Measles, also known as rubeola, is a highly contagious viral disease caused by the rubeola virus. It spreads easily through respiratory droplets in the air and can affect individuals of all ages, though it is often associated with childhood.
Initial Infection and Symptom Progression
The measles virus typically enters the body through the respiratory tract after inhaling contaminated air or touching infected surfaces. Following exposure, there is an incubation period, usually lasting between 10 to 12 days, during which no symptoms are apparent. The infection then progresses to a prodromal phase, characterized by a high fever that can reach 104°F (40°C), a persistent cough, a runny nose (coryza), and red, watery eyes (conjunctivitis).
A unique early sign of measles is Koplik spots, small, bluish-white spots with a reddish background found inside the mouth, typically opposite the upper molars. These spots usually emerge one to two days before the characteristic skin rash and may fade as the rash develops. The measles rash, appearing about three to five days after the initial symptoms, consists of flat red spots that first emerge on the face, often at the hairline and behind the ears. This rash then spreads downwards, covering the trunk, arms, and legs, eventually fading after five to seven days.
Systemic Effects and Manifestations
Beyond the visible symptoms, the measles virus impacts various bodily systems. The respiratory system is notably affected, with the virus inflaming the airways and leading to a severe cough. This inflammation can predispose individuals to secondary bacterial infections like pneumonia, a leading cause of measles-related deaths.
The measles virus significantly impacts the immune system, causing a temporary but profound suppression of its functions. This suppression makes the body vulnerable to other infections for weeks or months after the rash resolves, a phenomenon sometimes called “immune amnesia.” The virus directly infects immune cells, contributing to this compromised state.
The characteristic rash results from the immune system’s reaction to the virus within skin cells, leading to inflammation and discoloration. Measles can also affect the gastrointestinal system, potentially causing diarrhea, which is a common complication, particularly in younger children. The conjunctivitis experienced during measles can become severe and, especially in malnourished children, may contribute to vitamin A deficiency, raising the risk of blindness.
Potential Severe Complications
Measles can lead to several serious and potentially life-threatening complications. One such complication is encephalitis, a severe inflammation of the brain that occurs in about 1 in 1,000 measles cases. This condition can manifest with symptoms such as seizures and may result in permanent neurological damage.
A rare but devastating long-term complication is Subacute Sclerosing Panencephalitis (SSPE), a fatal degenerative neurological disease. SSPE can develop years after a seemingly full recovery from measles, typically appearing an average of seven years post-infection. This condition has no cure and progresses to severe neurological deterioration.
Other complications include ear infections (otitis media) and laryngotracheobronchitis, commonly known as croup. While these are less severe than encephalitis or SSPE, the risk of secondary infections due to measles-induced immune suppression remains a concern.
Immune Response and Recovery
The body’s immune system eventually mounts a response to fight off the measles virus. This process involves the generation of specific antibodies and immune cells that target and clear the virus from the body. Once a person recovers from measles, they typically develop lifelong immunity, protecting them from future infections by the same virus.
The recovery process from measles can take several weeks. During this time, individuals may experience lingering fatigue as their body regains full energy.