Genotyping

Genotyping of specimens that are positive for measles virus by RT-PCR.

Urine, nasopharyngeal (NP) swab, throat swab. All specimens should be collected as soon as possible after rash onset (within 7 days for urine and 4 days for NP/throat swabs). Viral isolates may also be sent. Specimens should already have been determined to be measles RT-PCR positive.

Refer to the information sheet for Measles Molecular Detection (specimens should already have been determined to be measles RT-PCR positive).

Ship a minimum of 0.5 mL of clinical specimen or viral isolate frozen (-70°C) on dry ice.

Shipping of specimens shall be done by a TDG certified individual in accordance with TDG regulations. For additional information regarding classification of specimens for the purposes of shipping, consult either Part 2 Appendix 3 of the TDG Regulations or section 3.6.2 of the IATA Dangerous Goods Regulations as applicable.

Confirmed measles cases (by RT-PCR).

Completed Measles, Mumps, and Rubella requisition form. Include date of rash onset, date of last measles vaccination (if recent), travel history case number and/or MARS identifier (from the Measles and Rubella Surveillance application on CNPHI) if available. Please specify if the specimen is from a suspected vaccine case.

Labs that perform their own measles RT-PCR testing should submit positive samples for genotype surveillance and reporting to the World Health Organisation. It is important to provide a complete patient history (including travel) for accurate genotype surveillance. The NML is a WHO/PAHO accredited Measles and Rubella Regional Reference Laboratory.

Measles genotyping has been standardised by the WHO (5,6). The entire hemagglutinin (H) gene and/or a portion of the nucleoprotein (N) gene (the N-450) is amplified by conventional RT-PCR and sequenced to determine the genotype of the measles virus.

21 calendar days. Stat testing available upon request.

Note: During measles outbreaks, there may be delays in receiving genotyping results. Specimens may be triaged, giving highest priority to cases from new importations and to suspected vaccine cases, and lowest priority to cases from outbreaks of already known genotype. Please, contact the laboratory for stat requests.

1. Measles and Rubella Elimination Working Group, Health Canada, Public Health Agency of Canada. Guidelines for the prevention and control of measles outbreaks in Canada. CCDR. 2013; 39:ACS-3. Available at http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/13vol39/acs-dcc-3/index-eng.php#appa.
2. Tipples GA, M Gray, M Garbutt, PA rota, Canadian Measles Surveillance Program. Genotyping of measles virus in Canada: 1979-2002. J Infect Dis 2004; 189 Suppl 1:S171-176.
3. Tipples G, J Hiebert. Detection of measles, mumps and rubella viruses. Methods Mol Biol. 2011; 665: 183-193.
4. World Health Organization. Manual for the laboratory diagnosis of measles and rubella virus infection. 2007. WHO/IVB/07.01
5. World Health Organization. Measles virus nomenclature update: 2012. WER. 2012;87:73.80.