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.

EAR MITES, OTODECTES CYNOTIS, ON WILD FOXES (PSEUDALOPEX SPP.) IN CHILE.

We found the ear mite parasite (Otodectes cynotis; Acari: Psoroptidae) in two distant insular endangered fox populations in Chile. We identified O. cynotis in both the Darwin's fox (Pseudalopex fulvipes) from Chiloé and the Fuegian culpeo (Pseudalopex culpaeus lycoides) in Tierra del Fuego. These populations are approximately 2,000 km apart. Infestation rates were high for both endemic foxes: 76% (19/25) of Darwin's foxes were affected, and 73% (11/15) of Fuegian culpeos had ear mites. Two Darwin's foxes had abundant ear discharge, and one of these also exhibited secondary infections of Morganella morganii and Geotrichum sp. fungi. Mites were characterized molecularly as Otodectes spp. for the Fuegian culpeo samples. Genetic analyses of two mites found the O. cynotis genotype I, as well as what appeared to be a new allele sequence for O. cynotis. These results confirmed the hypothesis of a worldwide distribution species of ear mite. Introduced chilla foxes (Pseudalopex griseus; n=11) on Tierra del Fuego Island and domestic dogs (Canis lupus familiaris; n=379) from both islands were also sampled, but they showed no signs of infection. Our findings provided insight into the genetic diversity, the origins, and the possible impact of this globally distributed mite on endemic free-ranging populations of foxes.

Quantifying parasite presence in relation to biological parameters of harbour porpoises Phocoena phocoena stranded on the Dutch coast.

Harbour porpoises are often found to be infected by endoparasites in several organs including the lungs and stomach as well as the heart, liver and ears. Nevertheless there is still little knowledge about the impact, ecology, transmission, and virulence of these parasitic infections. Here, we profile the presence of parasites in 4 frequently infected organs (lungs, stomach, liver and ears) in relation to biological parameters of harbour porpoises stranded along the Dutch coastline between December 2008 and December 2013. We found that parasites were common, with prevalence of 68% in lungs, 74.4% in ears, 26% in stomach and 23.5% in liver. We used generalised linear models to further quantify parasite presence in relation to biological data gathered during necropsy (sex, body length and nutritive condition). Body length (used as a proxy for age) was significant in explaining parasite presence for all organs with increasing probability of having the parasite with increasing body length. For the parasitic infections in the ears and stomach the nutritive condition was an additional significant factor, with a higher probability of parasite presence in porpoises in a poorer nutritive condition. The results of this study can be used as a baseline for assessing parasite presence in harbour porpoises and are a first step towards linking parasite infections to basic biological data gathered during necropsy.

RECURRENT EAR MITE (OTODECTES CYNOTIS) INFESTATION IN THREE RELATED GROUPS OF PATAGONIAN CAVIES (DOLICHOTIS PATAGONUM).

: Two of three groups of Patagonian cavies ( Dolichotis patagonum ) contracted Otodectes cynotis infestations after exposure to mite-infested feral cats. Otodectes cynotis infestations were initially identified in 9 of 10 cavies in group 1. Multiple feral cats with O. cynotis infestations were observed in the vicinity of the Patagonian cavies and were subsequently removed. The Patagonian cavies were initially treated with ivermectin (0.4 mg/kg s.q.) every 2 wk, but ivermectin was discontinued after the third treatment due to injury to one of the Patagonian cavies during capture. Sixteen months after initial treatment, clinical signs of scratching the pinnae, hemorrhagic lesions on the ear margins, head shaking, and O. cynotis mites in the auricular canal were again noted in all Patagonian cavies in group 1. Repeated administration of ivermectin (0.4 mg/kg s.q. every 2 wk for three treatments) failed to eliminate the mites in two of the Patagonian cavies. Selamectin administered (20 mg/kg, topically between the shoulder blades) to all Patagonian cavies eliminated the mite infestation after a single application. The Patagonian cavies remained O. cynotis mite free for 2 yr, until males (group 2) and females (group 3) were separated for population control. Three months after separation, 8 of the 12 females in group 3 again were infestated with O. cynotis mites. Feral cats with O. cynotis infestations were again noted in the vicinity of group 3. A single dose of selamectin applied topically eliminated all mites in all treated Patagonian cavies. Group 2 was not exposed to feral cats and remained mite free.

