Chikungunya Virus: The Canadian Perspective

Transcription

1 Chikungunya Virus: The Canadian Perspective Kimberly Holloway, M.Sc., Zoonotic Diseases Michael Drebot, PhD, Director Zoonotic Diseases and Special Pathogens

2 Environment Canada Quote According to Environment Canada, stiff northwesterly winds will combine with the possibly record setting temperatures to produce wind chill values of between 30 and 40 overnight and on Monday morning. The temperature will then improve somewhat on Monday afternoon, according to Environment Canada. During the extreme cold, the weather agency is warning residents to dress appropriately as frostbite is possible on exposed skin within 10 minutes.

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4 Canada Population of 35.5 million (0.037 million) (4.6 million) (0.044 million) (0.037 million) 2.5 million visits to Caribbean countries annually Top 10 warmer travel destinations 1. USA 2. Mexico 3. Cuba 4. Dominican Republic 10. Jamaica 2012 Stats Can data (4.1 million) (1.2 million) (0.53 million) (1.1 million) (13.7 million) (8.2 million) (0.15 million) Edward Island Winnipeg (0.9 million) (0.75 million)

5 Number of Annual Requests for Chikungunya Testing at NML Number of Requests for Serological Testing 1926 Submissions In 2014 As of Feb 26, 2015 NML has received 781 requests for Chikungunya serology and / or PCR Year

6 Diagnostic Algorithm, NML Prior to 2014, HAI (in house produced SMB antigen) and / or commercial IFA (Euroimmun) As of February 2014 All samples tested by IgM ELISA based on the CDC developed methodology (tissue culture derived antigen, produced in house at NML) All equivocal samples tested by real time PCR All positives further tested by PRNT and real time PCR (date of onset / limited info?) 6

7 vrna Real Time PCR nsp1 nsp2 nsp3 nsp4 C E3 E2 6K E A non structural polyprotein gene Moscow/Como Lanciotti, 2014 E1 protein gene Pongsiri et al., Asian Pac J Trop Med. External Panels Positive for Chikungunya vrna Ct values of less than 38 with both primer / probe sets 1. European Network for Diagnostics of Imported Viral Diseases 2. Food and Drug Administration / WHO CBER CHIK working reagent

8 Number of Confirmed Cases of Chikungunya per year 250 Number of Cases Confirmed cases 127 Probable cases Year Gold Standard / Confirmatory Test Result : PRNT positive and / or PCR positive Data as of February 20, 2015

9 Number of Cases of Chikungunya per year 427 Confirmed cases 127 Probable cases 86 / 427 confirmed cases PCR positive 20% Viremic 64 / (427 confirmed probable) were PCR equivocal (one of two primer probe sets positive --- Ct less than 38) Will be subjected to Conventional & Nested PCR

10 Provinces with reported cases of Chikungunya infection (2014) as of February 20, 2014 Quebec (30%) Ontario (57%) Manitoba (2.4%) Newfoundland (0.2%) Saskatchewan (0.7%) Alberta (4.1%) New Brunswick (0.5%) British Columbia (4.3%)

11 In House Validation of Euroimmun IgM Chikungunya ELISA Specificity Testing 2 different ELISA kit lots used testing performed over a few month time period 60 samples In house ELISA IgM Negative 36 of the samples had documented travel history Euroimmun Results 1 Positive for Ross River virus IgM antibodies 1 Positive for West Nile virus IgM antibodies 10 Positive for Dengue virus IgM antibodies 58 samples were Negative for IgM antibodies 2 samples generated Equivocal results for IgM 97%

12 In House Validation of Euroimmun IgM Chikungunya ELISA Sensitivity Testing 2 different lots of ELISA kits were tested 100 samples In house ELISA IgM positive 71 had documented travel history 74 samples Confirmed by Chik PRNT Euroimmun 100 % sensitivity Samples confirmed by PRNT and / or real time PCR or HAI Euroimmun IgM ELISA commercial kit 4 samples PRNT negative PCR positive generated Equivocal IgM results 1 sample PRNT positive PCR not tested generated Equivocal IgM results 2 samples PRNT negative PCR positive generated Negative IgM results 93%

13 Travel History of Confirmed Cases Only 30% 130 /427 confirmed cases have travel history America s (93%) Africa (0.77%) Oceania (0.77%) Asia (5.4%)

14 Future Considerations Canadian Perspectives Canadian Travellers Need To Be Aware That No Chik Vaccines are Currently Available: So Preventative Measures to Decrease Risk Of Exposure Are Key (eg. bug repellent, awareness of virus circulation, etc) Future expansion of Chik is quite likely and the possibility of albopictus becoming established in Canada is possible - modeling research ongoing In Canada commercial ELISA kits have been evaluated for Tech Transfer to Provincial Health Labs to increase diagnostics/testing capacity Blood donations and Chikungunya, Will this be an issue? Are more Infected individuals asymptomatic than previously recognized?

15 Viral Zoonosis, National Microbiology Laboratory Dr Michael Drebot, Director Viral Zoonosis and Special Pathogens Dr Robbin Lindsay, A Chief Viral Zoonosis Kimberly Holloway Kristina Dimitrova Kai Makowski Maya Andonova

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