Where can strong treatments against bedbugs be found?

Where can strong treatments against bedbugs be found?
Where can strong treatments against bedbugs be found?

Understanding the Bed Bug Problem

Identifying Bed Bug Infestations

Recognizing Common Signs

Recognizing the early indicators of a bed‑bug problem is essential before selecting an effective control method. Visible evidence appears in several distinct forms:

  • Small, reddish‑brown insects about the size of an apple seed, often found in mattress seams, box‑spring folds, and furniture crevices.
  • Dark‑colored fecal spots resembling pepper grains on bedding, walls, or headboards.
  • Transparent exoskeletons left behind after molting, typically near the same hiding places.
  • Clusters of tiny, white eggs attached to fabric folds or wallpaper seams.
  • A sweet, musty odor that intensifies as the infestation grows.
  • Repeated, itchy welts or bite marks on exposed skin, usually in linear or clustered patterns.

Confirming at least two of these signs confirms the presence of bed‑bugs and justifies the procurement of potent eradication solutions. Professional exterminators, specialized pest‑control retailers, and reputable online suppliers provide the strongest treatments, ranging from regulated insecticide formulations to heat‑treatment equipment. Prompt identification of these signs enables swift acquisition of the appropriate products and prevents the infestation from escalating.

Confirming the Presence of Pests

Detecting bedbugs is the prerequisite for any effective eradication program. Visual inspection of mattresses, box springs, and furniture seams reveals live insects, exuviae, or dark spotting from feces. Use a bright flashlight and a magnifying lens to examine cracks, baseboard joints, and wall voids.

Professional tools increase reliability:

  • Interceptors placed under legs of beds and sofas capture wandering insects.
  • Carbon dioxide or heat‑lured traps attract hidden specimens.
  • DNA‑based swab kits detect trace biological material on surfaces.

A systematic approach improves confidence in the findings. Begin with a room‑by‑room checklist, record all evidence, and photograph suspect areas. Follow up with a secondary verification method, such as a sticky trap placed for 48 hours, to confirm initial observations.

When evidence is corroborated, proceed to select the most potent chemical or non‑chemical treatment available from reputable suppliers. The confirmation stage ensures resources are allocated only where infestation is proven, preventing unnecessary pesticide use and enhancing overall control success.

Why Strong Treatments are Necessary

The Resilience of Bed Bugs

Bed bugs demonstrate remarkable resilience through several biological and behavioral mechanisms. Their exoskeleton resists many contact insecticides, while a rapid life cycle—egg to adult in as little as five weeks—allows populations to rebound quickly after treatment. Genetic variability facilitates the development of resistance to pyrethroids, neonicotinoids, and other common chemical classes. Additionally, bed bugs can survive prolonged periods without feeding, remaining viable for months in dormant states that evade detection.

Effective control options are concentrated in three sectors:

  • Professional pest‑management firms: Companies that employ licensed applicators use integrated pest management (IPM) protocols, combining targeted chemical sprays with heat‑treatment units capable of raising room temperatures to 50 °C for several hours, a level proven to cause 100 % mortality.
  • Specialized chemical distributors: Suppliers of newer‑generation insecticides—such as desiccant powders (silica gel, diatomaceous earth) and insect growth regulators (IGRs) like methoprene—offer products specifically formulated to overcome known resistance mechanisms.
  • Regulatory and research institutions: Government agencies (e.g., EPA, USDA) and university extension services publish vetted treatment guidelines and maintain databases of approved products, ensuring access to scientifically validated solutions.

Choosing a strong treatment requires verification of product registration, confirmation of resistance‑management strategies, and, when possible, corroboration from certified pest‑control professionals.

Limitations of Conventional Methods

Conventional approaches to bed‑bug control suffer from several inherent drawbacks that limit their effectiveness. Chemical insecticides, once reliable, now encounter widespread resistance; populations develop mutations that diminish toxicity, requiring higher doses that increase health risks for occupants and pets. Residual sprays often fail to penetrate deep cracks, voids, and fabric folds, leaving hidden insects untouched and enabling rapid resurgence.

Heat treatment, prized for its non‑chemical nature, demands precise temperature control. Achieving and maintaining 50 °C throughout an infested space is technically challenging; temperature gradients leave cooler pockets where bugs survive. The process consumes significant electricity, incurs high labor costs, and may damage heat‑sensitive items.

