It is one of the commonest infectious diseases of children upto six years of age. One attack gives a high degree of immunity even for the whole life. Mother who had an attack of measles imparts immunity to her infants for the first six months of age.
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This disease has a world-wide distribution. It is endemic but tends to occur in epidemic form every 2-5 years.
Causative Organism:
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Measles is caused by RNA virus of paramyxovirus group commonly called Rubeola virus. It is present in nasopharyngeal secretions and in blood of infected persons. The measles virus cannot survive outside human body.
Mode of Spread:
Measles is one of the most readily transmitted communicable diseases. The mode of spread is direct from person to person, through droplet infection i.e. sneezing, talking, kissing etc.
Direct contact with fomite such as spoons, cups and other articles recently contaminated with secretions of nose and throat of the patient may also be a source of transmission of the infection.
Period of communicability is usually 4 days before and 5 days after the appearance of the rash. It is highly infectious during the first few days of illness i.e. during pre-eruptive stage and at the time of eruption of rash stage, afterwards infectivity decreases rapidly.
Incubation Period:
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Incubation period of measles is 10-14 days.
Signs and symptoms:
Signs and symptoms of the disease can be divided into two stages viz.
(a) Pre-eruptive stage, and
(b) Eruptive stage.
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(a) Pre-eruptive Stage (Prodromal Stage):
In early stage of the disease or during pre-eruptive stage there is high fever, sneezing, running of nose, watery and red eyes, cough and hoarseness of voice due to laryngitis.
Small bluish-white spots on a red base (known as Koplik’s spots) can be seen inside the cheeks around the opening of parotid gland. These spots are found in 80 percent cases. The presence of Koplik’s spots confirms the diagnosis of the disease. These signs and symptoms last for 3 to 4 days.
(b) Eruptive Stage:
This stage begins on 4th or 5th day of illness. During this stage a typical dusky-red macular rash appears, first on the face and neck and behind the ears and then rashes rapidly spread all over the body.
The rashes are caused by the multiplication of blood borne virus in the skin. The rashes fully appear on whole of the body in about 2-3 days. The rash subsides within 5-7 days leaving a brownish pigmentation of the skin which may last for a long time even after the disappearance of rashes from the body.
Complications:
Measles can be a deadly disease particularly in children who are malnourished due to deficiency of proteins, fats and vitamins. Secondary infection may lead to pneumonia, bronchopneumonia, conjunctivitis, stomatitis and gastro-enteritis.
Prevention:
The children should be immunised against measles. For this purpose live attenuated, tissue culture freeze dried vaccine is used. A single dose of 0.5 ml of vaccine administered at the age of 9-12 months appears to give 95 percent protection against measles for at least 15 years.
It is contraindicated in children who are ill, have history of allergy or are on steroids. When measles vaccine is contraindicated then immunoglobulin can be administered for preventing the infection.
Control:
(i) Isolate the patient as soon as the signs and symptoms of measles appear.
(ii) Protect the eyes of the patient from light and glare.
(iii) Disinfect the discharges of nose and throat of the patient.
(iv) Antibiotics may be given to the patient to prevent secondary infection.
(v) Immunise the susceptible children.