TERRI JOHNSON, MSS, CVT
We've all noticed changes in weather patterns in the last few years. Can these changes affect our pets and the things they're exposed to?
Climate change may be increasing the risk of spreading some pet diseases by impacting the life cycles of insects such as ticks and mosquitoes. And climate change has been shown to affect the following factors:
- The geographical distribution of insects (northern, southern and altitudinal distribution)
- The extension of seasonality and risk periods due to increased heat
- The increased incidence of disease because the risk of being bitten by an infected insect and developing symptoms may be increasing
Insects and ticks do not have temperature regulations of their own, so they're sensitive to changes. Insects such as disease-transmitting ticks and mosquitoes are now being found at higher altitudes where the seasons were previously too short or too cold for them to survive.
Dr. Paige Lorimer is the owner and medical director of AAHA-accredited Pet Kare Clinic in Steamboat Springs, Colo. Fleas, ticks and mosquitoes that carry heartworm disease aren't usually much of an issue for her patients due to the high altitude. But that doesn't mean these cases don't exist. "We're not seeing heartworm cases in local dogs, but we have seen some heartworm-positive dogs coming in from other states," she says.
Lorimer is also seeing mosquitoes in Steamboat Springs as early as April, and that's earlier than it used to be. "We're now recommending year-round heartworm preventives instead of what we used to recommend as the 6-month summer seasonal preventive."
The spread of disease
Diseases may be spread in a number of ways. Even if a disease isn't endemic to an area, it may be spread by insects and/or contact between animals and things that are in their environments. Many diseases can be transported and transmitted from other areas of the country and from other species because people and their pets are becoming more mobile. Additionally, living around wildlife has other ramifications for the spread of diseases.
"We're learning from other veterinarians in the state that they're seeing more cases of leptosporosis so we've added the leptosporosis vaccine to our recommended core vaccinations," says Lorimer. "We do have skunks and raccoons in the area so there's an increased likelihood that local pets may be exposed." Leptospirosis is a bacterial disease transmitted through the urine, saliva or blood of mice, raccoons, skunks, foxes and other small animals or by contact with contaminated objects or water. The disease impairs liver and kidney function and can result in kidney failure.
Leptospirosis can also be transmitted from animals to people. Symptoms are flu-like and may include vomiting, lethargy, muscle pain and diarrhea. The good news is that leptospirosis is treatable with penicillin and tetracycline drugs but is dangerous if left untreated.
Lorimer has also seen more hookworm, roundworm and flea cases in the last 5 years. She thinks this is due to unprotected animals that are being brought into the area. The social nature of dogs—going for walks, dog parks, playing together—allows more opportunity for the spread of fleas, ticks and diseases. They've even seen a few cases of lice in the area. "These are usually limited to a specific area, like a neighborhood, so it's very likely that a pet was brought to the area with lice," she says. It's important to identify these cases, begin treatment and start preventive measures to prevent any further spread.
Parasites, fleas and ticks
Lorimer's own dog has been diagnosed with Lyme disease, a form of infectious arthritis caused by bacteria transmitted through tick bites. Signs of Lyme disease include limping or lameness, warm joints and swollen lymph nodes. The disease can be treated with antibiotics, but preventive measures include vaccination and/or the use of topical flea and tick products. Vaccination is recommended for pets that live and are exposed to areas where deer are common.
If you live in areas where ticks are prevalent, it's important to monitor your pets for ticks every day. To transmit the infection, ticks usually have to be attached 24 to 48 hours. So, prompt location and removal of ticks, including the tick's head, with fine-tipped tweezers may help prevent your pet from contracting these diseases. If you are unsure of how to properly remove the tick, it's best to take your dog to a veterinarian.
Other diseases that can be transmitted by the bite of an infected tick include ehrlichiosis and anaplasmosis. The most common carriers of these diseases are the western blacklegged tick and the deer tick, both of which also transmit Lyme disease. Ehrlichia bacteria infect white blood cells and Anaplasma bacteria affect platelets. Symptoms of these two diseases can begin about 5 days after being bitten by an infected tick and may include fever, chills, nausea, lethargy, rash and hemorrhaging.
Parasites pose threats to both pets and people no matter the season, so it's important to guard against them. Plus, things keep changing; whether your pets are exposed to parasites because they're endemic to your area or because they're brought into the area by other pets or wildlife, it's important for you to understand how to prevent your pet from getting diseases and how to prevent the spread of disease in your community.
Talk to your veterinarian at least once a year about vaccination and preventive flea and tick treatments for dogs and cats. Preventives and treatments may need to be modified based on your pet's age, health status, home and travel environment, lifestyle and changes in your local climate. Vaccinations and preventive treatments are just part of an overall, individualized, comprehensive preventive health care plan, so it's important to talk to your veterinarian about what's right for you and your pets.
Photo Credit: ©iStockphoto.com/Chalabala, ©iStockphoto.com/Joseph Brewster
This article originally appeared in PetsMatter May / June 2013, published by the American Animal Hospital Association. Copyright © 2013 AAHA. Find out more.