Myiasis in Dogs - Causes And Treatment
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Myiasis is a form of parasitism which is carried by dipterous larvae of certain types of neoptera insects such as flies, mosquitoes and horseflies. These larvae are also known as maggots. They are laid in living or dead tissues of vertebrate animals on which they feed. This process ensures their survival, growth and development. When we see maggots in our dog's skin, it can be a very worrying sight and this is for good reason.
Have you noticed any worms or maggots on your dog’s skin or body? If so, take a look at this AnimalWised article where we tell you everything you need to know about myasis in dogs. Specifically, we look at the symptoms, treatment and removal of maggots in dogs. We also cover facts about whether it is contagious and how it can be prevented.
What is canine myiasis?
In 1940, English entomologist F.W. Hope was the first to use the word ‘myiasis’ to define this infestation of diptera in humans. It wasn't until almost a century later when Fritz Zumpt published Myiasis in Man and Animals In The Old World (1964) which provided a detailed description of maggots in dogs. It was Zumpt who first suggested that insects spent time feeding on a hosts dead tissue, bodily fluids or ingested food.
In their adult stage, these insects take advantage of the orifices or wounds of a host. They enter these openings to deposit their eggs as a way to continue their biological cycle. It can sometimes happen that certain species are able to penetrate through intact dermis, such as bot flies. This pathology can affect all types of vertebrate animals in any region, specifically during the wettest months of the year.
To learn about a specific insect, take a look at our article on whether blue bottles are dangerous.
Types of myiasis in dogs
There are three different criteria used to classify the types of myiasis in dogs. Here, we will mention the species that cause myiasis by laying eggs in the skin of a dog:
Clinical point of view:
- Traumatic myiasis: this occurs when eggs are deposited into the open wounds of dogs which have been caused by various types of trauma. Insects that cause this type of canine myiasis include Megaselia rufipes, Chrysomyia albicans, Phormia regina, Calliphora spp., Lucilia spp., Sarcophaga spp. and Wohlfahrtia magnifica.
- Ocular myiasis: this is the larval infestation of the eye and is also known as ophthalmomyiasis. Insects which infest the eye include O. ovis, R. purpureus, M. scalaris, W. magnífica and S. carnaria.
- Auricular myiasis: similar to ophthalmomyiasis, except the infestation enters the ear cancal. These include O. ovis and W. magnifica.
- Nasal, buccal and sinus myiasis: this is when the infestation affects the nasal passages, mouth and sinuses, respectively. They include W. magnifica, Sarcophaga carnaria, Calliphora vomitoria, Oestrus ovis and Rhinoestrus purpureus.
- Anal and vaginal myiasis: when the infestation occurs in the anal and vaginal canals, respectfully. They incldue W. magnifica, S. carnaria and Sarcophaga pernix.
- Compulsory or specific myiases: dipterous parasites that need a host for development in their larval phase.
- Semi-specific myiases and accidental miasis: here we mention the diptera that infests decomposing bodies or organic matter. It may happen that they opportunistically invade living tissue.
- Primary invader: penetrate the skin or take advantage of holes in the body.
- Secondary or tertiary invader: take advantage of wounds and traumas.
What is the life cycle of a maggot in dogs?
Diptera that are responsible for causing Myiasis usually have different forms in their biological cycle. They travel through a complete four-stage metamorphic cycle, the egg, larva, pupa and adult stages. In the last two phases they do not live in the host.
The larvae secrete an enzyme that can damage the dermis and cause various different health problems. If left untreated, the wound will increase in size and a dark discharge will appear. This can cause the attraction of other Diptera. Additional maggots will then also begin to deposit their eggs which creates a refuge or breeding ground for worms in a dog.
Are all dogs likely to get myiasis?
Any animal that does not receive adequate medical prevention measure or hygiene control is susceptible to myiasis. The most important way to prevent this type of parasitic disease is to implement proper deworming treatment in dogs. This means animals that are abandoned, sick, convalescent or live in wet and dirty environments are more predisposed to maggot infestation.