Physical removal methods such as vacuuming and steam application reduce visible numbers but cannot eradicate eggs. Incomplete coverage allows a portion of the population to persist, and the technique provides no residual effect to prevent re‑infestation. Moreover, the equipment must be properly maintained to avoid cross‑contamination between rooms.

Typical reliance on over‑the‑counter products introduces additional constraints. Formulations often lack the potency required for entrenched infestations, and user error—insufficient application frequency or improper placement—further diminishes outcomes.

Key limitations summarized:

  • Insecticide resistance reduces mortality rates.
  • Heat treatment requires uniform temperature, difficult to guarantee.
  • Mechanical methods fail to address hidden stages and offer no lasting protection.
  • Consumer‑grade products lack sufficient strength for severe cases.

These shortcomings explain why many practitioners turn to advanced, professionally formulated solutions that combine high‑efficacy chemicals, controlled‑temperature technologies, and integrated monitoring to achieve reliable eradication.

Professional Pest Control Solutions

Consulting with Exterminators

Assessing the Severity of Infestation

Assessing the severity of a bed‑bug infestation is the first step toward locating effective control products. Accurate evaluation determines the scale of treatment required and guides the selection of high‑potency solutions.

Key indicators include:

  1. Number of visible insects – count adults, nymphs, and shed skins in each room.
  2. Infestation spread – map locations where evidence appears, noting adjacent rooms and hidden areas such as mattress seams, baseboards, and furniture joints.
  3. Population growth rate – observe changes over a 48‑hour period; rapid increase signals a mature colony.
  4. Host reactionrecord skin bites and allergic responses; higher bite frequency correlates with larger populations.

Quantitative thresholds help categorize infestations:

  • Low: fewer than 10 insects, confined to a single piece of furniture.
  • Moderate: 10‑100 insects, spanning two to three rooms.
  • High: over 100 insects, presence in multiple zones, evidence of breeding sites.

Once severity is classified, professional suppliers and specialized retailers can be consulted for strong treatment options. Products such as concentrated pyrethroid‑based sprays, silica‑gel dusts, or heat‑treatment equipment are typically recommended for moderate to high levels. Low‑severity cases may be managed with over‑the‑counter formulations, but verification of potency remains essential.

Customizing Treatment Plans

Effective bed‑bug eradication depends on tailoring the control strategy to the infestation’s scope, environment, and resistance profile. Professionals begin with a thorough inspection to identify hiding places, population density, and any prior pesticide use. This data determines whether a single‑application product, a multi‑stage regimen, or an integrated approach is required.

Key sources for potent interventions include:

  • Licensed pest‑control companies that stock EPA‑approved, high‑efficacy insecticides such as pyrethroid‑based sprays, desiccant dusts, and heat‑treatment equipment.
  • Specialized retailers offering certified “strong” formulations, including silica‑gel powders and cold‑temperature foggers, often accompanied by usage guidelines.
  • Online platforms that provide access to professional‑grade products, provided the buyer complies with local regulations and safety instructions.

Customization also involves selecting delivery methods that match the infestation’s characteristics. For isolated bedroom units, targeted spray and mattress encasements may suffice. In multi‑room apartments, a combination of whole‑room fogging, baseboard dusting, and repeated follow‑up treatments reduces the risk of resurgence. When resistance is suspected, rotating chemical classes or integrating non‑chemical tactics—such as steam‑treatment or vacuuming—enhances efficacy.

Monitoring after the initial application verifies success. Inspectors use sticky traps, visual checks, and resident reports to gauge population decline. If residual activity persists, they adjust dosage, switch active ingredients, or extend treatment cycles. This iterative process ensures that the strongest available solutions are applied precisely where they are needed.

Advanced Treatment Techniques

Heat Treatments and Their Efficacy

Heat treatment eliminates bedbugs by raising ambient temperature to lethal levels. Research indicates that exposure to 45 °C (113 °F) for at least 30 minutes kills all life stages, while 50 °C (122 °F) reduces the required exposure time to 10 minutes. Uniform heat distribution is essential; uneven temperatures allow survivors to persist.

Professional exterminators employ portable heaters, industrial fans, and temperature‑monitoring devices to achieve and maintain target conditions throughout entire rooms, closets, and furniture. Certified technicians calibrate equipment, verify temperature logs, and document results to meet regulatory standards.

