Provincial health officials in British Columbia and national public health have confirmed a new species of bacteria closely related to Borrelia mayonii (B. mayonii) in three ticks since the summer.
“This is a rare discovery which highlights that our tick surveillance program is working at both a local and national level,” said Dr. Eleni Galanis, physician epidemiologist with the BC Centre for Disease Control (BCCDC). “While further investigation is warranted, the health threat posed by this new species of bacteria is extremely low.”
Borrelia mayonii is a newly-discovered species of bacteria that can cause Lyme disease in people. Until now, it had only been confirmed in the Midwestern United States. According to the Centers for Disease Control and Prevention in the United States, six of approximately 9,000 diagnostic samples from residents of Minnesota, Wisconsin, and North Dakota revealed the presence of B. mayonii.
- The first infected tick was removed from a dog in June 2016 that had been camping with its owner in the Lower Mainland. While the tick was positive for the new bacteria, the dog remains well and has no signs or symptoms of Lyme disease.
- The second infected tick was removed from a child in July 2016. The child is believed to have been bitten in the Central Interior of BC. The child also remains well and has had no signs or symptoms of Lyme disease.
- The third infected tick was removed from a dog in the Lower Mainland in September 2016. This dog also has no signs or symptoms of Lyme disease.
The BCCDC and Public Health Agency of Canada (PHAC) are studying the clinical implications of this discovery, and follow up has occurred with the pet owners and the family of the child involved.
“When the first tick with this B. mayonii-like bacteria was confirmed by PHAC’s National Microbiology Laboratory, the BCCDC Public Health Laboratory retested all tick samples that had inconclusive results over the last several years,” said Dr. Muhammad Morshed, clinical microbiologist with the BCCDC. “Of more than 19,000 ticks tested by PHAC, and nearly 2,800 more at the BCCDC, these are the only three that have been found with this B. mayonii-like bacteria.”
In BC, less than 1 per cent of ticks tested carry bacteria that can cause Lyme disease, and the prevalence of Lyme-causing bacteria in BC ticks has remained consistently low.
Two species of ticks in BC have been shown to carry the agent of Lyme disease: Ixodes pacificus and Ixodes angustus. These are different from the ticks that carry Lyme disease (primarily Ixodes scapularis) in central and eastern North America.
The three ticks infected with the B. mayonii-like bacteria in BC were all Ixodes angustus ticks. This tick species is found in low numbers across Canada and most often is found on rodents and rabbits; however, it does feed on domestic animals like dogs and cats and will occasionally bite humans.