Clinicopathological and Fecal Proteome Evaluations in 16 Dogs Presenting Chronic Diarrhea Associated with Lymphangiectasia

Canine intestinal lymphangiectasia (IL) is a condition characterized by variably severe gastrointestinal signs, frequently associated with laboratory abnormalities; the research for markers allowing a better understanding of the severity degree and/or obtaining an early diagnosis and/or monitoring is continuously progressing. In the present study, we investigated possible new diagnostic/follow-up markers in IL dogs, namely, serum C-reactive protein, serum bacterial lipopolysaccharide, serum cleaved cytokeratin 18, serum citrulline, and zonulin (in both serum and feces). A fecal proteomic study looking for possible confirmation and/or new marker candidates was also performed. All markers in both substrates, with the exception of serum citrulline, significantly differed between diseased and control dogs. Fecal proteomics allowed the retrieval of three proteins in IL dogs (Fc fragment of IgG-binding protein; transthyretin; proproteinase E) that were not previously found in clinically healthy subjects. Although further studies are needed, C-reactive protein, bacterial lipopolysaccharide, cleaved cytokeratin 18, and zonulin (in both serum and feces) resulted as promising markers for canine IL; similarly, fecal proteomics represents a road worthy of being pursued in the search for candidate biomarkers.

Effects of the Probiotic Mixture Slab51® (SivoMixx®) as Food Supplement in Healthy Dogs: Evaluation of Fecal Microbiota, Clinical Parameters and Immune Function

The gut microbiota plays a crucial role in several physiologic functions of the host. In humans and animals, manipulation of the intestinal microbiota by oral administration of probiotic lactic acid bacteria plays a significant role in modulating the immune system. The aim of this study was to evaluate the safety of the probiotic mixture Slab51® and the capacity of this mixture to stimulate immune function in healthy dogs. Twenty dogs were divided in two groups and received a control diet or the same diet supplemented with a dose of 400 billion cfu of lyophilized bacteria for a period of 60 days. Body weight, food intake, body condition score (BCS), fecal score (FSS), fecal immunoglobulin IgA concentration, plasma IgG concentration, and fecal microbiota composition were monitored. Weight, food intake, BCS, FSS, and biochemical parameters remained unchanged during the treatment in both groups of animals. The fecal microbiota showed a significant decrease in the abundance of Clostridium perfringens and a significant increase in the abundance of beneficial Bifidobacterium and Lactobacillus organisms (p < 0.05). Fecal IgA and plasma IgG levels were significantly higher in the group receiving the probiotic compared to healthy controls. These data show that dietary supplementation with the probiotic mixture Slab51® is safe and well-tolerated, modulating the composition of the intestinal microbiota, and enhancing specific immune functions in healthy dogs.

Proposal for rational antibacterial use in the diagnosis and treatment of dogs with chronic diarrhoea

Chronic diarrhoea is a frequent complaint in canine practice and the diagnostic path is often characterised by numerous diagnostic tests and stepwise empirical treatments, often applied before gastrointestinal endoscopy/mucosal biopsies. These include dietary interventions (novel protein, hydrolysed protein diet), parasiticides and still, in many cases, antibacterials. Indiscriminate use of antibacterial drugs risks detrimental consequences for both the individual patient (antimicrobial resistance, long‐term disruption of intestinal bacterial populations, potential worsening of gastrointestinal signs) and the general public. For that reason, in this Perspective essay we advocate use of antibacterials only after histopathologic evaluation of gastrointestinal biopsies or, for those cases in which endoscopy is not possible, after other therapeutic trials, such as diet/pre‐probiotics or anti‐inflammatory drugs have proven unsuccessful. They should be reserved, after appropriate dietary trials, for those canine chronic diarrhoeic patients with signs of true primary infection (i.e. signs of systemic inflammatory response syndrome or evidence of adherent‐invasive bacteria) that justify antibacterial use.