Use of oral fluralaner for the treatment of Psoroptes cuniculi in 15 naturally infested rabbits.

BACKGROUND: Psoroptes cuniculi, a nonburrowing ear mite, is a common ectoparasite of rabbits. Constant irritation of the auditory canal by the presence of this mite can lead to otitis externa or otoacariasis. OBJECTIVE: The goal of this study was to evaluate the effect of fluralaner on rabbits naturally infested with P. cuniculi and exhibiting clinical signs. ANIMALS: Fifteen female New Zealand domestic rabbits with otitis due to naturally occurring infestation with P. cuniculi. METHODS: The external ears and ear canals of each individual were examined; samples of otic exudate were extracted with cotton swabs and examined microscopically for identification of the ectoparasite. Each animal was treated with a single 25 mg/kg oral dose of fluralaner. The amount of otic exudate/cerumen was assessed and samples were obtained from the ears to evaluate for presence or absence of mites at 4, 8, 12, 16, 20, 40 and 90 days after receiving treatment. RESULTS: Post-treatment, the amount of otic exudate decreased rapidly in all animals; by Day 12 and until the end of the study all rabbits were judged to have low amount of exudate with normally visible canals. The percentage of ears positive for P. cuniculi decreased to 13.3% of ears sampled by Day 4, and by Day 12 all rabbits were negative for the parasite. CONCLUSION: Administration of a single oral dose of fluralaner was effective for the treatment of naturally occurring P. cuniculi infestation in rabbits during a 90 day period.

Pilot Study: Occurrence of Ear Mites and the Otic Flora in Domestic Ruminants on St. Kitts.

Psoroptes, a globally occurring mite, and Raillietia, a primarily tropical mite, have been attributed to otitis in ruminants. Within the Caribbean, little is known about the prevalence of these mites and their relation to the microbial flora of the ears. From May 2015 to May 2016, ears of cattle, sheep and goats brought to the St. Kitts abattoir were examined post-slaughter for mite infestations. No Raillietia spp. were seen and none of the sheep had ear mites. Psoroptes spp. were found in 2.6% of the cattle and 22.6% of the goats. Tick control programs, focused on cattle and sheep, might influence the occurrence seen in this study.

Diversity and distribution of tick species (Acari: Ixodidae) associated with human otoacariasis and socio-ecological risk factors of tick infestations in Sri Lanka.

Tick infestation in humans is a major public health concern. The diversity and distribution of tick species associated with human otoacariasis was studied in five districts: Anuradhapura, Kandy, Kurunegala, Nuwara Eliya and Ratnapura in the main agro-climatic zones of Sri Lanka. Ticks from patients attending the ear, nose and throat clinics of the General Hospitals were collected during a 3 year period. In total 426 ticks were collected. Most human otoacariasis cases were reported from Kandy (33.8 %) and the fewest from Nuwara Eliya (8.2 %). Of the five tick species identified, nymphs of Dermacentor auratus constituted 90.6 % of the collection. Rhipicephalus sanguineus, Hyalomma isaaci, Haemaphysalis bispinosa and Otobius megnini were found rarely infesting humans possibly as an accidental host; H. bispinosa and O. megnini in the human ear canal were first time records in Sri Lanka. Females and children under 10 years were identified as risk groups of human otoacariasis. Subsequently, a field study was carried out to determine socio-ecological risk factors of human tick infestations in the five districts. Based on hospital data, eight villages with high prevalence of otoacariasis were selected from each district. A total 40 villages were visited and 1674 household members were interviewed. Involvement in outdoor activities, presence of wild animals around the house, location of the house in close proximity to a forest and occupation were identified as major risk factors.

Ear Mite Removal in the Santa Catalina Island Fox (Urocyon littoralis catalinae): Controlling Risk Factors for Cancer Development.

