Ticks are large mites; bloodsucking parasites that exist virtually wherever animals live. Ticks transmit a large number and variety of infectious diseases including Rocky Mountain Spotted Fever, Lyme Disease, Ehrlichiosis, and Tick Paralysis. If you live in a wooded area where ticks are an everyday problem, careful tick control is necessary. Dog kennels, barns, and homes will require periodic treatment with chemicals to control the free-living stages of the different varieties of ticks. The house and yard should be treated every 2 weeks during the summer, or even year-round in the warmer climates where the brown dog tick is an on-going problem.

Ticks may be found anywhere on your dog's body, but the usual places are around the neck, ears, and between the toes, causing inflammation and irritation from their bites. A male tick or an unfed female is flat and brown. A blood-engorged female is fat, large and grey. It is not a good idea to use your fingers to pull a tick off your dog. If the tick bursts during removal you can be exposed to Rocky Mountain Fever or Tick paralysis. Instead, grasp the tick with tweezers and pull gently and slowly until it lets go.

TICK PARALYSIS

Ticks secrete a toxin which affects the nervous system and can actually cause paralysis in dogs. Toxicity is associated primarily with female ixocid ticks and is limited to a brief sucking phase of a few hours. The neurotoxin circulates in the dog and affects the nerve and muscle functions. Functional impairment during paralysis can also affect the nerve fibers which serve the respiratory muscle, increasing carbon dioxide levels and causing oxygen pressure and blood pH to fall.

The first sign in the dog is incordination and weakness as he becomes unable to move his hind legs. The paralysis slowly moves upward, involving the front quarters. The dog will usually have a normal temperature and show few signs of illness except he will be unable to function. Difficulty in chewing and swallowing follow, and in a heavy infestation, the paralysis can involve the dog's respiratory centers in the brain, causing difficulty in breathing and death in only a few hours. The incubation period is 5-7 days and paralysis can peak within a few hours, but timely removal of any ticks bring about a rapid recovery.

Diagnosis of tick paralysis is based on the presence of ticks and the sudden appearance of the paralysis, plus the rapid recovery upon removal of the ticks.

ROCKY MOUNTAIN SPOTTED FEVER

Rocky Mountain Spotted Fever is the most common tick-carried infection in humans in the country. The disease is not transmitted from dogs to humans but both can catch it from an infected tick. Or you can catch it when coming into contact with fluids from an engorged tick while removing it from your pet. For that reason careful handling of any tick when taking it off your dog is necessary.

Early signs in your dog may include a high fever, lack of appetite, depression, abdominal pain, coughing, and edema of the face and extremities. Additional signs are nosebleeds, blood in the feces and urine, enlarged lymph glands, hemorrhages of the mucous membranes and retinas, vomiting, altered mental states, staggering and convulsions. In severe cases there will be damage to the smooth tissue lining of the heart.

Blood tests may be needed for confirmation and immediate supportive treatment for dehydration and hemorrhages started. Tetracycline is the drug most effective and the therapeutic response is rapid and dramatic. Following recovery, immunity can be lifelong.

EHRLICHIA

The same brown dog tick that carries and transmits Rocky Mountain Spotted Fever is also responsible for the organism Ehrlichia canis, the cause of a blood infection in dogs. Although this organism affects dogs throughout the country, it is primarily found in the warmer southern states. Ticks carry it after feeding on an infected dog and may transmit the disease for up to 5 months after engorgement. Signs will show up in the newly-infected dog between 8-20 days after exposure. The first signs of infection can include a loss of appetite, mild fever, swollen lymph glands, discharge from the nose or eyes, lethargy, progressing to edema of the legs or scrotum, stiffness and reluctance to -walk and difficulty in breathing. This is the acute stage and clinical signs can improve with in 24-48 hours if the dog responds to treatment with tetracycline or doxycycline. The temperature returns to normal within 24-48 hours after treatment and the dog becomes more active and begins to eat. Death is rare, but the dog may remain asymptomatic, or chronic disease may ensue.

In chronic cases the bone marrow becomes hypoplastic, and depending on which organs are affected, the signs are variable. These include enlargement of the spleen, renal failure, pneumonia, kidney disease, inflammation of the eye, and meningitis with paralysis, loss of coordination of muscles, and severe weight loss. The organism lives and reproduces inside white blood cells, causing permanent and lethal changes in the bone marrow and varying grades of anemia. Dogs with only mild chronic cases will have less damage to the bone marrow and may be able to have the symptoms reversed with treatment and time, and survive. But in many chronic cases there are often lesions on the lungs accompanied by widespread hemorrhages. These abnormalities may persist for 3-6 months, although clinical response occurs much sooner. Supportive therapy may be necessary to fight off wasting and specific organ dysfunction, and even whole-blood transfusions given.

The disease can only be detected and diagnosed by blood tests done by your veterinarian or by a combination of clinical signs, and response to treatment. Any dog that tests positive for the disease must remain in isolation until cleared and all dogs exposed to a recurring problem of ticks should be put on a daily regime of tetracycline for several months through at least one tick season to hopefully eliminate the cycle.

LYME DISEASE (BORRELIOSIS)

Borreliosis is a tick-borne, immune mediated inflammatory disease of dogs, horse, wild animals, and man. The disease is carried by a spirochete, borrelia burgdorferi, and transmitted by ticks carried by raccoons, opossums, mice, and white-tailed deer. Areas of the first greatest incidences were in Olde Lyme, Connecticut, but it has rapidly spread to the upper midwest and Pacific states. The tick vectors are three-host ticks that hatch from eggs as uninfected larvae. Since both the larvae and nymphs may acquire infections by feeding on an infected reservoir host, they can transmit it to another host.

Lameness and fever are the first clinical signs of the disease followed by anorexia, lethargy, swollen lymph glands and swollen, painful joints constituting the most common problems. The arthritis may become chronic, especially with the joints of the forelegs becoming painful and hot to the touch. Additional signs such as kidney, cardiac and neurologic forms of the disease are characterized by laboratory abnormalities. Renal borreliosis is the second most common canine syndrome and is generally fatal. Facial paralysis and seizure disorders have also been reported in the neurologic form.

Diagnosis is based on clinical signs, history, laboratory data, and response to antibiotic therapy. Both antimicrobials in the penicillin and tetracycline groups have proven effective with a rapid response seen in the arthritic conditions. Although standard antibiotic doses and treatment have proven effective in higher doses in persistent cases, a long term therapy may be necessary.

In endemic areas, young dogs should be vaccinated before tick season starts to attain the highest percentage of protection. Since the tick does not transmit the spirochete immediately on attachment to the dog, frequent examination and removal of any tick immediately is the best prevention of the disease.