Should a dog be treated for fleas before worms, and how should it be done correctly?

Understanding the Parasite Threat

The Interconnectedness of Fleas and Worms

How Fleas Transmit Worms

Fleas act as mechanical carriers for certain intestinal parasites, most notably the canine tapeworm Dipylidium caninum. Adult tapeworms release egg packets in the dog’s feces; these packets are ingested by flea larvae while they develop in the environment. Inside the flea, the eggs hatch, and the oncospheres penetrate the flea’s body cavity, where they mature into infectious cysticercoid larvae. When a dog grooms itself or consumes a flea during normal activity, the cysticercoid is released in the gastrointestinal tract and attaches to the intestinal wall, completing the tapeworm life cycle.

The transmission pathway creates a direct link between flea infestation and tapeworm infection:

Fleas ingest tapeworm eggs from contaminated feces.
Eggs develop into cysticercoid larvae within the flea.
Dog ingests the infected flea.
Cysticercoid larvae mature into adult tapeworms in the intestine.

Because the flea is required for the tapeworm’s development, eliminating fleas removes the primary source of infection. Effective control therefore follows a two‑stage approach:

Apply a fast‑acting adulticide to reduce the current flea population on the dog.
Initiate a monthly flea‑preventive product to interrupt the life cycle and prevent reinfestation.
Conduct a broad‑spectrum deworming regimen targeting tapeworms and other common intestinal parasites.
Maintain environmental sanitation: vacuum carpets, wash bedding, and treat the yard with an appropriate insecticide to destroy flea eggs and larvae.

Treating the flea problem first breaks the transmission chain, ensuring that subsequent deworming addresses existing infections without immediate risk of re‑infection from residual fleas. This sequence maximizes therapeutic efficiency and reduces the likelihood of recurrent tapeworm infestations.

Risk Factors for Concurrent Infestations

Concurrent infestations of fleas and intestinal parasites pose a significant health challenge for dogs. The likelihood of simultaneous exposure rises when multiple risk elements intersect, demanding a comprehensive preventive strategy.

Key risk factors include:

Outdoor environments with tall grass, leaf litter, or wildlife habitats that harbor flea larvae and parasite eggs.
Inadequate or irregular administration of broad‑spectrum preventatives, leaving gaps in protection.
Young, elderly, or immunocompromised dogs whose defenses are less capable of repelling infestations.
Multi‑dog households where untreated animals serve as reservoirs for both fleas and worms.
Seasonal peaks, particularly spring and summer, when flea activity surges and parasite transmission intensifies.
Frequent contact with other animals, including stray or shelter dogs, which can introduce resistant parasite strains.
Poor sanitation of living areas, such as unclean bedding or untreated yards, that facilitate the life cycles of both organisms.
Prior history of either fleas or worms, indicating a predisposition to recurring infestations.

Understanding these factors enables veterinarians and owners to prioritize integrated treatments, synchronize dosing schedules, and maintain environmental hygiene, thereby reducing the probability of concurrent infestations.

Prioritizing Treatment: Fleas or Worms?

The Case for Treating Fleas First

Preventing Further Worm Infestation

Effective prevention of additional worm infection begins with a systematic approach that complements flea control. First, establish a regular deworming program based on veterinary recommendations; most dogs require treatment every three months, with adjustments after diagnostic testing. Second, perform fecal examinations at least twice annually to identify species and adjust medication accordingly. Third, maintain a clean environment: promptly remove feces from yards, wash bedding, and disinfect feeding areas. Fourth, restrict access to intermediate hosts such as rodents, insects, and raw meat; store food in sealed containers and supervise outdoor play. Fifth, use preventatives that target both internal and external parasites when available, ensuring consistent administration according to label instructions. Implementing these measures reduces the likelihood of reinfestation and supports overall canine health.

Alleviating Immediate Discomfort

Fleas produce intense itching, skin inflammation and secondary infections that can appear within hours of a bite. Intestinal worms usually cause discomfort that develops over days, such as mild abdominal cramping, occasional diarrhea or a subtle change in appetite. Because the flea‑induced irritation is more immediate, addressing it first provides the quickest relief for the dog.

