2018 has been a very busy year for West Nile Virus in the province. The combination of a warm spring and adequate moisture levels worked to create an early bloom of mosquito activity. In 2003, the first year the virus truly emerged in Alberta, we had 170 cases reported, with the next worst year being 2007 with 46 cases reported.
As of September 27, we had a total of 75 cases reported to the Office of the Chief Provincial Veterinarian (OCPV), most of which occurred in a narrow window of two to three weeks. A map (below) is provided to inform you of the locations and numbers of cases; note that cases have been detected across a significant portion of the province and in past years, cases have been seen in areas that seem unaffected this year. Note that the map does not include all cases for this year as some details are either incomplete or unavailable for some cases.
As horses are the only sentinel species for the province, we work closely with Alberta Health to advise them of case locations so that they can ramp up any awareness campaigns in the areas where horses test positive.
The big jump in cases this year should serve as a reminder of the importance to vaccinate horses for this disease; not only to protect the health of the horse population but also to reduce the risk to human health. While vaccinations should be considered in June to mid-July before mosquito activity peaks, you should speak with your veterinarian to optimize the timing of vaccinations.
Dr. Keith Lehman
Chief Provincial Veterinarian