Lyme Disease in Search and Rescue

Lyme Disease in Search and Rescue

Tick actual size Lyme Disease is major concern for any wilderness SAR personnel (especially on the East Coast!), we’ve posted some educational information about it. The following article will discuss ticks and Lyme disease, in both humans and canines. This article will cover:

  1. Prevention and Control
  2. Transmission
  3. Symptoms
  4. Diagnosis
  5. Treatment
  6. History

  

 

Tick identification chart Lyme  

PREVENTION and CONTROL
 

Chemical Prevention and Control of Tick Borne Illnesses
in Humans

There is no human vaccine for Lyme, therefore we rely on artificial repellents. The CDC recommends using DEET (on skin or clothing) or Permetherin (on clothing) to chemically prevent against tick bites.

Do NOT put DEET on your waterproof gaiters!!

Seed tick larvae on pants Physical Prevention and Control of Tick Borne Illnesses
in Humans

There are two simple physical factors which can prevent tick-borne illnesses.

Chemical Prevention and Control of Tick Borne Illnesses
in Canines

Tick prevention in dogs varies greatly. How you protect your dog from ticks and fleas is an individual choice. Some Handlers swear by the latest Lyme vaccine, even though it causes dogs to pop-"positive" on all future tests for Lyme. Once a dog is given the vaccine, the only test that will tell is the dog has contracted Lyme is a Titer. It is also important to note that veterinarians will not agree of the effectiveness of the canine Lyme vaccine. 

“If the lyme vaccine was so effective, how come they don’t use it for humans?”
-a veterinarian

Chemical Prevention and Control of Tick Borne Illnesses
in Canines

Brush your slowly with a flea comb dog after time spent outdoors (brush slowly, because you can break the tick apart without actually removing its infectious mouth). Be sure to check the sneaky folds of skin, under the collar, inside the ears, and around the anus for hiding spots where your dog cannot reach. There are also a variety of effective tick removal devices such as the tick key available at outdoor stores.

A very tricky spot to find ticks on a dog is between the toes.

 

TRANSMISSION

The exact bacteria in the tick, which carries Lyme Disease across species = borrelia burgdorferi .

The book, Coping with Lyme Disease: A Practical Guide to Dealing with Diagnosis and Treatment, which addresses Lyme in humans only, suggests that transmission can happen as soon as 4 – 24 hours, with the infection presenting days to months later, depending on how far the Borrelia burrow into tissues. Traditionally transmission/infection odds are highest around 48-hours after the tick attaches.

SEASONAL ATTACKS
Ticks are most active during Spring and Summer, though a temperate Fall can be just as hazardous. The nymphs (smaller, harder to see) do most of their feeding earlier in the year, though is bitten and infected, a human might not notice the symptoms until Fall. The life-cycle of a tick, from hatching from egg to laying of eggs is almost 2-years long. A good rule of thumb is if the temperature is not below freezing, you could be vulnerable. (I had a tick on me the day after a 16 degree night.)

(very) Technical explanation: Borrelia burgdorferi has proteins on it’s outside that are critical to the survival and transmission of the disease. The original 48-hour window of transmission from infected tick to mammal is based on the outer-surface-protein (OspC) sparking an immune response in the mammal. When infected ticks are in “feeding” nymphal phase, the spirochetes express this OspC protein – and the number of bacteria (spirochetes) having this OspC protein peaks at 48-hours. A second outer-surface-protein, OspA, is believed responsible for keeping the disease alive in unfed ticks. [ 2000 study in small mammals]. Tick Larva size CDC The study shows that Osp production drops off as an infected nymphal tick feeds, and the OspC production turns ‘on’ and therefore is believed to be part of the transmission process between tick and mammal. Since Lyme is similar to Syphilis in strain diversity, it is understood that a 100% effective vaccine is almost impossible.

Also, the book suggests that 80% of the Lyme disease transmission happens when the tick is in its nymphal stages (see technical tangent above), not the big and easily visible adult stage. You most likely won’t see the little nymphal bugger that has the highest odds of infecting your dog. Nymphal ticks are often mistaken for chiggers, but are often missed as they do not itch as badly.

