What are ticks and how do you know when to worry?
Ticks are what we call Ectoparasites- they survive outside of the animal. These pests are relatives of the spider (also hated, I’m told). The kinds of ticks you need to worry about will vary depending on your geographic location and general climate. Unfortunately they are something that cannot be entirely avoided regardless of your location.
Even pets that spend most of their time indoors are at risk.
The main reason these pests are cause for concern is due to their ability to transit viruses once they latch to your pet. There are many viruses that can be transmitted including Lyme Disease, of which people are the most familiar with.
How does my dog become infected?
Ticks are unable to “jump” per say, but transfer onto animals and humans when they come into contact with plants, brush, weeds, and long grass. They often go undetected due to their small size.
Take a look- before they cling to a host and become engorged from blood, ticks are actually very tiny. This is another reason they are so dangerous- by the time they are large enough to be detected, they may have had enough time to transmit any viruses they may be carrying.
Here you can see the difference in size between an unfed and an engorged tick.
When a tick finds a suitable host (ie: dog, cat, human, etc), it grasps the skin and cuts the surface. The tick then inserts its feeding tube into the host. May of them contain small barbs that help hold it into place. Some even secrete a cement like substance that aids the process. They also secrete a substance with anesthetic properties to allow them to feed without going noticed (sneaky little buggers)!
Infection may occur from the saliva of the tick itself, or may not occur until the tick begins bloodsucking. Pathogens may also be transmitted to tick from the host during this process. This process usually continues for a few days. Once the tick is engorged it drops off and awaits its next opportunity to infect the next host.
Almost all ticks go through 4 stages over the course of their life- egg, six-legged larva, eight-legged nymph, and adult. Ahh the circle of life!
Which ticks are causes for concern and what diseases can they transmit?
Of the ticks that exist, only a handful bite humans and pets. The ticks that are of concern will vary from state to state.
Here are some of the most common:
American dog tick
Commonly found: East of the Rocky Mountains; Pacific Coast
AKA: “Wood Ticks”
Highest risk period: Spring, summer and fall though bites reported anytime temperatures above freezing
Disease Transmitted: Tularemia; Rocky Mountain Spotted Fever
Commonly found: Northeast states; Midwest states
Highest risk period: Spring and summer
Disease Transmitted: Lyme Disease, Anaplasmosis, Babesiosis, Powassan Disease
Brown dog tick
Commonly found: Worldwide
Disease Transmitted: Rocky Mountain Spotted Fever
Note: Dogs are the primary host, though the tick may also bite humans
Gulf coast tick
Commonly found: Atlantic, Gulf of Mexico
Highest risk period: Risk persists throughout the year
Disease Transmitted: Rickettsia parkeri rickettsiosis (a form of spotted fever)
Lone star tick
Commonly Found: Southeastern and Eastern United States
Disease Transmitted: Ehrlichia chaffeensis and Ehrlichia ewingii (Ehrlichiosis), Tularemia, Southern Tick Associated Rash Illness
Rocky mountain wood tick
Commonly Found: Rocky Mountain states and Southwestern Canada
Disease Transmitted: Rocky Mountain Spotted Fever, Colorado Tick Fever, Tularemia
Western blacklegged tick
Commonly Found: Pacific Coast of the United States (especially northern California)
Disease Transmitted: Anaplasmosis, Lyme Disease
Rocky Mountain Spotted Fever
RMSF is caused by the bacteria Rickettsia rickettsii. The ticks most commonly associated with transmission are the American Dog Tick and the Brown Dog Tick. It is the most prevalent Tick Born Disease (TBD) in Arkansas though it is associated with many other regions in the United States.
Symptoms most commonly begin 2-14 days after a tick bite. It is a severe illness and can be fatal if left untreated. Symptoms are non-specific and are similar to other flu-like illnesses. Most complain of fever, headache, nausea, vomiting, and abdominal pain.
Rash is associated with RMSF, and often presents with the characteristic petechiae. This can help make the otherwise uncertain diagnosis, though the rash may not present until late in the illness after the patient becomes severely ill. Of course characteristic skin changes are more difficult to discern on a dog and may otherwise go unnoticed. This typically manifests as bruised/purplish spots on the skin. Dogs may also develop conjunctivitis (reddening of the eyes) as seen in humans.
Early cases can be treated with antibiotics. If intervened upon too late, both humans and dogs will progress to multiple system organ failure and die from the illness.
The rash of Rocky Mountain Spotted Fever:
Conjunctivitis in dogs associated with Rocky Mountain Spotted Fever:
Lyme Disease (LD) is caused by the bacterium Borrelia burgdorferi. Only 5-10% of dogs infected will become symptomatic, however due to the prevalence of the disease, Lyme Disease affects a significant number of dogs. Young dogs seem to be affected disproportionately.
LD also causes generalized, non-specific symptoms. The disease characteristically causes inflammation of the joints which can result in lameness. Lameness typically lasts a few days and then reoccurs weeks later- either in the same joints or in entirely different joints. Other associated symptoms include anorexia, weight loss, fever, depression, and rarely nervous system complications. Dogs do not develop the classic rash of erythema migrans (aka bulls eye rash) around site of the bite like humans do.
The disease is treated with antibiotics, though this does not always successfully eradicate the bacteria. In some canines symptoms will resolve and then return at a later date. The dog always remains at risk for later secondary complications including the development of kidney disease.
Read more about symptoms of LD in dogs here.
Check out this great site Pets and Parasites to look up the prevalence of Lyme Disease in your area (they break it down by state, city, and county).
Information on other tick born diseases
Tularemia in Dogs– Pet MD
Tularemia in Dogs– VCA Hospitals
Overview of Tularemia– Merk Veterinary Manual
Erlichiosis in Dogs– Pet MD
Powassan Disease – CDC
Anaplasmosis in Dogs – VCA Hospitals
Anaplasmosis in Dogs – Pet MD
Canine Anaplasmosis – Pet Health Network
Pesky Summertime Pests – Pet MD
Colorado Tick Fever:
Colorado Tick Fever – NY Times
They want to suck your pets blood! – Downtown Animal Care Center
Stay tuned! Next week Woof will show you how to properly remove a tick and we will review vaccinations for various tick born diseases.