Apparent tick paralysis by Otobius megnini in a cat.

In this study, we report a rare case of tick paralysis in a cat induced by Otobius megnini infestation. An 11-month-old female cat was admitted to a private veterinary clinic in Luling Texas, USA presenting with depression, tachycardia, and flaccid paralysis of the entire body. The four recovered ticks were morphologically and molecularly identified as O. megnini nymphs. Following initial tick removal and treatment with 0.1% milbemycin oxime in the ear canal on the first day of hospitalization, and additional tick removal and topical selamectin treatment on the second day of hospitalization the animal gradually improved. The recovery of the cat after tick removal supports the diagnosis of tick toxicosis. While tick antiserum is not available in North America, prevention of tick infestation and tick-induced paralysis can be effectively accomplished using repellent collars and the compliant use of other ectoparasiticide products year-round.

Safety and efficacy of a purified canine immunoglobulin G formulation for treatment of 76 cats clinically affected by the Australian paralysis tick (Ixodes holocyclus).

Acute adverse reactions in cats administered unrefined canine paralysis tick (Ixodes holocyclus) antiserum are commonly observed by veterinarians and can lead to significant morbidity and potentially fatal. A purified antiserum canine IgG concentrate was chromatographically prepared and aseptically formulated in single doses containing the equivalent of 5 mL of unrefined tick antiserum (TAS). The IgG was used for slow intravenous infusion into clinically affected cats at multiple veterinary clinics on the eastern seaboard of Australia. Overall, 72/76 (95%) of cats survived hospital discharge, an efficacy comparable to published data. A subset of 22 cats previously treated with unrefined TAS and considered high risk were included in the dataset. The safety profile was excellent with 0/76 acute adverse reactions although 2/76 (2.6%) developed mild facial swelling within 2 h of infusion that responded to the antihistamine. In conclusion, cats intravenously infused with purified IgG from canine TAS did not exhibit the expected frequency of acute adverse reactions during infusion and it was both safe and effective for the treatment of tick paralysis in cats.

Laboratory evaluations of the 3-month efficacy of oral lotilaner (Credelio™) against experimental infestations of dogs with the Australian paralysis tick, Ixodes holocyclus.

BACKGROUND: From three days following host attachment, the Australian paralysis tick, Ixodes holocyclus, secretes a neurotoxin that annually causes paralysis in approximately 10,000 domestic pets. Lotilaner, a novel isoxazoline formulated in a chewable flavoured tablet (CredelioTM), produces rapid onset of acaricidal activity in dogs, with an efficacy duration of at least one month. Two studies were performed to determine the efficacy of lotilaner against I. holocyclus infestations over 3 months. METHODS: Both studies included 16 dogs, ranked according to I. holocyclus counts on Day -5 (from infestations on Day -8) and blocked into pairs. One dog in each pair was randomized to be a sham-treated control, the other to receive lotilaner at a minimum dose rate of 20 mg/kg on Day 0. Dogs were dosed in a fed state. Infestations were performed in both studies on Days -8 (to determine the tick carrying capacity of each dog) -1, 28, 56, 70, 77 and 84, and additionally in Study 1 on Day 91, in Study 2 on Days 14 and 42. In Study 1, ticks were counted and assessed as alive or dead at 24, 48 and 72 h post-initial infestation and post-subsequent re-infestations. In study 2, ticks were counted at 24, 48 and 72 h post-dosing or post-re-infestation. Efficacy was determined by the percent reduction in live attached tick counts in the lotilaner group compared to control. RESULTS: Within 48 h post-treatment in Study 1 and within 72 h post-treatment in Study 2 all lotilaner-group dogs were free of live ticks. By 72 h post-infestation, efficacy in Study 1 remained at 100% through Day 87, except on Day 31 when a single tick was found on one dog, and through Day 59 in Study 2. Efficacy exceeded 95% through the final assessment in each study (Days 94 and 87 in Studies 1 and 2, respectively). CONCLUSION: These results demonstrate that lotilaner quickly kills existing I. holocyclus infestations. By providing 95.3-100.0% protection through at least 87 days post-treatment, lotilaner can be a valuable tool in reducing the risk of tick paralysis in dogs.

