Measles

Measles
source
Name	Measles
Specialty	Infectious disease, World Health Organization
Symptoms	Fever, cough, coryza, conjunctivitis, enanthem, maculopapular rash
Complications	Pneumonia, encephalitis, otitis media, subacute sclerosing panencephalitis
Onset	10–14 days after exposure
Duration	Acute phase ~7–10 days; complications variable
Cause	Morbillivirus (single-stranded negative-sense RNA), Centers for Disease Control and Prevention
Diagnosis	Clinical examination, serology (IgM), RT-PCR
Prevention	Live-attenuated vaccine (MMR), herd immunity, United Nations
Treatment	Supportive care, vitamin A, antibiotics for secondary bacterial infection
Frequency	Historically pandemic; now vaccine-preventable but resurging in undervaccinated populations

Measles Measles is an acute viral illness caused by a morbillivirus that produces a prodrome of fever, cough, coryza, and conjunctivitis followed by a characteristic maculopapular rash. Historically a major cause of childhood mortality, measles is now vaccine-preventable and the focus of global elimination efforts led by agencies such as the World Health Organization, Centers for Disease Control and Prevention, and national public health institutes. Outbreaks continue to occur in settings with declining vaccination coverage, refugee crises, and disrupted health services, drawing attention from organizations including United Nations Children's Fund and Médecins Sans Frontières.

Signs and symptoms

The prodromal phase typically includes high fever, cough, coryza, and conjunctivitis; Koplik spots on the buccal mucosa appear before the rash. Patients develop an erythematous maculopapular rash that spreads cephalocaudally and fades over days; complications such as otitis media and pneumonia can follow. Severe presentations occur in malnourished children and immunocompromised hosts, with increased risk of encephalitis and prolonged viral shedding; case-management protocols are influenced by guidance from World Health Organization, European Centre for Disease Prevention and Control, and national ministries of health such as the US Department of Health and Human Services.

Virology and pathogenesis

The etiologic agent is a single-stranded negative-sense RNA virus in the genus Morbillivirus, family Paramyxoviridae; viral entry is mediated by epithelial receptors and the fusion (F) and hemagglutinin (H) glycoproteins. Following inhalation, replication occurs in respiratory epithelium and local lymphoid tissue with viremia that seeds skin, conjunctiva, and other organs. Immune responses, including robust T‑cell activation and neutralizing antibodies, drive viral clearance and rash formation; immunopathology underlies complications such as acute postinfectious encephalitis. Molecular surveillance and genotype tracking have been coordinated by laboratories linked to institutions like Centers for Disease Control and Prevention, Wellcome Trust Sanger Institute, European Centre for Disease Prevention and Control, and regional reference centers.

Transmission and epidemiology

Transmission occurs via respiratory droplets and airborne spread in enclosed spaces with high infectivity and attack rates; the basic reproduction number (R0) is high in susceptible populations. Measles historically caused worldwide endemic cycles and large epidemics before widespread vaccination campaigns led by World Health Organization and national immunization programs. Outbreaks are documented in settings such as refugee camps, urban clusters, and regions with vaccine hesitancy or supply disruptions; public health responses often involve entities like UNICEF, Gavi, the Vaccine Alliance, Bill & Melinda Gates Foundation, and ministries of health. International travel, mass gatherings, and lapses in routine immunization contribute to reestablishment of transmission; surveillance networks including Global Outbreak Alert and Response Network and laboratory partnerships help detect and contain spread.

Diagnosis

Diagnosis is primarily clinical during outbreaks when the classic triad is present, supplemented by laboratory confirmation with measles-specific IgM serology or RT-PCR from respiratory or urine specimens. Differential diagnosis includes rubella, roseola, enteroviral exanthems, and drug eruptions; clinicians may consult guidance from American Academy of Pediatrics, Royal College of Paediatrics and Child Health, and national public health agencies. Laboratory confirmation and genotype analysis by reference laboratories such as those affiliated with the World Health Organization measles network inform outbreak investigation and elimination status.

Prevention and vaccination

Prevention relies on high population immunity via measles-containing vaccines, commonly administered as measles-mumps-rubella (MMR) or measles-rubella (MR) formulations in childhood immunization schedules endorsed by World Health Organization and national immunization technical advisory groups. Two-dose schedules increase effectiveness and support herd immunity targets; mass vaccination campaigns and supplemental immunization activities coordinated by UNICEF, Gavi, the Vaccine Alliance, and regional health authorities have reduced global incidence. Travel recommendations, school entry requirements, and outbreak control measures are informed by agencies such as Centers for Disease Control and Prevention, Public Health England, and the Pan American Health Organization. Cold-chain logistics and vaccine delivery often involve partnerships with organizations like International Federation of Red Cross and Red Crescent Societies and private manufacturers.

Treatment and management

Treatment is supportive: hydration, antipyretics, and monitoring for complications; vitamin A supplementation reduces morbidity and mortality in children in accordance with WHO guidance. Secondary bacterial infections receive appropriate antimicrobial therapy guided by local formularies and stewardship programs. Hospitalization is indicated for severe respiratory compromise, neurologic involvement, or high-risk groups including the immunocompromised and pregnant patients; clinical management protocols are available from World Health Organization, Centers for Disease Control and Prevention, and specialty societies such as the Infectious Diseases Society of America.

Complications and prognosis

Complications include pneumonia, acute encephalitis, otitis media, and late-onset subacute sclerosing panencephalitis; risk is higher in young infants, adults, malnourished individuals, and those with immunodeficiency. Case-fatality ratios vary by setting and access to healthcare; global mortality declines have followed vaccination scale-up spearheaded by WHO, UNICEF, and philanthropic initiatives such as the Bill & Melinda Gates Foundation. Post-exposure prophylaxis with immune globulin or expedited vaccination can modify disease course in susceptible contacts per recommendations from Centers for Disease Control and Prevention and national guidelines. Continued surveillance, immunization coverage, and coordinated responses from international organizations remain central to reducing measles burden worldwide.

Category:Viral diseases