Factors affecting the frequency of ear canal and face infestation by Otodectes cynotis in the cat

Prevalence and clinical findings of feline otitis externa in Midwest Brazil

This study was conducted to evaluate the prevalence of otitis externa (OE) in cats using cytology, direct otoscopic examination, and parasitological examination through swabs and curettage, and to compare the accuracy between collection methods for parasitological examination. Direct otoscopic evaluation of the external auditory canal (right and left), swabs for cytological examination of the external auditory canal, and collection of cerumen for parasitological examination through swabs and curettage of 137 cats from a veterinary hospital care were conducted between March 2021 and March 2022. The influences of age, sex, habitat, street access, and the presence of fleas on OE were evaluated. Cytological evidence of OE was observed in 25.5 % of cats and was statistically associated with flea and mite parasitism. Otodectes cynotis was found in 13.9 % of the cats. Cocci and Bacilli were the secondary factors in 34.3 % and 22.9 % of cats with OE, respectively. The Malassezia genus was a secundary factor in 57.1 % of the cats with OE. The frequency of OE was high in cats receiving hospital care. O. cynotis was a frequent primary cause of OE in cats. The curette sampling method is a great option for diagnosing O. cynotis infestation due to its ease of use.

Field efficacy and safety of Felpreva® (tigolaner, emodepside and praziquantel) spot-on for the treatment of natural ear mite infestations (Otodectes cynotis) and notoedric mange (Notoedres cati) in cats

The miticide efficacy of a single treatment with Felpreva® (tigolaner, emodepside and praziquantel) spot-on solution for cats was evaluated in two European field studies. One study was conducted in cats naturally infested with Otodectes cynotis. The other study was conducted in cats naturally infested with Notoedres cati. In both studies, the presence of viable mites was confirmed prior to treatment (Day -1/Day 0) and re-evaluated on Day 14 (O. cynotis study) and on Day 28 (both studies). Efficacy was calculated based on the number of viable mites found after treatment. In the O. cynotis study, the primary criterion was the percentage of mite-free cats after treatment with Felpreva® compared to a sarolaner/selamectin combination (Stronghold® Plus, Zoetis) as a positive control. In the N. cati study, the primary criterion was the difference between arithmetic mean mite counts of cats treated with Felpreva® and cats treated with a placebo formulation (solketal). Secondary criteria in both studies were changes in clinical lesion scores after treatment. In both studies, all Felpreva®-treated cats were mite-free (100% parasitological cure) on Day 28, 4 weeks after treatment. Signs of mange on Day 28 were clinically improved in all O. cynotis-infested cats (100%) and clinically cured in all N. cati-infested cats (100%). There were no records of any adverse events or application site reactions in Felpreva®-treated cats.

Efficacy of Felpreva®, a new spot-on formulation containing tigolaner, emodepside and praziquantel, applied as a single application to cats artificially infested with ear mites (Otodectes cynotis)

The efficacy of Felpreva® (Vetoquinol), a new spot-on application containing the novel acaricide and insecticide tigolaner in combination with emodepside and praziquantel, was evaluated in cats artificially infested with ear mites (Otodectes cynotis). A total of three pivotal dose confirmation studies were conducted, two of them designed as non-interference studies. Cats were artificially infested with O. cynotis mites and randomly allocated into groups of 8 cats based on pre-treatment mite counts. Cats were treated once on Day 0, either with Felpreva® (14.5 ​mg/kg tigolaner, 3 ​mg/kg emodepside and 12 ​mg/kg praziquantel) or with placebo. Studies with a non-interference design included two additional groups of cats, treated with Profender® spot-on solution (Vetoquinol) (3 ​mg/kg emodepside and 12 ​mg/kg praziquantel) and tigolaner as a mono product (14.5 ​mg/kg tigolaner). Efficacy was evaluated on Day 28/Day 30 based on total live mite counts after ear flushing. Efficacy was claimed when: (i) at least six control cats per group were adequately infested with mites; (ii) calculated efficacy was ≥ 90% based on geometric mean mite counts; and (iii) the difference in mite counts between Felpreva®-treated cats and control cats was statistically significant (P ​≤ ​0.05). In two of the three studies, Felpreva®-treated cats were mite-free (100% efficacy) on Day 28/Day 30 and almost full efficacy (99.6%) was seen in the third study. The difference in mite counts between Felpreva®-treated cats and control cats was significant (P ​< ​0.0001) in all three studies. All control cats were adequately infested in all three studies. The efficacy of Felpreva® against ear mite (Otodectes cynotis) infection in cats was confirmed.