 

SYMPTOMS

Though the disease is the same, symptoms of Lyme in humans and canine are not the same! According to the University of Washington’s webpage on Lyme in Animals: the nervous system and heart dysfunction in humans does not present in animals. The tell-tale human bulls-eye rash is also absent in most animals.

Symptoms of Lyme Disease
in Humans

CDC Tick Bulls eye rash According to the CDC, using references from 1987 - 2008, the most reported symptoms were:

  1. rash (70-80%)
  2. arthritis (60%)
  3. chronic neurological issues (5%)
  4. others (6%)

The symptoms can vary, and oftentimes mimic other diseases, like a common summer flu. When Lyme disease attacks humans’ nervous system; memory loss, paralysis, arthritis, and depression can occur as well as chronic fatigue syndrome. ( http://www.cdc.gov/lyme/signs_symptoms/index.html)

Symptoms of Lyme Disease
in Canines

The most common and noticeable symptom is lameness or arthritis which can shift from leg to leg. Other symptoms include lack of appetite, fever, dehydration and swollen lymph nodes. 

The Lyme Disease Association states that dogs are up to 50% more likely to contract Lyme Disease than humans! 

 

DIAGNOSIS - TESTS

The most common way to test for Lyme is to use blood and measure a level of antibodies (serologies). An important consideration with these tests is the amount of time from exposure. Like any infection, a longer infection produces more antibodies, which mean a more reliable test result. False-negative tests are probably more common than we want to know. 

Diagnosis of Lyme Disease
in Humans

The spirochete bacteria, Borellia burgdorferi, is evasive and adaptable. The bacteria can lose its cell wall, making it a smaller target for an immune response, therefore foiling test results and possible early treatment with antibiotics. The bacteria also can hide an immune response in immune complexes, returning a false-negative. 

Diagnosis of Lyme Disease
in Canines

Any canine vaccinated against Lyme Disease will show a positive result for the disease.

Unfortunately, the most effective diagnosis is a combination of factors: 1. exposure to an endemic area. 2. signs of joint stiffness and 3. good response to treatment. There are several blood tests that measures antibodies to the bacteria, but a positive result just means the dog was exposed to Borrelia burgdorferi. Not all exposed dogs will manifest the disease. 

TESTS

The CDC recommends running 2 tests. Running both the IgG and the IGM (recommended to run 2 tests) can cost around $200 out-of-pocket. An entire panel of all blood-borne tests as a result from a tick-bite (for humans) can run up to $960 [quoted in 2010].

( data from IGeneX Inc, a lab which runs the following tests)

 

TREATMENT

Since the bacteria, Borellia burgdorferi, causes the disease, an antibiotic is needed to kill the bacteria.

Treatment of Lyme Disease
in Humans

Understanding that treatment with antibiotics does not always kill the persistent bacteria for reasons still being studied (the bacteria is able to cross usually resistant body barriers that antibiotics cannot directly get to -like the blood-brain-barrier and into umbilical vein endothelial cell (presumably to fetus) [ 2004 study]) Also, antibiotics might only be killing the bacteria in certain phases of its life-cycle, and a colony of bacteria is not all in the same phase at the same time.

Treatment of Lyme Disease
in Canines

Antibiotics, usually doxycycline (tetracycline family), for 14 - 30 days. However, we keep a positively infected search dogs on the doxycycline for up to 45-days. This is consistent with the slow growth-cycle of the Borrelia species. ( Wikipedia entry states 12-18 hour doubling time) Aspirin or a non-steroidal anti-inflamatory drug can also be given to manage the pain

DOXYCYCLINE

Doxycycline is a broad-spectrum antibiotic. Luckily, doxycycline is also the treatment for similar tick-borne Ehrlichia canis and Rocky Mountain Spotted Fever. 

HISTORY

According to the University of Washington, Lyme Disease wasn’t identified in humans until 1975!! And not in canines until 1984. It’s first official appearance was in Lyme, Connecticut. Favorite snack of most ticks: deer.

Map Lyme disease USA 2010

 

References

 

VSRDA assumes no liability for injury to you or your pet incurred by following these descriptions or procedures. This article is provided for your education