Rapid Resolution of Large Bowel Diarrhea after the Administration of a Combination of a High-Fiber Diet and a Probiotic Mixture in 30 Dogs

Canine fiber responsive diarrhea is a form of chronic colitis that improves clinically after adding fiber to the diet. In the present study, we investigated the effect of a combination of a high-fiber, highly digestible, hypoallergenic diet with a probiotic mixture in 30 dogs with chronic colitis that were unresponsive to various dietary and/or pharmacological interventions. Fecal scores, canine chronic enteropathy clinical activity index (CCECAI) scores, the dysbiosis index (DI), and histologic images of colonic biopsies were evaluated. At baseline (day 0; T0) and after 30 days of treatment (T1), all variables evaluated in our patients (i.e., fecal and CCECAI scores and histopathology) improved significantly at T1, with the exception of DI. However, there was a numerical shift from a state of dysbiosis to one of normobiosis. The combination of the diet and the probiotic used in the present study induced the resolution of clinical signs in a mean of 8.5 days (maximum 15 days) and did not necessitate any other treatments or the further addition of alimentary fiber.

Enterocolic increase of cannabinoid receptor type 1 and type 2 and clinical improvement after probiotic administration in dogs with chronic signs of colonic dysmotility without mucosal inflammatory changes

BACKGROUND

Colonic dysmotility in dogs can cause different GI signs. Sometimes, histology of enterocolic biopsies does not reveal inflammatory infiltrates or mucosal lesions that are typically associated with clinical disease activity. It is speculated that, similarly to humans, colonic dysmotility may be anxiety-based, although recent data demonstrate that irritable bowel syndrome (IBS) could result from acute infectious enteritis. Specific Lactobacillus spp. strains administered orally in humans induced the expression of μ-opioid and cannabinoid receptors in mucosal enterocytes, modulating intestinal morphine-like analgesic functions. We investigated the potential association of GI signs caused by colonic dysmotility and mucosal expression of cannabinoid receptors in intestinal epithelial cells and the number of mucosal mast cells.

METHODS

Ten to 15 endoscopic biopsies were collected from colonic mucosa of 20 dogs diagnosed with dysmotility disturbances before and after probiotic (Slab51 bacterial blend; Sivoy^® ) administration (3-month period). Number and distribution of mast cells (MCs), and cannabinoid receptor type 1 (CB1) and type 2 (CB2) were evaluated by immunohistochemistry and PCR. Results were compared to data obtained from five clinically healthy dogs (archive samples).

KEY RESULTS

Decreased numbers of MCs (P < .0001) and increased CB1- and CB2-positive epithelial cells (P < .0001) in diseased dogs were positively associated with post-treatment CCECAI scores (P < .0001).

CONCLUSIONS AND INFERENCES

Our results suggest that probiotic administration can reduce signs of colonic dysmotility, possibly due to microbiota modulation and epithelial cell receptor-mediated signaling in intestinal mucosa.

Effects of a probiotic (SLAB51™) on clinical and histologic variables and microbiota of cats with chronic constipation/megacolon: a pilot study

Chronic constipation (CC) and idiopathic megacolon (IMC) occur frequently in cats. The aim of the study was to investigate the effects of a multi-strain probiotic (SLAB51™) in constipated cats (n=7) and in patients with megacolon and constipation (n=3). Ten pet cats with a diagnosis of chronic constipation, non-responsive to medical management received orally 2×10¹¹ bacteria daily for 90 days. For microbiota analysis, selected bacterial groups were analysed by qPCR. Histological samples in megacolons were evaluated for interstitial cells of Cajal (ICC), enteric neurons, and neuronal apoptosis. Biopsies were compared at baseline (T0) and after the end of treatment (T1), and with those obtained from healthy control tissues (archived material from five healthy cats). Constipated cats displayed significantly lower ICC, and cats with idiopathic megacolon had significantly more apoptotic enteric neurons than controls. After treatment with SLAB51™, significant decreases were observed for feline chronic enteropathy activity index (FCEAI) (P=0.006), faecal consistency score, and mucosal histology scores (P<0.001). In contrast, a significant increase of ICC was observed after probiotic therapy. Lactobacillus spp. and Bacteroidetes were increased significantly after treatment (comparing constipated cats before and after treatment, and control healthy cats to constipated cats after treatment), but no other differences in microbiota were found between healthy controls and constipated cats. Treatment with SLAB51™ in cats with chronic constipation and idiopathic megacolon showed significant clinical improvement after treatment, and histological parameters suggest a potential anti-inflammatory effect of SLAB51™, associated with a reduction of mucosal infiltration, and restoration of the number of interstitial cells of Cajal.

