Tick Borne Disease Transmission and Prevention in Pets in Illinois
According to the Centers for Disease Control and Prevention, 60,000 cases of tick-borne disease were reported in humans in the last year, which has doubled since only 2004. Ticks can feed on mammals, birds, reptiles, and amphibians as their host, meaning they can spread these diseases to both humans and our pets. In Illinois 3,685 tick borne disease cases were reported between 2004-2016, while Wisconsin had 33,255 cases reported (1). Currently in Illinois the following ticks can be found: the American Dog Tick, Blacklegged Tick, Brown Dog Tick, and Lone Star Tick. Diseases transmitted by those ticks include but are not limited to: Lyme Disease, Rocky Mountain Spotted Fever, Anaplasmosis, and Ehrlichia (2).
Tick control is a key aspect of preventing these diseases and is better understood by acknowledging the tick life cycle and where animals come into contact with ticks. The tick life cycle is broken into four phases: egg, larva, nymph, and adult. Ticks must ingest blood meal at each life phase after they hatch in order to survive. Most ticks will feed on different hosts/animals during their life cycle, although the Brown Dog Tick prefers to feed on dogs for each stage. The life cycle length varies by tick but by average is about two to three years (3). Ticks and their pathogens can survive various temperatures and environmental conditions. Depending on the species, some can survive sub-zero temperatures.
Ticks find their hosts by detecting breath (Carbon Dioxide), body odor, vibrations, shadows, and body heat. While ticks are unable to fly or jump, they typically wait on foliage or grass and climb onto a new host as they approach (3). On the other hand, the Brown Dog Tick tends to inhabit indoor areas including dog kennels and human dwellings and can be difficult to completely eradicate from the environment. This tick prefers warm temperatures and can climb walls; it can be found residing in false ceilings which can make it extremely challenging to detect and remove (5).
Once aboard a host, the tick will find a preferred area of attachment to feed. This process can take anywhere from ten minutes to two hours. Some ticks prefer to find an area of thinner skin, like behind the ears. The tick cuts the hosts’ skin and inserts a feeding tube which contains a cement-like substance that allows it to remain adhered to the host while feeding. Tick saliva contains an analgesic agent which prevents the host from being able to feel the tick feeding. If the host contains any blood-borne pathogens, the tick will pick them up while feeding. The pathogen then travels to the tick’s midgut and resides there before it disseminates to the saliva. Once the tick’s saliva contains a pathogen, it may transmit it to the next host while feeding (3, 4). Another means of potential disease transmission is by passage of pathogen-containing feces from the tick into the tick-bite site or other wounds on the hosts’ body (6).
Most of the common pathogens that cause disease in dogs and cats can be transmitted by an infected tick after it is attached to the host for at least 24 hours. However, laboratory studies investigating transmission time have shown inconsistent results and it can vary depending on host species, ambient temperature, and tick species (4). Additionally, viruses and bacteria are constantly mutating and evolving, which can allow them to become smarter and more apt to survive. Therefore, ongoing research is needed to better understand the time of disease transmission from tick to host.
The best way to prevent transmission of tick-borne diseases in pets is by rapid kill of ticks, thorough and regular scanning for presence of ticks, and timely removal if any are found. The most effective veterinary tick prevention products currently on the market kill ticks within 12-24 hours and are available in oral and topical formulas, and depending on the product may have to be administered monthly. It is important to discuss with your veterinarian which tick preventative is most ideal given your pet’s lifestyle and any concurrent diseases, sensitivities, or allergies. Take into consideration the tick prevalence of any geographic region your pet is exposed to. When deciding how often to administer tick preventatives, it is important to understand that ticks and their associated pathogens are hardy organisms that can survive harsh, freezing conditions, and the Brown Dog Tick can be found indoors year-round. Finally, it is prudent to keep up with new information regarding novel tick-borne pathogens and changes in risk of disease transmission.
1. Centers for Disease Control and Prevention. (2018, May). Illness on the Rise from Mosquito, Tick, and Flea Bites. Retrieved from https://www.cdc.gov/vitalsigns/vector-borne/infographic.html#graphic3
2. Centers for Disease Control and Prevention. (2019, January). Geographic Distribution of Ticks that Bite Humans. Retrieved from https://www.cdc.gov/ticks/geographic_distribution.html
3. Centers for Disease Control and Prevention (2019, April). How Ticks Spread Disease. Retrieved from https://www.cdc.gov/ticks/life_cycle_and_hosts.html
4. Richards, S.L. et al. “Do Tick Attachment Times Vary between Different Tick-Pathogen Systems?” Environments 4.2 (2017).
5. Ford. R.B. (2016). Tick-Borne Disease Diagnosis and Management
6. Alleman, A.R. (2015). Understanding the Transmission of Tick-Borne Pathogens with Public Health Implications