Introduction
Measles is a highly contagious disease caused by the measles virus. It spreads easily and therefore very fast when an infected person breathes, coughs, or sneezes. Symptoms can be severe and its complications serious some of which can cause death. Though it can affect you at any age, it is most common in children.
Measles is mostly a childhood infection caused by the measles virus. Once a common disease, it has been effectively contained with the widespread use of the measles vaccine (the MMR vaccine).
Also called rubeola, measles is highly contagious and spreads easily. It can lead to serious infections and can even be fatal for small children.
The disease still kills more than 200,000 individuals (mostly children) a year, despite the effective containment of the disease through aggressive vaccination programs.
Measles can be a serious disease in all age groups. Some age groups are more susceptible and likely to suffer from its complications: These are children below the age of 5 years and adults above the age of 20 years.
Know what causes it, its different modes of transmission, the symptoms that manifest, and its complications that can handicap or even kill.
Causes and Transmission
The measles virus (MV), scientifically named Morbillivirus hominis, is a single-stranded non-segmented RNA virus of the genus Morbillivirus belonging to the family Paramyxoviridae.
The measles virus causes measles. Humans are the only natural hosts of the virus with no known animal reservoirs.
The measles virus originates in the infected person’s saliva and respiratory secretions and is expelled into the air by coughing, sneezing, talking, or even breathing.
Measles is highly contagious about four days before the rash appears to four days after the rash appears.
About 90% of people who don’t have immunity against measles will catch measles after exposure to someone with the measles virus. People who don’t have immunity include those who are not are not vaccinated and those who have not been infected with measles before.
Its highly contagious nature can be gauged from the fact that one infected person can spread and infect 9 out of 10 people sharing living space (domestic contacts) if they have not been protected.
Measles patients are contagious from 1-2 days before the onset of symptoms. Healthy children are also contagious during the period from 3-5 days before the appearance of the rash to 4 days after the onset of the rash.
During its infectious phase, measles can spread in the following ways:
- Being an airborne virus, it spreads easily when an infected person breathes, coughs, or sneezes releasing the respiratory droplets with the virus into the air. The infectious droplets can float in the air for about an hour. If you happen to be in close vicinity, you may inhale these droplets and contract measles.
- It can also spread through direct mouth-to-mouth contact such as kissing and through nasal secretions.
- Sharing food and drinks with a measles-infected person
- Shaking hands or hugging someone with measles
- Researchers at The Centers for Disease Control and Prevention have claimed that the virus expelled into the air can land on hard surfaces and can stay infectious for up to two hours. Anyone touching these hard surfaces within those two hours and then touching his nose, mouth, or eyes, becomes a potential candidate for measles infection.
- A pregnant woman infected with measles can pass on the infection to her baby during pregnancy or delivery.
Symptoms
The first symptoms of measles usually appear 7 to 14 days (average, 10-12 days) after exposure to the virus. During these initial asymptomatic days, there are no signs or symptoms suggestive of measles.
In most cases, the first and early warning sign of measles is high fever and this early phase is also marked by malaise, anorexia, and the characteristic three symptoms of conjunctivitis, cough, and coryza (the “3 Cs” of measles). These early symptoms typically last 4 to 7 days.
Symptoms that mostly develop include:
Rash of measles
- A red, spotty, itchy rash is the most visible symptom that usually starts on the face at the hairline, sides of the neck, and behind the ears. It begins 7 to 18 days (average 14 days) after exposure and lasts for 5 to 6 days.
- It spreads to the rest of the body including the arms, chest, and back, then over the thighs, lower legs, and feet in about three days.
- There may be mild itching.
- Within 48 hours, the raised bumps and spots join together to form patches and plaques that spread downwards from head to toe. After 5 -6 days they begin to resolve again beginning from the head downwards towards the toes.
- The illness is most infectious during the first or second day of the rash.
- Patients with compromised immunity may not develop a rash.
Fever
- The fever of measles is mostly high and develops suddenly. It may spike to over 104° F (40° C) or more and is often the earliest sign of measles.
- It usually lasts 4–7 days.
A barky cough
- A dry cough with bronchiolitis stays throughout the illness and is mainly responsible for the transmission of measles. It lasts about 8 to 10 days. It may be the last symptom to appear.