How Serious Are Health-Related Welfare Problems in Unowned Unsocialised Domestic Cats? A Study from Denmark Based on 598 Necropsies

Free ranging unsocialised domestic cats are widely believed to suffer from a high load of welfare problems. We assessed the validity of this belief by performing necropsies on the corpses of 598 unsocialised cats, originating from all parts of Denmark, that had been euthanised by two Danish cat welfare organisations. We selected a number of variables for health-related cat welfare that could be assessed through necropsy (e.g., gross lesions, ectoparasites and body condition) or by laboratory analysis (e.g., infection with feline immunodeficiency virus (FIV), and by feline leukaemia virus (FeLV)). Each finding was classified as having either a major or minor welfare impact on the cat. More than 83% of the cats had no major finding, and 54% had no finding indicating a welfare issue at all. More than 83% of the cats had a body condition within normal range. Only 0.3% were emaciated. The most common finding was infestation with ectoparasites, with 15.9% infected with lice, 12.3% with fleas, 4.7% with ticks, and 6.7% with ear mites. FIV and FeLV were detected in 9.2% and 1.2% of the cases, respectively. The most common lesion related to the cats’ teeth. Overall, unsocialised cats in Denmark have a moderate level of health-related welfare problems.

Chronic Otitis in Cats: Clinical management of primary, predisposing and perpetuating factors

PRACTICAL RELEVANCE

Chronic otitis can be one of the most frustrating diseases to manage for a small animal practitioner. While it occurs less commonly in the cat than the dog, it is no less challenging. The purpose of this review is to discuss the common and uncommon causes of chronic otitis in the cat within the clinical framework used for diagnosis and treatment. The focus is on diseases that affect the ear canal, rather than those restricted to the pinnae.

CLINICAL CHALLENGES

Otitis is multifactorial, which complicates management. A common clinical mistake is to focus solely on treating the infection present. Only by addressing all factors will a clinician successfully control chronic otitis. For the purposes of this review, the authors have adopted the established model of separating primary, predisposing and perpetuating causes of otitis. Primary factors are those that directly cause otitis (inflammation); predisposing factors are those that put the patient at risk for development of otitis; and perpetuating factors are those that result in ongoing clinical signs of otitis or that prevent clinical resolution.

AUDIENCE

This review is aimed at veterinarians who treat cats and particularly those with an interest in feline dermatology and otology.

EQUIPMENT

While many practitioners rely on a hand-held otoscope, a video-otoscope can be very helpful for the diagnosis and treatment of chronic otitis.

EVIDENCE BASE

This review presents up-to-date information regarding the diagnosis and treatment of chronic otitis in cats, with emphasis on the most recent peer-reviewed literature.

Safety evaluation of a novel topical combination of esafoxolaner, eprinomectin and praziquantel, in reproducing female cats

NexGard® Combo, a novel topical endectoparasiticide product for cats, is a combination of esafoxolaner, eprinomectin and praziquantel. The safety of this novel combination administered to females during reproduction and lactation was evaluated per analysis of breeding parameters and adverse reactions observed on females and offspring. Females with successful breeding history were randomized to three groups, a placebo group and groups treated with the novel formulation at 1× or 3× multiples of the maximum exposure dose. Females were dosed at 28-day intervals, at least twice before mating, then during a period including mating, pregnancy, whelping and 56 days of lactation. In the placebo, 1× and 3× groups, 10, 9 and 10 females, respectively completed the study (nine, seven and nine females achieved pregnancy), and were dosed 7.1 times on average. Breeding parameters included success of mating, success of gestation, length of gestation, abortion rate, number of live, dead and stillborn kittens at birth, number of kittens with abnormalities, weight of kittens after birth and at weaning, growth of kittens, proportion of male and female kittens, and proportion of kittens born alive and weaned. No significant adverse reactions related to the novel combination were observed on females and on kittens; no significant and adverse effects on breeding parameters were observed.

Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against ear mite (Otodectes cynotis) infestations in cats

Esafoxolaner, a purified enantiomer of afoxolaner with insecticidal and acaricidal properties, is combined with eprinomectin and praziquantel, nematodicidal and cestodicidal compounds, in NexGard® Combo, a novel topical endectoparasiticide formulation for cats. The efficacy of this formulation was assessed against Otodectes cynotis in two laboratory studies conducted in South Africa and in the USA with local isolates, and in one field trial conducted in Europe. In each study, cats were randomly allocated to a placebo-treated control group and a novel formulation-treated group. In the laboratory studies, cats were treated at the minimum recommended dose; in the field trial, cats were treated at label dose. All included cats were diagnosed positive for O. cynotis prior to treatment by otoscopy. The main variable of efficacy was a comparison of the number of live O. cynotis collected in both ear canals of all cats in the treated and control groups, one month after treatment. Efficacy of the novel topical formulation exceeded 97% in the three studies. These studies demonstrated the high effectiveness of NexGard® Combo in cats for the treatment of O. cynotis infestations. No health abnormalities were attributed to the treatment in any of the studies.

Efficacy of Oral Sarolaner for the Treatment of Feline Otodectic Mange

Otodectes cynotis is a mite with a cosmopolitan distribution that is the primary agent for the development of otitis externa in feline species. The aim of this study was to evaluate the efficacy of the oral administration of sarolaner for the treatment of feline otodectic mange. We used 20 adult cats of both sexes that were naturally infested with O. cynotis. The mite infestation scoring was performed by video-otoscopy before treatment. The cats were randomized according to the infestation score and divided into two groups (treated and control). The treated group underwent oral administration of sarolaner in a single dose of 2–4 mg/kg. The evaluations were performed by video-otoscopy to evaluate the reduction of infestation score 2, 4, 6, 24 and 48 h and 7, 14, 21 and 28 days after medication. At the end of the study, the cats were sedated to enable the recovery of live and dead mites to determine efficacy. No adverse effects or laboratory changes were observed in these cats. Sarolaner showed 100% efficacy 48 h after treatment. Based on the results, a single oral dose of sarolaner was effective in controlling otodectic mange in naturally infested cats.

Otodectic and bacterial etiology of feline otitis externa in Tripoli, Libya

Background

Feline otitis externa is a dermatological disorder with a multifactorial complex etiology.

Aim

This study aimed to investigate the prevalence of different etiological agents, particularly the parasitic and bacterial, responsible for the cases of feline otitis externa in Tripoli, Libya, and to assess the antimicrobial susceptibility of the bacterial isolates from those cases.

Methods

Cerumen and otic discharges of the suspected cats were collected for parasite detection and bacterial culture. Kirby-Bauer's disk diffusion method was used for antimicrobial susceptibility testing.

Results

The results showed that otodectic mites and bacterial causes were equally the most prevalent in those cases, with a prevalence of 47.1% each. Otodectes cynotis infestation was more frequently bilateral and severe. Staphylococcus spp. were the most prevalent among bacterial causes (75%), followed by Proteus spp. (16.6%) and Pseudomonas spp. (8.4%). Norfloxacin and gentamicin were the most effective antimicrobials against bacterial isolates, as they were effective against 83.3% and 70.8% of isolates, respectively.

Conclusion

Otodectes cynotis infestation and staphylococcal infections constituted the most common etiology of feline otitis externa in Tripoli, Libya, and norfloxacin represented a cogent antibacterial for the treatment of otitis externa.

Distinguishing Between Dermatologic Disorders of the Face, Nasal Planum, and Ears: Great Lookalikes in Feline Dermatology

Facial dermatitis in cats can be caused by a broad range of infectious, allergic, immune-mediated and neoplastic disorders with very different treatments and prognoses. Baseline dermatologic diagnostics (skin scrapings for mites, cytology for infection and to characterize inflammatory infiltrate, and dermatophyte culture) are required, as well as possible further diagnostics, including therapeutic trials for parasites and feeding a hypoallergenic diet, bacterial culture, and skin biopsies for histopathology in order to achieve a diagnosis. Clinical presentations of diseases affecting different parts of the feline face are presented and discussed.