Treating fleas effectively requires a three‑part approach:

Apply a veterinarian‑approved topical or oral product according to the dog’s weight and species‑specific label instructions.
Wash or replace bedding, vacuum carpets and upholstery, then discard the vacuum bag to remove eggs and larvae.
Repeat the adulticide treatment after seven to ten days to break the flea life cycle.

Once the flea burden is under control, initiate deworming:

Use a broad‑spectrum anthelmintic that targets common intestinal parasites (roundworms, hookworms, tapeworms, whipworms).
Administer the dose recommended for the dog’s weight; many products require a second dose after two weeks to eliminate newly hatched larvae.
Perform a fecal examination three weeks post‑treatment to confirm parasite clearance and schedule future preventive dosing.

By eliminating the source of immediate itching first, the dog experiences rapid comfort, while the subsequent deworming program resolves less urgent but potentially serious internal parasitism. This sequence maximizes short‑term relief and maintains long‑term health.

When Concurrent Treatment Might Be Considered

Severe Infestations

Severe infestations present immediate health risks and demand rapid, systematic intervention. Flea populations that reach high density cause anemia, skin irritation, and transmit bacterial infections; worm burdens of similar magnitude can lead to intestinal blockage, nutrient loss, and organ damage.

Flea control must begin promptly. Topical or oral adulticides eliminate existing insects, while insect growth regulators (IGRs) prevent development of eggs and larvae. A single application of a fast‑acting product, followed by a repeat dose after 7–10 days, reduces the adult population and interrupts the life cycle.

Worm treatment follows flea eradication. Broad‑spectrum anthelmintics administered after the flea protocol ensure that the gastrointestinal tract is not compromised by concurrent medication absorption issues. A single dose of a modern dewormer, repeated after 14 days, clears most common species; a fecal examination after treatment confirms efficacy.

Recommended sequence for severe cases:

Apply a rapid‑acting flea adulticide (spot‑on or chewable) on day 1.
Administer an IGR in the same product or as a separate treatment on day 1.
Repeat flea treatment on day 7–10 to cover emerging adults.
Conduct a fecal test on day 14 to identify worm species.
Give a broad‑spectrum anthelmintic based on test results.
Perform a follow‑up fecal test 2 weeks after deworming to verify clearance.

Adhering to this order prevents drug interactions, maximizes parasite kill rates, and restores the dog’s health efficiently.

Veterinary Recommendations

Veterinary protocols prioritize external parasites because they reproduce quickly and cause immediate irritation. Effective flea control eliminates adult insects, eggs, and larvae, reducing the risk of dermatitis, anemia, and vector‑borne infections.

Internal parasites require systematic deworming based on fecal examinations, age, and risk factors. Some worms, such as roundworms and hookworms, can be transmitted through the skin or ingestion of contaminated fleas, linking the two parasite groups.

A practical regimen includes the following steps:

Perform a comprehensive health assessment and fecal test to identify worm species.
Apply a fast‑acting flea adulticide or spot‑on product that also disrupts the life cycle (egg and larval stages).
Administer a broad‑spectrum dewormer targeting the identified species, following the dosage schedule recommended for the dog’s weight and age.
Repeat flea treatment according to the product’s re‑application interval (typically 30 days) and schedule follow‑up fecal exams to confirm worm clearance.
Maintain environmental hygiene: vacuum carpets, wash bedding, and treat the home environment with appropriate insect growth regulators.

Concurrent use of flea and worm products is acceptable when both are approved for simultaneous administration; otherwise, separate applications with a 24‑hour interval prevent drug interactions. Regular monitoring ensures the dog remains free of both external and internal parasites.

Correct Treatment Protocols

Effective Flea Treatment Methods

Topical Spot-Ons

Topical spot‑on products deliver insecticidal and acaricidal agents through the skin, providing rapid control of fleas on dogs. When a dog is simultaneously at risk for intestinal parasites, the conventional sequence prioritises external parasite elimination before internal deworming because flea infestations can cause skin irritation, secondary infections, and rapid reinfestation that compromise overall health.

Application of a spot‑on begins with a clean, dry coat between the shoulder blades. The entire dose, measured in milliliters, is placed directly onto the skin, allowing absorption into the bloodstream within minutes. This systemic distribution kills adult fleas and prevents new infestations for up to a month, depending on the product’s label.