Effects of probiotic bacteria on mucosal polyamines levels in dogs with IBD and colonic polyps: a preliminary study

Spermine (SPM) and its precursor putrescine (PUT), regulated by ornithine decarboxylase (ODC) and diamino-oxidase (DAO), are polyamines required for cell growth and proliferation. Only a few studies have investigated the anti-inflammatory and tumour inhibitory properties of probiotics on mucosal polyamine levels. We investigated the effects of a high concentration multistrain probiotic for human use on colonic polyamine biosynthesis in dogs. Histological sections (inflammatory bowel disease, n=10; polyposis, n=5) were assessed after receiving 112 to 225×10⁹ lyophilised bacteria daily for 60 days at baseline (T0) and 30 days after treatment end (T90). Histology scores, expression of PUT, SPM, ODC and DAO, and a clinical activity index (CIBDAI) were compared at T0 and T90. In polyps, cellular proliferation (Ki-67 expression), and apoptosis (caspase-3 protein expression) were also evaluated. After treatment, in inflammatory bowel disease significant decreases were observed for CIBDAI (P=0.006) and histology scores (P<0.001); PUT, SPM and ODC expression increased (P<0.01). In polyps, a significant decrease in polyamine levels, ODC activity, and Ki-67, and a significant increase in caspase-3 positivity and DAO expression (P=0.005) was noted. Our results suggest potential anti-proliferative and anti-inflammatory effects of the probiotic mixture in polyps and inflammation, associated with reduced mucosal infiltration and up-regulation of PUT, SPM, and ODC levels.

The importance of histologic parameters of lacteal involvement in cases of canine lymphoplasmacytic enteritis

BACKGROUND

The most frequent form of inflammatory bowel disease (IBD) in dogs is represented histologically, by lymphoplasmacytic enteritis (LPE), a histological category, often associated with other morphologic alterations including lymphangiectasia (LE). However, literature data on this latter topic are quite scarce and have mostly been obtained in single reports or in small series.

AIM

We evaluated some morphologic parameters of intestinal villi and lacteals in a large cohort of dogs, and correlated them with serum albumin and cholesterol values.

PATIENTS AND METHODS

We investigated 136 dogs (94 with LPE, and 42 with gastrointestinal problems different from IBD) and analyzed their clinical, laboratory (albumin and cholesterol values), endoscopic, and histologic variables.

RESULTS

The LPE group showed significantly impaired clinical, laboratory, endoscopic, and histologic variables compared to controls. Affected dogs showed significant correlations between canine inflammatory bowel disease activity index (CIBDAI) scores and endoscopic and histologic variables. Moreover, the grade of hematologic changes were strongly related to the intestinal histologic variables, in particular those concerning villous and lacteals morphology.

CONCLUSION

Dogs with LPE had intestinal histologic abnormalities (height, width, height/width ratio, calculated for both villi and lacteals), whose degree correlated with the severity of hypoalbuminemia and hypocholesterolemia. Evaluation of endoscopic and histologic variables in association to the clinical findings may reveal useful insights for the pathogenesis of LPE and, hopefully, might lead to more targeted therapeutic approaches.

Evaluation of the Helicobacteraceae in the oral cavity of dogs

OBJECTIVE

To determine the Helicobacter spp present in the oral cavity of dogs and the relationship of those organisms with gastric Helicobacter spp to better define the potential for dog-human and dog-dog transmission.

SAMPLE

Saliva and dental plaque from 28 dogs and gastric biopsy specimens from a subset of 8 dogs.