Otodectes cynotis in urban and peri-urban semi-arid areas: a widespread parasite in the cat population

The ear mite Otodectes cynotis is a parasite of cats and dogs of considerable veterinary importance, being the most common etiological agent of otitis externa in pets. This study investigates the presence of this parasite in 296 cats from Murcia municipality (SE Spain), and describes possible factors associated with the infestation. Cats were grouped by sex, age, lifestyle, season and provenience. Scraping samples were examined by a microscope to identify the mite. Chi square test was computed and odds ratio was used to measure the association of risk factors with parasite prevalence. Additionally, the spatial distribution of prevalences was investigated and represented through GIS software. Around 30% of the cats (CI₉₅ 25-35%) were found positives to O. cynotis. The mite infestation was significantly higher in adult cats, during the winter and in individuals from peri-urban areas. The ectoparasite was found to be widely distributed in the cat population of the study area, with an increased risk of infestation in specific peri-urban areas. The results highlight that O. cynotis is a common parasite in areas with Mediterranean semi-arid climate. Given the importance of otodectic mange, and considering that O. cynotis is not a parasite specific to cats, but may also affect dogs and wild carnivores, the information provided by this study is of great value to both pet owners and veterinarian practitioners, and it might help to implement appropriate preventive and control strategies, mainly in free-roaming cats.

Otoscopy and aural cytological findings in a population of rescue cats and cases in a referral small animal hospital in England and Wales

OBJECTIVES

Otitis externa is seen clinically in cats, although studies investigating this condition within the UK are lacking. The objective of this study was to investigate the prevalence of Otodectes cynotis mites and microbial infection in the ear canals of cats in various rescue centres and a referral hospital.

METHODS

Otoscopy was performed in 332 cats. Otoscopic findings were noted, including the gross visualisation of Otodectes species. A sample of cerumen was collected for cytological evaluation and a cerumen smear for detection of Otodectes mites if there was a large amount of aural exudate present.

RESULTS

O cynotis infestation was noted in 3/341 cats (0.9%, 95% confidence interval [CI] 0.3-2.6). A total of 129/341 (37.8%; 95% CI 32.7-43.0) cats were found to have Malassezia species within one or both ears. Bacteria were found unilaterally in 9/341 (2.6%; 95% CI 1.4-4.9) cats. Analysis of the cytological findings showed an increased likelihood for Malassezia species to be present as age increased (n = 293; Pearson r = 0.204, P <0.001). There was also an increased likelihood of finding Malassezia species in both ears if found within one ear (n = 327; r = 0.499, P <0.001). There was a positive correlation between the number of Malassezia organisms and the quantity of aural exudate (n = 338; r = 0.778, P <0.001). Cats in which Otodectes species infestation were noted (n = 3) had moderate or large quantities of cerumen.

CONCLUSIONS AND RELEVANCE

This study shows that there was a low prevalence of O cynotis in this cohort of cats. In normal cats it was not unusual to find Malassezia microorganisms upon aural cytology, bacteria were noted far less frequently and in two cats this was associated with underlying anatomical pathology.

The Construction of Full-Length cDNA Library for Otodectes cynotis

BACKGROUND

Otodectes cynotis (Hering, 1838) is the pathogen of otodectic mange distributed worldwide. The mite mainly infests carnivores and, sometimes, humans. However, due to the lack of cDNA library, research on its pathogenesis has been challenging.

METHODS

To solve this problem, the present study first sampled O. cynotis mites from an infested cat from Xi'an, China, for RNA extraction. Then, the full-length cDNA library was constructed using the SMART technique. Finally, positive clones > 500 bp and Hsc70-5 gene fragment specifically amplified from the cDNA library were sequenced and analyzed to verify the library's reliability.

RESULTS

Results showed that RNA extracted from 300 mites had good quality with a concentration of 149 ng/μl and OD260/OD280 of 1.99. The library satisfied the quality standard of a good library with a titer of 5.02 × 10⁵ PFU/ml and a combination rate of 97.61%. In addition, clone 4 and Hsc70-5 showed 98.38% and 99.72% identity with Ef1-α and Hsc70-5 gene sequences of O. cynotis in GenBank, respectively.

CONCLUSION

The cDNA library of O. cynotis constructed here was successful and reliable, creating the basis for research on RNA sequencing and functional genes of O. cynotis.

