Dog health

The health of dogs is a well studied area in veterinary medicine.

Dog health is viewed holistically; it encompasses many different aspects, including disease processes, genetics, and nutritional health, for example.

Some diseases and other health problems are common to both humans and dogs; others are unique to dogs and other animals. Dogs are susceptible to various diseases; similarly to humans, they can have diabetes, epilepsy, cancer, or arthritis.

Timely vaccination can reduce the risk and severity of an infection. The most commonly recommended viruses to vaccinate dogs against are:

• Rabies
• CDV (canine distemper)
• CAV-2 (canine hepatitis virus or adenovirus-2)
• Canine herpesvirus
• Canine influenza
• CPV-2 (canine parvovirus)
• Kennel cough^[1]
• Leptospirosis
• Lyme disease

Infectious diseases

An infectious disease is caused by the presence of organisms such as viruses, bacteria, fungi, or parasites (either animalian or

Viral diseases in dogs can be serious, especially in kennels.

Bacterial diseases

Bacterial diseases in dogs are usually not contagious from dog to dog; instead they are usually the result of wound colonization, opportunistic infections secondary to decreased resistance (often the result of viral infections), or secondary to other conditions (pyoderma secondary to skin allergies or pyometra secondary to cystic endometrial hyperplasia). These examples are not considered infectious diseases because they do not satisfy Koch's postulates – for example Staphylococcus intermedius, a commonly isolated bacteria from skin infections in dogs, would not cause pyoderma when introduced to a healthy dog. In all likelihood that type of bacteria is already present on the skin of a healthy dog.

There are some bacteria that are contagious from dog to dog. The most notable of these are Bordetella bronchiseptica, one of the causes of kennel cough, Leptospira sp, which cause leptospirosis,^[3][4] and Brucella canis, cause of brucellosis in dogs. There are also common tick-borne bacterial diseases, including Lyme disease, ehrlichiosis, and Rocky Mountain spotted fever.

Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira. Humans and dogs become infected through contact with water, food, or soil containing urine from infected animals. This may happen by swallowing contaminated food or water or through skin contact, especially with mucosal surfaces, such as the eyes or nose, or with broken skin. In dogs, transmission most commonly occurs by drinking puddle, pond, or ditch water contaminated by urine from infected wildlife such as squirrels or raccoons. The liver and kidney are most commonly damaged by leptospirosis. Vasculitis can occur, causing edema and potentially disseminated intravascular coagulation (DIC). Myocarditis, pericarditis, meningitis, and uveitis are also possible sequelae.^[5]

Brucellosis in dogs is caused by Brucella canis. It is a sexually transmitted disease, but can also be spread through contact with aborted fetuses. The most common sign is abortion during the last trimester or stillbirth. Other symptoms include inflammation of the intervertebral disc and eye (uveitis), and inflammation of the testicle (orchitis) and prostate (prostatitis) in males.^[6]

There are several fungal diseases that are systemic in nature, meaning they are affecting multiple body systems. Blastomycosis, caused by Blastomyces species including Blastomyces dermatitidis, is a fungal disease that affects both dogs and humans. It is transmitted through the inhalation of fungal spores. It is found mainly in the United States in the Mississippi River and Great Lakes areas. It has also been reported in four Canadian provinces; Saskatchewan, Manitoba, Ontario and Quebec. Signs include weight loss, cough, fever, enlarged lymph nodes, draining skin lesions, eye inflammation with discharge, blindness, and lameness. Because dogs are ten times more likely to become infected from the environment than humans, they are considered to be sentinels for the disease. Treatment requires a minimum 60–90-day course of oral antifungal medication or in severe cases intravenous antifungal injections.^[10]

