Everything you need to know about measles

Measles is an infectious disease. It is also called rubeola. It is characterized by fever, cough, coryza and typical skin rashes. It was a common disease in the pre-vaccination era. With acceptance of the vaccination in many countries the incidences of of this disease are decreasing consistently.

Still it continues to be a common disease in countries where vaccination coverage is incomplete and vaccine acceptance is low.

Finding the global burden of total measles cases is difficult as surveillances are done differently in parts of the world. According to WHO estimate in 2018 around 140000 deaths occurred because of the disease. Total number of deaths occurring early has decreased by 73% compared to the year 2000 which was 5.36 lakh deaths because of measles. Measles vaccination has prevented nearly 2.3 million deaths from 2000 to 2018.

What is the cause of measles?

Measles disease is caused by infection of the measles virus. Measles virus is a morbillivirus and it belongs to family paramyxovirus. It is a single stranded RNA virus.

How does measles spread?

It is a highly contagious disease which spreads from one person to another. Measles is an airborne infection it spreads by following modes:

• Airborne spread by respiratory droplets occurs when a patient with measles sneezes coughs.
• It can also spread from mother to baby in pregnancy, delivery or while nursing the baby.
• Measles also spreads through saliva while kissing.
• Measles can spread by direct skin to skin contact.
• Measles can also spread by touch to surfaces which harbour the virus.
• Measles is so contagious that ninety percent of total susceptible persons get infected when they are exposed to the infected people. Infected person can spread the virus 4 days before through 4 days after the appearance of the rash.

What is the incubation period of measles?

Incubation period for measles is 10 to 14 days. Incubation period is a time interval between getting infection and appearance of the first symptom in the exposed patient.

What are symptoms of measles?

Symptoms of measles disease range from mild to very severe. Those who are suffering from very severe disease may present with complications and can cause death.

In the initial stages present with cough, cold and redness of the conjunctiva. 

Koplik spot is a characteristic feature of measles; it is the appearance of erythematous rash in the mouth opposite to the premolar, sometimes molar teeth. Though these spots are characteristic, many times they are difficult to identify. Dr Koplik first described Koplik spots in 1896. Koplik spots when present are considered as diagnostic and pathognomonic signs of the measles. But these are not uniformly present in all the patients of the measles.

Fever can be mild initially and can progress to moderate to high grade fever. 

Patients who have a tendency of febrile seizure may present with convulsions because of this fever.

Measles is characterized by the presence of rashes. Measles rash initially appeared behind the ears and on the forehead. This rash spreads to other parts of the face and body parts over some days.

Along with the symptoms, they may complain of fatigue, headache and loss of appetite.

There may be a cause of swelling below the jaw and on the neck because of swelling of lymph nodes present in this area; this is called lymphadenitis. Disease of lymph nodes is called lymphadenopathy. Measles lymphadenopathy can occur in cervical, axillary and inguinal regions. Measles can cause generalized lymphadenopathy.

What does the rash of measles look like?

Measles rashes have characteristic presentation. For the first time rashes appears behind the ear or on the forehead. They may spread to other parts of the face and progressively spread to the torso and limbs involving the palms and soles. Look like multiple reddish spots which are flat and sometimes few bumps can be noted.

After 2-3 days these rashes unite to form characteristic measliform rash.

The rashes may be difficult to identify in people who have dark skin. Addition to this fact many other diseases may present with similar rashes.

How do you diagnose measles?

Measles is identified by its typical symptoms and characteristic rashes. Your doctor will examine you and take your detailed history. With presence of typical symptoms and characteristic rash the measles is diagnosed clinically.

For the confirmation of the diagnosis of the measles following tests may be done.

• Serum IgM level against measles can be detected after 1-2 days of appearance of the symptoms. Serum IgM level against measles can remain high upto 1 month of getting infection. Those antibodies can be detected from serum obtained from your blood.
• Serum IgG against measles can be changed in patients with measles. 4 fold rise of serum IgG against measles on serum sample at 2nd and 4th week compared. Comparison of acute and convalescent serum level of IgG against measles is a reliable test.
• Viral culture done on samples obtained from throat blood and urine mainly detect measles virus. Viral culture facility is available at state labs.
• Polymerase chain reaction to detect measles virus can be conducted on swabs obtained from the nose and throat of the patient. Facilities of polymerase chain reaction to detect measles virus generally available at state central labs.

