Ticks on Cats

In the Literature

Little SE, Barrett AW, Nagamori Y, et al. Ticks from cats in the United States: patterns of infestation and infection with pathogens. Vet Parasitol. 2018;257:15-20.

The Research …

The assumption that cats are careful groomers that can readily remove ticks has been studied in recent research. A handful of studies have suggested that ticks may pose a greater risk to cats in the United States than previously believed.^1-3

In this study,* 796 ticks removed from 332 cats were submitted by 41 veterinary practices in 18 states, covering all 4 US geographic regions. Most ticks were identified as Ixodes scapularis (53.1%), Amblyomma americanum (28.4%), and Dermacentor variabilis (16.5%). Submissions occurred in all months, with peak submissions coinciding with peak activity of the tick species identified. Greater numbers of adult D variabilis and A americanum and nymphal I scapularis were submitted in May and June, whereas submissions of adult I scapularis peaked in October and November. The spatial distribution of submissions aligned with the known range of each tick species. I scapularis submissions were predominately from the northeast, A americanum submissions were mostly from the south, and D variabilis were from all regions. Tick-borne pathogens were detected in 17.1% of ticks; the most common pathogen was Borrelia burgdorferi found in I scapularis.

Patient age, sex, weight, spay/neuter status, site of tick attachment, and time spent outdoors were noted for each submission. Patients covered a wide age and weight range. Most were male and altered and spent >30% of time outdoors. Cats reported to be completely indoor also had ticks. Site of tick attachment varied by tick species, with I scapularis noted being predominately attached to the dorsal head and neck, D variabilis to the back and ears, and A americanum to the legs and feet, perianal area, and the abdominal, axillary, and inguinal regions.

Greater attention should be paid to tick burden in cats. Cats are susceptible to several tick-borne pathogens, including Cytauxzoon felis and Anaplasma phagocytophilum.⁴ Cats also live in close association with humans and other pets and may introduce ticks into shared environments.⁵ Year-round tick control should be considered for all cats, regardless of level of outdoor exposure.

… The Takeaways

Key pearls to put into practice:

• Clinicians should be aware of the ticks prominent in their geographic region of practice; I scapularis, A americanum, and D variabilis pose the greatest risk to cats in the United States. Risk is greater during peak tick activity (ie, May to June, October to November) and in geographic regions with known tick populations.

• The possibility of ticks being present should not be ruled out in any feline patient, as ticks can be found on any cat, including those that do not frequent the outdoors. Location of tick bite varies greatly and is influenced by tick species.

• Tick control should be considered for all cats, even those that have limited to no outdoor exposure.

*Funding to support this research was provided by a grant from Merck Animal Health, Madison, New Jersey, US, to Oklahoma State University.