Fleas

Fleas can make your pet's life miserable because their saliva can induce an allergic skin reaction in many dogs. Fleas progress through several distinct life stages in which the pests transform from eggs into larvae, then into pupae, and then finally into reproducing, blood-sucking adults.

A flea infestation can lead to flea allergy dermatitis, which can cause excessive itching and skin infections. Fleas often carry tapeworm larvae, so your dog can get tapeworms after eating a flea. A large infestation with fleas can also lead to anemia. While dog and cat fleas don't prefer humans, flea bites in two-legged family members are possible.

The best way to treat dogs with fleas is to use a veterinarian-approved flea control product. These can be given orally or applied topically. It's also important to treat the home environment where eggs, larvae, and pupae may live.

Ticks

Ticks can attach themselves to the skin of dogs as well as to humans. While you might wear protective clothing when in tick-prone areas, your dog is exposed. Early detection and removal of ticks is important as it takes some time for the tick to transmit tick-borne diseases to their hosts. Diseases spread by ticks to dogs include:

• Lyme disease
  
• Bartonellosis
• Ehrlichiosis
• Babesiosis
• Rocky Mountain spotted fever
• Anaplasmosis

Some species of ticks can also cause tick paralysis, which usually starts at the back end and ascends towards the head. This can become fatal if the muscles that control breathing become paralyzed, but the symptoms will go away as long as the tick can be found and removed.

The best way to treat and prevent ticks is to use a tick control product recommended by your veterinarian. It's also important to check your dog for ticks regularly, especially after spending time in nature where ticks are found.

Mange Mites

Mange is a condition where tiny mites live in the skin or hair follicles and cause disease.

Demodectic mange is the most common type of mange seen in dogs. These mites can live in hair follicles in small numbers without causing problems, but puppies and immune-compromised dogs may not be able to fight them off. Demodicosis causes itching and hair loss. Treatment options include topical applications, medicated baths, and oral drugs.

Sarcoptic mange, often called scabies, is a contagious type of mange that causes severe itching, redness, scabs, and hair loss. Treatment involves multiple topical and oral medications as well as baths.

Cheyletiella mites are often called "walking dandruff" because you may see flakes of hair move on the dog, though the mites themselves are microscopic. These contagious mites cause dry, itchy skin and dandruff. Treatment typically consists of topical antiparasitic medications and baths.

Hookworms

Hookworms are small, thin worms that are less than an inch long that live in the intestines and suck the host's blood. Three species of hookworms affect dogs. Some can also affect humans by migrating through the skin and causing infection.

Dogs get hookworms by ingesting larvae in the environment or eating infected animals such as cockroaches. They can also be transmitted to puppies from the mother's milk. Symptoms include diarrhea, loss of appetite, anemia, weight loss, or failure to gain weight.

A veterinarian can check for hookworm eggs in the stool. Treatment includes deworming medications that must be used repeatedly to eliminate the larvae as they mature. Regular deworming will help prevent recurrence.

Whipworms

Whipworms are small worms with thin, whip-like front ends and thicker back ends. They attach themselves to the walls of the large intestine, feeding on blood.

Dogs pick up whipworm eggs transmitted through the stool in the environment. A mild infection may have no symptoms, but severe infections can result in weight loss, diarrhea, or anemia. A veterinarian can typically detect the eggs under the microscope during a stool examination.

Whipworms are resistant to many of the usual dewormer medications, so a different medication is often used. Keeping the environment clean of feces is the best prevention as the worm eggs take weeks to become infectious.

Roundworms

Roundworms are long worms that live in the intestines and absorb nutrients from the food the dog eats, which results in less being available for the dog. Infection can occur after ingesting eggs shed in the stool of other animals. Puppies get roundworms from larvae transmitted during pregnancy or in the mother's milk.

A dog with roundworms may show vomiting, lethargy, weight loss, diarrhea, and a pot belly. A veterinarian can detect roundworm eggs in the stool by using a microscope. Several doses of deworming medication are necessary to clear the roundworms as they mature. A regular deworming protocol is needed to prevent reinfection.

Roundworms can be transmitted to humans. They cause inflammation and can migrate to various tissues and organs.

Tapeworms

Tapeworms are flat, ribbon-like parasites that live in the intestines. Happily, they rarely cause serious disease. They are usually transmitted by ingesting fleas, but some species can be contracted by eating raw meat.

Tapeworms reproduce by shedding segments in the stool, which can irritate the anus. Dogs may scoot around on the floor or lick their rear ends. Long-term infestation can result in poor nutrition for the dog or, in severe cases, an intestinal blockage.

A veterinarian can diagnose tapeworms by examining the area around the anus. Their eggs don't usually show up on microscopic analysis. Medication is needed to clear the infection, accompanied by good flea control and keeping the dog from eating dead prey.

Giardia

Giardia are single-cell organisms (protozoa) that infect the small intestine. Dogs can contract giardia by drinking from streams, puddles, and other contaminated water sources. It can also be acquired through direct contact with the stool of other infected animals.

Giardiasis can cause diarrhea, vomiting, and weight loss, but some dogs are asymptomatic at first. Giardia can't usually be detected on a standard fecal test, so your veterinarian may send out a stool sample to a laboratory for specific testing.

Treatment for giardia typically involves more than one medication. Many vets will prescribe a specific dewormer along with the antibiotic metronidazole to kill giardia.

Heartworms

Heartworm disease is caused by large worms that live mainly in the heart and the blood vessels of the lungs. Mosquitoes can carry and transmit heartworm larvae through their bites. While heartworm disease is most prevalent in the southern United States, it has been seen in every state.

Your veterinarian typically tests for heartworms during your dog's yearly check-up. A dog with heartworm disease may show no symptoms at first, but as it progresses it can be fatal. Dogs can develop a cough (including coughing up blood), become exhausted from exercise, faint, and have severe weight loss.

Heartworm treatment occurs over several months and involves multiple medications, including to kill the adult heartworms. The dog will need complete rest during the treatment period to prevent dangerous complications from the dying worms.

Fortunately, heartworm disease is easy to prevent with proven, safe heartworm preventative. These are usually administered monthly to kill heartworm larvae before they can mature into adults and cause disease.

Although rare, heartworms can be transmitted to humans via mosquito bites. In humans, the parasite most often causes lung lesions. Preventing the disease in your pets can help protect you as well.

Ear Mites

Ear mites are microscopic mites that can live in dog’s ears, where they breed and cause thick black debris and discomfort.  Ear mites are highly contagious, and animals become infested by direct contact with another infested animal.

Your dog may show head shaking, scratching at the ears, and crusty or waxy discharge that looks like coffee grounds. Your veterinarian can diagnose ear mites by looking at a sample of ear debris under a microscope. Ear mite treatment can require one or more repeated treatments. Fortunately, ear mites don't occur in humans.