Parasite: A smaller organism that lives and feeds on a larger organism. The relationship is usually not symbiotic, as the host does not usually benefit from this union.
* The heartworm
Internal parasites for dogs
Heartworm is the only parasite covered here, both very common and very dangerous if left untreated. In fact, heartworm can be fatal despite treatment.
heartworm
Heartworm is an extremely common parasite transmitted by mosquitoes. If you care about a dog, you've probably heard how bad it can be. Each individual female parasite can reach a length of 6 to 14 inches, while males are half that length. They are very similar to live pasta noodles.
Unfortunately, it may take several years for your dog to show symptoms. Once this point is reached, there may already be up to 250 parasites nestled in your dog's heart tissue (heart, lungs, surrounding blood vessels).
Adult dogs can harbor up to 300 of these parasites, all of which clog blood vessels when they are finally diagnosed. Infections are often very serious after this point. Even if your pet survives the necessary medications / injections, they could suffer from permanent heart failure and require lifelong medication.
Prevention of heartworm disease
Professionals always recommend an annual heartworm test and monthly preventatives only after the test is negative (the drug can be dangerous for dogs with a live infection).
Heartworm Treatments
An injectable medicine called melarsomine (Immiticide) is given serially to kill your adult parasites. Many dogs are also often treated with an antibiotic for any bacteria that may be inhibiting the heartworms themselves.
Mosquitoes
Mosquitoes are an intermediate host for several parasites, but the heartworm is the most common. Because mosquitoes tend to thrive in warmer or especially tropical and humid climates, you are likely to see them during the warmer months near a water source.
However, the weather can be unpredictable, the eggs can be very tough, and it is rarely below 50 degrees F. inside a home. Your pet may still be infected during the winter, so continued treatment is essential.
Intestinal parasites for dogs
These are parasitic organisms that live inside a dog's intestines. Below the specific description of the parasite, several oral antiparasitic drugs (Shelter Medicine) are often prescribed for treatment.
Tapeworms
These intestinal parasites are flat, segmented worms that can be found not only in dogs, but in several other animals around the world (including humans).
Dogs (and humans) will ingest worms from another host. At this point, they make their way to the interesting little one, where the evil pests settle in and thrive. Once the worm is mature, segments containing worm eggs begin to rupture and eventually end up in the host's stool.
Veterinarians can diagnose tapeworms by examining stool samples. Sometimes segments will be left around the opening of the anus. Your dog might even drag his on a carpet or rough floor.
Unfortunately, it's quite common for dogs to eat the droppings of other dogs (or even other animals), which creates a convenient mode of travel for the parasite.
- Fenbendazole
- praziquantel
- Epsiprantel
- Pyrantel + praziquantel
- Pyrantel + praziquantel + febental
- Round
These parasites also call the intestines home, where they can thrive on partially digested food. Roundworms are actually the most common of all gastrointestinal parasites that we find in dogs. These can also be transmitted to humans.
Again, these worms are prevalent in a dog's feces. Unlike tapeworms, they are microscopic and cannot be seen with the naked eye.
Roundworms present the biggest problems for puppies. Fewer eggs are passed out in the feces, creating a bigger problem for diagnostics and treatment. Symptoms can include stunted growth and frequent diarrhea, which can cause a problem with dehydration in small dogs.
- Pyrantel
- Fenbendazole
- Febantel
- Piperazine
- Pyrantel + praziquantel
- Pyrantel + praziquantel + febental
- Hookworms
Using hook-shaped mouthparts to anchor themselves to the host's intestinal wall, hookworms ingest quite a bit of blood for their ⅛ ”size. Several of them can easily lead to both intestinal inflammation and life-threatening anemia (lack of red blood cells).
The eggs are passed through the wastes of infected animals, sleeping in the ground until a host picks them up by the feet while grooming or eating / sniffing the feces.
Once they gain access to the host's body, the larvae begin to migrate either to the intestinal tract or to the animal's trachea (windpipe) where they are swallowed.
