If you are a new reader who happened upon this (while trying to find the Tick-Tock Man from Lud performing dance moves on a Chinese espionage website), welcome to the wonderful world of BLOG blog!
At last it is October! Hopefully you will be enjoying pleasant weather on these festive occasions:
Oct 3 is billed as Look at the Leaves Day, so you have permission to ogle the foliage.
In a nod to the card attached to his headwear, 10/6 is Mad Hatter Day. This is as good a reason as any to dress up and have an unbirthday tea party; just remember to avoid the mercury vapors.
Oct 11 is the federal holiday that honors General Casimir Pulaski, the Polish born general in the Continental Army who became known as “Father of the American Calvary”. Some locations celebrate him now, others have an observance in his honor in March and his namesake skyway can take you to Jersey City anytime (except when it’s under construction).
Global Handwashing Day is Oct 15, just in case you need a little reminder. It is also a good day to appreciate the power of hygiene to combat disease.
Oct 20 is International Sloth Day as well as National Day on Writing. I must admit I have already started celebrating this combined holiday with this late blog entry.
At this point in the year, you are probably not thinking about parasites. After all, the weather is cooler (in the northern hemisphere anyway) but it is not Oscar season yet. That does not mean they are not thinking of you and your pet. Since I already rambled at length about fleas in last year’s Fleas Navidad (feel free to go to our web site to read or re-read it), this entry shall be devoted to the blood sucking tick.
Ticks belong to the arachnid class of creepy crawlies, along with spiders and scorpions, but not the kind of bugs that are a threat to national security. They are hardy and adaptive enough to have survived for 100 million years and can be found on every continent. (Yes, there is even one that lives in Antartica and feeds on penguins.) There are hundreds of species of ticks worldwide, divided into 2 large families and one outcast species found in southern Africa that shares some characteristics of each of the other types but refuses to attend either group’s family reunions. The Argasidae family (the so-called “soft ticks”) feature mouthparts on the underside of their leathery bodies. They are rarely seen, because they feed intermittently on the host and spend the rest of their time in the surroundings. The Ixoidae (aka “hard ticks’) are characterized by a shield-like plate (scutum) that covers part of their back, a head that is visible when viewed from above and a lifestyle that requires the female to stay continuously attached and feed from a host for several consecutive days. The hard ticks are the ones most people are familiar with (the big bloated ones you see are adult females of a hard tick variety), the most common ones found on people and pets, the source of variety of diseases and henceforth the primary subject of this BLOG blog.
Most ticks have four stages in their life cycle – egg, larva, nymph and adult. (The obvious exception to this is the superhero whose mysterious origin varies with each incarnation.) After hatching, they need to feed on blood to progress to the next stage of development. The entire life cycle usually takes a couple of years and involves multiple hosts. The specifics vary with weather conditions and the availability of hosts. Ticks have been known to live for months (and in some cases, years) without feeding.
Eggs usually hatch in the spring. Six legged larvae emerge and seek blood from small mammals (like mice) or birds. After this first meal, they molt into the nymph stage (now with all eight legs). Then these beautiful maiden personifications of nature…oops, wrong kind of nymph…
The nymphs also take a blood meal, usually from a small animal and then shelter in grass and leaf litter to molt into the next stage, adulthood. Statistically, the nymphs are the stage of tick that are most likely to spread disease to humans. This is due to the high prevalence of disease amongst these youngsters as well as their small size which makes it easier for them to feed unnoticed. They also reach their peak activity in late spring and early summer, which coincides with peak human outdoor activity.
The adults look very much like the nymphs, only larger. They seek yet another host (usually larger than the previous victims) so they can have yet another blood meal before engaging in mating. Most tick species mate on the host after the female is engorged with blood. The male dies (of natural causes, not cannibalism) shortly thereafter. The female drops off the host to find a suitable dark, moist spot to lay her eggs; she dies shortly after ovipositing thousands of potential parasites.
Since they have a multi-year life cycle, they do not die off in the winter. In fact, adult ticks in need of a blood meal may be out looking for food as long as the temperature is above 35 degrees Fahrenheit and the ground is not covered in snow. As weather patterns change, there will likely be more such days, and higher incidence of human-tick interactions.
