Peruvian Dogs Don’t Have Lyme Disease: Why You Should Care

from one of our collaborators, CLIMATE MD, a blog by Sarah Lovinger, MD. Dr. Lovinger blogs about the health implications of climate change.

Posted on October 16, 2013

Lyme disease rates have been increasing, and the spread of Lyme disease is linked to climate change.  Warmer winter in areas with a heavy Lyme disease burden–parts of New England and the Upper Great Lakes–favor survival of the ticks that carry B. burgdorferi, the bacteria that causes Lyme disease, making disease spread easier.

Just like humans, dogs get Lyme disease.  Canine Lyme is transmitted by the same bacterium, B. burgdorferi, as human Lyme is.  It’s also transmitted by deer ticks to dogs, the same transmission that humans experience.  It causes symptoms of arthritis in dogs, who may experience sudden lameness and severe pain. Dogs can also become lethargic and develop fevers and lack of appetite.  As in humans, dogs suffering from Lyme disease can be treated with antibiotics.

Lyme disease in dogs is obviously important to veterinarians, but this blog focuses on human health.  How is canine Lyme disease related to human Lyme disease trends?

Researchers have found that areas of the US that have low rates of canine Lyme also have low rates of human Lyme.  They have also determined that areas with higher canine Lyme disease rates have higher human Lyme disease rates.

Researchers who published an article in Emerging Infectious Diseases investigating the link between rates of human and dog Lyme disease concluded: “Our findings suggest that canine seroprevalence >5% can be a sensitive but nonspecific marker of increased risk for human Lyme disease. Because dogs do not transmit infection directly to humans (or humans to dogs), this association reflects similar susceptibilities to tick-borne infection. In some circumstances, high canine seroprevalence appears to anticipate increasing rates of human infection at the county level. Conversely, canine seroprevalence <1% is associated with little to no local risk for human infection. Canine seroprevalence is a useful adjunct to human surveillance for Lyme disease.” [see citation below]

Richard Lerner, DVM, MPH, and co-director of PAZ, who has studied Lyme disease in Peruvian dogs, explains:

“Dogs are not a danger to people, but because they are screened routinely at veterinary offices, they can be what is called a “sentinel” species. A veterinarian seeing an increase in Lyme, especially outside of New England and the Upper Midwest, might want to talk to his local public health officials. Unfortunately, this rarely happens.
I am not an entomologist, but you can be sure that as the frost line creeps northward, there will be increased ranges for most vector-borne diseases. My own guess is that Lyme will move further north, and ehrlichiosis which is generally a problem more to the south, will start entering our area with increased frequency. I can tell you that unlike when I started practicing in the 90s, I now find ticks on dogs every month of the year when we have mild winters. Worldwide, we keep finding more tick-borne diseases, and some of them are much worse than Lyme. It’s also scary, to me at least, how many unknowns and controversies still exist about Lyme, over 20 years into the epidemic.”

Dr. Lerner’s research on Lyme and other infections in Peruvian dogs was published here:

Dr.Lerner explains the project: “We drew blood from approximately 100 dogs, and used the IDEXX ® 3DX® test, which is a point-of-care test for heartworm, Ehrlichia canis, and Lyme. Not a single dog had antibodies against Lyme. This assay is supposedly very specific for Borrelia burgdorferi.”
Public health researchers following disease trends in humans rarely focus on veterinary public health.  But our four-legged mammal friends have a lot to teach us about climate change-related disease trends.  Many of us love and care for dogs. Perhaps we should also pay attention to research on climate-related disease trends that humans and dogs share.
This article represents the first in a series of collaborations with Pan American Zoonotic Research and Prevention, or PAZ, a non-profit devoted to infectious disease research in Latin America.  Cross-fertilization makes the world a better, safer place.
citation:
Paul Mead, Rohan Goel, Kiersten Kugeler
Emerg Infect Dis. 2011 September; 17(9): 1710–1712. doi: 10.3201/1709.110210
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