Lyme Disease is a tick-borne illness caused by a bacteria, Borrelia burgdorferi, that likely originates not with the ticks themselves, but with Peromyscus leucopus, the white-footed mouse. This disease is becoming a more prevalent issue with over 300,000 cases reported per year.
The problem is, however, that due to the nature of Borrelia burgdorferi, Lyme may be drastically misreported (either over-diagnosed, or under-reported). B burgdorferi is a spirochete that lacks many of the factors found in bacterial pathogens, such as toxins or lipopolysaccharide (LPS), and though related to pathogens that have long been known to cause human ailments, such as Treponema pallidum¹, this particular spirochete is unique in it’s atypical DNA form and complex effects on humans.
It has been speculated that due to B. Burgodorferi not evolving to effect humans and because of it’s rather strange biology, it can mimic symptoms of a variety of other health conditions and is capable of effecting multiple body systems simultaneously. This is one reason that those later diagnosed with Lyme may have previously been diagnosed with multiple sclerosis, various mood disorders, Parkinson’s, or arthritis.
So we have this odd bacteria resulting in widespread disease with almost no consistent symptoms. What are some key facts to know about it?
- Blood tests for Lyme are often unreliable. The blood screening checks for antibodies produced by an infection, however these antibodies may not yet be present at the time of the test, and may also persist far after an infection is no longer present. Therefore, a you might get a negative reading even if you are infected, or a positive reading even if you are not infected.
- A tick likely needs to feed on its host for at the very least 24 hours to result in an infection. Typically, however, infections do not result unless the tick has been attached to the host for >36-48 hours.
- Lyme Disease is virtually always transmitted via tick nymphs, as ticks host on mice and other rodents at this stage in their lifecycle, and are therefore far more likely to being carrying B. Burgodorferi. Because of their incredibly small size, these nymphs often have a higher chance of going unnoticed by their host, and thus have a greater chance of staying attached for prolonged periods of time.
- Symptoms considered objectively relevant to Lyme are erythema migrans, fever and Bell’s palsy. If you have these three symptoms, you’re unlikely to have anything but Lyme and will probably not be misdiagnosed.
- Lyme Disease is completely distinct from tick paralysis. Tick paralysis occurs during or shortly after a tick bite, presumably due to toxins found in the parasite’s saliva, and may go away when the tick in question is removed. Symptoms of tick paralysis can include ascending flaccid paralysis, restlessness, irritability, fatigue, muscle weakness, numbness/tingling, pupillary dilation, and may finally (if left unaddressed), result in fatal respiratory weakness wherein the host is no longer able to breathe. The vast majority of those affected with tick paralysis are females age 16 or younger, though women in general are far more affected than men. Additionally, it is thought to be much more complicated to diagnose tick paralysis than Lyme Disease, and tick paralysis is thought to only be caused by egg-bearing females.
Due to the epidemic that is Lyme Disease, there have been many efforts to greatly reduce its prevalence. Some of these methods tend to be less effective than others. For example, some regions have resorted to increasing deer hunting in an attempt to get rid of the tick’s primary host, thus perhaps starving it.
While it is true that ticks are abundant in regions their hosts are abundant, this method is flawed for the following reasons: a) As previously discussed, nymphs are the primary transmitters of Lyme and their primary hosts are rodents and birds rather than deer, and b) This results in other ecological issues due to disrupting the role of deer in local environments.
Methods that have been proven to be more effective in reducing risk or prevalence of Lyme include:
- Educating the public. Those aware of an issue are less likely to encounter the issue. By wearing appropriate clothing during time spent outdoors, using tick repellent, and routinely checking for ticks, you can significantly reduce your chances of getting infected with Lyme Disease. It is also important to take notice of your bioregion: Lyme is more prevalent in the Northeast and Southwest, and Lyme-bearing ticks vastly prefer fragmented deciduous forests over coniferous forests, plains, or desert environments. Be aware that you are also more likely to be bitten by an infected tick during the spring or summer.
- Increasing tick predators. Ensuring the optimum environment for the predators may be effective in reducing their numbers. Though many of these predators may have a “bad rep,” they are extremely ecologically significant in this regards. Primary predators of ticks include opossums, the fungus Metarhizium anisopliae, wolf spiders, parasitic wasps, and turkeys.
- Wildlife tick repellent. If you live in a rural or semi-rural area, you or someone you may know may use deer feeders. These are very effective at drawing deer in, but they may also be useful in reducing your local tick population. Using a 4-poster tick control deer feeding device, you will be able to simultaneously feed the deer and apply tick repellent. Also available are rodent bait-boxes, wherein trapped mice are exposed to tick repellent.
- Rodent control. By ensuring healthy populations of snakes, owls, bobcats, weasels, foxes, and other nocturnal/crepuscular predators, you may help reduce the number of infected white-footed mice.
- Keep an eye on pets. Dogs and cats are often hosts for ticks in more urban environments. Regularly checking your dog for ticks after having been outside or on a walk can help prevent tick exposure to those in the household. Cats should likewise be checked, or better yet, kept indoors.
- Remove leaf litter from high-traffic areas. Leaf litter is crucial to the survival of ticks. By raking your lawn and disposing of or relocating the leaves, you may drastically reduce contact with ticks. Similarly, prevent children and pets from playing in leaf litter or be sure to rigorously check them for ticks afterwards. On a rather positive note, collecting leaf litter for compost is means of tick prevention that can also help your lawn/garden!
- Garden more, use wood chip mulch. Flowerbeds and similar spaces do not provide an ideal habitat for ticks. Wood chip mulch holds less moisture and is prone to becoming warmer which effectively reduces the likeliness of ticks coming into this area. These spaces can provide a border to your lawn, especially as a sort of barrier to any nearby wooded areas that may have a high concentration of ticks. In addition, flowerbeds and other garden spaces are unlikely to be used as a walking space, and thus limit your ability to unknowingly come into contact with a tick anyway.
- Remove invasive species. It has been found that a greater density of invasive plant species correlates to a greater density in infected ticks. Removing invasive plant species, those that are not native to your bioregion, can have many benefits for your local ecosystem- including reducing ticks!
- The Dilution Effect. When ticks have a greater diversity in potential host species, they are less likely to use infected white-footed mice. Therefore, they may still be a parasitic pest, but much less likely to carry Lyme. By encouraging biodiversity, you can encourage this dilution effect.
Other interesting and potentially useful information on ticks:
- Ticks do not travel far to find a host. They will only move from 3-6ft in any given direction to obtain a host. This is why minimizing your exposure to tick-prone spaces (such as yard leaf litter or unmowed grasses) is critical to avoiding ticks. Questing ticks will not actively seek you out.
- Ticks may have as few as three hosts throughout its lifespan. A blood feeding is necessary for each cycle of its life, typically one host in a year for three years. Most die when unable to find a host for the next lifecycle.
- Ticks are constantly avoiding desiccation. Because they need moisture to survive their molts and to survive all stages of their lives, they tend to stay in damp/moist areas (like the aforementioned leaf litter).
¹Bacteria known to cause yaws, printa, and syphilis.