Version May 2024
INTRODUCTION — The imported fire ant (IFA) is an aggressive, venomous insect that inhabits the Southeastern United States and is spreading westward and northward. Originally from South America, it has also become established in the Caribbean islands, Australia, and Asia as well.
This topic review discusses the medical entomology of the IFA, its clinical impact, recommendations to prevent the indoor infestation of health care facilities, and the chemical and biologic control of this insect pest. Treatment of IFA stings and allergy to IFA venom are reviewed separately. (See "Stings of imported fire ants: Clinical manifestations, diagnosis, and treatment".)
MEDICAL ENTOMOLOGY
Species — The term "imported fire ant" (IFA) refers to two members of the Solenopsis genus as well as a hybrid of the two species [1,2]:
●The red IFA, Solenopsis invicta (a native of Brazil, Argentina, and Paraguay)
●The black IFA, Solenopsis richteri (a native of Argentina and Uruguay)
IFAs are believed to have entered the United States through the port of Mobile, Alabama in the early 1900s. They have subsequently spread through natural behaviors, the shipment of infested agricultural products, and floods [3]. The red IFA is the most abundant, widespread, and damaging species.
Territory — The red IFA infests more than 367 million acres in at least 15 states (Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia) with limited infestations in Arizona, Maryland, Delaware, and Kentucky [4]. Regularly updated maps of the IFA range and agriculture quarantine areas are available. Agriculturally quarantined areas are those with extensive IFA infestations.
Documented infestations also occur in several Caribbean islands, including Puerto Rico, the Bahamas, the British and United States Virgin Islands, Antigua, and Trinidad. Red IFAs have also been detected in Mexico [5], Australia [6], China [7], Taiwan [8], South Korea, and Japan [9].
The habitat of the black IFA is significantly smaller and is limited to a small area of northwestern Alabama, northeastern Mississippi, and into Tennessee/Kentucky.
IFAs will continue to appear in new areas because of large-scale movement of agricultural products, especially nursery stock, throughout the United States. Although their ultimate range in North America is unknown, a temperature-dependent model suggests that they will likely inhabit at least 25 percent of the continental United States [10]. Global warming and/or increased cold tolerance could allow them to expand farther north within the United States.
By the time new infestations are discovered, they may be several years old and well established. Although the United States Department of Agriculture (USDA), the Animal Plant Health and Inspection Service (APHIS), and the Plant Protection and Quarantine (PPQ) regularly update quarantine regulations and maps of IFA infestations, these maps will always lag behind the actual infestations and will not indicate the true expansion of IFAs.
Mounds — IFAs live in dome-shaped mounds (nests) of soil. Newly forming mounds may be a few inches wide, while mature mounds can be up to 2.5 to 3 feet (0.8 to 0.9 meters) across and up to 1.5 feet (0.5 meters) high that are easily visible during most times of the year (picture 1). The internal structure of these nests is complex (figure 1). Most are located in sunny, open areas, such as pastures, lawns, and along roadsides. However, they can also be found at the base of trees, in rotten logs, and in landscape timbers.
Mounds may be less visible in sandy soils or drought conditions. During dry conditions, ant colonies may move under paved areas, such as highways and sidewalks, and even into buildings.
Ant identification — The mounds house the colony and provide security for the queen and her brood. Each colony contains one or more mated queens [1,3], thousands of workers, immature ants (eggs, larvae, and pupae), winged males, and winged females (unmated queens).
The ants responsible for stings are worker ants. Workers are sterile females and are of two types that are distinguishable by size: the smaller minor workers and the larger major workers, which can weigh up to 10 times more (figure 2). Workers range from one-eighth to one-fourth of an inch in length (or 3 to 6 mm) and are reddish brown to black in color. The minor workers are far more numerous. All workers are very aggressive and will attack anything that disturbs them.
Feeding behavior — IFAs are omnivorous, feeding on many invertebrates, small animals, plant tissues, and seed oils [3]. Workers ingest only liquid foods, with solid foods being eaten only by the fourth larval stages of a colony.