Symptoms of myiasis in dogs
Although we have gone into the specific types of myiasis in dogs, we can group them into the general categories of cutaneous, cavitary, systemic and wound. In some cases, symptoms are less apparent than in others. There are also several different cases of cutaneous myiasism, including furuncular, rampant, traumatic and serpiginous. Cutaneous myiasis can also progress systemically, infecting various organs as it does so.
In the early stages of a myiasis infestation, you might notice a small bite, lesion or abscess in the dog's skin, usually in a hairless area. You will later notice this wound grows and a pustule will form from where bloody fluid emerges. Pay attention to these symptoms of myiasis in dogs:
- Skin irritation
- Skin lesions
- Movement of worms
- Intense itching
- Ear movements
- Excessive licking
At this point, and if left untreated, the larvae can penetrate deeper into the dermis layer. It will then form nodules or simply create a much larger abscess. This process can lead to the a serious infection and in some cases, even shock.
Learn more about abscesses in dogs with our related article.
Diagnosis of myiasis in dogs
Diagnosis only requires a simple physical examination by a veterinarian to achieve diagnosis. This will be due to the presence of maggots in the dog's skin, eyes, ear canal or other infested area. If you notice any of these symptoms in your dog or assume that your dog has been infected we suggest visiting your veterinarian as soon as possible. A professional will be able to diagnose and treat the myiasis accordingly.
Treatment of myiasis in dogs
Treatment of Myiasis in dogs should always be done under the supervision of a veterinarian. These small carnivorous maggots can cause secondary pathologies, so you should never try to treat canine myiasis without the help of a specialist.
The first step in treating myiasis in dogs is cleaning and disinfecting the area. Some specialists choose to directly perform the extraction and clean the wound after, but this will be at their own discretion.
How to remove maggots from dogs
The removal of worms in wounds should always be done with the use of a clamping tool such as tweezers. It is a laborious and slow process. in areas where there is little funding, veterinarians may try to remove the maggots from the dog by hand. This is not ideal as it can further damage tissue, as well as break the larvae while trying to remove them from the parasite-infested area. This process might need to be repeated several times.
Use of antiparasitic drugs and hygiene.
After removing the fly larvae, a veterinarian will shave the affected area to prevent bacteria or eggs from remaining on the fur and dermis. They will then apply an antiseptic solution, and remove any dead tissue in favor of skin healing.
A local antibiotic and an aerosol or paste which is used to kill maggots should then be applied. Permethrin for dogs is a common insecticide used for this purpose. Finally, the affected area should be bandaged to keep it clean and prevent further contamination.
In some cases, it may be necessary for a vet to prescribe the dog with some antibiotics for dogs, fluid therapy or other measures appropriate for the individual case. Sometimes, if the infestation is quite severe, you might have to visit a veterinarian more than once to remove and treat the maggot-infested area.
Can myiasis in dogs be transmitted to humans?
As mentioned before, myiasis can affect any vertebrate animal. Therefore, Myiasis can be transmitted to humans.
People who live in a home with a dog that is suffering from Myiasis should take certain precautions in order to avoid possible parasitization. It is essential to monitor any wound and cover it, remain incredibly hygienic, use insect repellents and avoid dense, wet and hot areas. You should be extra careful if you have a baby, are sick or are elderly.
Prevention of canine myiasis
Although myiasis is not a common problem in large cities, it is more prevalent in rural areas where dogs regularly flock to rivers and forests. In terms of myiasis prevention, it is sufficient enough the simply check the dermis of your dog regularly, paying special attention to hairless areas.
Maintaining a good level of hygiene, including brushing and bathing your dog regularly will also be an important factor. This will help you notice promptly if your dog has been bitten, which will prevent more serious complications such as maggots in dogs. In addition, you should always follow your dog’s deworming and vaccination schedule strictly.
It is also very important to go to the veterinarian as soon as you notice any symptoms mentioned above. This is especially so if itching, scratching and the appearance of infected wounds occur.
This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.
If you want to read similar articles to Myiasis in Dogs - Causes And Treatment, we recommend you visit our Parasitic diseases category.
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