Getting rid of intestinal worms, or deworming, is an important part of keeping pets like dogs and cats healthy. Deworming medications help eliminate parasitic worms that live in the intestines and feed off of partially digested food. Some common intestinal worms include roundworms, tapeworms, hookworms, and whipworms.
When a pet is diagnosed with an intestinal worm infection, a veterinarian will prescribe an oral or topical deworming medication. But how long does it take for these medications to fully get rid of the worms? Here’s what pet owners need to know about the deworming timeline and when their pet will be worm-free.
How Deworming Medications Work
Deworming, also known as anthelmintic, medications work by either killing the worms or causing them to be expelled from the body:
- Some dewormers like fenbendazole and pyrantel pamoate kill worms slowly, over the course of a few days.
- Other dewormers like moxidectin and ivermectin work more rapidly, killing worms and causing them to be eliminated from the intestines within 24 hours.
In addition to killing adult worms, some deworming medications like ivermectin can also prevent the larvae and eggs of some worms from maturing and reinfecting the pet. This provides a longer lasting deworming effect.
Factors That Determine Deworming Timeline
There are a few key factors that determine how long it takes a deworming medication to fully clear an intestinal worm infection:
- Type of worms – The timeline can vary based on the type of intestinal worms. Roundworms and hookworms are often eliminated more rapidly than whipworms or tapeworms.
- Severity of infestation – Pets with mild cases may clear worms faster than those with heavy worm burdens.
- Deworming medication used – The type of deworming medication and how quickly it starts working will impact the timeline.
- Additional doses – For heavy infestations, repeat doses are often required which extends the timeline.
- Reinfection potential – If a pet has continued exposure to sources of worms, reinfection can occur and prolong elimination.
Knowing the type of worms involved and the medication prescribed allows veterinarians to provide pet owners with an approximate deworming timeline.
How Long Until Roundworms Are Gone?
Roundworms are intestinal parasites that resemble spaghetti noodles in appearance. They are a common worm in puppies but can infect cats and adult dogs too.
Many puppies are born already infected with roundworms from their mother. Deworming medications are typically given starting at 2 weeks of age, then repeated every 2-4 weeks until about 8 weeks of age. It often takes repeat doses to fully eliminate roundworms in puppies.
In adult dogs, roundworms are often eliminated within 24 hours of deworming administration. Here are some general timelines for roundworm clearance based on medication type:
- Fenbendazole – 3-5 days
- Febantel – 1-2 days
- Ivermectin – 24 hours
- Pyrantel pamoate – 1-2 days
A follow up fecal test may be recommended 2-4 weeks after treatment to check that roundworm eggs are no longer being shed.
How Long Until Hookworms Are Gone?
Hookworms attach themselves to the intestinal wall and feed on blood, sometimes causing anemia. They can be transmitted in contaminated soil.
Like roundworms, puppies commonly have hookworms transmitted from the mother dog. Repeat deworming is often needed to fully clear hookworms in puppies. In adult dogs, a single dose of dewormer may eliminate hookworms but confirmation testing is recommended.
General timelines for hookworm clearance based on medication type:
- Fenbendazole – 7-10 days
- Milbemycin oxime – 1-2 days
- Moxidectin – 24 hours
- Pyrantel pamoate – 1-2 days
Hookworms eggs can be detected in feces about 3-4 days after infection. Fecal testing 2-4 weeks after treatment is recommended to check hookworm elimination.
How Long Until Whipworms Are Gone?
Whipworms are an intestinal parasite that can cause bloody diarrhea. They can be more difficult to eliminate than other worm types.
It often takes at least 3 successive monthly treatments to fully clear whipworm infections. A single dose of dewormer may start killing adults but not completely interrupt the lifecycle.
General timeline expectations for whipworm clearance:
- Fenbendazole – 10-14 days
- Ivermectin – up to 2 months with repeat doses
- Milbemycin oxime – up to 2 months with repeat doses
- Moxidectin – up to 2 months with repeat doses
Whipworm eggs may appear in feces 3-6 months after infection. Multiple fecal tests may be needed to confirm elimination after treatment.
How Long Until Tapeworms Are Gone?
Tapeworms are flat, segmented intestinal parasites. They are transmitted when a dog swallows an infected flea during grooming.