- Pyrantel
- Fenbendazole
- Febantel
- Pyrantel + praziquantel
- Pyrantel + praziquantel + febental
- Whipworm
Another common intestinal parasite, these attach themselves to the lining of the large intestine. These usually cause bloody stools, diarrhea, weight loss, and anemia. Whipworms cause the most illness among all intestinal parasites found in dogs.
The eggs pass through the animal's feces, able to stay alive in the external environment for five years. Once swallowed by a host, they begin a new cycle of infection.
Any dog with chronic episodes of diarrhea is encouraged to have stool samples examined for whipworm and suspected of carrying the parasite even if test results show a (false) negative.
- Fenbendazole
- Febantel
- Pyrantel + praziquantel + febental
- Coccidia
These are single-celled microscopic parasites that will live in your dog's intestinal walls. Most associated animal infections do not actually cause any type of clinical signs or symptoms, but infected animals can develop diarrhea.
Diarrhea is more common (and also leads to dangerous dehydration) in puppies. You might also see abdominal distress and vomiting.
Most often (in cases that present problems), vets will prescribe an antibiotic along with IV fluids to combat any dehydration.
Giardia
Have you ever suffered from food poisoning, perhaps after drinking untreated water in a foreign country? Giardia is a microscopic parasite found on soil, food, or water contaminated with infected animal or human feces.
Symptoms will be similar in dogs and humans. Guardia causes severe abdominal cramps, vomiting, diarrhea, nausea, and weight loss (among others).
Spirochetes
Although it may seem unknown, you may have heard of leptospirosis. Spirochetes are a spiral form of bacteria (not parasites), capable of causing both leptospirosis or Lyme disease depending on the type
External parasites for dogs
These are parasites that live on a dog's body, usually very small but visible to the naked eye. Most feed on blood or dead skin and dander.
Lice or fleas
Fleas are extremely common insect parasites that live on the blood of a host animal. Fleas can reproduce very quickly, and the larvae can live for long periods of time anywhere in your home.
If you have a flea problem, you've probably seen tiny "ground coffee" type objects jumping between your pet's fur. Your dog may have an extremely itchy problem, causing patches of bald skin or even open sores.
Fleas can multiply very quickly, both on the host animal and throughout the house. Once an "infestation" is reached, it can be very difficult to deal with it. In just two months, you could have thousands of fleas in your home.
Ticks
Ticks are very small parasites that feed on the blood of a host. They are very small (but still visible) and can infect both animals and humans.
Ticks can carry several pathogens, some very dangerous (eg Lyme disease, Rocky Mountain spotted fever), and can be difficult to spot on humans, let alone dogs or cats.
Removing ticks can be complicated because improper technique can cause the mouthpieces in the animal to rupture.
* Cayenne tick, natural to tropical areas, southern United States, Mexico, Central America, etc.
Mites
Mites are common parasites in dogs and can cause the development of a wide range of skin conditions. Common concerns range from dry skin to hair loss and extreme irritation. These can often be found under the fur or in the ears.
Mange (caused by mites) is a very painful condition for dogs, causing oozing sores with crusted skin and hair loss. There are two classifications of scabies, but only sarcoptic scabies is highly contagious and transferable to humans.
* Yellow mite, covers a wide range of species.
Lice
Lice in dogs are small insects that can be found on dogs of three types: blood-sucking, biting, and a third rare type of bite that feeds on blood. The second can serve as an intermediate pipe for tapeworms (see above).
Lice can be visual itchy, scratching, and biting (similar to flea symptoms), all signs your pet may have a problem.
Insecticides and repellents for dogs
Insecticides are pesticides specially created to kill or repel insects. Some insecticides work to disrupt the insect's central nervous system, while others can damage the exoskeleton or repel / control them in some other way.
Insect repellents are able to repel insects without killing them. Unlike insecticides, these are not harmful to the host, while protecting the body from the dog's external parasites.
