Identification of canine osteoarthritis using an owner-reported questionnaire and treatment monitoring using functional mobility tests

Objectives

To investigate the diagnostic value of an owner‐completed canine osteoarthritis screening checklist to help identify previously undiagnosed osteoarthritis cases, and assess their response to carprofen treatment by monitoring pain and functional mobility.

Materials and Methods

Dogs (n=500) whose owners reported ≥1 positive response to the osteoarthritis checklist were examined to identify dogs with previously undiagnosed osteoarthritis. Eligible dogs (n=133) were evaluated for pain and video mobility analysis by Helsinki Chronic Pain Index and visual analogue scale scores, respectively, following carprofen treatment, administered for 30 days (n=95) or up to 120 days (n=38). Dogs were filmed at clinics performing activities (walking, jogging, sitting/lying, walking up and down stairs), and scored at days 0, 30 and 120 using visual analogue scale by an independent blinded expert.

Results

A diagnosis of osteoarthritis was confirmed by a veterinarian in 38% (188 of 500) of dogs. Balance of sensitivity and specificity across the original group of nine screening questions was optimised to approximately 88 and 71%, respectively, after elimination of three questions. Pain measured by Helsinki Chronic Pain Index and functional mobility improved over time in response to treatment with carprofen. Mean ability scores for activities significantly improved between days 0 and 30 for walking, jogging, sitting/lying and walking down stairs, and days 0 and 120 for sitting/lying and walking up stairs.

Clinical Significance

More osteoarthritis cases were identified in study dogs than previous prevalence estimates, indicating the screening checklist's potential to help identify for further evaluation cases that could otherwise remain undiagnosed. Improvements in function were demonstrated after carprofen treatment.

A multicenter evaluation of the effectiveness of Quest Gel (2% moxidectin) against parasites infecting equids

Controlled trials with a common protocol were conducted in Idaho, Illinois and Tennessee to evaluate anthelmintic effectiveness of Quest Gel (QG; 2% moxidectin) against lumenal parasites in horses. Candidate horses were required to have naturally acquired nematode infections, as confirmed by presence of strongylid eggs in feces. At each site, 24 equids were blocked on the basis of pretreatment strongyle fecal egg counts (EPG) and randomly assigned to treatments within blocks. Within each block of two animals, one received QG on Day 0 at a dosage of 0.4 mg moxidectin/kg b.w. and one was an untreated control. Body weights measured the day before treatment served as the basis for calculating treatment doses. Horses assigned to treatment with QG received the prescribed dose administered orally with the commercially packaged Sure Dial syringe. Horses were necropsied 12-14 days after treatment, and lumenal parasites and digesta were harvested separately from each of five organs, including the stomach, small intestine, cecum, ventral colon and dorsal colon. Parasites from stomachs and small intestines were identified to genus, species and stage. Micro- (i.e., < 1.5 cm) and macroparasites (i.e., > 1.5 cm) in aliquots from the cecum, ventral colon and dorsal colon were examined in aliquots of approximately 200 parasites until at least 600 parasites had been identified to genus, species and stage or until all parasites in the 5% aliquot were examined, whichever occurred first. Data were combined across sites and analyzed by mixed model analysis of variance to assess the fixed effect of treatment and random effects of site and block within site. Because QG does not contain a cestocide, efficacy of QG against tapeworms was not significant (P > 0.05). Based on geometric means, however, efficacy of QG was greater than 90% (P < 0.05) against 38 species and developmental stages of cyathostomes, strongyles, bots, larval pinworms and ascarids encountered in at least 6 of 36 control horses in the combined data set. None of the horses treated with moxidectin exhibited evidence of adverse effects. Study results demonstrate QG, administered to horses with naturally acquired endoparasite infections at a dosage of 0.4 mg moxidectin/kg b.w., was highly effective against a broad range of equine parasitic infections.