Advantages of heat‑based control include:

  • No chemical residues; safe for occupants after cooling.
  • Immediate eradication of eggs, nymphs, and adults.
  • Ability to treat large infestations in a single operation.

Limitations involve:

  • High energy consumption; utility costs rise during treatment.
  • Sensitive items (electronics, heat‑intolerant fabrics) may require removal or protection.
  • Inadequate insulation or HVAC deficiencies can create cold spots, compromising efficacy.

Consumers can locate reliable heat‑treatment services through pest‑control licensing boards, industry associations such as the National Pest Management Association, and online directories that list certified providers. Many companies advertise “heat‑kill” programs on their websites, offering free inspections and detailed treatment plans.

For individuals preferring self‑application, portable heat chambers and insulated tents are available from specialty suppliers. Successful DIY implementation demands:

  1. Accurate thermometers with continuous logging.
  2. Sufficient heater capacity to raise room temperature quickly.
  3. Sealing of doors, windows, and vents to prevent heat loss.
  4. Post‑treatment verification that temperature stayed above lethal thresholds for the required duration.

Overall, heat treatment stands as a proven, chemical‑free method for rapid bedbug elimination, provided that temperature control is precise and coverage is comprehensive.

Cryonite Freezing Methods

Cryonite freezing is a non‑chemical method that eliminates bedbugs by exposing them to temperatures below ‑100 °C. The process uses liquid nitrogen to freeze insects within their harborages, causing rapid cellular rupture. Because the treatment leaves no residue, it is suitable for sensitive environments such as hotels, hospitals, and historic buildings.

Professional pest‑control firms that specialize in cryogenic solutions operate in most major metropolitan areas across the United States, Canada, the United Kingdom, and parts of Europe. Companies typically advertise “cryogenic bed‑bug eradication” or “Cryonite services” on their websites and can be identified through:

  • Certified pest‑management associations (e.g., NPMA, BIPM) that list members offering cryogenic treatments.
  • Online directories of licensed exterminators that include filter options for “cryogenic” or “freezing” methods.
  • Direct contact with manufacturers of Cryonite equipment, who often provide referrals to authorized service providers.

When selecting a provider, verify the following credentials:

  1. Certification by a recognized pest‑control authority.
  2. Documentation of equipment calibration and safety protocols.
  3. References from recent bed‑bug projects that utilized Cryonite.

The method is most effective when applied after a thorough inspection to locate all infestation sites. Technicians use handheld probes to target cracks, seams, and voids where insects hide, ensuring comprehensive coverage without damaging furnishings.

Regulatory guidance in most jurisdictions permits Cryonite use without special permits, but operators must follow occupational safety standards for handling liquid nitrogen. Compliance with these standards guarantees both efficacy and worker safety.

In summary, strong, non‑chemical bed‑bug treatments are accessible through certified pest‑control providers that offer Cryonite freezing. Prospective clients should consult professional directories, verify certifications, and request case studies to confirm the method’s suitability for their specific environment.

Chemical Insecticides and Their Application

Chemical insecticides remain the primary avenue for eliminating bedbug infestations. Products containing pyrethroids, neonicotinoids, and pyrroles are widely marketed for residential and commercial use. Pyrethroids, such as deltamethrin and bifenthrin, act on the insect nervous system, providing rapid knock‑down. Neonicotinoids, including imidacloprid, interfere with nerve signal transmission, while pyrroles like chlorfenapyr disrupt cellular respiration, delivering delayed mortality that can overcome resistant populations.

Effective application requires adherence to label instructions and proper coverage. Spray formulations must reach all harborages—mattress seams, bed frames, cracks, and baseboards. Foggers are unsuitable for bedbugs because particles settle before contacting concealed insects. Residual sprays maintain activity for weeks, reducing the need for repeated treatments.

Key considerations for selecting a strong treatment include:

  • Active ingredient class and documented efficacy against Cimex lectularius.
  • Resistance profile of the local bedbug population.
  • Safety certifications for indoor use and occupancy restrictions.
  • Compatibility with integrated pest management practices, such as heat treatment or vacuuming.

Professional pest‑control services often have access to higher‑concentration formulations and equipment that ensure thorough penetration of hiding places. Purchasing from reputable suppliers guarantees product authenticity and compliance with regulatory standards, essential for achieving reliable eradication.

