After a long winter, we know your dog is ready to stretch its legs and get his nose on all those summertime scents. But before you gear up and head to the trails, make sure your dog is prepared for the Great Outdoors. We talked to Front Range veterinarians and canine experts to find out what health concerns dog-owners should watch out during warm-weather adventuring.

For trails to explore with your canine companion, click here.

Blue-Green Algae Poisoning

This summer, at least six lakes in Colorado have tested positive for Cyanobacteria, commonly known as blue-green algae, a microscopic bacteria that can be fatal to dogs if infected. The bacteria, which occurs when a body of water has an influx of nutrients from stormwater or agricultural run-off, can “bloom” (giving the water a blue-green coloring) and produce harmful toxins. Dogs are more likely to become infected by the bacteria during peak adventuring in the summer. While most lakes in Colorado appear to be toxin-free, if your dog appears sick after swimming (vomiting and diarrhea), head to the vet immediately.

Overexposure to Heat and Sun

While summers in Colorado are known to be moderate (the temperature averages 88 degrees Fahrenheit in July), heat and sun exposure are risk factors dog owners should be aware of. According to Dr. Courtney Turner from the Center of Animal Wellness in Denver, heat risks or heat associated risks can span anything from heat exhaustion to sun burns. “Dogs that have fair skin—you know the “pink” pups with pink around eyes, on their belly, and underneath their arms—will burn,” Turner says. She recommends putting a pet-friendly, sunscreen with a high SPF on your dog, especially if you plan to be outside for long periods of time, with little to no shade.

“You can also put a shirt on them or avoid sun-intense areas,” says Dr. Ashley Ackley, a veterinarian at Evans East Animal Hospital. Sun-shielding tees can be found online or at local pet stores (we’re a fan of Gold Paw’s).

To avoid heat exhaustion, Turner suggests owners plan ahead before adventuring. “Take them out when it’s cooler: in the early morning or in the evening. Or make sure you’re on a shaded trail,” she says. “Bring plenty of water with you and stop for water breaks.”

“When the pavement is too hot, dogs will literally get blisters and they can almost wear off their paw pads,” Turner says. To avoid road rash,. Turner suggests staying off the trails and roads during the hot times of the day. “And if you absolutely have to get out in the heat of the day, use booties.” Turner also advises owners to exclusively seek out trails with lots of shade, dirt, and grass.

Lastly, never leave your four-legged friend in a hot car. “Even if it’s 70 degrees out, it’s usually 20 degrees warmer in a car,” Ackley says. Dogs left in hot cars can overheat and succumb to heatstroke.


While your dog will be tempted to cool off in a nearby lake or river when out exploring, be cautious—you never know what parasite is lurking in the water. For instance, Giardia is a protozoan parasite that can be found in water that has been contaminated with feces from other infected animals. “Dogs can either come into contact with it by eating feces or by getting into or drinking water contaminated with feces,” Turner says. Puppies are more susceptible to Giardia because they have young and immature immune systems.

According to Ackley, there is a higher risk of contracting Giardia as more people move to the Front Range. In the same respect, Turner thinks dogs are more likely to come into contact with it the more they venture outside. “I think there are more opportunities for infection in the times of the year when we’re going to be out hiking, running around, and going to the dog park,” she says.

While you don’t have to truly worry about fleas in Colorado—they require humidity to thrive—you should be concerned about your dog getting ticks.

“I’ve been seeing more and more each year,” Turner says. “I probably saw 7-10 dogs with ticks last year.”

Ticks, which feed on the blood of its host, live in heavily-wooded and grassy areas. Because much of Colorado’s high country meets the criteria for tick habitation, running into a tick or two might be inevitable. “If you’re going to be doing a lot of hiking in the woods, or going to the bigger dog parks with taller grass, I recommend doing a preventative,” Turner says. “I usually treat my own dogs during July and August, when it gets hot here.”

“Some of the diseases that ticks carry can be really challenging to treat,” Ackley says. Certain species of ticks carry Lyme Disease, which can cause lethargy, pain, discomfort, loss of appetite, and fever in dogs. If it goes untreated, it can be fatal.

“I think it’s easier to prevent it, then have to deal with it,” Ackley says.

Bacterial Infections

Make sure to bring plenty of water for your pup to drink along the trail as many warm, stagnant bodies of water can be breeding grounds for leptospirosis, an infectious disease shed from the urine of infected wildlife. “Big offenders are going to be raccoons, skunks, rats, and deer,” Turner says. “It’s shed through their urine and gets in our water and soil, and dogs can come into contact with it when they’re doing water activities or playing in moist soil.”

While Leptospirosis isn’t that common for dogs to catch, it can be deadly.

“It’s a big deal. I can’t stress it enough,” Turner says. “When you see enough cases of it…it’s scary.” Her office saw two leptospirosis cases this year, with one of them ending in euthanasia.

When a dog is infected with Leptospirosis, the bacteria will multiply in the bloodstream and cause damage to the kidney and liver. The dog that passed away from the disease last year was being treated very aggressively, Turner says. “We get really mixed results when we try to treat it,” she says.

“In the past we didn’t see it as much in the city, but it has moved to urban Denver, probably with the population boom.” Turner says. “It’s something I would stress for anyone that’s going to be out with their dog.”

Discover our favorite local products, hikes and more in Dog-Friendly Denver, a dog-lover’s guide to the Mile High City.

Victoria Carodine
Victoria Carodine
Victoria Carodine is a Denver-based writer and a former editor on 5280's digital team.