Investigation of the efficacy of fluralaner spot-on (Bravecto®) against infestations of Ixodes holocyclus on cats.

BACKGROUND: Infestation of cats with the Australian paralysis tick, Ixodes holocyclus continues to be a threat because of the paralysis that can result from attachment of just a single tick. The outcome can be fatal, particularly if tick removal and treatment is not initiated soon after the onset of paralysis. However, there are no published studies to guide veterinarians and owners on preventive measures. A study was therefore initiated to determine the efficacy of a systemically-acting, spot-on formulation of fluralaner (Bravecto®) for cats against existing I. holocyclus infestations, and to investigate the duration of protection following a single administration. METHODS: Healthy domestic cats, short or long-hair, immunized against holocyclotoxin, were randomly allocated to two groups of 10 cats per group, to receive either a single topically applied fluralaner treatment or no treatment. Fluralaner treatments were administered on Day 0 at a dose rate of 40 mg/kg. All cats were infested with 10 adult unfed female I. holocyclus on Day -1 and on Days 14, 28, 42, 56, 70 and 84. Ticks were assessed at 24 and 48 h after fluralaner treatment and 24, 48 and 72 hours after each subsequent re-infestation. Ticks were counted but not removed at the 24- and 48-h post-challenge assessments and were removed following the 72-h counts. RESULTS: The efficacy of fluralaner spot-on against an existing I. holocyclus infestation was 100% at 48 h post treatment. Following re-infestations, efficacy remained at 100% at the 72-h assessments for all challenges from Day 14 to Day 84. Differences between mean live tick counts on treated versus control cats were significant at all time points from the first post-treatment assessment (t-test: t(18) = 23.162; P < 0.0001) through the final challenge on Day 84 (t-test: t(18) = 21.153; P < 0.0001). No treatment-related adverse events were observed and there were no abnormal observations at the product application sites. CONCLUSIONS: A single treatment of fluralaner spot-on was well tolerated and provided 100% efficacy against I. holocyclus ticks for at least 84 days. Fluralaner spot-on can be a valuable tool to prevent tick infestation in cats, and to control the risk of I. holocyclus-induced paralysis.

Suspected tick paralysis (Ixodes holocyclus) in a Miniature Horse.

A 9-year-old Miniature Horse gelding infested with ticks (Ixodes holocyclus) was presented with flaccid motor paralysis causing recumbency. Neurological examination and other diagnostic tests did not identify an alternative aetiology, leading to a presumptive diagnosis of tick paralysis. The gelding was treated with tick antiserum and intensive supportive care. He made a gradual recovery over the 48 h following presentation and was discharged without further complications. This case report describes in detail the clinical signs and successful treatment of a Miniature Horse with flaccid paralysis caused by suspected envenomation by Ixodes holocyclus.

Tick paralysis.

Tick paralysis is a rare, but readily treatable condition that if missed can lead to significant morbidity and death. The classic clinical presentation of tick paralysis is the development of an unsteady, ataxic type gait followed by an acute symmetric ascending flaccid paralysis. Symptoms generally begin within 2 to 6 days of tick attachment. If the tick continues to feed, the weakness ascends to the upper extremities over a matter of hours, followed by cranial nerve involvement. Due to the similarity in its presentation, tick paralysis is often misdiagnosed as Guillain-Barré's syndrome, particularly the Miller Fisher's subtype, given its cranial nerve involvement. However, the weakness seen in tick paralysis progresses more quickly than what is generally seen in Guillain-Barré's syndrome and the protein concentration is not elevated in the cerebrospinal fluid. The mainstay of treatment for tick paralysis is tick removal. The time to full neurologic recovery after tick removal is estimated to be around 1.5 days with initial improvement generally within hours.

An outbreak of tick paralysis in free-ranging mouflon (Ovis ammon musimon).