Demodex cati and feline immuno­deficiency virus co-infection in a cat

A case of co-infection due to Demodex cati and feline immunodeficiency virus in a cat is described. A 5 year-old neutered male cat was presented to the Small Animal Clinic at the Faculty of Veterinary Medicine, Trakia University with lethargy, diarrhoea, pyrexia, anorexia, adipsia, skin lesions, intense itching and alopecia. Parasitological, mycological and serological examinations were carried out. Adult D. cati mites and antibodies against FIV were detected. A proper therapy with an endectocide, antibiotic and antihistamine drug was prescribed. The improvement of the general condition was observed after a month of treatment. Later, the disease recurred twice and the animal was humanely euthanased for medical reasons and at the owner’s request.

Efficacy of fluralaner plus moxidectin (Bravecto® Plus spot-on solution for cats) against Otodectes cynotis infestations in cats

Background

The efficacy of the fixed combination of fluralaner plus moxidectin for the treatment of Otodectes cynotis infestations was evaluated in cats after topical application.

Methods

Sixteen cats experimentally infested with O. cynotis were allocated randomly to two groups of 8 cats each. One group was treated topically with the fixed combination of fluralaner plus moxidectin at the minimum dose rate of 40 mg fluralaner and 2 mg moxidectin/kg body weight. The other group was treated with physiological saline solution. Before and 14 and 28 days after treatment the ears of all cats were examined otoscopically for live mites and for the amount of debris and cerumen. Twenty-eight days after treatment, the cats were sedated and had both ears flushed to obtain the total number of live mites per animal. Efficacy was calculated, based on the results of the ear flushing, by comparing mean live mite counts in the fluralaner plus moxidectin treated group versus the saline group.

Results

A single topical application of the fixed combination of fluralaner plus moxidectin to cats reduced the mean mite counts by 100% (P < 0.001) by 28 days after treatment. No mites were visible during otoscopic examination at either 14 or 28 days after treatment. All fluralaner plus moxidectin treated cats had less ceruminous exudate 28 days after treatment compared to pre-treatment and 14 days after treatment. No treatment related adverse events were observed in any cats enrolled in the study.

Conclusions

Single topical application of the fixed combination of fluralaner plus moxidectin was highly effective against O. cynotis infestations in cats.

Efficacy and safety of sarolaner in the treatment of canine ear mite infestation caused by Otodectes cynotis: a non-inferiority study

BACKGROUND

Various treatments are available for ear mite infestations in dogs.

OBJECTIVE

The efficacy of sarolaner was evaluated against ear mite infestation caused by Otodectes cynotis in dogs and compared with topical moxidectin/imidacloprid in a single-masked, multi-centre field study.

ANIMALS

Client-owned dogs with O. cynotis infestation were treated monthly with oral sarolaner (n = 163) or topical moxidectin/imidacloprid (n = 78).

METHODS

The presence of mites in the ear canals and the clinical signs associated with otoacariasis (including head shaking, pruritus/ear scratching, trauma or alopecia of the pinnae, and erythema, ulceration and debris in the ear canals) was evaluated on days 0, 14 and 30, and, if applicable, on day 60. Dogs were considered cured of mite infestation following one (on day 0) or two (on days 0 and 30) monthly treatments, if no live mites were found in either ear. Non-inferiority was evaluated at days 14 and 30.

RESULTS

Parasitological cure was achieved in 76.4%, 90.5% and 93.3% of the sarolaner-treated and in 53.9%, 63.5% and 66.7% of the moxidectin/imidacloprid-treated dogs on days 14, 30 and 60, respectively. At study completion, on day 60 at the latest, parasitological cure was achieved overall in 99.4% of sarolaner-treated and 87.8% of moxidectin/imidacloprid-treated cases. The parasitological cure rate for sarolaner was non-inferior to moxidectin/imidacloprid at days 14 and 30. The clinical signs of otoacariasis improved throughout the study in both groups. There were no treatment-related adverse events.

CONCLUSIONS

A single oral administration of sarolaner was safe and highly effective in the treatment of O. cynotis infestation in dogs.

Efficacy of fluralaner against Otodectes cynotis infestations in dogs and cats

Background

The efficacy of fluralaner for the treatment of Otodectes cynotis infestations in dogs and cats was evaluated after oral (dogs) or topical administration (dogs and cats).