Flea prevention methods for dogs
Since fleas are so common, you will find countless forms of treatment available on the market right now! Not all are created equal, and some may be more effective than others, while some may in fact be more detrimental to your dog's health.
Topical Flea Treatments
Sometimes called "spot on" treatments, these are usually applied between the dog's shoulder blades (the dog cannot reach), under the coat. The drug is then absorbed through the skin. Most today will kill active fleas and larvae and also prevent further infestations.
Flea shampoos
Shampoo is most effective at killing existing insects that are already living on a dog's body. Shampoos are best for larger infestations and should be used before any topical treatment (so as not to wash them out).
Flea shampoos usually only work on a temporary basis and should not be considered a long term cure.
Flea collars
By gradually releasing pesticides (see above), flea collars are able to kill parasites living on surrounding tissue. Flea collars are controversial, don't always work well, and the pesticides released can become toxic to your dog.
High frequency collar: works by releasing a high-pitched sound, effective only to repel fleas
Gas-Based Collar: A gas-based toxin will kill fleas on contact, but will only work in the covered area
Absorption-based collar: releases an insecticide that will be absorbed through a dog's skin
EM necklaces
"EM" actually stands for "Effective Microorganisms", a brand name representing a family of related products. They use specialized ceramic beads to emit infrared waves as a means of repelling ticks.
Oral and chewable tablets
After your pet ingests the flea medicine as an oral insecticide, the medicine will start to work throughout the body. These are generally the best forms of flea control because they are easy to administer and cover the widest range of potential scenarios.
Your vet can help you choose the best medicine. Some popular brands today include:
NextGard
After ingestion, this drug begins to spread throughout the dog's body. Much like Bravecto below, any fleas or ticks that bite your dog will die soon after. The drug can start killing fleas in just 4 hours, eight for tics.
NextGuard will remain active for 4-6 weeks after dosing, but is normally given once a month.
Bravecto
It is a preferred chew flea treatment for dogs. Able to kill newly matured parasites very quickly, before they have a chance to lay eggs, Bravecto can be a very effective flea control solution.
Using the fluralaner (specific name), the drug is distributed throughout the dog's body after ingestion. Whenever fleas or ticks (covering both parasites) bite the infected animal, they are exposed to the drug and eventually die after their meal.
The drug is also sometimes used to treat forms of scabies, but this is for off-label (not FDA-certified) use. “Off-label” doesn't necessarily mean “bad,” and countless vets across the United States will be prescribing treatments for their off-label effects.
Eliminate the whole problem
Like most other treatments, none of these treatments will kill any fleas you might see immediately. Unfortunately, fleas like to lay eggs in carpets, bedding, and just about anywhere in the house. The actual bugs won't die until they bite the animal and get exposed to the drug, so you might have fleas hatching and looking for a meal for quite a long time.
To completely eradicate the infestation in your home, you have several possible options.
The first is to "bombard" the house with pesticides, but this will require you (and all animals) to be away for an extended period of time. These chemicals are very dangerous and you need to be careful.
You can purchase insecticide sprays at your local hardware store (or most other stores). Again, you will need to make sure that no humans or animals come in contact with these.
Your vet will often recommend that you vacuum and wash all bedding / clothing / other washable items immediately and then frequently.
Antiparasitic drugs
These are drugs used to treat parasitic disease or to manage the infestations themselves.
Macrocyclic lactones
These can treat parasitic skin disorders in dogs, although the use is "off-label" (other than FDA approved use).
Insect growth regulators
These disrupt or completely stop the immature growth of some insects, ultimately resulting in death. They can be extremely effective against pests like fleas, flies, and mosquitoes.
Chloronicotinyls
These are used to kill fleas and lice.
Phenylpyrazoles
These have a wide range of action, effective against lice, ticks, fleas and mites. These are usually administered in topical form.
