Dealing with ectoparasite problems - Veterinary Practice
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Dealing with ectoparasite problems

Assessment of the efficacy of treatments for Malassezia dermatitis in dogs

Amelie Negre and others, Veterinary Clinic, le Chatelet-en-Brie, France

The lipophilic yeast Malassezia pachydermatitis is part of the normal cutaneous microflora of many warmblooded vertebrates. It is commonly found on various parts of the skin and mucosal membranes of healthy dogs but may become pathogenic as a result of changes in skin surface microclimate or host defences. It may then cause clinical signs of erythema, mild to severe pruritus, alopecia, greasy exudation and scaling.

The authors evaluate the efficacy of antifungal treatments described in 14 trials appearing in the veterinary literature. They conclude that there is strong evidence for recommending one topical treatment consisting of 2% miconazole nitrate and 2% chlorhexidine twice weekly for three weeks.

There was also reasonable evidence to support the use of two systemic treatments with ketoconazole at 10mg/kg bodyweight or itraconazole at 5mg/kg daily for three weeks.

Veterinary Dermatology 20 (1): 1-12.

Dogs as a sentinel species for monitoring the spread of Lyme disease

Sarah Hamer and others, US Department of Fisheries and Wildlife

Ixodes scapularis, the black-legged tick, is abundant in the north-eastern and upper mid-western United States and is expanding its range into previously uninfested areas. The tick is the vector responsible for human Lyme disease and a form of acute arthritis and arthralgia in dogs. The authors examined canine serum samples and collected ticks from dogs in areas adjoining the current range. They suggest that veterinary practitioners can help in the early detection of Lyme disease risks by collecting ticks found on dogs for testing.

American Journal of Veterinary Research 70 (1): 49-56.

Efficacy of a strategy for protecting unmulesed sheep from blowfly strike

Peter James and others, Department of Primary Industries, Yeerongpilly, Queensland

Infestation with Lucilia cuprina larvae is one of the major health problems in the Australian sheep industry. Attacks can be minimised by mulesing, removing strips of skin in the perianal region, but welfare concerns have prompted a search for alternatives. The authors tested a strategy involving crutching (removing wool from the sheep’s hind parts) and topically applied dicyclanil. Their results suggest that this combination is effective in preventing blowfly strike especially if the chemical is applied six weeks after crutching.

Australian Veterinary Journal 87 (4): 138-141.

Review of the animal and human health implications of Rift Valley fever virus

Brian Bird and others, University of California, Davis

Rift Valley fever virus is a mosquitoborne pathogen of livestock and humans that has caused devastating outbreaks throughout Africa and the Arabian peninsula. There are many potential vector species on other continents and the virus is classified as a major zoonotic threat. The authors suggest that farm animal practitioners are likely to be the first medically-trained professionals to encounter the virus if it does stray outside its current range. They review the biology of the virus and assess current knowledge of its diagnosis and treatment.

Journal of the American Veterinary Medical Association 234 (7): 883-891.

Prevalence of antibodies against Borrelia burgdorferi in horses in north-western USA

Kathryn Metcalf and others, Honahlee, Sherwood, Oregon

Borrelia burgdorferi is a spirochaete that causes Lyme disease in humans across large areas of the USA. It also causes disease with rather non-specific clinical signs in horses and so its diagnosis can be challenging. The authors conducted a serological survey of 196 asymptomatic horses in heavily tickinfested areas of the north-western states of Oregon and Washington. They found 14.8% of the sample had B. burgdorferi antibodies in Western blot and ELISA tests, with two of 196 positive to a commercial point-of-care test kit.

Journal of Equine Veterinary Science 28 (10): 587-589.

Culicoides species attracted to horses with and without insect hypersensitivity

Renske van der Rijt and others, Utrecht University, The Netherlands

Insect hypersensitivity is a chronic, seasonally recurrent dermatitis found in horses around the world. It can result from bites from a range of insect species of which Culicoides midges are reported to be the most common initiators. The authors examined which Culicoides species are most commonly attracted to horses and whether hypersensitive horses attract more insects than healthy animals. They found that healthy horses actually attracted more midges than their hypersensitive herd-mates, with C. obsoletus the most common species.

The Veterinary Journal 178 (1): 91-98.

Investigations into a West Nile virus epidemic at a horse farm

Manu Sebastian and others, Columbia University, New York

West Nile virus is an arthropod-borne Flavivirus infection causing encephalomyelitis in humans and animals. It was first described in Uganda in the 1930s and reached the USA in 1999, where it is now widely dispersed. The authors investigate an outbreak affecting four horses on a holding in Kentucky. Samples from both house sparrows and mosquitoes trapped on the farm were positive for the virus. The authors suggest that unusually hot, dry environmental conditions at the time may have been a contributing factor in the outbreak.

Transboundary and Emerging Diseases 55 (2): 134-139.

Fungal culture of samples from canine sinonasal aspergillosis cases

Frederic Billen and others, University of Liege, Belgium

Sinonasal aspergillosis is a common cause of chronic rhinitis in dogs. Its diagnosis usually requires a combination of methods because of the incidence of false positives or false negatives with most techniques. The authors assess the effects of sampling method and incubation temperature in determining the success of attempts at fungal culture of samples from clinical cases. They found that a positive culture is more likely to be achieved using mucosal biopsies or fungal plaques than with nasal secretions, and also when incubated at 37 degrees C.

Journal of Small Animal Practice 50 (2): 67-72.

Lufenuron pre-treatment in the management of feline dermatophytosis

Francesca Mancianti and others, University of Pisa, Italy

Lufenuron is a drug used as a flea treatment which interrupts chitin synthesis. That polysaccharide is also a component of the fungal cell wall and so lufenuron has potential applications in the treatment of dermatophytosis. The authors assess its value as a pre-treatment before using enilconazole or griseofulvin therapy. Although the drug was ineffective used alone, clinical cures were achieved in all cats receiving it before other agents. It is suggested that it should be used only in cases which do not respond to standard treatment.

Journal of Feline Medicine and Surgery 11 (2): 91-95.

Infection of the nasal subcutis of a cat with Mucor species

Jonathan Wray and others, Animal Health Trust, Newmarket

A 14-year-old neutered female domestic shorthair cat was presented for investigation of a non-painful subcutaneous swelling of the nasal dorsum at the site of a scratch injury. Cytological evaluation demonstrated a granulomatous reaction and many variably-shaped organisms consistent with yeasts or fungi. Subsequent biopsy and culture yielded a pure growth of a Mucor species. The cat was successfully treated with the antifungal agent posaconazole for a period of five months and there had been no recurrence a year later.

Journal of Feline Medicine and Surgery 10 (5): 523-527.

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