One afternoon, Roberta and her dog, Robert, met Samantha and her dog, Samson. During doggie greeting time, Samantha casually mentions that Samson has mange. Roberta reacts quickly by pulling Robert away from Samson. Samantha leaps into defensive mother loving mode and starts hugging Samson. Roberta is in shock. What Roberta does not realize is that Samson has demodectic mange, which generally occurs in young dogs and is not contagious.
Roberta’s reactions were not entirely unjustified. Her mind probably jumped to the highly contagious sarcoptic mange (scabies). Even humans need to be careful around dogs diagnosed with scabies. Although humans may have irritation from contact, the canine scabies mite does not stay on humans.
What is interesting is that mites affect immunocompromised dogs, cats and humans more than those with healthy immune systems.
For some of you, that may not make any sense. It is certainly an odd concept to grasp regarding parasites. One would assume that if you put 2 dogs in a room with 50 mites evenly distributed that each dog would get 25 mites and the same reaction, but that’s not true. It is definitely easier to understand that biting insects could carry worms, bacteria or viruses that can then enter the bloodstream and be spread between humans and animals. It is also easier to understand that cats can develop tapeworms by ingesting fleas when they groom themselves.
Let’s look at scabies. As previously mentioned, scabies is highly contagious and worrisome. For humans, we categorize scabies into two types: ordinary scabies and crusted (Norwegian) scabies. The veterinary community does not divide scabies into types with dogs and cats. However, many veterinary dermatologists believe that scabies needs to be considered more often with itchy pets, as sarcoptic mange is a tell-tale sign but occurs in an advanced stage of the infestation.
Now, your first thought might be that the mite mutates to cause different bodily outcomes, and it could do so. However, the kicker about scabies and the way we need to start thinking about skin parasites is described below. According to an article written by Shelley Walton, “Crusted scabies is caused by the same species of mite that causes ordinary scabies with no evidence that mites in patients with severe disease differ in virulence to mites in ordinary scabies.” What this means is that it is not the mite, but the host body’s response to the mite. Indeed, dogs also present different immunological responses to the parasite: one dog in a household could be infested and another one might not be; and, one dog might have a more severe case than another.
We know that antibodies and cells respond to parasites to fight them or manage them. Otherwise, we have no control over them. If the response is a genetic predisposition factor, an environmental exposure issue, or genetic predisposition triggered by environmental factors depends on the parasite and research on this aspect is still evolving.
If the immune response is genetically determined, why do we need to maintain a generally healthy immune system? In essence, if a pet is predisposed to have an infestation of scabies, logically there’s not much you can do about it except to avoid any exposure. This is both right and wrong, as you cannot live life in a bubble.
With that in mind, scabies and other mite-driven infestations can lead to secondary conditions such as fungal or bacterial infections, which perpetuate and exacerbate the problem and may lead to other acquired clinical conditions. Antibodies can activate a group of immune system proteins called complement, which assists in killing bacteria, viruses, or other microbe-infected cells. So, the body truly needs to have the whole immune system functioning as efficiently as possible.
Treatment for mites depends on the species infested but generally we look to antiparasitic medications such as ivermectin. Lime sulfur, an all-natural and highly effective treatment, is very smelly. These options should be discussed with your veterinarian as your dog or cat may have a secondary fungal or bacterial infection that also will need to be addressed.
The Healthy Immune System
Creating and maintaining a healthy immune system sounds like a general, nonspecific and ephemeral phrase. It may not stop a potential infestation due to genetic susceptibility, the environmental impact on this susceptibility, the environmental conditions present or even the pest load counts. Again, our goal is to create a healthy immune system to rebuff a potential infestation, get a current infestation under control, minimize a possible infestation, and rely less on medications. No reason exists why you cannot try these tips with yourself or your pet. In fact, these steps may appear so simple that they seem too good to be true. They are good, and they are true.
Vaccination suppresses the immune system and can trigger immune-mediated (autoimmune) diseases. These diseases include those affecting many tissues of the body such as the blood, thyroid, adrenal glands, joints, kidneys, liver, bowel, reproductive organs, muscles, nervous system, eyes, skin and mucous membranes.
Additionally, if a dog or cat is known to have or is redisposed to a compromised immune system, some veterinarians who may usually advise vaccinating pets annually, will correctly recommend that these pets nor receive vaccine boosters, even for rabies.
Research studies have proven that both the beneficial and pathogenic bacteria that populate the gut also impact the immune system. Food is stated to be the origin of everything, so this makes sense.