General signs and symptoms of parasites for dogs
Many of these symptoms will indicate a clear problem. All you need to do is pay attention and be ready to contact a vet if you notice any issues starting to arise. Is your pet behaving strangely, sluggish or constantly itchy?
Unfortunately, some of the worst parasites (eg heartworm) don't show symptoms right away, so you will still need to be vigilant with monthly preventive measures and vet checkups.
Diarrhea can be caused by frequent stools (feces) that will be loose or watery. It is often accompanied by other symptoms on this list and can lead to dehydration (especially in puppies).
Abdominal pain can be caused by a number of things, but any animal should be examined by a veterinarian.
Vomiting is your (or the dog's) way of expelling stomach irritants (as well as diarrhea). This is the body's defense mechanism, but it can also cause dehydration in dogs.
The prone appearance can mean that your dog is suffering from internal inflammation in certain areas. Heartworm medications (non-preventative) can also cause this effect.
Lethargy can be caused by a lack of nutrients, dehydration, or many other issues.
Dehydration can be especially dangerous in puppies or small dogs. Frequent vomiting or diarrhea can lead to dehydration.
Nutritional deficiencies and anemia: Anemia is caused by a lack of red blood cells, preventing adequate oxygen supply to body tissues.
Bowel Blockage or Pneumonia: Pneumonia is caused by filling the alveoli in the lungs with fluid, making it impossible to provide adequate infusion (oxygen supply). A bowel obstruction can cause a life-threatening rupture or other infection and may need to be removed surgically.
Blood in the stool (bright red or darker purple) means there's probably a big problem in the digestive tract.
Weight loss can be caused by poor appetite, vomiting / diarrhea, loss of nutrients, etc.
Poor coat appearance can be caused by a general lack of nutrients.
How to prevent parasites in dogs
Simply by maintaining a clean house and surroundings, in addition to regular visits to the vet, you will be able to eliminate most parasites or parasitic infections.
Use a monthly flea / tick preventer. Your veterinarian can discuss the options with you.
Always provide monthly heartworm medication! Heartworm can mean a slow and possibly painful death sentence. Expensive treatment options are not a guaranteed cure.
Research your options and choose what works best for your dog. Many of the pests listed above can be prevented by several options available on the market today, each different.
Be careful !
Always watch your pet for any signs of discomfort or unusual behavior! Contact your vet if you notice anything that is not working. It is one of the best ways to prevent parasites in dogs.
Scratch
Scratching can be a very simple visual signal that there is a problem, especially if it is combined with excessive biting and hair loss. You might see bald patches start to form and open sores.
Open wounds can lead to secondary infections which may in fact be worse than the original problem caused by the dog's parasite, leaving a wide window open for bacteria, viruses and anything else that can now enter that open barrier.
Vomiting and / or diarrhea
It is how the body expels irritants from the digestive tract. We do it all the time (eg Parasites), and it's very natural. Unfortunately, this can also easily result in dehydration (loss of water), which will result in lower circulatory volume.
Extreme dehydration means your pet will not be able to oxygenate their body tissues properly and can lead to hypovolemic shock. This is extremely dangerous for humans and dogs; your veterinarian will need to administer IV fluids immediately.
This can be accompanied by abdominal pain, lethargy, and several other symptoms listed above.
Sources cited
Intestinal Parasite Control Guidelines. Medicine from the refuge. Recovered from
https://www.uwsheltermedicine.com/library/resources/intestinal-parasite-control-guidelines
Ward, Ernest. DVM. Sarcoptic mange in dogs. VCA hospitals. Recovered from
https://vcahospitals.com/know-your-pet/mange-sarcoptic-in-dogs
(2008,9,9). Shock due to decreased circulation in dogs. PetMD. Recovered from
https://www.petmd.com/dog/conditions/cardiovascular/c_multi_shock_hypovolemic
AKC staff. (2015, 17,4). Parasites for dogs. American Kennel Club. Recovered from