• Fleas and ticks of various species can be acquired and brought home by a dog, where they can multiply and attack humans (and vice versa). These two parasites are particularly important to note, now that tick-borne Lyme disease has become endemic throughout a large area, in addition to other similar diseases such as Rocky Mountain spotted fever. Although dogs do not seem to be as susceptible to such diseases as humans, similar rickettsial diseases have been spread by dogs to humans through such mechanisms as a dog killing an infected rabbit, then shaking itself off in the house near enough to its owners to fatally infect most of the family.^[14]
• Various mites cause skin problems such as mange.
• Mosquitos
• Lice infestations (pediculosis) cause intense pruritus, scratching, and hair loss. The two species of chewing lice that affect dogs are Trichodectes canis and Heterodoxus spiniger. The dog sucking louse is Linognathus setosus.^[15]

Internal parasites

• tapeworms and roundworms, can be transmitted in a dog's feces. Some tapeworms have fleas
  as intermediate hosts: the worm egg must be consumed by a flea to hatch, then the infected flea must be ingested (usually by the dog while grooming itself, but occasionally by a human through various means) for the adult worm to establish itself in the intestines. The worm's eggs then pass in the feces, and the cycle begins again. Intestinal worms cause varying degrees of discomfort.
• heartworm prophylactics
  , which contain a compound that kills the larvae immediately upon infection without harming the dog. Often they are combined with other parasite preventives.
• tapeworms
  .

Skin diseases are very common in dogs.

Physical elements of certain dog breeds also affect susceptibility of individuals to skin problems, such as wrinkled skin or excessive skin folds. For instance, skin-fold dermatitis is a skin infection more prevalent in breeds such as the bulldog, cocker spaniel, and English Springer spaniel.[19]

Orthopedic diseases

Orthopedic diseases in dogs can be developmental, hereditary, traumatic, or degenerative. Because of the active nature of dogs, injuries happen frequently. One of the most common of these is an

Hereditary orthopedic diseases are mainly found in purebred dogs. Hip dysplasia is a common problem that primarily affects larger breeds. Hip dysplasia is a defect in the shape of the hip joint which can, depending on the degree of hip luxation, be quite painful to the dog as it ages. Over time it often causes arthritis in the hips. Dysplasia can also occur in the elbow joint. Luxating patellas can be a problem for smaller breeds. It can cause lameness and pain in the hind legs.

Developmental orthopedic diseases include panosteitis and hypertrophic osteodystrophy. Panosteitis occurs in large and giant breed dogs usually between the age of five and fourteen months and manifests as fever, pain, and shifting leg lameness. Hypertrophic osteodystrophy is also seen in young large and giant breed dogs and is characterized by pain, lameness, fever, and swelling of the long bone metaphysis.

Tumors and cancer

Both

Frequently seen cancers include

Due to the indiscriminate nature of a dog's appetite, gastrointestinal upset is a frequent occurrence in dogs. The most common symptoms are anorexia, vomiting, and diarrhea. Foreign body ingestion can lead to acute obstruction of the gastrointestinal tract, a very dangerous condition. Acute pancreatitis can also result from dietary indiscretion.

Bloat and gastric torsion

Eye diseases are common in dogs.

The frequency of bilateral glaucoma with a genetic base in purebred dogs is higher than in any species except humans.[24] Cataracts in dogs either have a genetic base or can also be caused by diabetes. Nuclear sclerosis resembles a cataract but is actually a normal age-related change.

Vestibular disease

Signs of vestibular disease include head tilt, circling,

In 2018, the U.S. Food and Drug Administration (FDA) issued a report citing a possible link between certain diets and canine dilated cardiomyopathy (DCM) in dog breeds without the genetic predisposition. Researchers at University of California, Davis School of Veterinary Medicine announced the results of their own study in early 2019, confirming the connection and identifying a particular concentration found among Golden Retrievers. Diet-related DCM is associated with grain-free and/or legume-rich diets, as well as "boutique" dog foods containing exotic ingredients (such as bison or kangaroo meat). In the treatment of dietary DCM, food change and taurine supplementation is typically indicated, in addition to traditional medical treatments as needed.

Other diseases and psychological issues

Other diseases affecting dogs include

Psychological anxieties affecting dogs include noise phobia and separation anxiety.