PROCEDURES

PCR-based screening for Helicobacter spp was conducted on samples obtained from the oral cavity of 28 dogs. Comparative analysis was conducted on Helicobacteraceae 16S rDNA clone libraries from the oral cavity and stomach of a subset of 8 dogs (5 vomiting and 3 healthy) that had positive PCR results for Helicobacter spp.

RESULTS

Helicobacteraceae DNA was identified in the oral cavity of 24 of 28 dogs. Analysis of cloned 16S rDNA amplicons from 8 dogs revealed that Wolinella spp was the most common (8/8 dogs) and abundant (52/57 [91%] clones) member of the Helicobacteraceae family in the oral cavity. Only 2 of 8 dogs harbored Helicobacter spp in the oral cavity, and 1 of those was coinfected with Helicobacter heilmannii and Helicobacter felis in samples obtained from the stomach and saliva. Evaluation of oral cavity DNA with Wolinella-specific PCR primers yielded positive results for 16 of 20 other dogs (24/28 samples were positive for Wolinella spp).

CONCLUSIONS AND CLINICAL RELEVANCE

Wolinella spp rather than Helicobacter spp were the predominant Helicobacteraceae in the oral cavity of dogs. The oral cavity of dogs was apparently not a zoonotically important reservoir of Helicobacter spp that were non-Helicobacter pylori organisms.

Cutaneous progressive angiomatosis on the muzzle of a dog, treated by laser photocoagulation therapy

A 10-year old, female, cocker spaniel was presented with a bleeding lesion on the muzzle and nasal planum observed initially as a small raised nodule at 1 year of age. This became clinically more pronounced at 5 years of age, progressively enlarged thereafter and was diagnosed initially as a vascular tumour. On clinical examination, multiple confluent nodules of variable diameter (0.5-1.5 cm) deformed the outline of the nose. Histological examination revealed a progressive angiomatosis with multifocal infiltrative growth of increased dermal vascularization with different sized and type of anastomosing vessels lined by a monolayer of reactive endothelium, often arranged as papillary projections into the lumina. Partial nosectomy, the first therapeutic approach, was unsuccessful and the lesion relapsed within 6 months. However, subsequent laser photocoagulation therapy provided a good cosmetic outcome, no relapse 1 year later, and appeared to provide an effective alternative to ablation surgery.

Tracheobronchial Neuroendocrine Carcinoma in a Cat

A tracheobronchial neuroendocrine carcinoma in a 10-year-old cat with a history of coughing, dyspnoea and anorexia is described. Endoscopic examination revealed a yellowish mass protruding into the trachea and partly obstructing the right bronchial lumen. Histological examination of biopsy samples revealed a hypercellular tumour consisting of sheets or ribbons of small hyperchromatic cells, with oval to spindle-shaped nuclei and minimal cytoplasm; nucleoli and mitotic activity were absent. The findings were confirmed on post-mortem examination. The small neoplastic cells were immunolabelled to varying degrees by antibodies against neuron-specific enolase, S-100 protein, synaptophysin and vimentin. Ultrastructural studies revealed scattered neurosecretory granules and scanty cellular junctional complexes, including desmosomes and tonofilaments, in neoplastic cells.

Detection of Helicobacter spp. DNA in the oral cavity of dogs

The mode of acquisition of gastric Helicobacter spp. infection in dogs has not been determined. It is suspected that oral-oral and faecal-oral transmission may be involved. The present study sought to determine if Helicobacter spp. DNA is present in the oral cavity of healthy and vomiting dogs. Thirty-eight pet dogs (27 vomiting and 11 clinically healthy) were studied. The presence of Helicobacter spp. was determined by single and nested PCR evaluation of DNA extracted from saliva, dental plaque and gastric biopsy samples. Helicobacter spp. DNA was detected by nested PCR in 36 (94.7%) gastric biopsies, 17 (44.7%) dental plaque and 19 (50%) saliva samples out of the 38 dogs examined. Overall 27 (71.1%) dogs screened by nested PCR were found to harbour Helicobacter spp. DNA in the oral cavity (dental plaque and/or saliva). There was no significant difference in the prevalence of Helicobacter spp. DNA in the oral cavity of vomiting and healthy dogs, and the time from vomiting to oral sampling did not have significant impact. This study confirms the high prevalence of gastric Helicobacter spp. infection in dogs, and reveals that Helicobacter spp. DNA is detectable in the oral cavity of over 70% of dogs. These findings support the possibility of oral-oral transmission between dogs and that the canine oral cavity may act as source of non-pylori Helicobacter spp. infection for humans.

