Measles

Measles, also known as rubeola, is one of the most contagious diseases caused by the measles virus. It mostly affects children, but it is not limited to that age bracket and can affect all age groups. Vaccine against measles was introduced in 1963, after which the worldwide incidence has dramatically decreased. However, it is still endemic in certain developing countries and causes many preventable deaths per year.

Measles is caused by the measles virus, which belongs to the family of viruses called Paramyxoviridae. The natural host for the measles virus in humans. It spreads through:

• Droplet contamination via coughing and sneezing
• Contact contamination via close contact with infected persons

There are no types of the disease, but it is often confused with German measles, also called Rubella. Measles or rubeola is also called standard measles, hard measles, or red measles.    

Following are the risk factors for the spread of measles:

• Immunocompromised children with diseases such as HIV/AIDS or on immunosuppressive therapy, even if they have been vaccinated against the disease
• Travel to areas where the disease is endemic
• Children who are not breastfed and do not develop passive antibodies against the virus
• Malnutrition
• Pregnancy
• Vitamin A deficiency

The worldwide incidence of measles has decreased drastically after the introduction of the vaccine in 1963, for which two doses are administered in childhood. According to WHO, the developing countries have approximately 30 million cases yearly, 1 million deaths, and about 150,000 cases of blindness.
Although it is a disease of childhood, unvaccinated and immunocompromised individuals of any age can be affected. It affects males and females equally and has no association with race; people of all races are equally susceptible.

The incubation period for measles is around 7 to 14 days. The period of infectivity starts 1 to 2 days before the onset of symptoms. Signs and symptoms of measles include:

• High-grade fever
• Malaise
• Anorexia
• Rash that starts from the neck and spreads to extremities
• Small greyish blue spots with a red base inside the mouth that resemble grains of sand and are called Koplik spots
• The classic triad is marked by three Cs, i.e., conjunctivitis, cough, and coryza (nasal discharge with sneezing and watery eyes)
• Photosensitivity
• Periorbital swelling
• Body aches

Although diagnosis can be established by careful clinical examination, certain laboratory tests can also prove useful. These include:

• Complete blood count- that shows leukopenia and thrombocytopenia with compensatory lymphocytosis.
• Liver function tests- with increased transaminase levels.
• Serologic test- IgG and IgM antibodies against measles virus. Measles-specific IgM titers remain positive for up to 30 days after the illness. More than a four-fold increase in IgG titers confirms measles.
• Throat and nasal swabs for viral culture.
• Blood, urine, nasal, and throat samples for PCR to isolate viral antigens.
• Chest radiography- to see the presence of pneumonia.
• Lumbar puncture- for CNS involvement

Complications of measles usually develop due to immunosuppression and include the following:

• Pneumonia- it is the most common complication
• Pleural effusion
• Blindness
• Otitis media
• Exacerbation of tuberculosis
• Diarrhea
• Hepatitis
• Disseminated intravascular coagulation (DIC)
• Acute encephalitis and permanent brain damage

Differential diagnosis includes other viral diseases with a similar rash and some other illnesses such as:
1.      Conjunctivitis (pink eye)
2.      Meningitis
3.      Kawasaki disease
4.      Rubella
5.      Scarlet fever
6.      Toxic shock syndrome
7.      Drug hypersensitivity reactions

• Rehydration to avoid dehydration due to fever, vomiting, and diarrhea can be life-threatening. Intravenous rehydration may be indicated in extreme cases.
• Vitamin A supplementation in infected individuals who develop signs and symptoms of vitamin A deficiency.
• Post-exposure prophylaxis is indicated for all unvaccinated individuals.
• Strict compliance with the proposed regimen and follow-up visits are recommended to avoid complications.

• Ribavirin, an antiviral, is an effective medicine used against the measles virus in immunocompromised and severely affected individuals.
• Besides that, vitamin A supplementation, immunoglobulins, and measles virus vaccine for post-exposure prophylaxis are also used.
• Live MMR (measles, mumps, and rubella) vaccine induces active immunity against the virus.
• Antibiotics are given to protect against secondary bacterial infections.

Measles is rarely fatal, and the infection has a good prognosis. One-time infection confers lifelong immunity against the disease, but care should be taken to avoid complications that can be life-threatening.
In the United States, the death rate due to measles is only 0.1-0.2 percent. Although death is rarely a consequence of infection, complications can develop. Measles is the most common cause of childhood blindness.