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Ticks become a full-time menace: warmer weather and an increase in their carrier combine to extend their reach and health threat.

Milder winters and greater numbers of deer--the most common tick carrier --have turned ticks from a seasonal threat to a year-round menace to both pets and people. Ticks are increasing in numbers and spreading beyond their normal locales. That's bad news for dogs and humans, who as a result face greater risk of acquiring tick-borne illnesses such as Lyme disease and Rocky Mountain spotted fever.

The Companion Animal Parasite Council (CAPC) predicted a banner year for ticks in 2016. Its reports for last year aren't in yet, but this year is likely to be the same, says Dwight D. Bowman, Ph.D., professor of parasitology at Cornell University College of Veterinary Medicine.

Hardy Survivalists. Contrary to popular belief, ticks survive very well in winter, Dr. Bowman says. If it's warm enough, they will usually come out in December for a blood meal. Otherwise, snow cover or fall leaf litter will shelter ticks from extreme temperatures, and their numbers will increase, though massive drought might hurt, he says. "A super-cold winter with no snow could hurt them."

Neither scenario is predicted, so dog owners can expect tick numbers to remain high. That means the risk of tick-borne diseases is higher, too.

Ticks are tiny members of the arachnid, or spider, family. They hop onto a victim--the host--sink their specialized mouthpiece into the skin and suck blood for sustenance. In the process, they inject disease-causing bacteria, viruses and protozoa.

Both dogs and humans are susceptible to various tick-borne illnesses. While dogs are less likely than humans to acquire it, Lyme disease can affect them. The most serious threats are Lyme disease and Rocky Mountain spotted fever (RMSF). Other tick-borne diseases include anaplasmosis, ehrlichiosis and babesiosis. Of these, Lyme disease is probably best known. While they are less likely than humans to acquire it, Lyme disease can affect dogs.

According to the CAPC, infection with Borrelia burgdorferi, the organism that causes Lyme disease, is common in the Northeast, upper Midwest and West Coast. Prevalence of canine infection ranges from as little as 1.4 percent in the West to as high as 13.3 percent in the Northeast. In some surveys, CAPC reported more than half of questing nymphs--immature ticks seeking hosts--and adult ticks were shown to harbor B. burgdorferi infections, creating a high risk of infection for pets living in tickinfested environments.

Sudden Onset. The disease can develop suddenly. Charlie, a female English Shepherd who's a search and rescue dog belonging to Heather Houlahan, went from being completely normal at dinnertime to lame and crying in pain the following morning. Houlahan, a trainer who farms 26 acres in Harmony, Penn., has also had two other dogs with the disease. She says the signs were different and often subtle with each animal until stress brought the signs to the forefront.

Signs include fever, lameness that shifts from leg to leg, swollen joints, enlarged lymph nodes, depression and lack of appetite. They can resolve quickly after aggressive treatment with antibiotics, as they did in Charlie's case.

Dogs with chronic cases may develop persistent polyarthritis and acute progressive renal failure. Neurological signs such as behavior changes may also occur. Living in tick country as they do, Houlahan advises training clients to ask their veterinarian to run a tick panel--a specialized test--if their dog suddenly becomes depressed, fearful or aggressive, or any combination of those.

A vaccine against canine Lyme disease is available. It may benefit dogs at high risk of exposure. Ask the veterinarian if it's recommended for your locale.

Most cases of Rocky Mountain fever are spread by the American Dog Tick, delivered by the bite of an infected tick. The brown dog ticks that spread RMSF are found in every state except Alaska and Hawaii. Signs of infection include high fever, appetite loss, muscle and abdominal pain, vomiting, diarrhea and a stiff gait.

East of the Mississippi. The disease can be deadly in dogs if it's not diagnosed, Dr. Bowman says. It's also more widespread than is generally believed. "Most people don't realize Rocky Mountain spotted fever is east of the Mississippi," he says. "We've had cases of RMSF in people in Long Island."

American canine hepatozoonosis, which does not affect humans, was first identified in the U.S. in 1978 on the Texas Gulf Coast. Since then it has traveled north and east, diagnosed in Oklahoma, Louisiana, Alabama, Tennessee, Georgia and Florida.

