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7 Springtime Dangers for Dogs

dog in field
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When the weather warms up, chances are you and your dog spend more time outdoors enjoying the fresh air. But as the ground begins to thaw and flowers start to bloom, new threats also emerge. Seasonal changes in your dog’s lifestyle, coupled with shifting weather patterns, present a variety of risks, such as parasites, diseases, and toxins.

Here are seven springtime dangers for dogs you should know about.

7 Springtime Dangers for Dogs


dog drinking from puddle

Leptospirosis is a bacterial disease that can affect dogs and people, as well as several other mammalian species. While cases can occur any time of the year, your dog is at higher risk of contracting leptospirosis in the warmer months, from late spring through early autumn. Rain levels seem to impact prevalence, such that more rain causes more risk. 

Dogs can become infected with leptospirosis through contact with contaminated urine, water, or soil. Infected animals that can contaminate the environment include rodents, squirrels, raccoons, pigs, and cattle. In seasons of extreme rain, or times of natural disaster, such as flooding, environments can become newly exposed since the contaminated water sources can flood from rural areas into urban areas.

Clinical signs of leptospirosis in dogs include decreased appetite, vomiting, diarrhea, increased thirst and urination (due to effects on the kidneys), yellowing of the skin (due to the effects on the liver), and potentially death.

There is an annual vaccine available that is effective against four strains of leptospirosis. Talk to your veterinarian about your dog’s risk. It may be included in your dog’s annual vaccine program. If not, he or she may recommend scheduling vaccination before the high season of risk.

Lyme Disease (and Other Tick-Borne Illnesses) 

Lyme disease is a common tick-borne disease that is well recognized to affect both humans and dogs. Because the disease is transmitted by both immature (nymph) and adult ticks, your dog could become infected in any season. 

Ticks often climb tall grasses or shrubs and wait for a potential host, such as your dog, to brush against them so they can grab on and start feeding. This behavior is called questing. Infected ticks can transmit the Lyme disease bacteria and other serious diseases.

Ticks begin questing when the temperature goes above 4.4 degrees Celsius (40 degrees Fahrenheit). Some species of ticks even like cooler weather. One study found that black-legged ticks quest in temperatures as low as 31 degrees Fahrenheit (1). Thus, it is important to use an effective tick and flea control product year-round, such as Credelio® (lotilaner), that kills ticks and fleas fast. 

See important safety information below for Credelio®.

Only a small percentage of infected dogs will exhibit clinical signs of Lyme disease, which can range from lethargy and limping to kidney disease and anemia. Certain breeds may have increased risk for illness once infected by ticks.  

Your veterinarian may recommend screening your dog for exposure to the bacterium that causes Lyme disease. Depending on your dog’s lifestyle and risk factors, your veterinarian may recommend a vaccine against Lyme disease. The vaccine is given twice initially (2-4 weeks apart) and then annually (2). 


dog in grass scratching

Fleas thrive in warm and humid weather, when breeding conditions are ideal. This presents an increased risk for your pet. Fleas can hop onto your dog from a contaminated environment and start feeding on his blood.

It is imperative to keep your pet on tick and flea protection, since fleas are a risk year-round.

If your dog is very itchy or you notice dark, crusty debris on the skin over his back and belly, you should see your veterinarian, as this may be a sign of fleas. In some dogs, flea bites can cause an allergic reaction called flea allergy dermatitis, in which they may scratch themselves raw. 

Fleas can also carry and transmit internal parasites, such as tapeworms (Dipylidium caninum), or bacterial infections. By controlling fleas on your dog, you can help reduce but not eliminate the likelihood of these infections.

Your veterinarian can recommend an effective flea control product for your dog. Products should only be used as directed, as some products that can be used in dogs should not be used in cats.

Heartworm Disease 

Mosquitoes also become more active as the weather warms up, putting dogs at even greater risk for heartworm infections during the spring and summer. The disease is spread through the bite of an infected mosquito.

Overall, the number of dogs infected with heartworms is increasing in the United States. From 2013 to 2016, positive heartworm tests in dogs increased by 15.28 percent, data from the Companion Animal Parasite Council reveals (3). The increased rate of infection could be due to lack of preventive use and the emergence of drug-resistant heartworms. 

Heartworm preventives for dogs are highly effective when administered properly. Monthly, year-round use ensures there are no gaps in your dog’s protection—even one missed dose can leave your dog vulnerable to infection. A broad-spectrum dewormer, such as Interceptor® Plus (milbemycin oxime/praziquantel), is effective against five of the most common worms your dog is at risk from. It prevents heartworm disease by killing heartworm larvae after an infected mosquito bites your dog, before the larvae can mature and become adult heartworms. Some heartworm disease medications are only effective against heartworm and a smaller number of other worms. 

See important safety information below for Interceptor® Plus.

Clinical signs of heartworm in dogs vary based on severity of disease but can include lethargy and coughing. These dogs can also present in more advanced stages with heart failure and severe changes on chest X-rays. 

The disease is difficult (and painful) to treat but prevention is very effective, thus it is recommended that dogs should receive heartworm prevention year-round.  

Intestinal Parasites 

Heartworm prevention products also provide protection against another threat: intestinal parasites. As dogs spend more time outside in the spring and summer, they are often exposed to more parasites, so it is essential to ensure they are protected. Different products provide varying degrees of coverage, so you need to make sure the product you are using provides coverage against the most common types of intestinal parasites. Common intestinal worms in dogs include hookworms, whipworms, roundworms, and tapeworms. 

