Measles Virus - Rubeola

Clinical Background

Measles is a highly contagious disease caused by the measles (rubeola) virus.

Prevalence – minimal number of cases yearly in U.S. due to the high rate of vaccination
- >750,000 deaths worldwide
- Occasional small outbreaks from imported cases of measles primarily infecting unvaccinated individuals
Transmission
- Via respiratory droplets
- Highly contagious; >90% transmission among non-immune individuals

A single-stranded RNA virus and the only member of genus Morbillivirus (Paramyxoviridae family)
Humans are the only natural reservoirs

Highly contagious, acute, exanthematous respiratory disease with pathognomonic Koplik spots on the buccal mucosa
- Cutaneous rash starts centrally and spreads to the periphery
Diagnosis based on clinical exam may be difficult, especially in atypical cases
- In atypical measles, rash begins peripherally and moves centrally
- Atypical measles has occurred in patients who received killed vaccines and later came in contact with wild virus strain
Severe, often fatal pneumonia can occur in patients with deficient cell-mediated immunity
Complications
- Pulmonary – primary giant cell pneumonia (Hecht pneumonia)
  - Severe, often fatal pneumonia can occur in patients with deficient cell-mediated immunity
- Neurological – coma, seizures, encephalitis
  - Subacute sclerosing panencephalitis (SSPE) – rare, progressive encephalitis that may result in dementia and death
  - Acute disseminated encephalomyelitis (ADEM)
  - Measles inclusion body encephalitis in immunocompromised patients
- Gastrointestinal – disease mimicking appendicitis
- Cardiovascular – myocarditis, pericarditis
- Occular – corneal ulceration and scaring
- Gestational – increased incidence of pneumonia in pregnant women, spontaneous abortion, premature delivery and low birth weight babies

Prevention includes measles, mumps and rubella (MMR) vaccine administered to 12-15 month old children, with revaccination between 4-12 years
- High fever and pulmonary infiltrates can occur in patients exposed to measles that were vaccinated with MMR between 1964-67
  - Symptoms believed to be hypersensitivity reactions to the vaccine
- Mass U.S. immunization has greatly reduced measles infections
  - However, some individuals may be susceptible to measles due to vaccine failure or non-immunization
Because vaccine is live, attenuated virus, do not use in pregnant patients or those with significant immunosuppression

Serum testing for antibodies
- Confirm acute infection with measles using IgM and IgG serial testing
- Confirm seroconversion after vaccination using IgG testing
- IgM, IgG cerebrospinal fluid (CSF) testing to identify SSPE (which may occur years after original infection using IgG testing)
Viral culture
- Nasopharyngeal and blood cultures are most sensitive if collected during prodrome up to 1-2 days after onset of rash
- Virus can be isolated from urine culture up to 1 week or more after onset of rash
- Difficult to isolate from CSF and brain tissue
RT-PCR – not widely available, but useful for testing CSF

Tests generally appear in the order most useful for common clinical situations
Click on number for test-specific information in the ARUP Laboratory Test Directory

Test Name and Number	Recommended Use	Limitations	Follow Up
Measles (Rubeola) Antibodies, IgG & IgM 0050375 Method: Enzyme-Linked Immunosorbent Assay	Diagnose measles	Low IgM antibody levels occasionally persist >12 months post-infection or immunization	Residual IgM response may be distinguished from early IgM response by testing patient sera 2-3 weeks later for changes in specific IgM antibody levels
Measles (Rubeola) Virus Culture 0065055 Method: Cell Culture/Immunofluorescence	Gold standard test for nasopharyngeal aspirate/washing, throat swab, lung tissue, CSF or urine samples
Measles (Rubeola) Antibody, IgG 0050380 Method: Enzyme-Linked Immunosorbent Assay	Screen for vaccination
Measles (Rubeola) Antibody, IgM, CSF 0054441 Method: Enzyme-Linked Immunosorbent Assay	Diagnose rare but fatal subacute sclerosing panencephalitis (SSPE) in CSF samples	Rubeola CSF antibody detection may indicate central nervous system infection; however, consider possible contamination by blood or transfer of serum antibodies across blood-brain barrier
Measles (Rubeola) Antibody, IgG, CSF 0054440 Method: Enzyme-Linked Immunosorbent Assay	Diagnose rare but fatal subacute sclerosing panencephalitis (SSPE) in CSF samples	Rubeola CSF antibody detection may indicate central nervous system infection; however, consider possible contamination by blood or transfer of serum antibodies across blood-brain barrier

Additional Tests Available

Click the plus sign to expand the table of additional tests.

Test Name and Number	Comments
Measles (Rubeola) Antibody, IgM 0099597 Method: Enzyme-Linked Immunosorbent Assay
Encephalitis Panel, CSF with Reflex to HSV Type 1 & 2 Glycoprotein G-Specific Ab, IgG 2001741 Method: Enzyme-Linked Immunosorbent Assay/Indirect Fluorescent Antibody
Encephalitis Panel, Serum with Reflex to HSV Type 1 and Type 2 Glycoprotein G-Specific Ab, IgG 2001742 Method: Enzyme-Linked Immunosorbent Assay/Indirect Fluorescent Antibody
Meningoencephalitis Panel, CSF with Reflex to HSV Type 1 & Type 2 Glycoprotein G-Specific Ab, IgG 2001765 Method: Enzyme-Linked Immunosorbent Assay/Indirect Fluorescent Antibody
Meningoencephalitis Panel, Serum with Reflex to HSV Type 1 & Type 2 Glycoprotein G-Specific Ab, IgG 2001764 Method: Enzyme-Linked Immunosorbent Assay/Indirect Fluorescent Antibody/Chemiluminescent Immunoassay