Measles: Causes, Clinical Presentation, Risk Factors, Complications, Diagnosis, Treatment And Vaccinations

A contagious illness known as measles results in fever, a red rash, a cough, and red eyes. It may result in severe side effects like encephalitis, which can in turn lead to hearing loss. By receiving a vaccination, you can prevent the measles.

Measles is a highly contagious airborne virus-caused disease. After being exposed, symptoms may appear eight to twelve days later. There is a 10- to 14-day symptom duration. Other names for measles include rubeola, 10-day measles, and red measles.

Read this blog further to get a quick overview of this important topic for MICROBIOLOGY to ace your NEET PG exam preparation.

Causes of Measles

Measles is an extremely contagious disease. It can therefore spread to others extremely quickly. A virus that can be identified in a child or adult with the measles' infected nose and throat is what causes the disease. 

Measles-carrying individuals can spread the disease to others by coughing, sneezing, or talking, which releases infected droplets into the air. The contagious droplets can remain suspended in the air for roughly an hour.

The contagious droplets may also touch down on a surface, where they can survive and spread for a number of hours. By wiping your eyes or putting your fingers in your mouth or nose after touching a contaminated surface, you could contract the measles virus.

Epidemiological Determinants

Three types

1. Agents
2. Host factors
3. Environmental factors

1. Agents

It is a Single-stranded negative sense RNA virus belonging to the family Paramyxoviruses

• Source of infection
  • Case of measles
  • No subclinical cases
  • No carriers
  • Animal reservoir is not present.
  • Only one serotype of the virus that is responsible for infection
• Period of Communicability:
  • 4 days before and 4-5 days after the appearance of rash
  • Secondary attack rate for measles: 80%
  • Immunity: One attack gives lifelong immunity

2. Host Factors

Affect both developed and developing countries. In developing countries the Age group affected is 6 months-3 years whereas In developed countries the Age group affected is more than 5 years old. It is equally susceptible for both males and females. Malnutrition is a predisposing factor.

3. Environmental Factors

It follows a seasonal distribution. It is most commonly seen in winter and early spring. Measles follows a cyclical seasonal distribution. Epidemics in the unvaccinated population can be repeated for every 2-3 years. Measles are endemic all over the world. But it becomes epidemic when the proportion of susceptible children increases more than or equal to  40. 

If measles is introduced in a virgin (completely unimmunized) community then more than 90% of children can get infected. The mode of transmission is Droplet and droplet nuclei. The size of the droplet is  5 microns. It travels a distance of more than 1 meter. Incubation period is the period between the entry of the organism and the first appearance of signs and symptoms is called the Incubation period. In measles, the incubation period is:

• 10-14 days (natural IP)
• 10 days from exposure to fever
• 14 days from exposure to the appearance of rash

Post-vaccination period is  7-10 days (Antibody formation). Measles vaccination can be given to children in the post-disaster phase within 3 days of exposure because in post-vaccination the incubation period is less than the natural incubation period. 

Clinical Presentations of Measles

1. Prodromal phase: It includes
   • Fever
   • Cough
   • Conjunctivitis
   • Coryza
   • Koplik’s spot (Specific)-  1 mm grayish white spots on the reddish areola. It appears 24-48 hours before the rash is formed. As the rash appears, the koplik spot will disappear.

2. Eruptive phase

In this phase the Rash is formed. Features of rash:

Maculopapular confluent rash (starts behind the ear). It is retro auricular in origin. It Fades in the same direction. The rash appears after the koplik spot.

Measles vs Rubella rash

Risk Factors of Measles

Measles risk factors include:

• Not being immunized. You are far more prone to contract the disease if you haven't received the measles vaccine.
• Foreign travel. You run a larger risk of contracting measles if you visit nations where the disease is more prevalent.
• Deficiency in vitamin A. You have a higher risk of developing more serious measles symptoms and complications if your diet is deficient in vitamin A.

Complications of Measles

Measles complications can include:

• Vomiting and Diarrhea. Dehydration (too much water is lost from the body) can be brought on by diarrhea and vomiting.
• Otitis Media-  A bacterial ear infection is one of measles' most frequent side effects.
• Croup, laryngitis, or bronchitis- Measles can cause croup, which is an airway inflammation and irritation. It may also result in bronchitis, an inflammation of the inner walls of the primary airways of the lungs. Laryngitis, an inflammation of the voice box, can also result from measles.
• Pneumonia- Pneumonia, an infection of the lungs, is frequently brought on by measles. A particularly serious type of pneumonia, which can occasionally be fatal, is more common in those with weakened immune systems.
• Encephalitis- About 1 in 1,000 measles patients will get the complication known as encephalitis. The brain becomes inflamed and swollen during encephalitis. The risks of the illness may be more dangerous for those with weakened immune systems. 
• Maternity issues-  Pregnant women should take extra precautions to avoid getting the measles because it can result in preterm birth, low birth weight, and fetal death.