After the spot‑on has been administered, a deworming agent can be given at the next scheduled interval, typically 24 hours later. This timing avoids potential interference between the two chemical classes and ensures that the dog’s metabolic pathways are not overloaded. Some veterinarians recommend a short waiting period (12–24 hours) before feeding a worming tablet to maximize gastrointestinal absorption.

Key considerations for correct use:

Verify the product’s concentration matches the dog’s weight range.
Use only one spot‑on per treatment period; stacking multiple brands increases toxicity risk.
Observe the dog for adverse reactions (excessive drooling, skin redness) for at least 30 minutes post‑application.
Store products at room temperature, away from direct sunlight, to preserve efficacy.

Following these steps ensures effective flea control with spot‑ons while maintaining safe and efficient deworming protocols.

Oral Medications

Oral parasite control requires a clear sequence to avoid drug interactions and maximize efficacy. Flea infestations produce immediate discomfort and can lead to skin infection; oral flea products act within hours, providing rapid relief. Worm infestations develop more slowly, but untreated intestinal parasites can cause anemia, weight loss, and organ damage. Treating fleas first eliminates the most urgent health threat and prevents secondary complications that could interfere with subsequent worm therapy.

Oral anthelmintics target roundworms, hookworms, whipworms, and tapeworms. Many formulations are safe to administer after flea medication, provided a short interval separates the doses. Overlapping systemic agents may increase the risk of gastrointestinal upset or hepatic stress, especially in puppies or dogs with pre‑existing conditions.

Recommended protocol:

Administer the prescribed oral flea medication according to label dosage (usually based on weight).
Observe the dog for 24–48 hours to ensure no adverse reaction.
Give the oral dewormer at the appropriate dose, following the same weight‑based guidelines.
Repeat the deworming schedule as indicated (often every 2–4 weeks for puppies, then quarterly for adults).
Maintain regular fecal examinations to confirm worm clearance and adjust treatment if necessary.

Accurate weight measurement, adherence to product intervals, and veterinary oversight are essential for safe and effective parasite management.

Flea Shampoos and Dips

Flea shampoos and dips are topical agents designed to eliminate adult fleas and interrupt their life cycle. They contain insecticides such as pyrethrins, pyrethroids, or insect growth regulators (IGRs) that act on the nervous system of fleas or prevent egg development. When applied correctly, they reduce the immediate flea burden and lower the risk of secondary skin infections.

In a treatment protocol that addresses both ectoparasites and internal parasites, fleas should be managed before administering anthelmintics. Removing the external irritant lessens stress on the animal, improves grooming behavior, and prevents ingestion of flea debris that could interfere with oral deworming medications.

Correct use of flea shampoo:

Wet the coat thoroughly, avoiding eyes and ears.
Apply the recommended amount of shampoo, lather, and retain contact for the time specified on the label (usually 5–10 minutes).
Rinse completely; residual product may cause irritation or affect oral drug absorption.
Dry the dog before any subsequent treatment.

Correct use of flea dip:

Choose a dip formulated for the dog’s size and hair type.
Dilute according to manufacturer instructions if required.
Apply evenly to the skin, focusing on the neck, back, and tail base; avoid mucous membranes.
Allow the dip to dry fully before feeding or giving oral medications.

Both products should be used in accordance with veterinary guidelines regarding frequency—typically every 2–4 weeks during peak flea season. After the flea control step is completed, deworming can proceed with the appropriate anthelmintic, ensuring no overlap of topical and oral drug administration within the same hour to avoid potential interactions.

Monitoring for adverse reactions, such as excessive scratching, redness, or gastrointestinal upset, is essential. Any signs of toxicity require immediate veterinary evaluation. By following these procedures, flea shampoos and dips become an effective first line of defense, paving the way for safe and effective internal parasite treatment.

Environmental Control Measures

Environmental control is essential for effective parasite management in dogs. Reducing flea populations in the home and yard limits re‑infestation after medication, while proper sanitation lowers the risk of worm transmission from contaminated soil or feces.

Key actions include:

Regular vacuuming of carpets, upholstery and floor edges; immediate disposal of vacuum bags or cleaning canisters.
Frequent washing of bedding, blankets and removable pet accessories in hot water (≥ 60 °C) to kill eggs and larvae.
Application of approved insect growth regulators (IGRs) to indoor areas where fleas develop, following label instructions.
Removal of animal waste from yards daily; composting or sealed disposal prevents eggs of hookworms and roundworms from maturing.
Maintenance of a tidy yard: trimming grass, clearing debris, and limiting wildlife access reduce habitats for both fleas and worm vectors.