Ear mites (Otodectes cynotis) and ear canal tumors are highly prevalent among federally endangered Island foxes (Urocyon littoralis catalinae) living on Santa Catalina Island off the coast of Southern California. Since studies began in the 1990s, nearly all foxes examined were found to be infected with ear mites, and ceruminous gland tumors (carcinomas and adenomas) were detected in approximately half of all foxes ≥ 4 years of age. We hypothesized that reduction of ear mite infection would reduce otitis externa and ceruminous gland hyperplasia, a risk factor for tumor development. In this study, we conducted a randomized field trial to assess the impact of acaricide treatment on ear mite prevalence and intensity of infection, otitis externa, ceruminous gland hyperplasia, and mite-specific IgG and IgE antibody levels. Treatment was highly effective at eliminating mites and reducing otitis externa and ceruminous gland hyperplasia, and mite-specific IgG antibody levels were significantly lower among uninfected foxes. Ceruminous gland hyperplasia increased in the chronically infected, untreated foxes during the six month study. Our results provide compelling evidence that acaricide treatment is an effective means of reducing ear mites, and that mite removal in turn reduces ear lesions and mite-specific IgG antibody levels in Santa Catalina Island foxes. This study has advanced our understanding of the underlying pathogenesis which results in ceruminous gland tumors, and has helped inform management decisions that impact species conservation.

Clinical evaluation of the safety and efficacy of 10% imidacloprid + 2.5% moxidectin topical solution for the treatment of ear mite (Otodectes cynotis) infestations in dogs.

A clinical field investigation was conducted to evaluate the safety and efficacy of 10% imidacloprid/2.5% moxidectin for the treatment of ear mites (Otodectes cynotis) in dogs. The study was a multi-centered, blinded, positive controlled, randomized clinical trial conducted under field conditions with privately owned pets. A total of 17 veterinary clinics enrolled cases for the study. An otoscopic examination was performed to confirm the presence of O. cynotis residing in the ear of the dog prior to enrollment. A single-dog household was enrolled in the study if the dog had 5 or more ear mites and an acceptable physical examination. A multi-dog household was eligible if at least one dog in the household had 5 or more mites and all dogs in the household had acceptable physical exams and met the inclusion criteria. Qualified households were randomly assigned to treatments to receive either 10% imidacloprid+2.5% moxidectin topical solution or topical selamectin solution (positive control product) according to a pre-designated enrollment ratio of 2:1, respectively. If more than one dog in a multiple dog household had adequate numbers of ear mites, one dog was randomly selected to represent the household for efficacy evaluation prior to treatment. Treatments were administered twice per label and dose banding directions for each product approximately 28 days apart (Days 0 and 28), by the dog's owner at the study site. All dogs in a household were treated on the same day and with the same product. The owners completed a post-treatment observation form one day after each treatment. Post-treatment otoscopic examinations were performed by the investigators or attending veterinarian on Days 28 and 56. Physical examinations were performed on Days 0 and 56. One hundred and four (104) households were evaluated for efficacy on SD 28, and 102 households were evaluated for efficacy on SD 56. The dogs' ages ranged from 2 months to 16 years. A total of 247 dogs were evaluated for safety. Percent efficacy was based on the percentage of dogs cleared of ear mites. Mite clearance on Day 28 was 71% for the imidacloprid+moxidectin group and 69% for the selamectin group. Mite clearance on Day 56 was 82% for the imidacloprid+moxidectin group and 74% for the selamectin group. No serious adverse events associated with either product were observed during the study. The study demonstrated that 10% imidacloprid+2.5% moxidectin applied using two topical treatments, 28 days apart, was safe and achieved similar efficacy against O. cynotis as selamectin treatments applied and evaluated under the same conditions.

Myiasis of the ear: a review with entomological aspects for the otolaryngologist.