Microbiology Related Articles:

Diagnosis of Measles

The typical measles rash and Koplik's spot, a small, bluish-white patch on a bright red backdrop on the inside of the cheek, can both be used to make the diagnosis. Your doctor could inquire about recent overseas travel, vaccination status for you and your child, and whether you've come into touch with anyone who has a fever or rash.

Although many healthcare professionals have never encountered measles. The rash might be confused with a variety of various illnesses. A blood test can confirm the rash's diagnosis of measles if further confirmation is needed. Another test that typically requires a urine sample or a throat swab can be used to confirm the presence of the measles virus.

Treatment of Measles

 Measles does not have a specific therapy. Viral infections are not susceptible to antibiotic treatment like bacterial infections are. Generally speaking, the virus and its symptoms vanish within two to three weeks.

People who may have been exposed to the virus have access to a number of interventions. These can lower an infection's severity or assist prevent it. 

They comprise a dose of immunological proteins known as immunoglobulin, taken after six days of exposure, and the measles vaccination, administered within 72 hours of contact. To aid with your recovery, your physician might advise the following:

• Rest to strengthen your immune system, acetaminophen (Tylenol) or ibuprofen (Advil) to lower fever
• Drink lots of water
• Vitamin A supplements a humidifier to soothe a sore throat and cough

Complications of Measles

• Most common complication in young children is otitis media. Measles and otitis media are covered under the Integrated Management of Neonatal & Childhood Illnesses program.
• Most common fatal complication is Pneumonia
• Most common cause of death in measles is  Pneumonia
• If measles occur after 5 years in developed countries then diarrhea is the common complication
• Rare complication of measles resulting in mortality is SSPE (subacute sclerosing panencephalitis)
• After measle infection, there is a stage known as post measle stage. In this stage, complications include
  • Weight loss
  • Fatigue
  • Diarrhea

Isolation period is 7 days from the onset of rash.

Prevention of Measles

Immunoglobulins

Measles may be prevented by administering immunoglobulin early in the incubation 

• Dose: 0.25 ml per kg body weight
• Schedule: Within 3-4 days of exposure followed by measles vaccine after 8-12 weeks (post immunoglobulins)
• Susceptible contacts can be given measles vaccine- If the child is in 9-12 months: Measles vaccine is given within the three days of exposure.

Target Year for Measles Elimination

It was for 2022, but it was extended.

• By now, we are targeting to eliminate it as soon as possible.
• For that we have started a Measles rubella elimination campaign
  • Catch Up- Measles rubella elimination campaign:
    • All children between 9 months-14 years of age are given a dose of MR vaccine, irrespective of disease status or previous immunization status
    • These are the supplementary doses given along the routine dose
  • Keep Up
    • Keep up routine vaccination
    • Under the NIS, we are targeting to achieve 95% immunization
  • Follow Up
    • Subsequent nationwide vaccination campaigns 
    • It is conducted every 2-4 years targeting usually all children born after the catch-up campaign.

WHO Measles Elimination Strategy

Which vaccine is given at 9 completed months along with the MR vaccines?

• Vit A Prophylaxis (if the child is Vit A deficient along with the measles, the chances of mortality increase)
• So, Vit-A is preferred.
• Dose: 1ml or 1 lakh IU 
• For every six months- 5 years age: 2 ml or 2 lakh IU
• Total doses of MR vaccine: 9 doses
• Total amount: 17 lakhs IU

Can a Measles Vaccine be Given Before 9 Months?

For the first six months, the baby is protected from maternal antibodies. From 6 to 9 months, the antibodies will start decreasing. At the end of the 9th month, there will be no antibodies. So, it can be given from 6-9 months in the cases of the measles outbreak.

 It can also be given to children who are traveling to areas where measles are highly endemic. If the child is given the MR vaccine in the 8th month, the regular dose is given in the 9 completed months. The gap to be maintained between two doses of measles vaccine is 28 days.

 If the child was 9 months and 10 days (an outbreak happened), the MR vaccine is not given. Because the gap should be maintained for 28 days rather it would be given in the 10th month.

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