Runny nose and sneezing
- Sneezing releases droplets of infected nasal secretions into the air and causes its spread. Cold can last 4 to 7 days.
Red, watery eyes
- Red inflamed watery eyes, known as conjunctivitis develop.
Koplik spots
- Koplik’s spots are small bluish-grey white spots on a red base that appear on the buccal mucosa inside the oral cavity near the second molars, two to three days after symptoms start and last for 3-5 days. They are typically described as “grains of salt on a red background”. They are not painful. They are characteristic of measles but not always present.
Sore throat and hoarseness
- A sore throat with or without hoarseness of voice may be present.
Enlarged lymph nodes
- Enlarged lymph nodes may appear a week before the rash and last for several weeks. The lymph nodes involved are the mastoid (behind the ear), posterior cervical, and suboccipital lymph nodes.
Other possible early symptoms include
- Photophobia
- Periorbital edema (edema around the eyes) and
- Muscle aches
You should see your doctor if you or your child experience any of the symptoms or have come in close contact though for a short time with anyone diagnosed with measles. This is especially so if you or your child have not been vaccinated or have not had measles in the past. This is because the child is highly vulnerable then.
Complications
Despite an effective vaccine, measles remains one of the leading causes of death among children globally.
Mortality from measles mainly results from the consequences of bacterial infections. Complications usually develop in those in whom fever does not drop within 1 or 2 days after the onset of the rash.
The most common complications of measles are:
- Ear complication
- Otitis media. Bacterial ear infection is one of the most common complications of measles in children especially those under five years old. About 14% of such children with active infection are affected. The measles virus can spread to the middle ear through the eustachian tube that connects the middle ear with the nasal-sinus cavity. This results in inflammation and blockage that can lead to secondary bacterial infection.
- Lung complications
- Bronchitis, laryngitis, or croup. Measles may lead to inflammation of the airways. This is referred to as croup. Croup (laryngotracheobronchitis) is commonly a viral respiratory infection that affects young children. Croup causes inflammation and swelling of the child’s larynx (voice box) and trachea (windpipe). This inflammation causes the bronchi (airways) to narrow due to increased mucus formation, which makes breathing difficult. Inflammation of the airways is called bronchitis.
- Pneumonia. Pneumonia could be due to the measles virus itself or could be due to secondary bacterial infection. It accounts for six out of ten deaths due to measles. It is the most common complication of measles that causes death. People with weakened immune systems and those not vaccinated are most susceptible.
- Gastroenteritis tract complications
- Diarrhea and vomiting. Diarrhea is reported to develop in less than 1 out of 10 people with measles. Diarrhea and vomiting can cause dehydration due to the loss of too much fluids from the body.
- Central nervous system complications. The central nervous system complications of measles after days or years of the acute infection are often severe.
- Encephalitis. Encephalitis is inflammation of the brain parenchyma due to the viral infection of the neurons. About 1 to 3 in 1,000 people with measles can develop this complication. Encephalitis can cause permanent brain damage and death, especially in unvaccinated people and those with weakened immune systems. It can develop right after measles or can develop months later.
- Subacute sclerosing panencephalitis (SSPE). SSPE is a progressive neurological complication with no cure. It is rare but has a very high mortality rate and typically affects children and adolescents several years after the initial measles infection.
- Pregnancy problems.
- Fetal complications. In pregnant women, measles can cause premature birth, low birth weight, and fetal death. Special care, therefore, should be taken if you develop measles during pregnancy.
- Maternal complications. Pneumonia is the most serious post-measles complication in pregnant women that usually requires hospitalization.
- Eye complications of measles. Measles can cause a number of eye complications and even blindness. These include:
- Conjunctivitis (pink eye). Conjunctivitis is inflammation of the conjunctiva, the membrane that covers the inner part of the eyelids. This is a common complication of measles that causes inflamed, red, and watering eyes.
- Keratitis. This is an infection of the cornea. It is the transparent, dome-shaped outer layer of the eye that covers the pupil and iris, facilitating the entry of light rays into the eye.
- Corneal ulcers and scarring. Measles can cause corneal ulcers, which can lead to scarring after the ulcers heal. This can damage the cornea and even lead to blurred vision or even loss of eyesight.
- Keratomalacia. This is a serious eye complication in which the cornea gets cloudy and softens. It can occur in those with vitamin A deficiency and lead to blindness.