The emerging disease is spread by the Gulf Coast tick (Amblyomma maculatum) but in an unusual way. Instead of being transmitted by the bite of a tick infected with Hepatozoon americanum, infections occur when a dog ingests either an infected tick or infected intermediate host such as a rabbit. The disease, which is lifelong, can be deadly, with signs including fever, depression, weight loss, muscle atrophy, soreness and weakness.

"Dogs relapse repeatedly," Dr. Bowman says. "It causes horrible muscle pain and [the bone disease] hypertrophic osteopathy." Even with antibiotic treatment, improvement is usually temporary. Dogs often die within two years of the diagnosis.

Dogs are safest from these diseases if they are treated with tick preventives year round. They can be monthly spot-ons or tick collar that can last for months. Tick preventives repel ticks or kill on contact. With others, the tick dies only if it bites the dog. Seeing a tick on your pet does not necessarily mean the preventive isn't working.

Parasitology experts recommend prevention year round throughout a dog's life. Talk to your dog's veterinarian about the best choice.

NORTH, SOUTH, EAST, WEST--THEY'RE OUT THERE

The type of tick that attaches to your dog can vary, depending on your location. Here's an overview and the effects on dogs and humans:

* Northeast: deer or black-legged ticks (Ixodes scapularis) can spread Lyme disease to dogs and humans; babesiosis to humans and anaplasmosis to dogs and humans. The brown dog tick (Rhipicephalus sanguineous) may also feed on dogs and transmit ehrlichiosis and canine babesiosis.

The American Dog Tick (Dermacentor variabilis) feeds on dogs and humans and can spread Rocky Mountain spotted fever. The Lone Star tick (Amblyomma americanum), characterized by the bright white spot on its back, spreads the human bacteria ehrlichiosis and tularemia and is occasionally diagnosed in dogs.

* Southern and Midwestern U.S.: Dogs and humans are at risk from the same ticks found in the Northeast.

* West Coast: Dogs may acquire Lyme disease and anaplasmosis from black-legged ticks (Ixodes pacificus). In this area, Rocky Mountain spotted fever is spread by American Dog Ticks, brown dog ticks and Rocky Mountain wood ticks (Dermacentor andersoni).

SAFE, EFFECTIVE TICK REMOVAL

You may have heard several tales about how to remove ticks. Ignore them. Never try to burn the tick off by applying a hot match or a lighted cigarette. You are more likely to injure your dog with these methods.

Other ineffective techniques include covering the tick with Vaseline or mineral oil. These methods are messy at best, injurious to your dog at worst. They may even cause the tick to release more bacteria or protozoa into the bite site.

If you can't safely remove the tick yourself, take your dog to the veterinarian and let a professional do it. Otherwise, start by putting on gloves to protect your skin from possible infection if the tick bursts. With tweezers or a special tick removal device, grasp the tick as near to the skin as possible and tug firmly. Place the tick in a sealed container filled with alcohol to kill it. Avoid flushing live ticks down the toilet; they have air sacs that allow them to survive in water.

After removing a tick, wash your hands thoroughly with soap and warm water. Apply antiseptic to the area where your dog was bitten, and give him a treat to take away the sting.

NOT EXACTLY CANARIES...

Dogs don't spread tick-borne diseases to humans but are excellent sentinels of risk for infection in humans. In other words, if a dog gets Lyme disease or Rocky Mountain spotted fever, there's a good chance family members could also come in contact with infected ticks.

"They say that when 5 percent of the dogs in a county get Lyme disease, that's when you start to see human cases," says Dwight D. Bowman, Ph.D., professor of parasitology at Cornell. "If you look at the CAPC (Companion Animal Parasite Council) maps for New York now, the entire state is greater than 5 percent."

It's not unheard of for a dog's diagnosis to help solve a human medical mystery as well. Dr. Bowman recalls the case of a dog who died of what was thought to be cancer. His owner had also been ill, and her life was saved when her doctor was notified after a necropsy found that the dog's death was caused by Rocky Mountain spotted fever.
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Publication:Dog Watch
Date:Mar 1, 2017
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