Pet Parasites and Prevention

Pet parasites like fleas, ticks, heartworms, and intestinal worms pose a year-round threat to your pets, often causing intense itching, significant pain, and sometimes life-threatening disease.¹ These pests can also, in some cases, be transmitted to your human family members.²

Find out how to identify common internal and external pests, recognize their symptoms, and prevent them from hitching a ride on (or in) your furry friend.

What Are the Most Common Parasites in Pets?

Many different parasites can affect pets, both inside and outside the body.

External parasites

External parasites live right on the surface of your pet. They hide in their fur, burrow into their skin, and can cause immense discomfort. Some common external pests to watch out for include:

• Fleas: These tiny, wingless insects are famous for their jumping abilities. They feed on your pet's blood and lay hundreds of eggs in a matter of days.³ Symptoms include frantic scratching, red patches of skin, hair loss, and flea dirt (which looks like tiny black pepper flakes). Fine-toothed combs or specialized flea removal tools can help remove fleas from your pet’s fur. Treatment typically involves shampoos, sprays, or other topical medications, which you can get over the counter or from your veterinarian.^3,4
• Ticks: Ticks hang out in tall grass and wooded areas waiting for a host to brush by. They latch onto your pet's skin and engorge themselves on blood. Tick bites can spread serious illnesses such as Rocky Mountain spotted fever and Lyme disease. You might find them around your pet's neck or ears. If you find a tick on your pet, the number one goal is to remove it promptly with tweezers or a tick removal tool. Monthly preventatives, medicated collars, and topical solutions can help prevent future tick attachments.³
• Ear Mites: These microscopic pests love the dark, warm environment inside your pet's ear canals. They cause intense itching. If your cat or dog constantly shakes their head or scratches their ears, look inside. A dark, crumbly discharge that resembles coffee grounds is a classic sign of ear mites.⁵
• Lice: Lice are tiny insects that attach to your pet's fur, causing severe itching, small wounds from bites on the skin, and hair loss around the neck and ears. They usually spread through direct contact with infected animals or contaminated grooming tools. Regular checks are important, especially if your pet frequents areas with other animals. Treatment typically involves topical medications prescribed by a veterinarian.⁶

Internal parasites

Other parasites hide out of sight, multiplying inside your pet. The most frequent internal pests include:⁷

• Heartworms: Mosquitoes transmit heartworms in dogs and cats, which travel directly to the heart and lungs. Early symptoms include a mild yet persistent cough, lethargy after moderate exercise, and decreased appetite. Left untreated, heartworm disease causes severe heart failure and even death. Heartworm prevention is key. Treatment for dogs can take months and require veterinarian-prescribed medication.⁸
• Roundworms: Roundworms resemble pieces of spaghetti. Pups and kittens often get them from their mothers before birth or while nursing. They also spread through contaminated soil or by licking dirty paws. A serious infection can lead to weight loss, vomiting and diarrhea, a pot-bellied appearance, dull coat, and coughing.⁹
• Hookworms: These dangerous parasites have hook-like mouthparts that they use to latch onto the intestinal lining. Like roundworms, hookworms suck blood directly from your pet. Dogs and cats catch them by swallowing infected larvae from feces or walking on contaminated soil, where the larvae penetrate the skin. Severe hookworm infections cause diarrhea, bloody stools, weakness, and life-threatening blood loss, especially in young animals.¹⁰
• Tapeworms: Your pet usually catches tapeworms by accidentally swallowing an infected flea while grooming or by eating small rodents. Tapeworms look like long strips of tape, and they shed small segments that resemble dried grains of rice. Found in both cats and dogs, you might spot these segments wiggling around your pet's tail or stuck to their bedding.⁷
• Giardia and Coccidia: These microscopic, single-celled organisms damage the lining of the small intestine. Pets ingest them by drinking contaminated water, eating dirt, or licking infected paws. They cause watery diarrhea, weight loss, and dehydration. You can’t treat these with standard deworming medications because they’re protozoan parasites, not worms, so proper diagnosis from a vet is key.^{10, 11}

Intestinal parasites and single-celled organisms reproduce in the intestines, stealing vital nutrients. Others, like heartworms, attack vital organs directly.^{7, 12} They can be tough to diagnose and generally require a stool test performed by your veterinarian. Not all parasites present symptoms, so routine checkups and fecal exams are critical.⁷

After they’re identified, deworming medications are typically administered, depending on the type of worm present (roundworms, hookworms, tapeworms, etc).⁷ Always follow your vet’s instructions for retreatment or additional doses, especially for puppies and kittens who may require scheduled deworming.