While ticks may be nigh invulnerable, they do not have the ability to fly. They also can’t jump, so they spend a lot of their time lying in wait for a tasty vertebrate to come their way. They climb up a blade of grass or other piece of vegetation and extend their front legs so they can hang onto anything that comes within reach. This behavior is called “questing”. In order to increase the odds of reaching a reachable host, ticks can detect breath or body odor, body heat, moisture or vibrations; they can then alter their position before their arms get too weary. Prime questing location also relies on size. The larger the tick, the higher it can climb and the better its chance of finding a larger host. The little larvae are usually at ground level, the nymphs a little higher up, and the adults higher still. They are primarily ground dwelling and do not climb trees and fall onto the heads of unsuspecting passers-by.
Once a tick boards a host, it wanders around in search of a desirable location to enjoy their sanguineous repast. Some of the preferred spots on pets are the head (including eyes and ears), neck (even under a collar), the groin area and between toes. Once they get settled in a nice, comfy spot, it’s feeding time. Ticks do not actually bite, because they don’t have teeth. Instead, they grasp the host’s skin and cut into it. They insert their specialized mouthparts into the skin and secrete local anesthetic (so the host can’t feel them), cement proteins (to keep them from getting dislodged), anticoagulants (to keep the blood flowing freely) and compounds that suppress the host’s immune response to the incursion. Although the length of a tick’s blood meal varies with species and life stage, they will usually feed for several days if left to their own devices. In general, the youngsters (larvae and nymphs) hang on for about 3 days. The adult females need more time to fully engorge, and will remain feeding on the host for 7-10 days if given the opportunity.
As blood-sucking parasites, ticks are repulsive in their own right. But wait, there’s more! They are also vectors of infectious disease!
Since ticks are exposed to the blood of multiple hosts during their lifetime, they can transmit bacteria, viruses and parasites during the feeding process. Often, they bite an infected host, ingest some microbes with their blood meal and then spread the pathogen to their next unfortunate host. In some cases, however, an infected female can also transmit disease directly to her offspring.
The prevalence of tick-borne diseases varies with geography. Your (and your pet’s) risk of being affected depends on how many and what kind of ticks live in your vicinity.
There are a variety of spotted fevers and tick fevers, caused by biologically similar organisms but with geographical names based on their common distribution. The group of bacteria that cause these conditions are closely related to each other and share the characteristic of needing to live inside a cell of another organism. Several different classifications of these pathogens have names that are variations of the word rickettsia. Trying to clearly define and succinctly differentiate them is a microbiological rabbit hole in which I have spent entirely too much time and will not impose upon you. Instead, with apologies to microbiologists everywhere, I shall offer this superficial, simplified description of these illnesses.
The name Rickettsia comes from the American pathologist Howard RIcketts, not the weak bone disease caused by a Vitamin D deficiency. His research revealed the pathogens that cause and the arthropods that spread diseases like Rocky Mountain Spotted Fever and typhus. He has the dubious distinction of having disease-causing organisms named after him because of his dedicated research (and death due to the typhus he was studying), not because his wealthy father paid for it. Ticks are a common means of spreading these rickettsial diseases, including the aforementioned Rocky Mountain Spotted Fever, Mediterranean Spotted Fever, Israeli Spotted Fever, Siberian Tick Typhus, African Tick Bite Fever etc. etc. etc. There are also related pathogens named Ehrlichia and Anaplasma that are sources of tick-borne diseases. Thankfully for the sake of this already behind-schedule BLOG blog, these conditions have very similar signs and are treated in a similar fashion. Human patients typically present with a sudden onset of fever, headache, lethargy and rash combined with a history of recent travel to a tick-laden locale. Dogs (and, to a lesser extent, cats) tend to present with fever, lethargy, reduced appetite and/or lameness. Antibiotic therapy, in the form of Doxycycline (a relative of tetracycline with no apparent connection to dachshunds) is usually successful.
There is also a condition called tick paralysis that can affect people and pets. It is caused by neurotoxins secreted in the saliva of some ticks (not by attempting to watch all 36 of the cartoon episodes in a row). Incoordination and paralysis (possibly accompanied by numbness or tingling) starts in the lower limbs (back legs in quadrupeds) and moves up the body. With removal of the offending tick and supportive care, the condition usually resolves completely.
I would be remiss if I did not mention that ticks can also spread diseases like Babesiosis (microscopic parasite infecting red blood cells) and tularemia (bacteria, commonly found in rodents, rabbits and hares). They are truly contagious overachievers, not just padding their resume.
Arguably the most famous tick-borne disease (in the US, anyway) is named for the town in Connecticut where it first gained notoriety in 1975. The bacteria that causes it has been around for thousands of years, but the outbreak of uncommon arthritic symptoms in children and adults in Lyme eventually garnered enough attention to secure funding for surveillance, education and research.