Efficacy of a single milbemycin oxime administration in combination with praziquantel against experimentally induced heartworm (Dirofilaria immitis) infection in cats

The efficacy of a combination of milbemycin oxime and praziquantel in preventing the establishment of experimentally induced heartworm (Dirofilaria immitis) infection was investigated in a study involving 24 young domestic short-hair cats. The animals were inoculated with 50 infective larvae on day 0. Subsequently they were divided into two groups of 12 animals each. The animals in group 1 were treated once with medicated tablets containing 4 mg milbemycin (minimum dose 2 mg/kg body weight) and 10 mg praziquantel (MILBEMAX) on day 30 after infection. Cats in group 2 received placebo tablets on the same day. On day 183 post-infection a blood sample was taken from each animal before euthanasia and necropsy. The blood samples were tested for the presence of microfilariae and the necropsied animals were examined for the presence of adult worms. Microfilariae were not found in any of the investigated cats. No heartworms were found in the animals in group 1 (treated with medicated tablets). Out of the 12 placebo-treated cats 1 was heartworm-free, whereas all the others were found to be infected with 1-3 adult heartworms.

Effective treatment and control of biting lice, Felicola subrostratus (Nitzsch in Burmeister, 1838), on cats using fipronil formulations

The efficacy of 0.25% fipronil spray (Frontline Spray, Merial), 10% fipronil spot-on (Frontline Spot-on for Cats, Merial) and 10% fipronil/12% (S)-methoprene (Frontline Plus for Cats, Merial) against the biting louse Felicola subrostratus on cats was assessed and confirmed under laboratory conditions. A field study evaluated the efficacy of a single topical application of Frontline Spray, and spot-on against the parasite on cats. In the laboratory studies, animals were allocated based on pre-treatment louse counts to the treatment groups: (1) untreated control and (2) 10% fipronil spot-on in the exploratory study or (1) untreated control, (2) 0.25% fipronil spray, at 6 ml/kg; (3) 10% fipronil spot-on as per label and (4) 10% fipronil/12% (S)-methoprene as per label in the confirmation study. Cats in treatment groups 2-4 were treated twice topically on Days 0 and 28. No live F. subrostratus were found on cats treated with fipronil formulations at any post-treatment examination. The difference from controls was significant (P < 0.01) for each product at each examination. Based on whole body counts at Day 42, the efficacy of each product was determined to be 100%. In the field study, cats were allocated in strict order of presentation. Cats were randomly allocated to one of the three treatment groups: (1) propoxur collar (Bolfo, Bayer); (2) 0.25% fipronil spray, at 6 ml/kg and (3) 10% fipronil spot-on as per label. Cats were treated once topically on Day 0. Louse counts of cats treated with fipronil formulations were not different than those of cats receiving the propoxur collar. The efficacy was determined to be > 98% on Day 2 and 100% on Days 28 and 42 in all treatment groups. The results of these studies demonstrate that fipronil in topical formulations is effective for treatment and control of biting lice (F. subrostratus) infestations on cats.