Common signs of intestinal parasites in dogs include vomiting and diarrhea, although your dog may not have symptoms in the early stages of infection. Intestinal parasites can also cause more significant illness in your pet, such as weight loss, blood loss, or electrolyte abnormalities, which can make dogs feel really sick if they have a severe parasite burden. In rare cases, these infections can even be fatal. 

Broad-spectrum dewormers like Interceptor® Plus can be used to treat and control worm infections in dogs. 

See important safety information below for Interceptor® Plus.

Due to the ever-present risk of intestinal parasites, your veterinarian should conduct a fecal test every six or 12 months to screen your dog for parasites. 

Spring Plants

dog in garden

As spring-flowering bulbs start to pop up in gardens, you should be aware of which plants are toxic to dogs. Tulips, hyacinths, daffodils, crocuses, and lily of the valley can all pose a threat to your dog’s health.

Tulips, hyacinths, and daffodils can cause vomiting, diarrhea, and drooling if ingested due to irritation of the gum tissue or the lining of the esophagus and stomach. With significant ingestion, your dog may also have difficulty breathing or cardiac issues. The spring blooming crocus can cause gastrointestinal upset, including vomiting or diarrhea. Lily of the valley is another spring flower that can make your dog sick due to toxins known as cardiac glycosides in the plant. Ingestion causes vomiting, diarrhea, cardiac arrhythmias, and possibly seizures. 

If you suspect that your dog has ingested a toxic plant, call your veterinarian immediately.

Bee Stings

Dogs can get stung by bees or wasps during the spring and summer—especially if they enjoy nosing around flowers in the garden or chasing and snapping at flying insects. While dogs are most likely to be stung on their face, snout, or paws, they can get stung anywhere on the body.

Signs of wasp or bee stings on dogs include small areas of swelling, redness, itchiness, and sensitivity to touch. You may also notice your dog limping if she got stung on her leg or foot, or scratching at a specific area. If symptoms do not improve within a day or so, or get worse, you should call your veterinarian.

In more serious cases, where a dog is allergic to bee stings or gets stung multiple times by bees or wasps, severe symptoms can occur. Signs may include swelling that spreads to the throat, difficulty breathing, lethargy, vomiting, and collapse. If your dog is having a severe or life-threatening allergic reaction to bee stings, take her to the veterinarian immediately.

By staying cognizant of springtime dangers for dogs, you can help keep them happy, healthy, and safe throughout the season.

Credelio Indications

Credelio kills adult fleas and is indicated for the treatment and prevention of flea infestations, treatment and control of tick infestations (lone star tick, American dog tick, black-legged tick, and brown dog tick) for one month in dogs and puppies 8 weeks and older and 4.4 pounds or greater.

Credelio Important Safety Information

Lotilaner is a member of the isoxazoline class of drugs. This class has been associated with neurologic adverse reactions including tremors, incoordination, and seizures. Seizures have been reported in dogs receiving this class of drugs, even in dogs without a history of seizures. Use with caution in dogs with a history of seizures or neurologic disorders. The safe use of Credelio in breeding, pregnant or lactating dogs has not been evaluated. The most frequently reported adverse reactions are weight loss, elevated blood urea nitrogen, increased urination, and diarrhea. For complete safety information, please see Credelio product label or ask your veterinarian.

Interceptor Plus Indications

Interceptor Plus prevents heartworm disease and treats and controls adult roundworm, hookworm, whipworm, and tapeworm infections in dogs and puppies 6 weeks or older and 2 pounds or greater.

Interceptor Plus Important Safety Information

Treatment with fewer than 6 monthly doses after the last exposure to mosquitoes may not provide complete heartworm prevention. Prior to administration of Interceptor Plus, dogs should be tested for existing heartworm infections. The safety of Interceptor Plus has not been evaluated in dogs used for breeding or in lactating females. The following adverse reactions have been reported in dogs after administration of milbemycin oxime or praziquantel: vomiting, diarrhea, decreased activity, incoordination, weight loss, convulsions, weakness, and salivation. For complete safety information, please see Interceptor Plus product label or ask your veterinarian.

Disclaimer: The author received compensation from Elanco US Inc., the maker of Interceptor Plus and Credelio, for her services in writing this article. 


  1. Terry L. Schulze, Robert A. Jordan, Robert W. Hung, Effects of Selected Meteorological Factors on Diurnal Questing of Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae) , Journal of Medical Entomology, Volume 38, Issue 2, 1 March 2001, Pages 318–324, https://doi.org/10.1603/0022-2585-38.2.318
  2. Lyme Disease: A Pet Owner’s Guide. American Veterinary Medical Association. Retrieved from https://www.avma.org/resources/pet-owners/petcare/lyme-disease-pet-owners-guide
  3. Drake, J., Wiseman, S. Increasing incidence of Dirofilaria immitis in dogs in USA with focus on the southeast region 2013–2016. Parasites Vectors 11, 39 (2018). https://doi.org/10.1186/s13071-018-2631-0

Credelio and Interceptor are trademarks of Elanco or its affiliates.

© 2020 Elanco.  PM-US-20-0712

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