Twenty-four dogs and sixteen cats were experimentally infested with O. cynotis and randomly allocated to equal sized groups (n = 8/group). Dog groups were treated once, either orally with fluralaner at a minimum dose of 25 mg/kg body weight, topically with fluralaner at a dose of 25 mg/kg body weight or topically with saline solution (control). Cat groups were treated once, either topically with fluralaner at a dose of 40 mg/kg body weight or topically with saline solution. Ears of all animals were examined otoscopically for live visible mites and the amount of debris and cerumen before, and 14 and 28 days after treatment. Twenty-eight days after treatment, animals were sedated and both ears were flushed to obtain the total number of live mites per animal. The efficacy was calculated, based on the results of the ear flushing, by comparing mean live mite counts in the fluralaner treated groups versus the saline solution treated group.

Results

A single topical treatment of cats with fluralaner reduced the mean mite counts by 100% (P < 0.001) at 28 days after treatment. Similarly, a single oral or topical treatment of dogs with fluralaner reduced the mean mite counts by 99.8% (P < 0.001) at 28 days after treatment. Cats treated topically with fluralaner had no mites visible during otoscopic examination at either 14 or 28 days after treatment. All dogs treated orally or topically with fluralaner had no mites visible during otoscopic examination at 28 days after treatment. At 14 days after treatment, only 1–2 mites were visible in three dogs (oral treatment: 2 dogs, topical treatment: 1 dog). All fluralaner-treated animals showed improvement in the amount of cerumen exudation compared with observations performed before treatment. No treatment related adverse events were observed in any dogs or cats enrolled in these studies.

Conclusions

In this study, fluralaner administered topically to cats and orally or topically to dogs was highly effective against Otodectes cynotis mite infestations.

Parasites of domestic owned cats in Europe: co-infestations and risk factors

BACKGROUND

Domestic cats can be infested by a large range of parasite species. Parasitic infestations may cause very different clinical signs. Endoparasites and ectoparasites are rarely explored in the same study and therefore multiparasitism is poorly documented. The present survey aimed to improve knowledge of the prevalence and risk factors associated with ecto- and endoparasite infestations in owned cats in Europe.

METHODS

From March 2012 to May 2013, 1519 owned cats were included in a multicenter study conducted in 9 veterinary faculties throughout Europe (Austria, Belgium, France, Hungary, Italy, Romania and Spain). For each cat, ectoparasites were checked by combing of the coat surface associated with otoscopic evaluation and microscopy on cerumen samples. Endoparasites were identified by standard coproscopical examinations performed on fresh faecal samples. Risk factors and their influence on parasitism were evaluated by univariate analysis followed by a multivariate statistical analysis (including center of examination, age, outdoor access, multipet status, and frequency of treatments as main criteria) with logistic regression models.

RESULTS

Overall, 50.7% of cats resulted positive for at least one internal or one external parasite species. Ectoparasites were found in 29.6% of cats (CI95 27.3-32.0%). Otodectes cynotis was the most frequently identified species (17.4%), followed by fleas (15.5%). Endoparasites were identified in 35.1% of the cats (CI95 32.7-35.7%), including gastro-intestinal helminths in 25.7% (CI95 23.5-28.0), respiratory nematodes in 5.5% (CI95 4.2-7.0%) and protozoans in 13.5% (CI95 11.8-15.3%). Toxocara cati was the most commonly diagnosed endoparasite (19.7%, CI95 17.8-21.8%). Co-infestation with endoparasites and ectoparasites was found in 14.0% of the cats, and 11.9% harbored both ectoparasites and gastro-intestinal helminths.Age, outdoor access, living with other pets, and anthelmintic or insecticide treatments were significantly associated with the prevalence of various parasites.

CONCLUSIONS

This survey demonstrates that parasitism is not a rare event in European owned cat populations. The prevalence of multi-parasitism is significantly greater than expected by chance and hence there is tendency for some individual cats to be more prone to infestation by both endo- and ectoparasites due to common risk factors.