Efficacy of selamectin against biting lice on dogs and cats

The efficacy of selamectin was evaluated against naturally acquired Trichodectes canis infestations on dogs and against Felicola subrostratus infestations on cats. Twenty dogs and 18 cats were randomly allocated to treatment with either a placebo or selamectin (6 mg/kg), administered topically once only on day 0. The treatment had no adverse effects in either the dogs or the cats. Efficacy was assessed by counting the live lice (adults and nymphs) on each animal by using a coat-parting technique on days -3, 7, 14, 21, 28, 35 and 42 for the dogs, and on days -1, 7, 21, 35 and 42 for the cats. On day 43, the number of live lice on each dog was also assessed by using a whole-body combing technique. Selamectin was 100 per cent effective in killing biting lice on the dogs and cats throughout the period of assessment; the louse counts on the treated dogs and cats were significantly lower than the pretreatment counts (P = 0.0001) and were also significantly lower than on the placebo-treated dogs (P < 0.05) and cats (P = 0.0001). There was a marked reduction in the prevalence of clinical signs associated with ectoparasite infestation in the treated dogs and no clinical signs were observed in any of the treated cats.

Evaluation of the efficacy of fipronil formulations in the treatment and control of biting lice, Trichodectes canis (De Geer, 1778) on dogs

The efficacy of FRONTLINE SPRAY (0.25% (w/v) fipronil), FRONTLINE SPOT-ON FOR DOGS (10% (w/v) fipronil) and FRONTLINE PLUS FOR DOGS (10% (w/v) fipronil and 9% (S)-methoprene) against the biting louse Trichodectes canis on dogs was confirmed under laboratory conditions. A field study evaluated the efficacy of a single topical application of FRONTLINE SPRAY and FRONTLINE SPOT-ON against the parasite on dogs. A total of 48 dogs of mixed breeds, both sexes, aged 2 months-7 years and weighing 1.8-37.0kg were used. The animals were either experimentally (laboratory study) or naturally (field study) infested with lice. Dogs were housed individually in order to prevent contact between animals. In the laboratory study, animals were allocated based on pre-treatment louse counts from 38 hair coat-partings per animal. Dogs were randomly assigned to the four treatment groups: (1) untreated control; (2) FRONTLINE SPRAY, at 6ml/kg; (3) FRONTLINE SPOT-ON as per label and (4) FRONTLINE PLUS as per label. Dogs in treatment groups 2-4 were treated twice topically on Days 0 and 28. The number of live lice in the 38 hair coat-partings per animal were counted on Days 2, 7 and weekly to Day 63. In addition, a whole body comb count was performed on Day 63. No live T. canis were found on dogs treated with FRONTLINE formulations at any post-treatment examination. The difference from controls was significant (P<0.01) for each product at each examination. Based on the whole body comb count at Day 63, the efficacy of each product was determined to be 100%. In the field study, dogs were allocated in strict order of presentation. Dogs were randomly allocated to one of the three treatment groups: (1) BOLFO collar (propoxur); (2) FRONTLINE SPRAY, at 6ml/kg and (3) FRONTLINE SPOT-ON as per label. Dogs were treated once topically on Day 0. The number of live lice was determined by whole body searches on Days 0 (pre-treatment), 2, 28 and 42. Louse counts of dogs treated with either FRONTLINE SPRAY, or FRONTLINE SPOT-ON were not different than those of dogs receiving the propoxur collar. The efficacy was determined to be >98% on Day 2 and, 100% on Days 28 and 42 in all treatment groups. The results of these studies demonstrate that fipronil in topical formulations is effective for treatment and control of biting lice (T. canis) infestations on dogs.

[Prognostic systems in intensive care: TRISS, SAPS II, APACHE III]

BACKGROUND

To validate the accuracy of SAPS II, APACHE III and TRISS for the prediction of mortality in Intensive Care Unit (ICU) at polytrauma patients admission. The outcome of multiple trauma patients is often linked to the degree of physiologic dysfunction and to the extension of anatomic lesions, the age of the patient and the lesion mechanism.

METHODS

The study population consisted of 93 cases of multiple injured patients hospitalised at the ICU of the Padua hospital from October 1998 to October 1999; the term polytraumatized patient is referred to patients who have multiple lesions of which at least one potentially endangers, immediately or in a short term, their life. These cases were evaluated with the APACHE III, SAPS II, Revised Trauma Score and Injury Severity Score. The predictive power of each system was evaluated by using decision matrix analysis to compare observed and predicted outcome with a decision criterion of 0.50 and 0.40 for risk of hospital death.