Recognizing the Symptoms of Pet Parasites

Pet parasites are sneaky. Sometimes, the symptoms are obvious. Other times, it can be more subtle. Look out for symptoms like the following:^{3, 4, 7}

• Excessive itching or scratching
• Hair loss or bald patches
• Visible fleas, ticks, or worm segments
• Diarrhea or bloody stools
• Scooting or dragging the rear end
• Distended belly, especially in kittens and puppies
• Coughing
• Loss of appetite
• Unexplained weight loss

Pay close attention to changes in your pet’s health and behavior, and contact your vet if you notice any of the symptoms above.

Can Humans Get Parasites From Pets?

Unfortunately, if your pet has an infestation, the risk can spread to your entire household. Many pet parasites are zoonotic, meaning they can cross species and infect humans.² Once you understand how these bugs spread, you can implement stronger pet parasite prevention measures.

While children and the immunocompromised are most at risk, everybody should be vigilant about handwashing and other preventive measures, especially if there are pets in the home.²

Hookworm larvae, for example, hide in the soil. If you walk barefoot through an infected area, those tiny larvae can burrow straight through your skin.⁷ They create intensely itchy, winding red tracks known as “creeping eruption.”¹⁰

Then there are ticks, which can expose members of your household to severe diseases like Lyme. This infection may lead to symptoms such as joint pain, extreme fatigue, and even long-term neurological issues.¹³

Top Strategies for Pet Parasite Prevention

Parasites don’t take the winter off, and neither should you.¹ The best way to handle an infestation is to stop it before it starts. Focus on consistent, year-round prevention for both indoor and outdoor pets with these strategies:

Stick to year-round medications

Don’t skip a month of your pet's preventative medication. Your veterinarian can prescribe a monthly chewable tablet, a topical liquid, or a long-lasting collar. Many modern products combine protection against heartworms, fleas, ticks, and common intestinal worms into a single dose.

Always consult your vet to choose the right product based on your pet's specific needs, size, and lifestyle. Don’t use dog products on cats, as this can cause severe reactions.¹⁴

Maintain excellent hygiene and grooming

More than just helping them to look their best, grooming your pet regularly also gives you a chance to closely inspect their skin and coat. Brush your dog or cat daily and feel for small bumps, scabs, or signs of flea dirt.

After a hike or a walk in tall grass, run your hands thoroughly over your dog's body, paying special attention to the ears, armpits, and toes, to catch any ticks before they attach.

Keep the environment clean

The better you can manage your home and yard, the easier it will be to keep bugs away. Some tips:

• Pick up pet feces immediately from your yard and during walks to prevent eggs from contaminating the soil.
• Vacuum your carpets, rugs, and furniture frequently to remove flea eggs and larvae before they hatch.
• Wash your pet's bedding, blankets, and toys in hot water at least once a week.
• Keep your lawn mowed short and trim back overgrown bushes to eliminate hiding spots for ticks and mosquitoes.

Also, be sure to cover outdoor sandboxes when children aren’t using them to stop neighborhood cats from using them as litter boxes.

Schedule regular veterinary checkups

Don’t rely on your eyes alone to detect parasites. Many pet parasites show no symptoms until the infection has progressed.⁷ Veterinarians often recommend routine fecal testing twice a year for adult pets, depending on risk and lifestyle, as well as annual tests for heartworm and tick-borne diseases.¹⁵

MetLife Pet Could Help You Cover Parasite Prevention and Treatment Costs

Treating pet parasites can get expensive quickly, especially if the infestation leads to severe illness, like heartworm disease or Lyme.

A pet insurance policy from MetLife Pet may help cover the costs of diagnostic tests, lab work, prescription medications, and hospitalizations if your pet contracts a parasitic infection.

If you want proactive protection, consider adding the optional Preventive Care plan to your standard policy. With the Preventive Care add-on, you can get reimbursed for routine and wellness expenses up to your selected benefit limit. This includes coverage for your pet’s essential year-round parasite prevention medications, routine fecal exams, and annual blood tests.

Peanut, a French Bulldog, was experiencing symptoms of intestinal parasites and needed to see the vet. The exam cost more than $1,500, but thanks to a MetLife Pet policy, her family was reimbursed $1,100 of that cost.¹⁶

Get a free quote today and discover how you can customize your policy to meet your pet’s unique needs.