NATIONAL MEASLES LABORATORY

Specimen Collection and Transport

As a number of viral infections can mimic measles and cause measles-like rashes (eg rubella, parvovirus B19, enteroviruses etc.), confirmation by laboratory testing of clinically suspected cases is recommended.

1.    Serological Confirmation

In the first instance blood for serology should be collected.

Specimen required: 5 ml plain blood or serum.

2.    Other Investigations

Other samples for virological investigation should be collected in consultation with the laboratory. Timing and choice of sample is important for accurate diagnosis. 

  1. Combined nasopharyngeal and throat swab in virus transport media
  2. Blood in EDTA/ACD tube
  3. Urine - first passed, morning specimen preferred, collected as soon as possible after rash onset and at least within 5 days of rash onset.

3.    Specimen Transport

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Collection of Specimens for Detection of Measles Virus RNA by PCR

Photograph of virus transport medium with dry swabsMeasles virus can be assigned to one of 8 different clades of virus and further subtyped into 22 genotypes using PCR and sequence analysis of measles virus (MV) RNA. Measles genotyping is of practical use for differentiating the importation of virus from ongoing local measles virus transmission and for distinguishing vaccine strains from wild type virus.

The use of reverse transcriptase-polymerase chain reaction (RT-PCR) to detect measles virus RNA in various clinical specimens, including combined nasopharyngeal and throat swabs (NTS), nasopharyngeal aspirates (NPA), urine, CSF and blood has been described by several groups.

Reference

Riddell et al J Clin Microbiol 2001 39(l): 375-376.)

 

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Specimen Collection 

Identify patient with clinical symptoms of measles infection. (ie morbilliform rash, cough and fever at rash onset) within a few days (<5 days) after rash onset.

Virus is more likely to be present at the time of rash onset or within the first week after rash onset. Patients who have had rash onset within the last week should be sampled preferentially.

The specimen of choice is a nasopharyngeal swab and a throat swab from each patient combined together in a vial of viral transport medium (VTM). 

For laboratory isolates, viral culture supernatant, positive for MV growth, can also be sent for molecular analysis.

Please follow the instructions below to optimise chance of obtaining MV RNA from the patient.

  1. Nasopharyngeal Swab

    1. Diagram showing how to insert a sterile dry swab into the nasal cavity of patient.Insert a STERILE DRY SWAB into the nasal cavity of the patient and wipe the swab along the sides of the nasal passage. 
    2. Place the swab with the cotton tip end into the small vial (or leakproof screw top tube with 3-5 ml volume) of virus transport medium. KEEP TIP AND MEDIUM AS STERILE AS POSSIBLE.
    3. Break off (or cut off) the shaft of the swab at the top of the bottle so that the tip remains in the VTM and the lid can be screwed tightly shut.
    4. Please ensure the lid is on properly to prevent leakage.
    5. Label the VTM bottle with the patients ID, age, swab site (nasopharyngeal, throat or nasopharyngeal & throat) number of days post rash onset (if known). Swab tips (break or cut off shaft with scissors) from nose and throat of the SAME PATIENT can be combined into the same vial of VTM.

  2. Throat Swab

    1. Insert a dry STERILE DRY SWAB into the mouth and wipe along the back of the throat. It is important to take the sample from the back of the throat and NOT the sides of the mouth or cheek cavity, as the virus is mote likely to be found in the cells at the back of the throat.
    2. Follow steps 2-5 above.

  3. Additional requirements for Specimen Collection

    1. Sterile dry swabs must be sealed and sterile before use. Recommend use of a fresh sterile swab for each site to be sampled.
    2. Viral transport medium: (sterile, usually consisting of Hanks balanced salt solution and antibiotics to reduce bacterial contamination growth.) These should be available from your laboratory service provider or nearest virus laboratory.  Sterile medium should be asceptically dispensed into sterile leakproof bottles or tubes of 3-5 ml volume.
    3. Dry swabs or swabs placed into gel type transport media ARE NOT SUITABLE for recovery of viral RNA and are not recommended.Back to Top!

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Specimen Transport

Photograph showing label of Viral Transport MediumSamples should be transported to the laboratory strictly in accordance with the IATA dangerous regulations for transporting biological specimens within New Zealand.
Samples should be kept at 4° C whenever possible.
All samples must be accompanied by either a copy of the public health notification form or the New Zealand National Measles Laboratory Form.

  1. Place the specimen at 4ºC (in the fridge) DO NOT FREEZE.
  2. Samples should be transported to Virology Section, Microbiology Unit Canterbury Health Laboratories, Corner Hagley Ave/Tuam St, Christchurch.  Ph (03) 364 0355 Fax (03) 364 0750 on "wet ice"- DO NOT FREEZE as this may harm the MV-RNA and reduce the chances of a positive test result.
  3. Please contact the Virology Laboratory at Canterbury Health Laboratories when ready to ship specimens kevin.barratt@cdhb.govt.nz (03) 364 0356Back to Top!