Canine Nutrigenomics: The New Science of Feeding Your Dog for Optimum Health covers the topic of immune support extensively. The summary tips below fit both dogs and cats:
- High quality, grass-fed, locally raised protein sources
- Grain-free foods
- Moisture-rich diets such as freeze dried, dehydrated, or high pressure-pasteurized raw, or home-cooked
- Organic fruits and vegetables
- Foods that do not or are suspected to cause food intolerances in your companion pet
I know that these suggestions might feel overwhelming or be out-of-budget for several people. So, I recommend looking at the pet food brands you wish to feed, and where they source their ingredients.
For use if immune system is suppressed. Autoimmune diseases require a more careful balance.
- Vitamin E (A fat soluble vitamin; so be careful with it as very high doses can interfere with absorption of other vitamins A, D and K and cause serious health problems.)
- Vitamin B-6 (pyridoxine)
- Selenium (important in combination with vitamin E)
- Zinc (balance the amount with other minerals in the food to avoid toxicity)
- Omega-3 fatty acids
- Curcumin (turmeric)
- Lutein (great for athletic dogs, and eyesight)
- Taurine (great for athletic dogs, and cats)
- Thymus glandular (great for osteoarthritis and other immune functions)
Demodectic Mange Mites
- Demodex canis – dogs. These mites are commonly found on the skin of almost all dogs. If a dog has an underdeveloped or dysfunctional immune system, the mite population could grow exponentially because the body is unable to keep it in check. This causes demodectic mange, alopecia (hair loss), and secondary bacterial or fungal infections.
- Demodex cati – Demodex cati lives in the hair follicles of cats. Infestation is associated with immune and metabolic diseases, like diabetes.
- Demodex gatoi – Infectious and contagious mites that are commonly found in Florida and Texas. They live in the skin of cats, but can infect dogs too.
- Chiggers – Chiggers are members of the Trombiculid family and can infect cats, dogs and humans. These mites are found on blades of grass and then jump onto a host. Chiggers do not stick around like several other mites. Once they have their fill, they will typically jump off the dog or cat after a few days. They cause tiny, reddish dots that cluster on the head, feet or stomach. Intense itching can persist after the chiggers have jumped off.
- Ear Mites (Otodectes cynotis) – Ear mites are very common in cats but can also affect dogs. These mites burrow deep in the crevices of the external ear canal and can sometimes be found on the skin. Dogs and cats will shake their heads a lot and scratch. The scratching can become so intense that secondary bacterial or fungal infections set in and cause an odiferous black or brown discharge to develop and ooze.
- Scabies (Sarcoptes scabiei/sarcoptic mange) – Scabies are particularly scary because they are highly contagious, will jump from dog to dog, and will burrow under the skin. The worst part is that they have an expanded incubation period from 10 days to 8 weeks. They will wait to hatch, yet can still spread to other dogs before any clinical signs are apparent. Sarcoptic mange can then set in. Cats can get a different species of scabies, too, but it is rare.
- Ticks (several varieties) – Anaplasma phagocytophilum (anaplasmosis); Mycoplasma hemocanis, Hemobartonella felis (hemobartonellosis); Borrelia burgdorferi (Lyme disease, borreliosis); Dirofilaria immitis (heartworm disease, dirofilariasis); Ehrlichia canis (ehrlichiosis); Rickettsia rickettsia (Rocky Mountain Spotted Fever, rickettsiosis); Coccidioides immitis (Valley Fever, coccidioidomycosis), Babesia canis, Babesia gibsoni (babesiosis); and Leishmania infantum, Leishmania donovani (leishmaniasis). Leishmaniasis is a good example of a zoonotic, vector-borne disease that can be spread between species by ticks and other bugs.
- Walking dandruff (Cheyletiella yasguri) – The name hails from the appearance that dandruff is walking on the skin and hair but it is actually due to these whitish mites. They are contagious and can affect dogs, cats and humans. The skin will generally take on a scaly look.
Side note: Heartworm is spread by mosquitos. All dogs are susceptible to develop heartworm. Cats are too, but not nearly as much as dogs. Depending on the environmental conditions in your area, I advise monthly preventatives for this condition. For more on this subject, please see my heartworm article.
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Ferrer, L., I. Ravera, and K. Silbermayr. “Immunology and Pathogenesis of Canine Demodicosis.” Veterinary Dermatology 25.5 (2014): 427-E65. 16 Oct. 2014.
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