What are the complications of measles?

Measles is not just cough and cold with fever rash. Measles may cause complications and its complications are as follows.

Measles can affect your lungs and cause pneumonia. Common presentation of pneumonia rapid breathing, high grade fever, difficulty in breathing, in drawing of the chest while breathing, in some patients it can cause abdominal pain and chest pain. In pneumonia the lungs are filled with fluid and oxygen exchange is difficult. It can lead to death if not treated properly. The pneumonia in measles can be because of direct viral invasion or may be because of superinfection caused by bacteria.

Otitis media is an infection of the middle ear. Patients with measles are prone to get otitis media. This ear infection can occur because of superinfection. It can cause long-term sequelae like loss of hearing in some patients.

Diarrhoea and vomiting are another complication of measles disease. Watery diarrhoea of large volume can cause dehydration very rapidly in children. This dehydration can cause electrolyte in balance and in some patients.

Measles in pregnancy can cause complications like abortions, low birth weight babies and stillbirths, babies with congenital deformities.

Pericarditis and Myocarditis are other complications in measles disease affecting the heart. Symptomatic myocarditis has a high frequency of death because of cardiac failure.

Encephalitis and meningitis are another complication caused by measles. Encephalitis caused by which help can present with altered consciousness, convulsions, drowsiness and mental confusion.

Other complications of measles include bronchitis, conjunctivitis, and laryngitis, blindness.

Subacute sclerosing panencephalitis (SSPE) is a long-term complication of the measles. This complication is rare but irreversible. It causes the death of an affected person over a few years. Common presentations are changing personality, loss of coordination in movements, mental confusion and loss of consciousness confusion and loss. The condition finally leads to coma and death of affected person.

Who is prone to complications of measles?

People of following groups are prone to complications of measles with more frequency:

• Age less than five years all more than 20 years.
• Children who are malnourished.
• People who are consuming a healthy improper diet.
• Measles complications are more common in pregnancy.
• People who are immunocompromised because of steroids and diseases like AIDS.
• Unvaccinated people and children.

What is the treatment of measles?

Measles is a viral illness caused by measles morbillivirus. It does not have specific treatment. 

Measles is treated with supportive treatment. Being a viral illness antibiotics are not effective to treat the measles but they may be effective in treating superinfections.

Measles is treated with following strategy:

• Symptoms like fever are treated with antibiotic medicines paracetamol and Ibuprofen in appropriate dosages.
• Cold, cough can be treated with humidified air.
• It is important to maintain the hydration of the patient.
• Patients with loose motion may require treatment with oral rehydration solution.
• Patients with pneumonia may require oxygen support and antibiotics to treat superinfection.
• Patients with otitis media may require antibiotics to treat superinfection.
• Breastfeeding is to be continued to babies who are still breastfeeding.
• Plenty of oral fluids are encouraged to maintain the hydration.
• Doses of vitamin A given in appropriate doses may reduce the mortality of the measles and its complications.
• Patients with measles are to be treated in isolation as there are chances of spread of disease to unvaccinated people.
• Patients with complications involving the central nervous system may need anticonvulsant to stop the convulsions.

Why is vitamin A given in measles?

There is a role of vitamin A in treatment of measles. Provided with vitamin A, the mortality and complications of measles is found to be reduced by up to 82%.

WHO currently recommends a vitamin A dose of 2 lakh (1 lakh units for infants) units for 2 days in measles.

How to prevent measles?

The most effective way of preventing measles disease is the measles vaccine.

Since the start of measles vaccination in 1960 there has been a reduced incidence of measles and also reduced mortality because of measles.

Measles is still a prevalent disease where measles vaccination is not accepted or there is incomplete coverage.

Measles vaccine has proven its efficacy beyond doubt.

Post exposure prophylaxis for measles

If the susceptible person has come in contact with a measles patient, He/she is prone to get the infection. For such people post exposure prophylaxis for measles is indicated.

Human immunoglobulin concentrates are used for the post exposure prophylaxis of the measles. German STIKO recommends a single dose of human immunoglobulin 400 mg per kg as early as possible after the exposure.

NHS UK recommends human normal immunoglobulin (HNIG) for post exposure prophylaxis of measles in following group:

• Infants under age 6 months.
• Pregnant women who are unvaccinated.
• Immunocompromised patients.

Human normal immunoglobulin offers immediate short term protection against measles.

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