Lyme disease is spread by a blacklegged tick (aka deer tick) and often causes a “bull’s-eye” rash in humans. In dogs, the most common signs are fever, lameness and swelling. Cats seem to be highly resistant to the disease. So far, there have been no recorded cases of naturally-occurring Lyme disease in cats. The ailment has been found in most states in the US, but is most common in the Northeast, upper Midwest and northwestern areas of the country. With appropriate antibiotic treatment, most people and dogs recover quickly and completely.
It is important to note that the tick is the vector of these diseases. Humans and pets do not spread these conditions to each other directly. If they are sharing an environment with infected ticks, however, either or both species may be at risk.
The best way to avoid tick-borne diseases is, of course, to avoid ticks in the first place.
Ticks can dry out in direct sunlight, so they prefer dark, humid conditions. Tick real estate agents know that leaf litter provides a nice habitat for shelter and low-lying vegetation (grasses, shrubs, etc.) offers ample opportunities for attachment to an unsuspecting host. One particularly desirable location is near the edge of a wooded area.
There are some measures you can take to make your yard less inviting to these uninvited arthropods. A 3-foot barrier of bark or gravel between your lawn and a surrounding wooded area will discourage ticks from migrating into your yard. They are also not fans of sunny areas and short grass. If, however, your taste in landscaping leans towards shady tree cover, bushes and tall grass, the ticks will want to move in and start building condos.
If you and your dog (or leash trained cat) like to go hiking, you will need to take precautions. For people there are such things as protective clothing and repellents like DEET. Light colored clothing does not repel ticks, but it does make it easier to see any that climb on you. If possible, stay in the middle of the trail, out of reach of the tall grasses.
For dogs, there are oral and topical products that either repel the tick before it bites or kill the tick when it feeds. There are advantages and disadvantages to each type of product. The important thing is to consult your veterinarian about what is the best product for your pet. With the exception of the Seresto variety made by Bayer, don’t waste your time and money on flea and tick collars. Most of them are not effective.
If you should happen to find a tick on yourself or your pet, please take appropriate precautions when removing it. Avoid touching the tick with your bare hands, because, as previously discussed, they are revolting disease vectors. Also refrain from squeezing an attached tick as this may provide an extra incentive for it to regurgitate into the open wound.
Remove any and all attached ticks as soon as possible, because not only are they abhorrent, the longer they are attached, the more likely they are to spread disease. The exact removal method will depend on what you happen to have readily available. If you are a Boy Scout or if you live in a New England town famous for diseased arachnids (No, the sewer monster doesn’t count because it wasn’t actually a spider, but that form was the closest thing a human brain could compare It to) you may already have a tick removal device. There are many different designs (one called Ticked Off looks like a big “Spoooon!”with a notch cut out), but they share a common purpose of removing the offending parasite without actually touching it.
The most common recommendation is to use a pair of fine pointed tweezers to grasp the tick as close as possible to the victim’s skin. Pull straight out with firm, steady pressure until tick comes detached. Do not use twisting or rocking motion. Be careful not to squeeze the tick body in the process. After removing the offending tick, wash the bite area (and your hands) with soap and water or alcohol.
After detaching the parasite and cleaning the open wound, you need to dispatch the eight-legged menace. Instead of crushing it with your fingers, you should submerge it in alcohol, which will cause death by desiccation. If you would prefer to suffocate it, you can wrap it tightly in tape (duct tape, presumably), or seal it in a plastic bag. Think twice before flushing a tick down the commode; they can’t swim, but don’t drown easily and could potentially lead back to that sewer monster thing. Death by fire (or a long tumble in the dryer on high heat) is also an option; this is obviously only appropriate when tick is not attached to a host.
Do not use petroleum jelly, nail polish, dish soap, kerosene, glue or alcohol on attached tick. These methods may cause the tick to drop off eventually, but the longer it is attached, the better the odds of disease transmission. These techniques also leave you walking around with a loathsome (unless you used sparkly nail polish and make it a decorative accessory) parasite attached to you while you wait for it to die.
If you are looking for a natural source of tick control, you could consider a species that has been known to eat them in large quantities. Opossums fit this criterion, but it is debatable whether they are more visually appealing than their prey.
A final word of caution: as you are taking a pleasant autumn stroll, peeping at the leaves, be aware that, from beneath the fallen leaves, something may be peeping back at you.
I hope you have enjoyed this installment of BLOG blog. Until next time, Bored Surfer – Be excellent to each other.
Dr. Debbie Appleby