Toxic substances

Some common sources of toxins that pets encounter include some plants,^[33] human medications and cosmetics,^[34] cleaning products,^[34] and even some foods.^[35]

Dangerous foods

Some foods consumed safely by humans are harmful to dogs:

Chocolate

Cocoa within chocolate contains

Carob treats are often available as dog treats; these are unrelated to chocolate and are safe.

Grapes and raisins

Grapes and raisins can cause acute

Onions cause hemolytic anemia in dogs and cats.^[46][38] Allyl propyl disulfide has been reported as being considered to be the main cause of onion poisoning in dogs.^[46] Alkyl thiosulfate and N-propyl disulfide have also been implicated. Thiosulfate levels are not affected by cooking or processing. Occasional exposure to small amounts is usually not a problem, but continuous exposure to even small amounts can be a serious threat.^[38]

Plants in the genus Allium (onions, scallions, garlic, leek, chives, etc.) in general contain varying levels of organosulfoxides compounds including the two mentioned above. These chemicals are responsible for their signature spicyness, but also causes oxidative damage to red blood cells of dogs and cats. Poisoning have been reported from many such plants, with symptoms ranging from diarrhea and vomiting to pale gums and hemolysis.^[47]

Nutmeg

Ingestion of yeast, for example in uncooked bread dough, can cause intestinal obstruction. The yeast can also cause fermentation internally, resulting in ethanol (alcohol) poisoning.^[53]

Xylitol

Xylitol is a sugar substitute used in chewing gum, chewable vitamins, candy, toothpaste, and other products. Although a small preliminary study^[54] indicated xylitol may be safe for dogs, other studies show significant toxicity.^[55] There have been cases of foods, candies and gums containing xylitol causing toxic or even fatal liver damage in dogs.^[56][57][58] Ingestion may cause hypoglycemia.^[38]

Avocado

Avocado leaves, bark, skin, and pit are known to be harmful to a wide range of animals, including dogs and cats. Death can occur from a sufficiently high dose. The flesh of the fruit is not generally considered toxic to the two animals.^[59]

Common household substances

Some common household chemicals are particularly dangerous to dogs:

Antifreeze (ethylene glycol)

Further information:

activated charcoal to further reduce uptake of undigested product, and hemodialysis to remove toxins from the blood. Dogs should not be allowed access to any place in which an antifreeze leak or spill has happened until the spill is completely cleaned out. Some brands of antifreeze contain propylene glycol instead of ethylene glycol

for lower toxicity. Others are marketed as being less attractive to animals.

Alcohols

Isopropanol, methanol (common in household products), and ethanol (common in alcoholic beverages and rotten fruits) are all toxic to dogs. Isopropanol found in rubbing alcohol has twice the toxicity of ethanol; however, methanol found in windshield washer fluid does not have the same retinal and neuronal toxicity on dogs as it does to humans and primates due to the differences in the way its metabolite formic acid is processed.[60]

The effect of ethanol on dogs and cats is similar to its effect on humans, also causing intoxication. Death is unlikely given supportive care (only one death is known). Ethanol is also an antidote for ethylene glycol poisoning.^[47]

Mouse and rat poison

, anticoagulant type

Rodenticide is commonly found in the house or garage. This anticoagulant class of poison works by depleting stores of Vitamin K in the body; without these stores, blood cannot clot properly. Clinical signs of poisoning include depression, weakness, difficulty breathing, bruising, and bleeding from any part of the body. These clinical signs often take 3 to 4 days to appear. A blood test will confirm that the blood is not clotting properly. If the poison has only recently been ingested (within 2 to 3 hours), the dog should be given apomorphine or hydrogen peroxide to induce vomiting. Activated charcoal can be given to absorb any remaining poison in the gastrointestinal tract. Then the dog is given Vitamin K supplementation for 3 to 4 weeks, depending on the type of poison. At the end of treatment, the clotting times should be tested again. The prognosis is good in these cases. However, if the dog is already showing signs of poisoning, it is too late to try to remove the poison from the body. A whole blood transfusion or plasma is given to treat the anemia and to try to control bleeding. Vitamin K is also given. The prognosis is poor in these cases.

