Understanding Myiasis-Creepy Crawlers in Canines

Learning the life cycle of Myiasis producing flies

In canines, majority of maggots causing myiasis are larvae of blowflies or bottle flies which are characterized by metallic blue and green colours. Blow flies lay eggs on the skin wounds, eggs hatch in 24 hours and become larvae (maggots). These maggots have specialized mouth parts with hooks. They feed upon the liquid contents in the wound, pierce the skin, form tunnels and feed on decaying tissue as well as healthy tissue. After feeding and maturing for 5-7 days, the maggots leave the animal, enter the soil, becomes pupa and adult flies then emerge a few weeks later.

Factors causing Myiasis

Pets kept in poor hygiene, having chronic skin conditions, pre-existing open wounds due to scratching, fighting, cut wounds, tick bites, bacterial skin infections, sores and those dogs who are sick, convalescent, abandoned, with mobility impairment or live in wet and dirty environment are more susceptible for myiasis. Myiasis is more common in hot and humid environment and during the warm summer months when flies are active, laying their eggs. Any type of small wound, or moist coat soaked with faeces or urine can easily attract blow flies leading to myiasis.

Types of Myiasis

There are different types of myiasis, but the most prevalent types found in dogs are – cutaneous myiasis and cavitary myiasis. Cutaneous myiasis is the infestation with maggots on a dog’s skin, or within a wound. Cavitary myiasis is characterized by maggot infestation within natural body cavities such as the mouth, nostrils, ears, etc. Maggots also infest eyes, anal and vaginal regions and tail region.

Catch the infection and cut the pain

Initially, the maggots start to feed upon your pet’s dead or dying skin tissue, then moving on to feed on healthy tissue. The maggots remain in the wound, prevents wound healing, and can spread throughout the skin. If left untreated, they can burrow deeper into your pet’s skin and progress systemically, infesting the vital organs. The maggots release toxins that can make your pet sick very quickly, leading to fever, anaemia, and lethargy.

Infested pets will develop a foul, decaying smell as the maggots secrete an enzyme that necrotizes healthy skin tissues. In severe and untreated cases, maggots penetrate deeper into the dermis, lead to dangerous infections, and in some cases, this can be life threatening.

The art of clinical diagnosis

A simple physical examination is sufficient for diagnosis of myiasis. Maggot wounds are often swollen, with holes and a foul/decaying odour. Maggots can be seen on the wound surface/orifices or can be found tunnelling deep into the holes of the wound. Infested pets usually show these signs –

• Uneasiness/discomfort
• Depression
• Lethargy
• Lack of appetite
• Constantly getting up
• Scratching,licking, biting or self-grooming

Myiasis is a highly painful condition and severely infested pets starts to behave erratically. Clipping the hair in the suspected area of infestation reveals the presence of creepy crawling maggots. Depending on the severity of infestation maggots can be few or even hundreds in numbers.

Tailored treatment plans for your pooch

Myiasis is a serious condition and if you notice any of the above signs or fear maggots, take your pet to the vet immediately.

The primary treatment of myiasis is the physical removal of maggots one by one carefully using rat toothed forceps/tweezers from the skin/wound surface and the tunnels. Care should be taken not to crush the maggots while removal. Maggot removal is a delicate, laborious and time-consuming procedure. It may not be possible to remove all maggots at a single time and subsequent visits to the vet may be needed. It must be ensured that all maggots are removed to facilitate quicker wound healing.

After complete removal of maggots, the wound is dressed, applied with topical antiseptic solution and supportive treatment with antibiotics, anti-inflammatory drugs, analgesics, fluid therapy etc. Several herbal sprays/ointments are available for topical application to maggot wounds. Fly repellents such as neem oil can be smeared around the infested area to avoid further infestations.

Making the road to recovery easy

Once all the maggots are removed and after proper treatment, wound healing occurs eventually. Make sure you give your pet a healthy and nutritious diet and follow the routine for medications that the vet has suggested. Diets rich in protein and energy will help for a quick recovery.

Prevention is always better than cure, so take care

Myiasis can be easily prevented. If you notice any open wounds/sores/scratches/tick bites take your pet to the vet, even before you sport any maggots or maggot wounds. Daily skin inspection and proper grooming can prove to be saviours. Here are some tips to follow –

• Skin health of the pet should be maintained and infections should be treated promptly.
• Wounds should be cleaned and treated promptly.
• Urine and faeces if found on skin/hair should be thoroughly washed off daily.
• Weak and debilitated dogs should be kept indoors and frequently checked for urine/faecal staining.
• Vaccination and Deworming should be properly done as per the schedule provided by the veterinarian to maintain good health.
• Awareness should be created among pet parents about maggots and myiasis to ensure good health of the canine pets and to stay away from creepy maggots.

(Dr S.T. Bino Sundar – Associate Professor and Head, Dr K. Jeeva and Dr M.Aravind – Assistant Professors, Department of Veterinary Parasitology; Dr P.N. Richard Jagatheesan- Dean,Veterinary College and Research Institute, Veerapandi, Theni)