Prevalence of otitis externa in stray cats in northern Italy

Feline otitis externa is a dermatological disorder that has not been evaluated much in stray cats. One hundred and eighty-seven stray cats were randomly selected during a trap-neuter-release programme to investigate the prevalence of otitis externa in stray cat colonies in northern Italy. Swabs for cytological examination were obtained from the external ear canal of each cat. A direct otoscopic assessment of the external ear canal was made in 86/187 cats. Cytological evidence of otitis externa was present in 55.1% of cats. The influence on otitis of age, gender, habitat and season of sampling was tested, but no risk factors were found. Otodectes cynotis (as a sole agent or in combination) was the primary cause of otitis in 53.3% of cats. Cocci and rods, either alone or in combination with other agents, were perpetuating factors in 71.8% and 29.1% of cats, respectively. Pregnancy status was a risk factor for otitis caused by coccal infections. Malassezia species, alone or in combination, was the perpetuating factor in 50.5% of cats with otitis. Urban habitat and winter season were risk factors for otitis associated with Malassezia species. Demodex cati was identified as an incidental finding in two cats. There was good agreement between otoscopy and cytology with regard to the diagnosis of otitis externa. The results of this study show a high prevalence of otitis externa in stray colony cats and provide information on causal factors for feline otitis externa.

First feline case of otodectosis in the Republic of Korea and successful treatment with imidacloprid/moxidectin topical solution

In April 2010, pruritic symptoms were recognized in 3 privately-owned Siamese cats raised in Gwangju, Korea. Examination of ear canals revealed dark brown, ceruminous otic exudates that contain numerous live mites at various developmental stages. Based on morphological characteristics of adult mites in which caruncles were present on legs 1 and 2 in adult females and on legs 1, 2, 3, and 4 in adult males while the tarsus of leg 3 in both sexes was equipped with 2 long setae, the mite was identified as Otodectes cynotis. Ten ear mite-free domestic shorthaired cats were experimentally infected with O. cynotis to evaluate the efficacy of 10% imidacloprid/1% moxidectin spot-on. Live mites were recovered from 1 of 10 treated cats on day 9 post-treatment (PT) while no live mites were observed from the ear canals of treated cats on days 16 and 30 PT. The efficacy of 10% imidacloprid/1% moxidectin spot-on on O. cynotis in cats was, therefore, 90% on day 9 and 100% on days 16 and 30 PT. This is the first report of otodectosis in 3 cats naturally infested with O. cynotis in Gwang-ju, Korea. Both natural and experimental infestations were successfully treated with 10% imidacloprid/1% moxidectin spot-on.

Efficacy of a single dose of an otic ivermectin preparation or selamectin for the treatment of Otodectes cynotis infestation in naturally infected cats

Otodectes cynotis infestation is common in kittens housed in crowded environments like animal shelters. It is unknown how rapidly O cynotis is killed within the first 72 h of treatment with currently available products. Kittens ⩾4 weeks of age with live O cynotis in both ears (AU) were administered 0.5 ml of 0.01% ivermectin otic suspension (Acarexx; Idexx Pharmaceuticals) once, AU or selamectin (Revolution; Pfizer Animal Health) once, on the skin following the manufacturer's instructions. Repeat microscopic examination was performed on individual ears based on a randomization schedule during the 72 h after treatment. There was no evidence of toxicity with either drug and administration of 0.01% ivermectin significantly reduced the time to live mite-free status compared to selamectin. Both drugs have an effect against O cynotis as early as 10–12 h after administration with an increasing effect over time.

Factors associated with the prevalence of Otodectes cynotis in an ambulatory population of dogs

The objective was to evaluate the factors associated with the prevalence of Otodectes cynotis infestations in dogs assisted at the Dermatology Service of the Veterinary Hospital, Universidade Federal Rural do Rio de Janeiro. A total of 250 dogs were examined through direct smear of ear samples using a stereoscopic microscope, for the parasitological diagnostic. All dog owners were interviewed and data regarding the animals and their environments were individually recorded. Mite infestation was observed in 15 animals, with a prevalence of 6%. The variables were tested regarding their association with the mites, using the χ2 test and, when appropriate, the Fisher exact test. There were no evidences that age (p = 0,20), sex (p = 0,31), breed (p = 0,50), shape of ear (p = 0,66), type (p = 0,19) and length of hair (p = 0,14) and contact with other animals (p = 0,06) could act as potential risk factors for O. cynotis infestation. However, living environment (p = 0,03) and frequency of environmental cleaning (p = 0,005) may facilitate the infestation. The occurrence of pruritus was associated to the presence of mites (p<0,001), suggesting to be an effect of the parasitism.

