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:
Prevention and Control
Transmission
Symptoms
Diagnosis
Treatment
History
PREVENTION and CONTROL
Chemical Prevention and Control of Tick Borne Illnessesin 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.
DEET: Sold in different concentrations up to 100%. The higher the % = the longer the protection against insects.
Acts to repel (not kill) biting and sucking insects (mosquitoes, fleas and ticks)
DEET is mildly toxic and recommended for use externally on clothing. See the fact sheet below for technical information.
DEET should not be used on infants younger than 6 months of age, or on children under 6 years in higher concentrations than 12%, which should last about 2 hours.
DEET FACT SHEET PDF
(**NOTE: According to Wikipedia: “ DEET is an effective solvent, and may dissolve (part of) some plastics, rayon, spandex, other synthetic fabrics, leather, and painted or varnished surfaces.)
Do NOT put DEET on your waterproof gaiters!!
Permethrin: a natural or synthetic insecticide made from dried Chrysanthemum flower heads. Wikipedia states “[Pyrethrins] are far less toxic to mammals and birds than many synthetic insecticides and are non-persistent, being biodegradable and also breaking down easily on exposure to light. They are considered to be amongst the safest insecticides for use around food.”
REPELS: ticks, fleas, lice & mosquitoes.
Physical Prevention and Control of Tick Borne Illnessesin Humans
There are two simple physical factors which can prevent tick-borne illnesses.
CLOTHING: Create a physical barrier.
Wear long sleeves and long pants with calf-length socks.
Tuck your pants into your socks.
Tuck your shirt into your pants
Wear light colored clothing - so you can see the ticks on you before they attempt to get underneath.
TICK CHECK: no matter how hard you try to prevent ticks, they will still find their food. First thing when you return home, get in front of a mirror and perform a thorough body check! Ticks usually prefer warm, moist areas on your body.
Around the waist (a tick favorite)
Between the legs (groin)
In and around your ears
The backside of your legs and between your toes
Your hairline
Don’t forget to check your belly button!
Chemical Prevention and Control of Tick Borne Illnessesin 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
Monthly prevention of your choice (or a combination):
Spot-On Treatments like Frontline® Plus™ or K9 Advantix®
Collar like Preventic®
Spray-On Treatments like Frontline® Plus™
Bath your dog with tick-medicated shampoo.
Chemical Prevention and Control of Tick Borne Illnessesin 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 ATTACKSTicks 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]. 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 Diseasein Humans
According to the CDC, using references from 1987 - 2008, the most reported symptoms were:
rash (70-80%)
arthritis (60%)
chronic neurological issues (5%)
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 Diseasein 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 Diseasein 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 Diseasein 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.
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)
ELISA (IgG/IgM Antibody Serology) – can show more false positives than Western Blot due to mediocre sensitivity. (cheaper)
Western Blot tests (Immunoblot tests: IgG and IgM) – more sensitive than ELISA, and should always be used when ELISA returns a positive.
IgM – the first antibodies produced in response to an infection. Representative of a new infection or an existing infection that has become re-activated. The IgM antibody numbers will decline as the infection declines
IgG – these antibodies show up only if the infection has been around for awhile, and may be present even after the infection has cleared up. Therefore a positive result for IgG means that there is either a current infection or a past exposure/past infection. Remember, the Borrelia burgdorferi can hide in the body, not tripping an immune response.
PCR (multiplex polymerase chain reaction) – essentially checking for Borrelia burgdorferi DNA. (best for human testing)
TREATMENT
Since the bacteria, Borellia burgdorferi, causes the disease, an antibiotic is needed to kill the bacteria.
Treatment of Lyme Diseasein 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 Diseasein 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.
SIDE EFFECTS: (most common) are diarrhea, nausea, abdominal pain and committing. Also, UV rays will cause more skin damage during treatment.
DRUG INTERACTIONS: Do NOT take at the same time as iron supplements, calcium supplements (check your joint supplements), antacids or laxatives. (avoid calcium, iron, magnesium and aluminum) Therefore, do not take with dairy. All of the above minerals inhibit absorption of doxycycline. Pregnant or nursing mothers should NOT take doxycycline due to toxic effects on the development of bone.
-from the Tetracycline antibiotics group
BRAND NAME: Vibramycin, Vibra-Tabs, Oracea, Adoxa and more…
DOSING METHODS: Oral, IV, IM, Periodontal
NOTE: It is very important that you use all of the prescribed medication!! Improvement from the medication can begin as soon as 2-weeks. Stopping when you or your dog feels better can result in a recurring infection or a worse infection. If you miss a dose, do NOT double-up the next dose.
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.
CDC’s U.S. map of reported cases of humans contracting Lyme disease (state-by-state) in 2000 – 2010 http://www.cdc.gov/lyme/stats/chartstables/reportedcases_statelocality.html
CDC chart of reported Lyme “onset” by month 1992-2004. June & July – yikes! http://www.cdc.gov/lyme/stats/chartstables/casesbymonth.html
CDC map [PDF] of reported Lyme cases in 2010 http://www.cdc.gov/lyme/resources/ReportedCasesofLymeDisease.pdf PDF
CDC chart of reported Lyme by symptoms 1992-2004. Look for that rash!! http://www.cdc.gov/lyme/stats/chartstables/casesbysymptom.html
References
Centers for Disease Control and Prevention. 2012. Lyme Disease Transmission. http://www.cdc.gov/lyme/transmission/index.html
National Pesticide Information Center (NPIC) . 2008. Pesticide Fact Sheets. http://npic.orst.edu/npicfact.htm [NPIC is a co-op between Oregon State University and the EPA]
Wikipedia. http://en.wikipedia.org/wiki/Deet
Centers for Disease Control and Prevention. 2008. Lyme Disease and Animals. http://www.cdc.gov/healthypets/diseases/lyme.htm/
Lyme Disease Association. Aug 2009. Pet Spot. http://www.lymediseaseassociation.org/index.php?option=com_content&view=category&layout=blog&id=28&Itemid=149
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
Copyright © 2018 Virginia Search and Rescue Dog Association . All Rights Reserved. Site by Skywide Design
コメント