Mouse and rat poison, hypercalcemia type

Mouse and rat poisons containing

intravenous fluids (saline), diuretics, corticosteroids, and calcitonin

. Long term prognosis is good once the dog is stabilized.

Snail bait, metaldehyde type

Ingestion can cause anxiety, muscle twitching, seizures, rapid heart rate, dilated pupils, hypersalivation, vomiting, diarrhea, and high fever due to the

lavage, intravenous fluid administration, and/or administration of activated charcoal.^[38]

Most diseases that affect dogs or humans are not transferable between the two species. Diseases that can be transmitted from animals to humans are termed

Vaccinations are an important preventive animal health measure. The specific vaccinations recommended for dogs varies depending on geographic location, environment, travel history, and the activities the animal frequently engages in. In the United States, regardless of any of these factors, it is usually highly recommended that dogs be vaccinated against rabies, canine parvovirus, canine distemper, and infectious canine hepatitis (using canine adenovirus type 2 to avoid reaction). The decision on whether to vaccinate against other diseases, including leptospirosis, Lyme disease, Bordetella bronchiseptica,

Feeding table scraps to a dog is generally not recommended, at least in excess. Just as in humans, a dog's diet must consist of the appropriate mix of nutrients, carbohydrates, and proteins to give them the minerals and vitamins that they need. Dogs get ample correct nutrition from their natural, normal diet; wild and feral dogs can usually get all the nutrients needed from a diet of whole prey and raw meat. In addition, a human diet is not ideal for a dog: the concept of a "balanced" diet for a facultative carnivore like a dog is not the same as in an omnivorous human. Dogs will usually eat all the scraps and treats they are fed: usually too much food. While not all human delicacies are acutely toxic to dogs (see above), many have the same chronically unfortunate results as they do for humans.

Obesity may also be caused by some diseases, such as Cushing's disease or hypothyroidism.^[66]

Dog treats

Dog treats are often given to pets as a reward or just to let them chew on a bone, which works their jaw muscles and helps keep their teeth clean.^[67] Although dog treats carry high benefits for dogs' teeth, they can also be a source of problems like obesity when given excessively, especially human table scraps.

The type of food given directly affects the tendency of a dog to become overweight. Table scraps, treats, and even premium high-energy dog foods can contribute to obesity.

Coprophagia

Some dogs may attempt to consume feces. Some consume their own or other dogs' feces; others seem to prefer cat feces (which, due to the feline digestive system,^[69] are high in protein and consumed by many animals in the wild.) This can be harmful if the feces has any pathogens or parasites or contain excreted drugs.

Vitamins and supplements

It is not yet clear whether or not

Between approximately 10 and 30 percent of dogs in the United States receive nutritional supplements.[70] A survey of U.S. pet owners in 2006 found that the most commonly used supplements were multivitamins and chondroprotective agents.^[71]

Overdoses of vitamins can be harmful in dogs. As an example,

Spaying and neutering

Spaying (females) and neutering (males) refers to the sterilization of animals, usually by removal of the male's testicles or the female's ovaries and uterus, to eliminate the ability to procreate and reduce sex drive. Neutering has also been known to reduce aggression in male dogs, but has been shown to occasionally increase aggression in female dogs.^[73]

Animal control agencies in the United States and the

Because of the overpopulation of dogs in some countries, puppies born to strays or as the result of accidental breedings often end up being killed in animal shelters. Spaying and neutering can also decrease the risk of hormone-driven diseases such as mammary cancer, as well as undesired hormone-driven behaviors. However, certain medical problems are more likely after surgery, such as urinary incontinence in females^[75] and prostate cancer in males.^[76] The hormonal changes involved with sterilization are likely to somewhat change the animal's personality, however, and some object to spaying and neutering as the sterilization could be carried out without the excision of organs.

It is not essential for a female dog to either experience a heat cycle or have puppies before spaying, and likewise, a male dog does not need the experience of mating before neutering.

Female cats and dogs are seven times more likely to develop

References