BY SAMANTHA BARTLETT, DVM
The Companion Animal Parasite Council (CAPC) published a scientific article on prevalence of Lyme disease, caused by Borrelia burgdorferi, in the United States. The article, entitled A large-scale spatio-temporal binomial regression model for estimating seroprevalence trends, concluded that canine Lyme disease is rising in prevalence along with increased incidences of human cases and that prevalence in dogs is on the rise in non-endemic states, which suggests an increased risk to humans in these areas. The study was published in Environmetrics, the official journal of The International Environmetrics Society.
The researchers collected data from IDEXX laboratories on 16 million serologic Lyme tests conducted on dogs in veterinary clinics from January 2012 until December 2016. This data was then used to infer that exposure risks are increasing in areas of prevalence and alos to determine areas where tick population is increasing. The rate of increase was greater in known regions of high Lyme incidence including Maine, West Virginia, Virginia, and northern Minnesota and Wisconsin. Increasing trends are also seen as far south as North Carolina and Tennessee; areas where Lyme disease has traditionally been considered non-endemic. Other areas of increasing trends include Minnesota, Wisconsin, Iowa, Ohio, Indiana and Michigan. The prevalence of Lyme disease in endemic areas of the New England is stable.
In areas that a significant change of canine prevalence has been identified, there have not been reports of significant incidence in humans. However, the canine data can be used as a sentinel for risk to humans. West Virginia, Western Pennsylvania and Eastern Ohio are currently at the leading edge of this expanding territory. These regions were also noted to have increasing reports of ticks.
As tehse territories expand, humans and dogs are at greater risk when exposed to ticks when traveling in areas of growing incidence. Being aware of the growing incidence of Lyme disease will with diagnosis of any dog that may be exhibiting clinical signs and hopefully will increase testing on a routine basis. Tick prevention is vital to the control of Lyme disease. Educating pet owners also helps in control of this disease. Ticks are not just in wooded areas, but also in communities where wildlife share space. CAPC recommendations include regular screening in dogs, and year-round tick protection in dogs and cats.
CAPC provides monthly forecasts for Lyme disease and maps that show prevalence based on canine testing. These maps can be used to determine exposure risks across Canada and the United States. The CAPC maps can be accessed at petsandparasites.org. The monthly forecasts are published on petdiseasealerts.org.