Integrated Pest Management Approaches

Integrated Pest Management (IPM) for bedbugs combines chemical, physical, and biological tactics to achieve durable control while minimizing resistance and environmental impact. The framework emphasizes accurate detection, targeted application, and continuous monitoring, ensuring that interventions remain effective over time.

Effective treatments within an IPM program are available through several channels:

  • Licensed pest‑control operators who follow state‑approved protocols and possess access to registered insecticides such as pyrethroids, neonicotinoids, and desiccant dusts.
  • Professional heat‑treatment services that raise room temperatures to lethal levels (≥50 °C) for a prescribed duration, eliminating all life stages without chemicals.
  • Certified monitoring devices, including interceptor traps and passive adhesive stations, used to verify infestation levels before and after intervention.
  • Research institutions and university extension programs that publish validated treatment regimens and supply reference materials for practitioners.

Locating these resources involves consulting official directories maintained by agricultural or health departments, reviewing certification lists from professional pest‑management associations, and accessing peer‑reviewed publications from entomology departments. These avenues provide reliable access to the strongest, evidence‑based solutions for bedbug eradication.

Over-the-Counter and DIY Options

Selecting Effective Products

Understanding Active Ingredients

Active ingredients determine the efficacy of any bed‑bug control product. Synthetic pyrethroids such as deltamethrin, bifenthrin and lambda‑cyhalothrin disrupt nerve function, causing rapid paralysis. Neonicotinoids, including imidacloprid and acetamiprid, bind to nicotinic receptors, leading to overstimulation and death. Organophosphates like chlorpyrifos inhibit acetylcholinesterase, resulting in accumulated neurotransmitters and lethal convulsions. Inhalable formulations often contain pyrethrins combined with synergists (e.g., piperonyl butoxide) to enhance penetration through the insect cuticle.

Regulatory agencies require precise labeling of concentration, toxicity class and application limits. Products meeting EPA registration or EU Biocidal Products Regulation standards guarantee that active substances have undergone efficacy testing against Cimex lectularius. Certified professional‑grade sprays typically contain 0.05–0.1 % pyrethroid and may include additional desiccants to increase mortality in resistant populations.

When sourcing potent treatments, consider the following criteria:

  • Manufacturer accreditation by recognized pest‑control authorities.
  • Presence of a single, well‑studied active ingredient or a documented synergistic blend.
  • Availability of detailed safety data sheets and clear re‑entry intervals.

Understanding the mode of action and regulatory status of each active component enables informed selection of the most effective solutions for severe bed‑bug infestations.

Comparing Different Formulations

Strong bed‑bug control products vary primarily by their chemical formulation and delivery system. Understanding these differences helps locate the most effective options for severe infestations.

Spray concentrates dissolve in water and are applied with a pressurised nozzle. They penetrate cracks, reach hiding spots, and provide immediate knock‑down. Common active ingredients include pyrethroids, neonicotinoids, and insect growth regulators. Sprays are sold in hardware chains, home‑improvement outlets, and specialised pest‑control distributors.

Dusts consist of fine powders such as silica gel, diatomaceous earth, or desiccant‑based compounds. Their low toxicity to mammals and ability to remain active for months make them suitable for voids, wall voids, and under furniture. Dusts are available from professional pest‑control suppliers and online marketplaces that cater to exterminators.

Gel baits contain attractants and slow‑acting toxins that insects ingest. Formulations use hydramethylnon, indoxacarb, or fipronil. Gels are placed in concealed locations where bed bugs feed. Retailers with pest‑control sections and dedicated exterminator catalogs stock these products.

Heat‑based formulations include portable heating units that raise ambient temperature to lethal levels (≥50 °C) for a defined exposure period. Though not a chemical product, heat treatment kits are marketed by professional service companies and can be rented from equipment suppliers.

A concise comparison:

  • Spray: rapid action, broad coverage, widely stocked in retail chains.
  • Dust: long‑term residual effect, ideal for hidden voids, sold by specialist distributors.
  • Gel: targeted ingestion, low surface residue, available through pest‑control vendors.
  • Heat: non‑chemical, requires professional equipment, offered by service firms.