RESULTS

All trauma score systems under study showed high accuracy rates, above all if they are used with a 40% positive test.

CONCLUSIONS

The prognostic scales used in this study showed a good correlation between expected and observed cases, particularly with TRISS and APACHE III systems. The APACHE III system seems to be the most reliable of the different methods analysed. These prognostic systems are seldom or occasionally used in the ICU, in Padua and in the whole of Italy, so Italian data are not suitable to be compared to international ones. Due to urgency, the importance of the evaluation scales is often underestimated, but even if they require time and attention, they surely can be useful in the evaluation of the treatment, and not only of a polytraumatized patient.

The efficacy of selamectin in the treatment of naturally acquired aural infestations of otodectes cynotis on dogs and cats

The efficacy of a novel avermectin, selamectin, was evaluated against naturally acquired aural infestations of Otodectes cynotis on dogs and cats. In four controlled and masked studies conducted in the USA and Europe, animals were allocated randomly to treatment with either selamectin at a minimum dosage of 6mgkg(-1) (range, 6-12. 5mgkg(-1)) or the vehicle only from the commercial formulation of selamectin (negative control). Treatments were administered topically in a single spot to the skin of each animal's back at the base of the neck in front of the scapulae. Cats were treated on day 0 only, and dogs were treated either on day 0 only or on days 0 and 30. The ears of dogs were examined otoscopically on day 14 for the presence of viable mites. Mite counts were conducted on day 30 for animals that had received one dose and on day 60 for animals that had received two doses. Percentage reductions in geometric mean mite counts for selamectin treatment compared with the vehicle were 100% for all animals on all count days. Analysis of variance, confirmed by Savage Scores, showed that ln(mite count+1) values were significantly (P< or =0.0015) lower for selamectin than for the vehicle for all animals on all count days. Thus, selamectin administered topically at a minimum dosage of 6mgkg(-1) was safe and 100% effective against naturally acquired aural infestations of O. cynotis in dogs and cats after a single dose or after two doses administered 1 month apart.

Prevention of experimentally induced heartworm (Dirofilaria immitis) infections in dogs and cats with a single topical application of selamectin

In a series of six controlled studies (four in dogs, two in cats), heartworm-free dogs and cats were inoculated with Dirofilaria immitis larvae (L(3)) prior to topical treatment with the novel avermectin selamectin or a negative control containing inert formulation ingredients (vehicle). Selamectin and negative-control treatments were administered topically to the skin at the base of the neck in front of the scapulae. In dogs, selamectin was applied topically at dosages of 3 or 6mgkg(-1) at 30 days post-inoculation (PI), or of 3 or 6mgkg(-1) at 45 days PI, or of 6mgkg(-1) at 60 days PI. Cats were treated topically with unit doses providing a minimum dosage of 6mgkg(-1) selamectin at 30 days PI. Of the animals that were treated 30 days PI, some dogs were bathed with water or shampoo between 2 and 96h after treatment, and some cats were bathed with shampoo at 24h after treatment. Between 140 and 199 days PI, the animals were euthanized and examined for adult D. immitis. Adult heartworms developed in all control dogs (geometric mean count, 18.7 worms) and in 88% of control cats (geometric mean count, 2.1 worms). Selamectin was 100% effective in preventing heartworm development in dogs when administered as a single topical dose of 3 or 6mgkg(-1) at 30 days after infection, 3 or 6mgkg(-1) at 45 days after infection, or 6mgkg(-1) at 60 days after infection. Selamectin was 100% effective against heartworm infections in cats when administered as a single topical unit dose of 6mgkg(-1). Bathing with water or shampoo between 2 and 96h after treatment did not reduce the efficacy of selamectin as a heartworm prophylactic in dogs. Likewise, bathing with shampoo at 24h after treatment did not reduce the efficacy of selamectin in cats. These studies demonstrated that, at the recommended dosage and treatment interval, a single topical administration of selamectin was 100% effective in preventing the development of D. immitis in dogs and cats.

