Ticks from cats in the United States: Patterns of infestation and infection with pathogens

Abstract

Ticks are an important but under recognized parasitic threat to cats in many areas of the United States. To characterize the species and stages of ticks most commonly recovered from cats and determine the prevalence of disease agents in the ticks, we conducted a survey of ticks removed from cats at veterinary practices in 18 states from April 2016-June 2017. A total of 796 ticks were submitted from 332 cats from 41 different veterinary practices. A single tick was submitted from the majority of cats, with a mean infestation intensity of 2.4 (range 1-46). The most common tick was Ixodes scapularis, accounting for 422/796 (53.0%) ticks submitted, followed by Amblyomma americanum (224/796; 28.1%) and Dermacentor variabilis (131/796; 16.5%); a few I. pacificus, I. banksi, D. occidentalis, A. maculatum, Rhipicephalus sanguineus, and Otobius megnini were also submitted. A majority of ticks were adults (593/796; 74.5%); females predominated in all adult tick submissions including I. scapularis (277/327; 84.7% female), A. americanum (66/128; 51.6% female), and D. variabilis (75/126; 59.5% female). Immature ticks included 186 nymphs and 17 larvae and were primarily I. scapularis and A. americanum. Adult I. scapularis were most reported to be attached to the dorsal head and neck; A. americanum to the abdomen and perianal region; and D. variabilis to the back and ear. Ticks were collected in every month; the largest number of submissions were in May and June (42.5% of ticks) and October and November (35.9% of ticks). Adults of I. scapularis were most commonly submitted October through December, A. americanum March through June, and D. variabilis May through July. Cats with ticks were predominantly male (58.8%) and altered (76.2%), and most reportedly spent >30% of time outdoors, although 64/294 (21.8%) for which lifestyle estimates were provided were reported to live primarily (≤30% of time outside; n = 54) or entirely (100%; n = 10) indoors. Assay of ticks removed from cats revealed I. scapularis were infected with Borrelia burgdorferi (25.7%) and Anaplasma phagocytophilum (4.4%); A. americanum were infected with Ehrlichia chaffeensis (1.3%); and D. variabilis were infected with spotted fever group Rickettsia spp. (3.1%). No ticks in this study tested positive for Cytauxzoon felis. Pet cats, including those that live primarily indoors, are at risk of tick infestation, potentially exposed to tick-borne disease agents, and would benefit from routine tick control.

Adherence to Veterinary Recommendations for Ectoparasiticides Purchased by Cat Owners in the United States.

“…Year-round ea and tick treatment coverage for cats directly protects the cat, eradicates ea populations in the home environment, 13 and helps to reduce the risk of vector transmitted disease. 1 However, as seen in this study, cat owners typically acquired only one or two treatment doses, regardless of the duration of the ea and tick medication purchased and few owners obtained full-year ea and tick coverage (Table 4). Therefore, veterinary clinicians and practice staff may want to pay increased attention to owner education and use of repurchase reminders as additional components that contribute to increased owner adherence.…”

“…This is because of the high prevalence of ea infestation, the year-round risk of ticks, the risk of ea allergy dermatitis (FAD), the pathogens that eas and ticks vector, and the introduction of eas into the home. 1,2 Fleas, particularly Ctenocephalides felis felis, are very common and perhaps the most clinically important ectoparasite of cats and dogs worldwide. [3][4][5] Flea-related diseases could account for more than half of dermatologic cases presented to companion animal veterinarians.…”

“…3,10 Fleas and ticks also carry and transmit an assortment of vector-borne pathogens that can affect cats and people, including Bartonella spp., Ehrlichia spp., Rickettsia spp., Mycoplasma spp., as well as cestode, protozoal, and larial endoparasites. 1,2,4,13,14 Investigators have found that as many as 80% of eas collected from cat populations harbor feline or human pathogens of signi cance. 15 Safe and effective feline ea and tick treatment options are therefore an important component of the weeks after treatment.…”

Adherence to veterinary recommendations for ectoparasiticides purchased by cat owners in the United States of America.

“…In primary care veterinary practice, ea and tick control is an essential component of the preventive healthcare strategy for cats. This is because of the high prevalence of ea infestation, the year-round risk of ticks, the risk of ea allergy dermatitis (FAD), the pathogens that eas and ticks vector, and the introduction of eas into the home [1,2].…”

“…Fleas and ticks also carry and transmit an assortment of vector-borne pathogens that can infect cats and people, including Bartonella spp., Ehrlichia spp., Rickettsia spp., Mycoplasma spp., as well as cestode, protozoal, and larial endoparasites [1,2,4,13,14]. Investigators have found that as many as 80% of eas collected from cat populations harbor feline or human pathogens of importance [15].…”