Figure 1: Number of cases of measles (n=191) and rubella (n=1), by week of rash onset, as reported to the Canadian Measles/ Rubella Surveillance System (CMRSS) and Measles and Rubella Surveillance system (MARS), for the period ending April 11 2015 .
During epidemiological week 14, 2015, 8 new cases of measles were reported, by British Columbia (n=6) and Quebec (n=2). Rash onsets for these cases occurred in week 11 (n=2), week 13 (n=5) and week 14 (n=1). Recent cases in British Columbia have been linked to travel to China. Conversely, cases in Quebec have primarily been reported in a non-immunizing religious community, linked to travel to the USA.
One imported case of rubella was reported in Ontario, with rash onset during week 12.
The year-to-date total is 191 cases of measles and 1 case of rubella for 2015.
Note that when additional cases are reported in advance of the cycle, these cases will be described in the appropriate reporting cycle.
To date in 2015, 48 measles cases have been genotyped and the genotypes were: B3 (n=20), D4 (n=17), H1 (n=9) and D8 (n=2).
From Quebec, 20 cases were genotyped and were genotype B3, identical to the MVi/Harare.ZWE/38.09 sequence variant (GenBank accession number JF973033), and identical to the virus reported in a multi-state outbreak in the United States.
Nine cases from British Columbia were genotype H1 which is endemic in ChinaFootnote 2, consistent with travel and exposure history for these cases. All nine cases had N-450 sequences identical to the MVs/Hong Kong.CHN/49.12 sequence variant (GenBank accession number KC417295).
Figure 3: Distribution of measles genotypes detected in 2015 (n=48) by week of rash onset (if available, n=48) or specimen collection (n=0). Epidemiological weeks are assigned in accordance with WHO guidelines (WHO.WER.2012;9(87):73) with week 1 beginning on the first Monday of the year.
The current global distribution of measles genotypes can be found on the WHO Measles Surveillance website.
For information regarding the interpretation and use of measles genotyping (including a discussion of genotypes and sequence variants), refer to Hiebert J and Severini A. Canada Communicable Disease Report. 2014; 40-12: 257- 260.