patients or diabetics, the disease can be more severe with greater potential for complications.
Normally this infection occurs once in a life time in a person because the body develops antibodies against it. But an immune depressed individual is prone to develop recurrent attacks of herpes zoster.
Diagnosis is made by typical clinical features and serological tests. Treatment is mainly palliative to provide relief in itching.
Potential of the disease to infect others, develops with the onset of the infection but it is highly contagious in the stage when the eruptions dry up and shedding of scabs begins. Ironically at this stage the patient starts feeling good, hence more likely to move around and spread the infection. Ideally a patient of chicken pox should be isolated, till majority eruptions clear. The patient should be advised not to remove the scabs manually as it can cause permanent scarring.
Keeping the mouth covered while coughing or sneezing is a small measure but very useful to prevent transmission of all droplet infections including chicken pox.
Vaccination for prevention of varicella infection can be given to children 12 months and olders. Adults who test negative for antibodies to chicken pox can also take vaccination for prevention, which will be 2 doses of the vaccine.
Dr. Rachna Pande is a specialist in internal medicine at Ruhengeri Hospital