OBJECTIVE: Myiasis is the infestation of live humans (or animals) by fly larvae. Although the diagnosis is relatively straightforward, how to best treat aural myiasis has not been well described in the literature. This comprehensive literature review, therefore, was performed to identify current management principles in aural myiasis, especially with regard to the causative fly family. In addition, we explore the possible relationship between aural myiasis and the highly lethal intracranial myiasis. DATA SOURCES: Literature review using the Medline database (PubMed), Scopus, and Google Scholar. REVIEW METHODS: Manuscripts published in the English language between January 1, 1992, and December 31, 2012, were included. RESULTS: Forty-five cases of aural myiasis were reported in 34 manuscripts. Most cases were caused by species of the Sarcophagidae family (n=26/45, 57.8%). The majority of cases (n=40/45, 88.9%) were successfully treated with simple aural toilet and topical treatments alone. No deaths were reported and no cases were seen in conjunction with intracranial myiasis. CONCLUSION: Aural myiasis is a rare but benign fly infestation of the ear, most commonly by species of the Sarcophagidae family. The overwhelming majority of cases can be successfully managed without the need for surgical intervention.

Pain and bloody ear discharge in a returning traveler.

Cochliomyia hominivorax, the New World screwworm, was a serious livestock pest in the southern United States until the 1960s, when it was successfully eradicated by the release of sterile male flies. It remains endemic in parts of the Caribbean and South America, and there is concern that climate change may extend its geographic distribution. Cochliomyia hominivorax is voracious and can cause extensive damage to soft tissue and bone. We describe the case of a 26-year-old traveler who presented with otalgia and bloody otorrhea after returning from a vacation in the Dominican Republic, where exposure to screwworm flies most likely occurred during a nap on the beach. The causative agent was recognized by its characteristic larval anatomy, which includes pigmented dorsal tracheal trunks and posterior spiracles with an open peritreme.

Aural myiasis caused by Parasarcophaga (Liosarcophaga) dux (Thomson) in Thailand.

Herein is reported the first case in Thailand of aural myiasis caused by the flesh fly, Parasarcophaga (Liosarcophaga) dux (Thomson). A 5-day-old infant was taken to hospital with a slightly bloody ear. Two fly larvae exiting the ear and another recovered by a physician were alive, and confirmed as P. dux species from adult examination results. This case brought attention to the need for protection against synanthropic flies, particularly for infants and/or hearing impaired patients.

The first case of otomyiasis caused by Sarcophaga spp. (Diptera; Sarcophagidae) larvae in a goose in the world.

Otomyiasis was diagnosed in the right ear of a 3-month-old goose. Twenty-three of 25 larvae were in the meatus acusticus externus, and 2 larvae were under the skin. The larvae were in the third larval stage of Sarcophaga spp. by microscopic examination. A case of otomyiasis was reported in goose for the first time in the world on the basis of morphological characteristics (macroscopic and microscopic evaluation) in this communication.

Preventive efficacy of a topical combination of fipronil--(S)-methoprene--eprinomectin--praziquantel against ear mite (Otodectes cynotis) infestation of cats through a natural infestation model.

A study based on naturally infested cats was designed to evaluate the effectiveness of a single treatment with a topical formulation containing fipronil, (S)-methoprene, eprinomectin and praziquantel, for the prevention of Otodectes cynotis infestation in cats. Six treated cats and six untreated cats were housed with three chronically Otodectes cynotis-infested cats, respectively. The cats of each group were kept together in a 20-m(2) room for 1 month. Both clinical examination and ear mite counts were conducted on Day 28. All donor cats were confirmed to be chronically infested with Otodectes cynotis on Day -1 and Day 28. From untreated control cats, 129 live mites were recovered on Day 28 and all cats were found to be infested. In the treated group, three cats were found to be infested, with a total of five live mites recovered, the difference between the two groups being significant (p = 0.003). One treatment corresponded to 96% preventive efficacy at Day 28 based on ear mite counts. With regard to cerumen, the clinical score increased significantly for untreated cats between Day -1 and Day 28 (p = 0.00026) and not for treated cats (p = 0.30). The difference in cerumen abundance was significant between untreated and treated cats on Day 28 (p = 0.0035). Concerning the pruritic reflex in at least one ear, all cats were negative at inclusion. All six untreated cats became positive and showed a reflex on Day 28, whereas no treated cat showed ear pruritus (p = 0.00026).