Implementing these measures before administering flea or worm products creates a cleaner environment, allowing medications to work without immediate re‑exposure. When both parasite types are present, start with flea control, because adult fleas can quickly re‑populate, while deworming can proceed concurrently or shortly after, provided the environment remains uncontaminated.

Comprehensive Worming Strategies

Broad-Spectrum Dewormers

Broad‑spectrum dewormers are veterinary products that eliminate multiple internal parasites—nematodes, cestodes, and sometimes protozoa—with a single dose. Their formulation typically combines anthelmintics such as pyrantel, milbemycin, or praziquantel, allowing simultaneous control of roundworms, hookworms, whipworms, and tapeworms.

When planning parasite management, the timing of flea and worm interventions matters. Flea control agents act on the external ectoparasite, while broad‑spectrum dewormers target internal organisms. Treating worms first reduces the risk of secondary complications that can arise from intestinal irritation during flea medication absorption. Therefore, a standard protocol administers a dewormer, waits the product‑specific interval (usually 24–48 hours), then initiates flea treatment.

Correct administration of broad‑spectrum dewormers includes:

Selecting the appropriate dosage based on the dog’s weight; under‑dosing compromises efficacy, over‑dosing may cause toxicity.
Delivering the medication orally or topically as indicated on the label; ensure the dog swallows the full dose if given by mouth.
Observing the dog for adverse reactions—vomiting, diarrhea, or lethargy—within the first 24 hours; contact a veterinarian if symptoms persist.
Repeating the treatment according to the parasite’s life cycle; most guidelines recommend a second dose after 2–3 weeks to eliminate newly hatched larvae.

Integrating deworming with a regular flea prevention schedule—monthly topical or oral products—provides comprehensive parasite protection. Veterinary consultation confirms the appropriate product mix and timing for each individual dog.

Targeted Treatments for Specific Worms

Targeted treatments for specific intestinal parasites require identification of the worm species before medication is selected. Diagnosis can be achieved through fecal flotation, PCR testing, or antigen kits, which determine whether the dog is infected with roundworms, hookworms, whipworms, or tapeworms. Each parasite class responds to a distinct anthelmintic class, and using the appropriate drug maximizes efficacy and reduces resistance risk.

Roundworms (Toxocara spp.) – administered pyrantel pamoate or milbemycin oxime; single dose eliminates adult worms, repeat in two weeks addresses newly hatched larvae.
Hookworms (Ancylostoma spp.) – treated with milbemycin oxime, moxidectin, or fenbendazole; three‑day course of fenbendazole is effective for severe infections.
Whipworms (Trichuris vulpis) – require repeated dosing of fenbendazole or milbemycin oxate over several weeks because of low drug absorption by the parasite.
Tapeworms (Dipylidium caninum, Taenia spp.) – praziquantel or epsiprantel provides rapid clearance; a single oral dose is sufficient for most tapeworms, while Echinococcus spp. demand prolonged treatment and follow‑up testing.

Correct administration follows the label dosage based on body weight, with food intake considered when required for optimal absorption. For multi‑parasite infestations, combination products containing pyrantel, praziquantel, and milbemycin can address several worm types simultaneously, but veterinary guidance ensures that drug interactions and contraindications are avoided. Monitoring fecal output after treatment confirms success; persistent eggs indicate treatment failure or reinfestation and warrant repeat therapy or alternative medication.

The Importance of Fecal Testing

Fecal testing provides the only reliable evidence of intestinal parasite presence, intensity, and species. Without this diagnostic step, treatment may target the wrong organisms, waste medication, and allow resistant parasites to persist.

The test identifies:

Specific nematodes, cestodes, or protozoa infecting the dog.
Egg count, which indicates infection severity.
Seasonal or environmental patterns that influence parasite risk.

Proper execution involves:

Collecting a fresh sample from the rectum or a clean surface shortly after defecation.
Placing the sample in a sealed container with a small amount of preservative, if transport exceeds a few hours.
Delivering the specimen to a veterinary laboratory within 24 hours.
Using flotation or sedimentation techniques to isolate eggs and cysts, followed by microscopic examination.
Reporting results with species identification and quantitative data.

