Better Protection for Dogs Against Lyme but Human Protection on the Way (Eventually)
Tick disease is nearing epidemic proportions in the U.S. When people think of tick disease, they think of Lyme – which indeed is on the rise, albeit one of many dangerous tick diseases.
Lyme disease can mean months or even years of suffering undiagnosed or misdiagnosed, and can cause symptoms so debilitating that individuals stricken may be hospitalized on and off, and may be unable to work. So, aside from individual lives being impacted, all this effects all of us – even the U.S. economy to the tune of at least $1 billion in medical costs.
According to the Centers for Disease Control there are some 476,000 cases of Lyme annually, though many experts agree Lyme is often not diagnosed or misdiagnosed and the real number of people with Lyme is far higher.
Yet, veterinary medicine has known for years this onset of Lyme was coming, as dogs are a sentinel for Lyme, and there’s been a significant increase in Lyme in dogs for various reasons. One reason is awareness, you can’t diagnose something you’re not looking for, and increasingly, veterinarians are looking.
Why so much Lyme?
Proliferation of Lyme is also due to the unsuspected Lyme culprit, the white-footed mouse. According to one report, this seemingly cute and all too common rodent, infects about 95 percent of ticks with Lyme that feed on it.
In part due to favorable weather conditions, the population of white-footed mice is booming. Also, those same weather conditions provide more food, particularly the acorns they love to devour.
So, these mice are more well fed than ever, and have fewer natural predators because the owl, fox and coyotes that eat them are declining in number. And the mice gleefully live out their lives with potentially dozens of ticks on them without a detriment.
Out of the Woods
Also, it’s a mistake to believe that tick disease only occurs in the woods. Lyme has been identified with surprising and increasing frequency in urban centers like New York and Chicago. For years, dogs have been transporting ticks from upstate or mid-state New York back to Central Park in Manhattan or from summer cottages in Wisconsin or Michigan into Lincoln Park in the heart of Chicago. In these parks, the ticks have no shortage of blood meals, making “withdrawals” from raccoons, squirrels, opossum, and even city rats, not to mention unprotected people and unprotected dogs.
For all these reasons, tick disease is booming.
More to Prevent Tick Disease in Dogs than People
Interestingly, the news continues to be better for dogs than it is for people, starting with testing. Symptoms of tick disease in dogs include lameness (usually on alternating legs), swollen joints, lethargy, mild fever, and appetite suppression. Sometimes these symptoms, which typically come and go, may be mistaken (even by veterinary professionals) for other problems without appropriate testing. And, without testing, tick disease often goes undetected. For example, a dog that’s feeling “yucky” and running a mild fever may not be noticed by family members, as dogs have no way to tell us, and rarely call in sick to work.
So, testing is necessary. The SNAP 4Dx Plus Test identifies antibodies that are produced only as a result of a Borrelia burgdorferi infection (Lyme). The same test also detects antibodies to Ehrlichia canis or Ehrlichia ewingii (both are tick diseases) and indicates exposure and the transmission of infectious agents. (Additional testing is recommended in these patients to determine if there is an active infection.) The very same SNAP test also serves to identify exposure to another pair of nasty tick diseases: Anaplasma phagocytophilum and Anaplasma platys. But, the test is actually most often known by pet owners as “the heartworm test” because this four-way plus test also detects the mosquito-transmitted illness.
The SNAP 4DX Plus Test should be standard of care in most of parts of the country. If the test shows disease, the veterinarian will be able to respond.
And protection in dogs is nearly akin to a shield against Lyme, from various preventatives – from chewables to spot-on products – to a Lyme vaccine.
Lyme Vaccine for Humans
Finally, according to a recent National Geographic story, a long-awaited vaccine may be on the way for humans.
With several vaccines in development, researchers are optimistic they will be able to prevent the disease but it will take several more years. Arguably, human medicine is behind veterinary medicine.
A human vaccine developed by Pfizer and its French biotech partner, Valneva, is in Phase 3 trials. Moderna is working on an mRNA version. Researchers at MassBiologics of UMass Chan Medical School are developing an anti-Lyme antibody treatment.
Still, a part of the issue is that unlike veterinarians, human physicians might not even think about tick disease, particularly in parts of the country where Lyme has only recently spread.
Lyme disease was first recognized in Old Lyme, Connecticut in 1975. It drew attention when a cluster of children developed unexplained, rheumatoid arthritis-like symptoms. In 1982. Medical entomologist and self-described “tick surgeon” Wilhelm Burgdorfer identified the previously undiscovered spiral bacteria, Borrelia burgdorferi. The pathogen passes to humans through the bite of a black-legged (or deer) tick, but not all of them are carriers. A second, less prevalent Lyme bacterium, B. mayonii, was later found in the U.S.; two other species—B. afzelii and B. garinii—are responsible for most European infections. In western Europe, 200,000-plus cases are reportedly diagnosed each year, according to the CDC.
Ticks pick up the bacteria while feeding on infected hosts, including those white-footed mice (the primary disease reservoir), other small mammals, and white-tailed deer, which there are also more of than ever before. B. burgdorferi then sits in a tick’s intestine for months until the arthropod latches onto a new victim for its next meal. With the influx of blood into the tick’s gut, the bacteria transform. They stop producing an outer surface protein, OspA, that anchors them to the intestine, which allows them to move to the tick’s salivary glands. The bacteria then pass through the tick bite and into their new host.
If an unprotected pet or human is bitten, the secret is to remove the tick quickly since disease transmission usually take 36 to 48 hours. We know Lyme can be debilitating in humans, and similarly impacting dogs but most cats actually don’t become ill, as far as we know.
Human Lyme Vaccines
Human vaccine prospects currently in development target the bacterium’s OspA protein, creating antibodies that prevent the organisms from suppressing OspA when the tick next feeds. Moderna is currently applying mRNA technology—if that sounds a familiar, it the same technology the vaccine manufacturer used for its COVID-19 vaccines.
MassBiologics is using another approach. Instead of stimulating the body to produce antibodies, as vaccines do, this method introduces a single monoclonal antibody targeting OspA. The presumed benefit: Within days after you get the subcutaneous injection, you’ve absorbed enough of the antibody so you’re immediately immune.
No matter, it’s clear that in this instance, human medicine is catching up to vet medicine. Today, our dogs can be protected against tick disease more effectively than any of us.