OBJECTIVES: To describe clinical and epidemiological aspects of canine and feline screw-worm myiasis.
ANIMALS: Naturally infested dogs and cats, presented to five veterinary clinics in four Malaysian states from September 2017 to February 2018.
METHODS AND MATERIALS: Cutaneous screw-worm myiasis was diagnosed based on clinical signs and visual examination of burrowing larvae within lesion. Age, breed, gender, anatomical site of infestation and suspected underlying predisposing causes were investigated.
RESULTS: A total of 55 dogs and 21 cats were included in the study. Intact male mixed breed dogs (mean age 58 months) and intact male domestic short hair cats (mean age 24 months) with suspected fight-related wounds were most commonly presented with exudative and ulcerative lesions associated with screw-worm myiasis. The most common anatomical sites of infestation in the dogs were the external ear canals, followed by the perineum and medial canthus. For the cats, the most commonly affected areas were paws and tail. Five cats with screw-worm myiasis were concurrently infected with sporotrichosis.
CONCLUSION AND CLINICAL RELEVANCE: Aggression between unneutered animals is a likely underlying cause for cutaneous screw-worm myiasis in both cats and dogs. Sporotrichosis was also a potential predisposing cause for screw-worm myiasis in cats.
OBJECTIVES: To describe the treatment of cutaneous myiasis in three dogs caused by the larvae of Ch. bezziana in Malaysia and their treatment with spinosad plus milbemycin.
RESULTS: In all dogs, a single oral dose of spinosad plus milbemycin at the recommended dosage of 31-62 mg/kg and 0.5-1.0 mg/kg, respectively, was able to kill all larvae within 8 h. Most dead larvae fell off the host and those remaining on the host were dead and easily removed with simple saline flushing and gentle debridement. Neither general anaesthesia nor aggressive mechanical debridement were needed in any patient.
CONCLUSIONS AND CLINICAL IMPORTANCE: Oral spinosad plus milbemycin is a safe, licensed and effective treatment at the recommended dose for the rapid elimination of Ch. bezziana myiasis, with no need for sedation or anaesthesia.
RESULTS: The resazurin-based TB assay demonstrated that the L. cuprina larval extract was inhibitory against all tested bacteria, whilst the larval extract of S. peregrina and M. domestica were only inhibitory against the MRSA, with a MIC of 100 mg ml(-1). Subsequent sub-culture of aliquots revealed that the larval extract of L. cuprina was bactericidal against MRSA whilst the larval extracts of S. peregrina and M. domestica were bacteriostatic against MRSA. The GC-MS analysis had quantitatively identified 20 organic compounds (fatty acids or their derivatives, aromatic acid esters, glycosides and phenol) from the larval extract of L. cuprina; and 5 fatty acid derivatives with known antimicrobial activities from S. peregrina and M. domestica.
CONCLUSION: The resazurin-based turbidometric assay is a simple, reliable and feasible screening assay which evidently demonstrated the antibacterial activity of all fly larval extracts, primarily against the MRSA. The larval extract of L. cuprina exerted a broad spectrum antibacterial activity against all tested bacteria. The present study revealed probable development and use of novel and effective natural disinfectant(s) and antibacterial agent(s) from flies and efforts to screen more fly species for antibacterial activity using resazurin-based TB assay should be undertaken for initial screening for subsequent discovery and isolation of potential novel antimicrobial substances, particularly against the multi-drug resistant strains.