Effects of subcutaneous injections of a long acting moxidectin formulation in grazing beef cattle on parasite fecal egg reduction and animal weight gain

Trials were conducted in Arkansas, Idaho, Illinois and Wisconsin using a common protocol to evaluate effectiveness and safety of a long acting (LA), oil-based injectable formulation of moxidectin in beef cattle grazing spring and/or summer pastures. At each site, 150 cattle (steers and/or heifers) were blocked based on pretreatment fecal strongyle egg counts (EPG) and then randomly assigned to treatments within blocks. Presence of naturally acquired parasitic infections, confirmed by presence of parasite eggs in feces, was a prerequisite for study enrollment. Within each block of three animals, two received moxidectin LA injectable on day 0 at a dosing rate of 1.0 mg moxidectin/kg b.w. into the dorsal aspect of the proximal third of the ear, and one received a placebo control treatment. Cattle were weighed before treatment and on day 55 or 56 (55/56) after treatment. Fecal samples were also collected from 10 randomly selected blocks of animals at each site on days 14, 28 and 55/56 for EPG quantification. Average daily gain (ADG) was computed over the posttreatment period. Data pertaining to ADG and EPG were combined across sites and analyzed by mixed model analysis of variance to assess the fixed effect of treatment and random effects of site, block within site and the treatment by site interaction. Compared to placebo-treated controls, the geometric means of fecal EPG counts from cattle treated with moxidectin LA injectable were reduced 99.8% 14 days after treatment, 99.1% 28 days after treatment and 96.7% 55/56 days after treatment. Rate of weight gain by cattle treated with moxidectin LA injectable was 0.59 kg/day, or 23% (0.11 kg/day) more than placebo-treated controls (P<0.05). None of the cattle treated with moxidectin LA injectable exhibited signs of macrocyclic lactone toxicosis. Summarized across all study sites, proportions of cattle that received concurrent therapeutic treatments were similar among treatment groups. Study results demonstrate that moxidectin cattle LA injectable administered at a dosing rate of 1.0 mg moxidectin/kg b.w. to grazing beef cattle was effective and safe.

Persistent activity of moxidectin long-acting injectable formulations against natural and experimentally enhanced populations of lice infesting cattle

A study was conducted under a common protocol in Wisconsin and Wyoming, USA, to evaluate therapeutic and persistent efficacy of two long-acting injectable formulations of moxidectin against lice populations infesting cattle. At each site, 30 beef calves were blocked into groups of three based on naturally acquired Linognathus vituli populations, then randomly assigned to treatments within blocks. Treatments, injected subcutaneously into the proximal third of the ear on Day 0, included saline, a long-acting oil-based formulation containing 10% moxidectin given at the rate of 1 mg moxidectin/kg body weight (M10/1.0), or a long-acting oil-based formulation containing 15% moxidectin given at the rate of 0.75 mg moxidectin/kg b.w. (M15/0.75). Species of sucking and chewing lice were quantified on nine predilection sites before treatment, then 28, 63, 98, 133 and 168 days after treatment. During intervals between lice counts after Day 28, study animals from the three treatment groups were commingled for 32 days with two lice-free sentinels plus four to six seeder calves with infestations of both sucking and chewing lice. Following each 32-day commingling interval, seeder and sentinel animals were removed, and principal animals were sorted into pens by treatment. Lice were quantified on sentinel animals on the day of removal, and lice were quantified on principal study animals 3 days after removal of sentinel and seeders. Moxidectin was generally not efficacious against Bovicola bovis in the injectable formulations tested, whereas Haematopinus eurysternus infestations were inadequate to judge product effectiveness. Based on geometric means, both M15/0.75 and M10/1.0 provided statistically significant therapeutic efficacy against existing infestations of L. vituli and Solenopotes capillatus (100% efficacy on Day 28), and provided persistent protection against reinfestation with L. vituli and S. capillatus (efficacy >97%) for at least 133 days following treatment.