Measles

Overview of measles

Viral infections are very common in the tropics and the subtropics. These climatic zones are ideal for the propagation of these pathogens. Virus-induced diseases are prevalent in people who lack proper immunizations, although the risks remain in vaccinated people as well. Measles is one such viral disease caused by the measles virus.

According to the statistics of the World Health Organisation (WHO), in the year 2015, 134,200 cases of deaths due to measles were reported across the globe. This translated to 367 deaths per day. The WHO statistics have also shown that the mortality rates dropped by 79% from 2000 to 2015. Still, the scenario is quite grave in the low-income and underdeveloped countries where the awareness related to immunizations is very less. In these countries, measles and other viral diseases are contributing to the increasing burden of public health.

What is measles?

Measles is an infectious disease mediated by the measles virus that belongs to the Paramyxoviridae family. It is also known as measles virus. The patient suffers from fever, inflammation of eyes and runny nose. Rashes appear in the later stages. It is an airborne disease that is highly communicable. It is preventable mainly through the MMRV vaccine. At present, nearly 20 million people all over the world are suffering from the disease. The chance of death in those infected is nearly 0.2%.

What causes measles?

Measles is triggered by the measles virus. It is a single-stranded RNA virus of the genus Morbillivirus. It belongs to the family Paramyxoviridae. It was isolated for the first time in the year 1954 by John F. Enders and Thomas Peebles. Following are some of the risk factors for the disease-

• A weakened immune system in HIV and AIDS patients
• Loss of immunity after receiving an organ or a stem cell transplant
• Alkylating agents
• Corticosteroid therapy
• Traveling to areas where measles is common (endemic)
• Direct contact with an infected person
• Loss of passive inherited antibodies
• Pregnancy
• Immunodeficiency
• Vitamin A deficiency

How does the infection spread?

Measles is a highly contagious disease. It is air-borne and can spread through various transmission mediums. Given below are some of the transmission routes of measles-

• Respiratory droplets of the patient expelled while coughing, sneezing, laughing or simply talking
• Direct contact with the saliva or the nasal (and throat) secretions of the patient
• Sharing common items of use such as towels, bed-sheets, pillow covers
• Living in the same space or room
• Working in health clinics where one needs to take care of the infected patients

Nearly 9 out of 10 people who are immune to the disease and share living space with the patient inevitably catch the infection. The appearance of rashes marks the infectious stage of the disease. The chances of spreading the infection are the highest within 4-5 days of or before the eruption of the rashes.

What are the main signs and symptoms?

The signs and symptoms of measles are classified into two types- 4Ds and 3Cs. 4D indicates a four day fever. 3Cs indicate three conditions namely- a cough, coryza, and conjunctivitis. The general symptoms of the disease are given below-

• Four-day fever (4D)
• A cough (productive or non-productive)
• Coryza: fever, head cold, and sneezing
• Reddish or pinkish eyes (conjunctivitis)
• Inflammation of one or both eyes
• Fever can be as high as 104^oF
• A runny nose
• Koplik’s spots: small whitish spots formed inside the mouth
• Rashes: Reddish elevated bumps that appear days after the onset of fever. Starts on the back of the ears and spreads to the head and the neck. Slowly they spread to the other parts of the body as well. These rashes last 8 days.
• Itching and skin irritation
• Change of coloration of the rashes from red to brown (known as “staining of rashes”)

What are the associated complications of the disease?

In addition to the symptoms mentioned in the previous section, there are certain associated complications of the disease. These may aggravate and make the conditions worse. Some of the complications are listed below-

• Gastrointestinal disorders like diarrhea
• Pneumonia (viral or secondary bacterial pneumonia)
• Bronchitis (viral or secondary bacterial bronchitis)
• Infection of the middle ear (Otitis media)
• Corneal ulceration and scarring
• Brain inflammation
• Subacute sclerosing panencephalitis

People having a suppressed immune system due to infections like HIV and AIDS are likely to develop these complications. Pregnancy and Vitamin A deficiency are also two primary contributing factors of the aforementioned complications.

What diagnostic tests are available?

Very often, there is a confusion between measles and roseola. This occurs due to the similarity in the symptoms of these two diseases.

Hence a thorough diagnosis is necessary in order to detect the occurrence of the disease. The laboratory examinations help in the confirmation of positive measles IgM antibodies.

These tests also enable the isolation of the RNA of the virus. Saliva is often collected for the salivary measles-specific IgA testing.

Treatment and prevention

After the establishment of the infection, no treatment can help. However, soon after exposure, the vulnerable individuals (including infants) can be given a post-exposure vaccination which will reduce the severity of the infection. In this case, the measles infection manifests mild symptoms and the infection lasts for a shorter duration.

Infants, pregnant females, and individuals with a weakened immune response can be given injections of immune serum globulin within 6 days of exposure. These antibody injections can prevent the infection or make the symptoms milder. Treatment for symptomatic relief involves over-the-counter medications for fever such as acetaminophen, ibuprofen, naproxen sodium etc. Antibiotics can be administered by a physician in case of complications such as middle ear infection, pneumonia etc. A large dose of vitamin A (200,000 IUs in 2 days) is usually given as it lessens the severity of the infection.

Prevention of measles is by MMR vaccine. It renders immunity against measles, mumps, and rubella.2 doses of the vaccine should be administered. The 1^st dose is given at the age of 12 months to 15 months; 2^nd dose between 4 years to 6 years of age. The MMRV vaccine is also an option which protects against varicella (chickenpox) as well.

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