During November 2006, two live and one dead mouflon (Ovis ammon musimon) were presented with a history of weakness, tremors, and paralysis. After a detailed gross and histologic examination and a bacteriologic, parasitologic, and rabies evaluation, a preliminary diagnosis of tick paralysis was established. A thorough field search revealed 13 affected mouflons found in the open hunting ground "Sveti Juraj" near the town of Senj (Croatia), along with an additional 35 mouflon carcasses. All 13 mouflons were placed in a quiet, semidark stable. All detectable ticks were removed manually, and the animals were topically treated with 250 ppm of Amitraz water emulsion (Taktic 12.5% EC, Intervet International, 5830 Boxmeer, Netherlands). The collected ticks were identified as Ixodes ricinus, Dermacentor marginatus, and Haemaphysalis punctata. In the following 24 hr, all treated animals recovered fully. This report describes a naturally occurring outbreak of tick paralysis in free-ranging mouflons from a karst habitat.

Tick paralysis in children: electrophysiology and possibility of misdiagnosis.

The authors report six patients with tick paralysis seen over 5 years. Clinical and electrodiagnostic findings failed to adequately distinguish tick paralysis from Guillain-Barré syndrome in these patients. Finding a tick attached to the scalp or the nape of the neck and removing it resulted in rapid clinical improvement.

Reactions to tick antitoxin serum and the role of atropine in treatment of dogs and cats with tick paralysis caused by Ixodes holocyclus: a pilot survey.

OBJECTIVE: To determine the incidence and nature of adverse reactions of dogs and cats to tick antitoxin serum and to re-evaluate the role of atropine in the treatment of tick paralysis. DESIGN: A retrospective questionnaire of veterinarians. PROCEDURE: Questionnaires were posted to 320 veterinarians in tick-endemic regions of Australia. Questions referred to dogs and cats treated for tick paralysis over a period of three years: the number treated, treatment protocols and adverse systemic reactions to tick antitoxin serum. Ninety completed questionnaires were returned and responses analysed. RESULTS: Veterinarians reported that approximately 3% of dogs exhibited adverse reactions immediately following treatment with tick antitoxin serum. Eighteen percent of these reactions were described as anaphylaxis, with the remaining 82% attributed to the Bezold-Jarisch reflex. Six percent of cats treated with tick antitoxin serum reacted adversely and the majority of reactions (63%) were ascribed to the Bezold-Jarisch reflex. Atropine was used routinely by 10% of responding veterinarians in the treatment of dogs and cats with tick paralysis. A similar number of veterinarians used atropine only in selected cases. Most veterinarians (76%) reported that they never used atropine in the treatment of tick paralysis in either dogs or cats. Within the survey population, premedication with atropine reduced the number of Bezold-Jarisch reactions following tick antitoxin administration approximately five-fold in dogs and four-fold in cats. CONCLUSIONS: Data from this pilot survey indicate that more cats than dogs have adverse systemic reactions to tick antitoxin serum and that the majority of these reactions in both dogs and cats could be related to the Bezold-Jarisch reflex. The number of reactions to tick antitoxin serum in dogs and cats could be significantly reduced by the routine use of atropine prior to administration of tick antitoxin serum.

Infestation in the dog by the paralysis tick, Ixodes holocyclus. 5. Treatment.

In this study the value of drugs administered with hyperimmune serum in the treatment of advanced disease produced by Ixodes holocyclus was compared under controlled conditions. All control dogs died rapidly whereas one dog survived and 3 dogs died after receiving hyperimmune serum alone. When promethazine hydrochloride was administered with hyperimmune serum 2 dogs recovered rapidly while the remaining 2 died. Administration of dexamethasone and hyperimmune serum allowed 3 dogs to survive while administration of phenoxybenzamine hydrochloride in conjunction with hyperimmune serum allowed rapid recovery of all 4 dogs. Phenoxybenzamine hydrochloride, an alpha-adrenergic blocking drug, was chosen because of its potential to attenuate the arterial hypertension previously reported (Ilkiw et al 1988). The survival of all dogs together with the rapid return to normality indicated that this drug was beneficial in the treatment of dogs with advanced signs of tick paralysis.