The efficacy of selamectin in the treatment of naturally acquired infestations of sarcoptes scabiei on dogs

Selamectin, a novel avermectin, was evaluated for its effect on naturally occurring infestations of Sarcoptes scabiei in 42 dogs. In two controlled and masked laboratory studies conducted in the USA and Italy, infested dogs received treatment with either selamectin (6mgkg(-1); range: 6-12mgkg(-1)) or the vehicle only (negative control). Treatments were administered topically to the skin on each animal's back at the base of the neck in front of the scapulae. Study day 0 was defined as the first day of treatment administration. Dogs were treated on days 0 and 30, and efficacy was assessed by counting viable mites recovered from skin scrapings performed on each dog on days 14, 29 or 30, 44, and 60, and by categorising the clinical signs of canine scabies on the same days. Percentage reductions in geometric mean mite counts for selamectin, compared with vehicle, on days 14, 29 or 30, 44, and 60 were > or =98.1, > or =93.5, 100, and 100%, respectively. Analysis of variance, confirmed by Savage Scores, showed that ln(mite counts+1) values for selamectin-treated dogs were significantly lower (P< or =0.0391) than those for vehicle-treated dogs on all post-treatment assessment days. Clinical signs of scabies were markedly reduced in selamectin-treated dogs, compared with vehicle-treated dogs. Topical administration to the skin in a single spot of a single unit dose of selamectin, or of two unit doses given 1 month apart, each providing at least the recommended minimum dosage of 6mgkg(-1), was highly effective against naturally acquired infestations of S. scabiei in dogs, reducing mite counts by >93% (single dose) and 100% (two doses).

Efficacy of selamectin against experimentally induced and naturally acquired infections of Toxocara cati and Ancylostoma tubaeforme in cats

The efficacy of selamectin against experimentally induced and naturally acquired infections of adult ascarids (Toxocara cati) and adult hookworms (Ancylostoma tubaeforme) was evaluated in five controlled studies in cats. Two studies evaluated the efficacy of selamectin against both ascarid (natural or induced) and hookworm (induced) infections; two studies evaluated the efficacy of selamectin against single natural infections of T. cati or A. tubaeforme; and the fifth study evaluated the efficacy of selamectin against induced infections of A. tubaeforme. Cats received selamectin topically in unit doses designed to deliver a minimum of 6mgkg(-1). Treatments were applied to the skin on each animal's back at the base of the neck in front of the scapulae. For experimentally induced infections, cats were inoculated orally with approximately 500 embryonated eggs of T. cati 56 days prior to treatment and/or approximately 150-250 larvae (L(3)) of A. tubaeforme 30 or 42 days prior to treatment. For both induced and naturally acquired infections, cats were allocated randomly to treatments (6-12 cats per treatment) on the basis of fecal egg counts to receive either selamectin or a vehicle containing the inert formulation ingredients. In all studies, adult worm counts were performed at necropsy 14 days after the last treatment administration. Against T. cati, a single application of selamectin provided a 100% reduction in the geometric mean number of adult worms for both experimentally induced and naturally acquired infections. Against A. tubaeforme, a single administration of selamectin provided a 99.4% reduction in the geometric mean number of adult worms in cats with natural infections, and an 84.7-99.7% reduction in adult worms in cats with induced infections. Two doses of selamectin administered at monthly intervals provided a 91.9% reduction in the geometric mean number of adult A. tubaeforme worms in cats with experimentally induced infections. The geometric mean numbers of adult worms (T. cati and A. tubaeforme) from selamectin-treated cats were significantly (P< or =0.0018) lower than for vehicle-treated cats in all studies. Thus, a single topical unit dosage providing a minimum dosage of 6mgkg(-1) selamectin was highly effective in the treatment of naturally acquired and experimentally induced infections of T. cati and A. tubaeforme in cats.