Results direct deworming decisions. If the fecal exam reveals a significant worm burden, a targeted anthelmintic regimen should commence promptly, regardless of flea treatment status. Flea control can begin simultaneously, but the timing and choice of worm medication depend on the identified parasites and their life cycles. By basing therapy on concrete laboratory data, owners avoid unnecessary drug exposure, reduce the risk of resistance, and ensure comprehensive parasite management.

A Step-by-Step Treatment Plan

Consulting Your Veterinarian

Accurate Diagnosis

Accurate diagnosis is essential for deciding whether a dog should receive flea control before deworming and for applying each treatment safely.

Veterinarians determine parasite presence through specific observations and tests. Visible flea activity, such as adult insects or irritated skin, indicates the need for immediate flea treatment. Worm infections are identified by fecal examination, typically using flotation or centrifugation methods to reveal eggs or larvae. Molecular assays, like PCR, can confirm species when microscopic identification is ambiguous. Blood work may reveal anemia or eosinophilia associated with heavy worm burdens.

A systematic diagnostic workflow minimizes unnecessary medication and reduces resistance risk:

Inspect coat and skin for live fleas, flea dirt, or dermatitis.
Perform a flea comb test on a dampened section of fur; collect debris for microscopic confirmation.
Collect a fresh fecal sample; run a flotation test within two hours of collection.
If fecal results are negative but clinical signs suggest worms, repeat testing after 48 hours or use a coproantigen ELISA.
Consider a complete blood count if systemic signs (e.g., lethargy, weight loss) are present.

When both parasites are confirmed, treatment can proceed concurrently, provided each product’s label permits simultaneous use. If only one parasite is detected, treatment targets that organism first; subsequent re‑evaluation ensures the second parasite is not missed.

By relying on precise diagnostic data, clinicians avoid empirical treatment, tailor therapy to the dog’s actual parasitic load, and maintain optimal health outcomes.

Tailored Treatment Regimen

A customized parasite‑control program begins with a thorough assessment of the dog’s health, age, weight, and living conditions. Laboratory tests for intestinal worms and a flea‑infestation evaluation guide the choice of products and determine which parasite poses the most immediate risk.

The assessment should include:

Fecal flotation or PCR to identify worm species and load.
Physical inspection and flea‑trap counts to gauge flea pressure.
Review of recent treatments, drug sensitivities, and comorbidities.

When both flea and worm infestations are confirmed, the regimen can be structured in two ways. If the dog shows severe flea‑related dermatitis, initiate topical or oral flea control first, then introduce a dewormer after a 24‑ to 48‑hour interval. If worm infection is moderate to high, start with a broad‑spectrum anthelmintic and add flea treatment concurrently, provided the selected products have compatible mechanisms and no overlapping toxicity.

Correct execution requires:

Precise dosing based on the animal’s current weight.
Administration of the flea product according to label instructions (spot‑on, collar, oral tablet).
Delivery of the dewormer at the recommended interval (single dose or repeated schedule).
Follow‑up testing 2–4 weeks after treatment to confirm eradication and adjust future preventive measures.

Tailoring the schedule to the individual dog eliminates unnecessary drug interactions, maximizes efficacy, and reduces the likelihood of reinfestation. Regular re‑evaluation ensures the regimen remains aligned with changing risk factors such as seasonal flea activity or exposure to new environments.

Administering Medications Safely

Dosage and Frequency

When planning parasite control, dosage and frequency must be tailored to the dog’s weight, health status, and the specific products chosen for flea and worm management.

For flea treatment, most topical or oral products provide dosage tables based on kilograms or pounds. A typical oral tablet contains 0.5 mg of active ingredient per kilogram of body weight; a 10‑kg dog therefore receives a 5‑mg dose. Topical spot‑on formulations usually require 1 mL per 4 kg, applied directly to the skin at the base of the neck. The recommended interval ranges from four to twelve weeks, depending on the product’s residual activity and the level of environmental infestation. High‑risk environments (e.g., kennels, outdoor access) justify the shorter, four‑week schedule.

Worming protocols rely on the type of helminths targeted. Broad‑spectrum dewormers often prescribe a single dose of 5 mg/kg for nematodes and 10 mg/kg for tapeworms. For puppies, the first dose is administered at two weeks of age, repeated every two weeks until eight weeks, then monthly until six months of age. Adult dogs receive a monthly dose for nematodes and a quarterly dose for tapeworms, unless a specific infection is diagnosed, in which case a higher, single‑dose regimen may be indicated.