Movement of food through the colony takes place by a process called trophallaxis, in which one worker feeds several other workers that in turn pass this food along to others, including the queen and larvae. If dye-containing oil is experimentally fed to worker IFAs, it will travel through an entire colony within 24 to 48 hours.
This behavior is exploited in different control strategies. (See 'Control of imported fire ants' below.)
Mating behavior — "Mating flights" are seminal events in the life cycle of the IFA, in which large numbers of winged males and females fly out from mature colonies (over one year old), rise several hundred feet above the ground, and mate in a swarm. Depending on temperature, mating flights occur several times per year, usually in the spring, early summer, or fall. They take place in the late morning hours one or two days after a rain.
After mating, the males fall to the ground and die. Although the majority of newly mated queens land within 1 mile of their original nest, a queen can fly 12 or more miles with the aid of wind. Newly mated queens can be collected by the thousands for research purposes as they drop to the ground in open areas, such as parking lots. After finding a suitable nesting site, the queens chew off their wings, dig a small hole in the soil, seal the entrance, and begin to lay eggs.
Once the first workers (minims) are produced, they assume full-time care of the queen, who now spends the rest of her life producing eggs. Queens maintain complete control over the colony through the use of pheromones and egg production. A single queen can lay more than 2000 eggs per day and can live an average of six to seven years.
Workers mature from egg to adult in 20 to 45 days, depending on the temperature, and then live for two to six months. A new colony contains several thousand workers by the time it is six months old. The youngest workers, called nurses, feed and groom the queen and brood and move the eggs to the most favorable locations within the colony. Mature workers are responsible for colony maintenance, some food recruitment, and defense. The oldest workers are the foragers, who constantly search for food sources outside of the colony [3].
Implications of polygyne colonies — When IFAs were first observed in the United States, all the colonies had a single functional queen (monogyny). However, in the early 1970s, multiple-queen (polygyne) colonies were discovered that contained 20 to 60 egg-laying queens. Polygyne colonies now occur throughout infested regions of the United States.
There are several differences between these two colony forms. Single-queen colonies have approximately 100,000 to 240,000 workers that are fiercely territorial and limit the number of colonies that occupy the area to 40 to 150 mounds per acre. In contrast, multiple-queen colonies have 200,000 to 500,000 workers and are not territorial. Thus, more colonies can coexist per area. This adaptation has allowed for greater population densities and up to 200 to 800 mounds per acre. Therefore, polygyne populations cause more economic and environmental damage and have greater impact on humans.
IMPACT OF FIRE ANTS ON HUMANS — IFAs cause environmental and economic damage, as well as a variety of medical problems for humans, pets, and livestock.
Environmental impact — In infested areas, IFAs may become the dominant arthropods and reduce biodiversity by decimation of other arthropod species, as well as ground-nesting birds, turtles, and frogs [11].
Agricultural damage — IFAs are also responsible for damage to crops, such as soybeans, citrus, potatoes, corn, okra, and eggplants. Additional costs to agriculture arise from quarantine regulations mandating that all nursery stock, grass sod, and other plant materials must be treated with approved insecticides before being transported to noninfested areas [12]. The exact economic costs of IFA damage and control are unknown, although estimates for the Southeastern United States are one-half billion to several billion dollars per year [13,14].
Indoor infestations — Under extreme weather conditions (drought, cold, or flooding) and/or food shortages, IFAs will move indoors to inhabit wall voids, attics, spaces under carpets, cardboard boxes, and even clothing in drawers. Indoor IFAs present major risks in health care facilities where individuals with disabilities reside [15]. (See 'Invasion of health care facilities' below.)
Because IFAs are attracted to electrical equipment, large numbers of worker ants can accumulate in computers, fuse boxes, circuit breakers, and air conditioners and cause short circuits or mechanical failures [4].