Tapeworm infections are generally eliminated with a single dose of a deworming medication like praziquantel. The dead tapeworms are often visible in the stool within 24 hours of administration.
General timeline for tapeworm clearance after deworming:
- Epsiprantel – Within 24 hours
- Fenbendazole – 1-2 days
- Praziquantel – Within 24 hours
Occasionally repeat doses are needed for persistent infections. As tapeworm segments detach every few days from the adult worm, shedding can be intermittent. It may take 2-3 doses to fully clear an infection.
When Will Deworming Medication Take Full Effect?
While some deworming medications work very rapidly, it’s important to complete the full course of treatment as prescribed by your veterinarian. Otherwise, reinfection can occur.
Here are some general timeframes for when dewormers take full effect:
- Pyrantel pamoate – Within 24 hours
- Ivermectin – Within 24 hours
- Milbemycin oxime – Within 2 days
- Moxidectin – Within 2 days
- Fenbendazole – Within 5 days
Even after worms have been eliminated, pets may continue shedding dead worm segments, larvae, or eggs in the feces for 1-3 weeks after treatment.
How Soon Before Reinfection Can Occur?
After successful deworming, reinfection with worms is unfortunately quite common. This is because pets have continued exposure to sources of worm infestation in the environment.
Reinfection can occur through:
- Ingestion of worm larvae or eggs from contaminated soil, feces, or raw meat
- Consumption of transport hosts like cockroaches or mice carrying worm larvae
- Mosquito or flea vectors transmitting different worm species
Pets often reacquire new worm infections within just 2-4 weeks after elimination if the environment isn’t properly cleaned. Year round heartworm and flea control helps reduce reinfection risk in at risk pets.
Follow Up Fecal Testing
To check that deworming was fully effective, vets will often recommend a follow up fecal test 2-6 weeks after treatment is completed. This allows time for any worms to be eliminated and confirms the pet’s feces is free of worm eggs or larvae.
For pets with heavy parasite burdens or certain worms like whipworms, multiple fecal tests may be recommended spaced 1-3 months apart to ensure the intestines are clear.
If the follow up fecal test is positive, then repeat deworming is required. The source of reinfection should be identified and eliminated if possible.
Preventing Reinfection Between Treatments
To help prevent rapid reinfection between deworming treatments, pet owners can take these steps:
- Pick up and dispose of all pet feces promptly
- Disinfect pet living areas inside and out
- Bathe and groom pets regularly
- Give monthly flea and tick prevention
- Have other pets and family members dewormed
- Avoid eating undercooked meat or fish
Practicing good hygiene and infection control limits exposure to worms between treatments.
How Long Does It Take to Get Rid of Worms?
The bottom line is that the timeline for eliminating an intestinal worm infection can vary based on:
- Type of worms involved
- Number of worms present
- Deworming medication used
- Need for repeat dosing
- Reinfection potential
While some worms like roundworms and hookworms may be eliminated within days, whipworms and tapeworms can take weeks to fully clear. Severe cases may require several repeat doses spaced monthly.
It’s important to follow your vet’s recommended treatment schedule. Even after worms appear gone, continue giving prescribed doses to interrupt reinfection. Fecal testing helps confirm when pets are worms-free.
With prompt deworming and prevention measures, most pets can eliminate intestinal worms within 1-3 months and stay worm-free long term.
Key Points
- Deworming medications work by either killing worms or expelling them from the intestines
- Roundworms and hookworms often clear with 1-2 doses of dewormer within days
- Whipworms and tapeworms can take weeks to fully eliminate with repeat dosing
- Fecal testing 2-6 weeks after treatment checks for elimination
- Reinfection is common and can occur within weeks if repeat dosing not completed
- Proper hygiene helps prevent reinfection between treatments
- Most pets become worm-free within 1-3 months with consistent deworming
Conclusion
Deworming is an important part of pet health care. While a single dose of dewormer may seem to eliminate worms quickly, it takes vigilance to fully clear an infection. Sticking to the schedule of repeat doses prescribed by your vet is crucial, even if your pet seems worm-free. Combine this with steps to prevent reinfection, and your furry companion can stay worm-free long term.