Co‑administration of flea and worm products is permissible when both are labeled for simultaneous use. In such cases, maintain the individual dosage calculations for each product and adhere to the more frequent interval—typically the flea schedule—while ensuring that the total volume administered does not exceed the product’s maximum safe limit. Always verify the manufacturer’s instructions and consult a veterinarian before adjusting dosages.

Monitoring for Side Effects

When a dog receives flea and worm treatments, systematic observation for adverse reactions is essential. Immediately after administration, record the animal’s temperature, heart rate, and respiratory pattern. Any deviation from baseline values warrants prompt veterinary assessment.

Typical signs of intolerance include vomiting, diarrhea, excessive salivation, skin reddening at the injection site, or sudden lethargy. Persistent or worsening symptoms beyond two hours should trigger contact with a professional. For oral products, watch for loss of appetite or signs of gastrointestinal upset; for topical applications, inspect the coat for irritation or hair loss.

A practical monitoring routine:

Check the dog’s behavior and physical condition at 30‑minute intervals for the first two hours.
Perform a brief physical exam (pulse, mucous membrane color, gut sounds) at the one‑hour mark.
Document any abnormal findings in a log, noting time of onset and severity.
Contact the veterinarian if any sign persists more than 24 hours or escalates rapidly.

When multiple parasite controls are scheduled, stagger the treatments by at least 24 hours unless the veterinarian advises a combined protocol. This spacing reduces the likelihood of overlapping drug interactions and simplifies the identification of the offending agent if side effects appear.

Regular follow‑up appointments allow the veterinarian to adjust dosages, switch to alternative products, or implement supportive care such as anti‑emetics or antihistamines. Consistent monitoring ensures that parasite control is effective while safeguarding the dog’s health.

Post-Treatment Care and Prevention

Regular Flea and Worm Prevention

Regular flea and worm prevention forms a core element of canine health management. Fleas cause immediate skin irritation, anemia and serve as vectors for tapeworms; intestinal and heartworms produce systemic disease that develops over weeks to months. Because flea control eliminates a direct pathway for tapeworm infection, addressing fleas first provides immediate relief and reduces secondary parasite risk.

Effective protocol:

Choose a veterinarian‑approved flea product (topical spot‑on, oral chew, or collar). Apply according to label instructions, typically once every 30 days.
Wait 24–48 hours after flea application, then administer a broad‑spectrum dewormer. Select dosage based on the dog’s weight and target species (e.g., roundworm, hookworm, tapeworm, heartworm).
Repeat deworming at intervals recommended for each parasite (monthly for intestinal worms, every 6–12 months for heartworm prevention).
Record dates of treatment, monitor fecal exams, and adjust products if resistance or adverse reactions appear.

Integrating both programs on a synchronized calendar minimizes treatment overlap, preserves drug efficacy, and sustains a parasite‑free environment. Regular veterinary consultation ensures dosing accuracy and updates to prevent emerging resistance.

Maintaining a Clean Environment

A sanitary living area reduces the risk of reinfestation after parasite therapy. Flea eggs and larvae develop in carpets, bedding, and outdoor soil; intestinal worm eggs survive in feces left on the ground. Removing these reservoirs limits the number of parasites that can reach the dog, allowing medication to work without immediate re‑exposure.

Cleaning should precede both flea and worm treatments. Eliminating contaminated material lowers the parasite load that the dog must confront, making the first administered drug more effective and decreasing the likelihood of a second round of medication.

Steps to maintain a clean environment

Vacuum carpets, rugs, and upholstery daily; dispose of the vacuum bag or clean the canister immediately.
Wash all dog bedding, blankets, and toys in hot water (≥60 °C) weekly.
Sweep and mop hard floors with a pet‑safe disinfectant.
Remove feces from yards and walkways at least twice daily; compost or discard in sealed bags.
Treat outdoor areas with an appropriate insect growth regulator or nematode spray according to label instructions.
Rotate and clean feeding bowls, water dishes, and grooming tools after each use.

A well‑maintained environment supports the chosen treatment order, whether fleas are addressed before worms or vice versa, and contributes to long‑term parasite control.