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Measles

Clinical Information

Reporting Measles

Measles is a reportable disease in Arizona. The Arizona Administrative Code, R9-6-202 and R9-6-204, require providers and laboratories to report cases or suspect cases of measles within 24 hours.

Healthcare providers and labs can refer to the Office of Infectious Disease Services' Reporting of Communicable Diseases page to access information regarding the reporting of communicable diseases.

If any healthcare provider suspects measles as a possible diagnosis in a patient, they should notify their local health department immediately.

Laboratories are also required to submit any positive measles specimens to the Arizona State Public Health Laboratory at least once each week.

According to the Arizona Administrative Code R9-6-350 a local health agency shall:

  • Upon receiving a report under R9-6-202 or R9-6-203 of a measles case or suspect case, notify the Department within 24 hours after receiving the report and provide to the Department the information contained in the report;
  • Conduct an epidemiologic investigation of each reported measles case or suspect case;
  • For each measles case, submit to the Department, as specified in Article 2, Table 4, the information required under R9-6-206(D); and
  • Ensure that specimens from each measles case, as required by the Department, are submitted to the Arizona State Laboratory.

Clinical Information

Symptoms

Symptoms of measles include a generalized rash lasting more than 3 days, a temperature greater than or equal to 101.0°F, a cough, a coryza, or conjunctivitis.

Other symptoms of measles may include anorexia, diarrhea, especially in infants, and generalized lymphadenopathy.

Refer to the Case Definition ManualPDF for more information regarding the classification of measles.

Clinical Features

The incubation period of measles, from exposure to prodrome is often between 8-12 days in most cases. Time between exposure and rash onset averages 14 days (range, 7-21 days).

The prodrome lasts 2-4 days (range 1-7 days). It is characterized by fever, which increases in stepwise fashion, often peaking as high as 103°-105°F. This is followed by the onset of cough, coryza (runny nose), or conjunctivitis.

Koplik spots, rashes present on mucous membranes, are considered to be characteristic of measles. They occur 1-2 days before the rash to 1-2 days after the rash, and appear as speckled blue-white spots on the bright red background of the buccal mucosa.

The measles rash is a maculopapular eruption that usually lasts 5-6 days. It begins at the hairline, and then involves the face and upper neck. During the next 3 days, the rash gradually proceeds downward and outward, reaching the hands and feet. The maculopapular lesions are generally discrete, but may flow together, particularly on the upper body. Initially, lesions blanch with fingertip pressure. By 3-4 days, most of the lesions do not blanch with pressure. Fine shedding of the outer layers of the skin, or desquamation, occurs over more severely involved areas. The rash fades in the same order that it appears, from head to extremities.

In immunocompromised individuals, measles may present atypically.

Severity

Severity of the disease ranges from mild symptoms, which generally resolve between 7 to 10 days, to a severe illness that can lead to death.

Susceptibility

Anyone can become infected with measles if they have not been vaccinated or been infected with the disease previously. Before routine vaccination was introduced in the United States, measles was a common illness in infants, children and young adults. Because most people now have been vaccinated, measles is a rare disease in the United States.

Immunity after natural disease is usually lifelong. Immunity after vaccination is long term and thought to be lifelong.

Epidemiology

Before a vaccine was available, infection with measles virus was nearly universal during childhood. Measles is still a common and sometimes fatal disease in developing countries. The World Health Organization estimates there were more than 20 million cases and 242,000 deaths from measles in 2006.

Measles is very rare in the western hemisphere due to widespread vaccination against the virus. Any cases in the US generally originate outside the country, either brought in by American residents travelling outside the country or by foreign nationals. Measles virus is still widely circulating in areas in Europe, Asia, and Africa.

  • Mode of Transmission - The virus is usually spread through airborne transmission or droplet spread.
  • Incubation - The incubation period of measles, from exposure to prodrome averages 8?12 days. From exposure to rash onset averages 14 days (range, 7-18 days).
  • Reservoir - The only known reservoirs of the measles virus are human beings. There are no known animal reservoirs.

Diagnosis

A diagnosis requires that the case is laboratory confirmed and that it meets the clinical case definition. The ideal specimens for laboratory submission are a Dacron nasopharyngeal swab and blood. Specimen testing at the Arizona State Laboratory can be arranged by contacting your local health department.

Laboratory Specimen Type:

  • Measles virus can be detected using PCR from a nasopharyngeal swab placed in viral transport media (Hanks solution), ideally taken within 3 days of rash onset. If a specimen cannot be obtained within 3 days of rash onset, clinical specimens should be collected within 7 days (not to exceed 10 days) after rash onset.
  • Blood specimens collected for Measles IgM antibody testing also confirm an acute measles infection. Blood specimens should be collected no sooner than 72 hours after rash onset. Blood specimens collected sooner than 72 hours may yield false negative results.
  • Recent vaccination of a suspect measles case (within 1 to 2 months) may interfere with laboratory testing and make the results difficult to interpret.

Refer to the Instructions for Collecting Nasopharyngeal Swab Specimens guidePDF for detailed nasopharyngeal swab specimen collection instructions.