Selecting a formulation depends on infestation severity, access to treatment sites, and the distribution channel that provides the product. Strong options are typically found where professional pest‑control suppliers operate, supplemented by major home‑improvement retailers and vetted online platforms.

Implementing DIY Strategies

Preparation Before Treatment

Before applying any potent bed‑bug control product, thorough preparation maximizes effectiveness and reduces the risk of re‑infestation. First, confirm the presence of the insects by inspecting seams, mattress tags, and crevices for live bugs, shed skins, or fecal spots. Second, isolate the affected area: remove bedding, curtains, and clothing; place them in sealed plastic bags to prevent accidental spread. Third, launder all washable items on the hottest cycle the fabric tolerates, followed by a high‑heat dryer cycle of at least 30 minutes. Fourth, vacuum mattresses, box springs, upholstered furniture, and surrounding floors, discarding the vacuum bag or cleaning the canister immediately. Fifth, reduce clutter that could hide insects, storing items in airtight containers or removing them from the room entirely. Sixth, seal cracks, gaps, and openings in walls, baseboards, and furniture using caulk or expanding foam to limit migration pathways. Finally, mark treated surfaces and document the preparation steps to ensure consistent follow‑up and verification of product coverage.

Application Guidelines and Safety Precautions

Strong bedbug control products are typically available through licensed pest‑management firms, specialized hardware retailers, and reputable online platforms that verify active ingredients. When acquiring such treatments, verify that the product holds EPA registration or equivalent certification, and confirm that the label lists the correct concentration for the target infestation level.

Apply the product according to the manufacturer’s directions. Use a calibrated sprayer or dust applicator to achieve uniform coverage on cracks, seams, and hiding places. Do not exceed the recommended dosage; over‑application can increase toxicity without improving efficacy. After treatment, allow the prescribed dwell time before re‑entering the treated area.

Safety measures include:

  • Wearing disposable gloves, goggles, and a respirator rated for the chemical class.
  • Removing or covering food, utensils, and bedding before application.
  • Ventilating the space by opening windows and using fans for the period indicated on the label.
  • Storing unused product in a locked, child‑proof container away from heat sources.
  • Disposing of empty containers according to local hazardous‑waste regulations.

If any adverse reaction occurs—skin irritation, respiratory distress, or eye discomfort—immediately rinse the affected area with water and seek medical attention. Record the product batch number, application date, and location for future reference and for any required follow‑up inspections.

Monitoring for Re-infestation

Effective eradication of bedbugs requires ongoing surveillance after initial treatment. Continuous observation detects surviving insects, early signs of resurgence, and validates the potency of applied controls.

Professional inspection employs visual examination of mattress seams, headboards, and baseboards, complemented by passive devices such as interceptor traps placed under legs of furniture. Active devices include portable heat‑sensing cameras that reveal hidden clusters without disturbing the habitat.

A systematic monitoring schedule enhances reliability:

  1. Conduct a thorough visual check within 48 hours of treatment completion.
  2. Deploy interceptor traps at each bed leg and examine them daily for two weeks.
  3. Perform a second visual inspection after seven days, focusing on previously infested zones.
  4. Repeat trap analysis and visual surveys weekly for the next three weeks.
  5. Initiate monthly inspections for six months to capture delayed emergence.

Data recorded from each inspection—location, count, developmental stage—inform decisions about supplemental treatments. Persistent low‑level detections may signal resistance, prompting the use of stronger chemical or non‑chemical options sourced from certified pest‑control providers.

Preventing Future Bed Bug Issues

Proactive Measures for Homeowners

Regular Inspections and Cleaning

Regular inspections allow early identification of bedbug activity, enabling swift deployment of potent control agents. Inspectors should examine seams, mattress tags, and cracks each week, noting any live insects, shed skins, or fecal spots. Documented findings guide the selection of appropriate treatment formulations and prevent unnecessary widespread applications.

Consistent cleaning removes food sources and harbors, increasing the effectiveness of chemical and non‑chemical solutions. Key practices include:

  • Vacuuming upholstered furniture, floors, and baseboards with a HEPA‑rated device; discard the bag or empty canister outdoors.
  • Laundering bedding, curtains, and clothing at temperatures above 60 °C (140 °F) for at least 30 minutes.
  • Steaming infested areas for a minimum of 10 minutes to penetrate crevices and kill hidden insects.
  • Discarding or sealing infested items in airtight containers before treatment to avoid cross‑contamination.

