Measles virus: Structure, Pathogenesis, Lab Diagnosis

By Acharya Tankeshwar •  Updated: 05/24/22 •  6 min read

The name measles is derived from the Latin, misellus, meaning miserable. Measles (also called Rubeola-(from rubeolus, Latin for reddish) ) is usually a disease of childhood (aged 3-10 years) and is followed by life-long immunity.  Measles is a highly contagious and sometimes deadly disease that spreads through coughing and sneezing. It can spread like wildfire in naive populations. Measles is an important cause of childhood mortality in developing countries. Human is the natural host of this pathogen.

Structure of Measles Virus

Structure of Measles Virus
Structure of Measles Virus

Replication cycle of Measles Virus

Transmission and Epidemiology of Measles

Health Alert Sign in a Clinic

Pathogenesis

Clinical features of Measles

 Fig: Clinical features of typical measles - time course from onset of illness
Fig: Clinical features of typical measles – time course from onset of illness
Koplik's Spot
Koplik’s Spot
Child infected with Measles Source:: CDC
A child infected with Measles
Source:: CDC

Complications  because of Measles infections

Laboratory diagnosis of measles

Isolation and Identification of the virus

Nasopharyngeal and conjunctival swabs, blood samples, respiratory secretions, and urine collected from a patient during the febrile period are appropriate sources for viral isolation. Monkey or human kidney cells or a lymphoblastoid cell line (B95-a) are optimal for isolation attempts. Measles virus grows slowly; typical cytopathic effects (multinucleated giant cells containing both intranuclear and intracytoplasmic inclusion bodies) take 7-10 days to develop. Shell vial culture tests are completed in 2-3 days using fluorescent antibody staining to detect measles antigens in the inoculated cultures.  

However, virus isolation is technically difficult. It is not routinely performed for diagnosis as sensitivity is lower than serologic techniques.

Serology

 Immune responses in acute measles infection
Immune responses in acute measles infection

Serologic confirmation of measles infection depends on a fourfold rise in antibody titer between acute-phase and convalescent-phase sera (where the second serum sample is collected at least 10 days after the first, acute sample) or on the demonstration of measles specific IgM antibody in a single serum specimen drawn between 1 and 2 weeks after the onset of rash. IgM antibody levels peak after about 7-10 days and then decline rapidly, and are rarely detected after 6-8 weeks.  

ELISA, HI, and neutralization tests all may be used to measure measles antibodies, though ELISA is the most practical method.  IgG antibody levels peak within about 4 weeks and persist long after infection.  

The major part of the immune response is directed against the viral nucleoprotein. Patients with subacute sclerosing panencephalitis (SSPE) display an exaggerated antibody response, with titers 10 to 100 fold higher than those seen in typical convalescent sera.  

Haemagglutination–inhibition tests or ELISA antibody assays are the most practical, but plaque reduction neutralization tests are the most sensitive and specific. The virus has been isolated from respiratory tract secretions and rarely from urine or circulating lymphocytes during the prodromal phase of illness or within a few days after the rash onset.  

Immunofluorescence staining of nasal or throat secretions or urine has been successful but is not widely available. SSPE is confirmed based on characteristic EEG patterns and demonstration of measles antibody in the cerebrospinal fluid (CSF) with an increased CSF to serum measles antibody ratio, or by the demonstration of virus in brain tissue.  

Very high measles antibody titers aside from acute infection and SSPE are regularly seen in autoimmune chronic active hepatitis and occasionally in systemic lupus erythematosus.

Prevention of Measles


Measles can be prevented with MMR vaccine. The vaccine protects against three diseases: measles, mumps, and rubella.
The MMR vaccine is very safe and effective. Two doses of MMR vaccine are about 97% effective at preventing measles; one dose is about 93% effective.
CDC recommends children get two doses of MMR vaccine,

  1. the first dose at 12 through 15 months of age, and
  2. the second dose at 4 through 6 years of age.
    Teens and adults should also be up to date on their MMR vaccination.

Acharya Tankeshwar

Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. As an asst. professor, I am teaching microbiology and immunology to medical and nursing students at PAHS, Nepal. I have been working as a microbiologist at Patan hospital for more than 10 years.

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