Canine myiasis by sheep bot fly (Diptera:Oestridae)

Efficacy of eprinomectin 5 mg/mL topical solution administered pour on at 1 mg per kg body weight against Oestrus ovis myiasis in sheep and goats

The larvae of the nasal bot, Oestrus ovis, mainly parasitize sheep and goats and some species of wild Caprinae but other mammals and humans are also vulnerable to infestation. Eprinomectin 5 mg/mL topical solution (EPRINEX® Multi, Boehringer Ingelheim) administered at 1 mg eprinomectin per kg body weight pour on was recently authorized as an anthelmintic for sheep and goats with zero hours milk withdrawal in several countries in Europe. As the product in cattle has claims against a broad range of parasites including insect parasites and activity against O. ovis has previously been reported following extra-label use in sheep, its therapeutic efficacy against ovine and caprine O. ovis myiasis was evaluated in three regulatory compliant, masked clinical studies. Pre-study recovery of O. ovis larvae from five or six of six randomly selected animals per study site (Bulgaria, one site, sheep; Greece, two sites, sheep or goats) supported the inclusion of the animals from those sites into the studies. The study animals (34 animals per study) were ranked based on bodyweight and allocated randomly to remain untreated (control) or to be treated with eprinomectin 5 mg/mL topical solution at 1 mL per 5 kg body weight pour on. Treatment efficacy was determined based on O. ovis larval counts of eprinomectin 5 mg/mL topical solution-treated vs. untreated animals three weeks after treatment administration. Live O. ovis larvae, including all three instars in each study, were recovered from 13 or 16 of the 17 control animals in the sheep studies (range, 1 to 14 or 5 to 18 larvae, respectively) and from all 17 controls in the goat study (range, 7 to 18 larvae). In each study, eprinomectin 5 mg/mL topical solution-treated animals had significantly (p < 0.001) fewer live O. ovis larvae than the controls. Efficacy of the treatment was 100% and 91.3% against the combined parasitic O. ovis larval stages in sheep and in goats, respectively. The treatment was well accepted by all animals and no health problems were observed throughout the studies. The results of these studies demonstrated eprinomectin 5 mg/mL topical solution administered pour on at 1 mL per 5 kg body weight to be an efficacious and safe treatment of ovine and caprine oestrosis.

Botfly Cephenemyia ulrichii larvae in the nasal cavity and nasopharynx of a dog with respiratory signs

A Finnish Lapphund dog with acute upper respiratory signs and gagging was presented at veterinary clinic. During rhinoscopy, ten 1- to 2-mm long, actively moving larvae were found in the dog's nasal cavity and nasopharynx and identified as Cephenemyia ulrichii (Diptera: Oestridae). This moose (Alces alces) parasite is widespread in Finland but has not been reported before from an accidental canine host. Clinical signs resolved with imidacloprid/moxidectin spot-on formulation.

Oestrus ovis L. (Diptera: Oestridae) Induced Nasal Myiasis in a Dog from Northern Italy

A companion dog from Milan province (northern Italy), presenting with frequent and violent sneezing, underwent rhinoscopy, laryngoscopy, and tracheoscopy procedures. During rhinoscopy, a dipteran larva was isolated from the dog and identified as first instar larval stage of O. ovis by morphological features. Reports of O. ovis in domestic carnivores are sporadic and nevertheless this infestion should be considered as a possible differential diagnosis of rhinitis in domestic carnivores living in contaminated areas by the fly as consequence of the presence of sheep and goats. This report described a case of autochthonous infestion in a dog from an area where O. ovis was not historically present but it could be affected by a possible expansion of the fly as a consequence of climate change. This is the first record of Oestrus ovis infestion in a dog in Italy and, at the same time, the most northerly finding of larvae of sheep bot fly in the country.

Oestrus ovis infestation of a dog in the UK

In March 2011, a dog on a sheep farm in the Cotswolds, UK, expelled a mature live third-stage larva of the sheep nasal botfly, Oestrus ovis, after a violent and traumatic sneezing episode. The dog had been infected with first-stage larvae deposited by an adult fly the previous autumn; larval development had progressed throughout the winter and spring with few apparent clinical signs and possibly masked by ongoing immunotherapy for an unrelated condition. Identification of the parasite at the Liverpool School of Veterinary Science was made from a submitted puparium, the "chrysalis" stage to which the larva had progressed within days of its expulsion from dog's nose. To the authors' knowledge this is the first report of nasal botfly infestation of a dog in the UK.

Nasal myiasis in a cat caused by larvae of the nasal bot fly, Oestrus ovis

An 8-year-old desexed male Burmese cat, which lived on a sheep-grazing property in central New South Wales, Australia, was presented following the sudden onset of dyspnoea, moist coughing and violent sneezing. The respiratory distress started several hours after the cat had made an outdoor excursion. Anterior rhinoscopy demonstrated small, white objects moving across oedematous and moderately inflamed nasal mucosa. These were retrieved via a series of vigorous nasal flushes and subsequently identified as larvae of the nasal bot fly, Oestrus ovis. The cat was treated with ivermectin followed by selamectin 7 days later. It went on to make a complete recovery over 2-3 weeks.

Treating wounds in small animals with maggot debridement therapy: A survey of practitioners

Many small animals succumb to complications of serious wounds. Sometimes infection and sepsis overwhelm the animal; sometimes the costs of intensive care overwhelm the owner. Maggot therapy, a method of wound debridement using live fly larvae, could provide effective, simple, low cost wound care. All eight US veterinarians who had been provided with medicinal maggots were surveyed to determine if this treatment was being used for small animals, and for what indications. At least two dogs, four cats and one rabbit were treated with maggot therapy between 1997 and 2003. The most common indications for using maggot therapy were to effect debridement and control infection, especially if the wound failed to respond to conventional medical and/or surgical therapy. Practitioners reported the treatments as safe and often beneficial. Amputation and euthanasia may have been avoided. It is concluded that maggot therapy may have utility for small animals, and should be evaluated further.