By integrating systematic inspections with rigorous cleaning, pest‑management professionals can locate and apply the most effective bedbug treatments, reducing population levels and limiting re‑infestation risk.

Protecting Travel and Belongings

Travel exposes luggage and personal items to bedbug infestations, requiring immediate preventive actions.

Use hard‑shell suitcases or rigid containers that resist cracks. Place clothing, toiletries, and accessories inside zip‑lock or heat‑shrink bags before packing. Apply a portable heat device or a portable freezer to treat items at 120 °F (49 °C) for at least 30 minutes or at –20 °C for 48 hours; both temperatures eliminate all life stages of bedbugs.

Powerful treatments are available from:

  • Licensed pest‑control firms that sell professional‑grade heat chambers and cryogenic units.
  • Online retailers specializing in travel‑grade insecticide sprays, containing pyrethroids or neonicotinoids, approved for use on fabrics and luggage surfaces.
  • Airport or hotel pest‑management services that offer on‑site heat or steam treatments for checked bags.

Protect personal belongings by washing all fabrics on the hottest setting the material tolerates, then drying at high heat. Apply a residual spray to suitcase exteriors and interior seams after each trip. Inspect hotel mattresses and upholstered furniture for live bugs, and install disposable mattress encasements when staying in high‑risk locations.

Adhering to these measures reduces the likelihood of transporting bedbugs and ensures that effective eradication solutions are readily accessible during travel.

When to Seek Professional Help Again

Persistent Infestations

Persistent bed‑bug infestations occur when colonies survive multiple treatment cycles, often because of resistance, hidden harborages, or inadequate application. Such infestations demand interventions that exceed standard over‑the‑counter sprays.

Effective solutions are concentrated in three main channels. Professional pest‑management firms possess licensed insecticides, heat‑treatment equipment, and expertise in systematic inspections. Specialized retailers—both brick‑and‑mortar and e‑commerce sites—stock certified products such as desiccant dusts, pyrethroid‑free aerosols, and portable steam units. Public‑health agencies and university extension services provide guidance on approved products and may distribute treatment kits in high‑risk neighborhoods.

  • Licensed pest‑control companies: contact local offices listed in industry directories (e.g., National Pest Management Association) to arrange on‑site application of professional‑grade formulations.
  • Specialty retailers: purchase from vendors that list EPA‑registered bed‑bug products, ensuring the label includes active ingredients such as silica gel, diatomaceous earth, or neonicotinoids.
  • Online platforms: verify seller credentials and product certifications on sites that aggregate entomology‑approved items (e.g., professional‑grade sections of Amazon, PestControlDirect).
  • Government or university programs: request informational packets or low‑cost treatment kits through city health departments or extension offices.

When selecting a treatment, confirm that the product carries an EPA registration number, that the label specifies efficacy against resistant strains, and that the supplier offers technical support for proper deployment. Combining chemical, physical, and monitoring methods—heat treatment, encasements, and interceptor traps—maximizes eradication potential for stubborn infestations.

Large-Scale Re-occurrences

Large‑scale re‑occurrences of bedbug infestations present a persistent challenge for public health officials, hospitality operators, and housing authorities. When infestations resurface across extensive facilities, the need for potent control agents intensifies, demanding reliable sources that can deliver proven efficacy at scale.

Effective solutions are typically sourced from:

  • Certified pest‑management firms that hold state‑issued licenses and employ integrated pest‑management (IPM) protocols, including heat‑treatment units, desiccant dusts, and regulated insecticide formulations.
  • Government‑affiliated programs, such as health department distribution centers, which provide bulk‑purchased, EPA‑registered products and guidance on proper application.
  • Specialized wholesale distributors that stock professional‑grade chemicals (e.g., pyrethroid‑based sprays, silica‑gel powders) and offer technical support for large‑volume orders.
  • Academic and research institutions that develop novel biopesticides or resistance‑breaking compounds, often collaborating with commercial partners to scale production.

Key considerations for selecting a supplier include verification of product registration, documented field performance against resistant bedbug strains, and the capacity to deliver treatment equipment (thermal chambers, portable heaters) in quantities sufficient for multi‑unit deployments. Coordination with local regulatory agencies ensures compliance with safety standards and helps mitigate the risk of repeated infestations.