Otic cytology in health and disease

Accurate characterization of the primary cause and perpetuating factors is essential for successful management of ear disease in dogs and cats. Cytology is a simple, rapid, and practical diagnostic test that should be performed routinely on any and all patients presented for clinical signs consistent with otitis externa. In combination with clinical signs, otoscopic evaluation, and diagnostic testing of primary disease, serial cytology enhances the ability of veterinarians to diagnose secondary infections, monitor progression of disease, evaluate response to therapy, and make appropriate management decisions. Cytologic specimens should be evaluated for the presence, numbers, and characteristics of three key features: yeast, bacteria, and leukocytes. More than five yeast organisms or more than 25 bacteria per high-powered field is suggestive of significant microbial activity warranting therapeutic intervention. The presence of leukocytes, particularly with phagocytized bacteria, indicates "true infection" rather than overgrowth; if suppurative discharge is present, systemic therapy is needed. Cytology combined with culture and susceptibility is the best method for identification of bacterial overgrowth and infection; however, if only one test can be performed, always choose cytology. Culture results assist in the selection of appropriate antibiotic therapy, but cytology determines whether systemic antibiotics are indicated, which organisms are most significant, and when therapy can be discontinued.

Factors affecting the prevalence of mange-mite infestations in stray dogs of Yucatán, Mexico

The aim of the present study was to determine the factors affecting the prevalence of mange-mite infestations in stray dogs of Yucatán, Mexico. The study was carried out in 200 stray dogs of Mérida capital city of Yucatán, Mexico. Four samples (head, thoracic-abdominal area, extremities and ear) were taken from each animal by skin scraping and examined microscopically in 10% KOH solution to detect the presence of mites. Mites were also collected from the external ear canal of dogs using cotton-tipped swabs. The prevalence of different mite species was calculated. A primary screening was performed using 2xK contingency tables of exposure variables. All variables with P< or =0.20 were analyzed by a logistic-binomial regression. The overall prevalence was 34%. Demodex canis (23.0%) was the most frequent mite, followed by Sarcoptes scabei var. canis (7.0%) and Otodectes cynotis (3.5%). The following factors were found: body condition (bad, OR: 5.35, CI 95%: 1.66-17.3; regular, OR: 3.72, CI 95%: 1.39-9.99) and the presence of macroscopic lesions of dermatosis (OR: 42.80, CI 95%: 13.65-134.24).

Prevalence of ectoparasites in a population of feral cats from north central Florida during the summer

Ectoparasites are a common and important cause of skin disorders in cats. Ectoparasites are capable of disease transmission and can cause life-threatening anemia in young or debilitated animals. The objective of this study was to determine the potential feline ectoparasites in domestic cats by using a cohort of feral cats from north central Florida that have not received veterinary care and have no known exposure to insecticide application. A total of 200 feral cats were randomly selected for this study. Four monthly sessions were scheduled for feral cat ectoparasite examination and sample collection. Five minutes flea combing revealed that 185/200 (92.5%) of the cats were infested with fleas. The cat flea, Ctenocephalides felis was the most common flea infesting 92.5% feral cats (mean = 13.6; standard deviation +/- 16.4 fleas per cat). Pulex simulans was identified on 9/200 (4.5%) (mean = 1 +/- 0.50 fleas per cat). Echidnophaga gallinacea was found on 11/200 (5.5%) of cats (mean = 14.8 +/- 9.63 fleas per cat). There was a significant difference (P = 0.0005) in the average number of C. felis counted per cat between months. Mean counts in June (18.3 +/- 2.4) and July (16.6 +/- 2.1) were significantly (P < 0.01) higher than in August (8.4 +/- 2.5) and September (7.7 +/- 2.0). Only 15/200 cats had skin disease. Flea infestation may potentially be the underlying cause in 10/15. Otoscopic examination of both ears revealed mite movement and black ceruminous exudate typically indicative of the presence of Otodectes cynotis in 45/200 (22.5%) cats. Examination of a swab specimen from both ear canals of all cats revealed O. cynotis in 74/200 (37%) cats. Of 74 cats positive on ear swab, 8 (10.8%) showed a normal ear canal appearance (no or mild ceruminous exudate) in both ears upon otoscopic examination. A total of nine ticks were recovered from five cats. The number and species of ticks recovered were: one adult female Rhipicephalus sanguineus; one adult female Amblyomma americanum; one adult male A. americanum; five adult female Dermacentor variabilis; and one adult female Ixodes scapularis. All superficial skin scrapes were negative. Hair clippings from the abdomen of all cats revealed 2/200 (1%) of the cats were infested with Felicola subrostratus.