General medical impact — IFAs inflict painful stings on humans, pets, domestic animals, and wildlife. A significant majority of people residing in an IFA-infested area are stung each year. IFA venom is also highly allergenic, and a variety of allergic reactions are observed. (See "Stings of imported fire ants: Clinical manifestations, diagnosis, and treatment".)
INVASION OF HEALTH CARE FACILITIES — Patients in long-term care facilities may not be aware of their surroundings, may be immobilized by disease, or otherwise unable to respond if fire ants come into contact with them. Once foraging IFAs have made contact with a potential victim, a variety of stimuli, including simple movement of the patient, might trigger a stinging event, leading to multiple stings in a very short period of time.
Clinicians may be asked to help formulate institutional management plans for the control of IFAs. In parallel with professional pest control services, a medically oriented plan should be devised that provides clear and detailed instructions on how to proceed when ants are encountered in rooms or on patients.
Some common sense suggestions for prevention of outdoor and indoor IFA infestations have been developed (table 1 and table 2). If IFAs are found inside, attempts should immediately be made to mitigate their effects. An algorithm is provided to summarize this approach (algorithm 1) [16].
A facility's medical staff, as well as the maintenance and housekeeping staff, should be educated regarding the appearance, stinging behavior, and potential health risks of the IFA. Some form of pest documentation should be in place (eg, a pest-sighting log) to inform the pest control technician of pest sightings, locations, times, etc. Sighting of IFAs in patient rooms should trigger an established plan of action. When IFAs are spotted in a room, patients should be removed until the pest control service has had a chance to investigate and perform adequate control measures (algorithm 1).
Policies for facility staff regarding how to evaluate a patient who appears to have sustained one or more IFA stings have been published (algorithm 2).
CONTROL OF IMPORTED FIRE ANTS — Insecticides are the only effective method for control of IFAs (table 3) [16]. There are no methods that permanently control IFAs in an area and none that can permanently eradicate them.
In the past, large-scale aerial applications of environmentally damaging chemicals, such as heptachlor and dieldrin, were used for control. However, they were soon banned.
This led to the development of less toxic chemicals and baits. The mammalian toxicities of these newer formulated insecticides are much less than those of the past and therefore less hazardous to humans and pets. However, chemical insecticides are only effective for short-term control (3 to 12 months), require periodic reapplication, and are costly [3]. Although not economical for large acreage situations, such as farms, ranches, roadsides, and natural areas, they can be used effectively to control infestations of individual properties and institutional facilities.
An understanding of the general approaches to IFA control is useful for the clinician practicing in an IFA-endemic area, as questions about how to deal with this formidable pest frequently arise. The four basic strategies used for controlling IFAs with chemicals are:
●Broadcast bait or granular insecticide applications
●Individual mound treatments
●A combination of broadcast bait and individual mound treatments
●Barrier and spot treatments
Some of these methods are approved for indoor use (see 'Indoor treatments' below). Biologic control of IFAs through the use of natural predators and pathogens is also discussed. (See 'Biologic control agents' below.)
OUTDOOR TREATMENTS
Broadcast bait and granular applications — The easiest, least expensive, and most effective IFA control method is the use of IFA baits [17]. Bait-based insecticides are the most effective means of residential IFA control. Consultation with a licensed pest control specialist should be considered for extensive exterior infestations and all interior infestations to prevent potential harm to people, pets, and the environment. Baits reduce IFA populations by using a small amount of insecticide dissolved into an attractant food source (eg, soybean oil) (table 3).
The attractant oil containing the toxicant is then absorbed into a carrier (such as corn grits) to allow easy handling, and then the preparation is dispersed over an area using a hand-powered spreader [17]. Most IFA baits are applied at rates of 1 to 2.5 lbs bait per acre. Regular applications should be made in the spring and fall to reduce or prevent reinvasion, as adjacent untreated areas serve as reservoirs.
Insecticides used in baits are usually slow acting, so the foraging worker ant can pick up the bait, extract the toxic oil, and feed it to the queen and other ants before dying. Depending on the active ingredient, the queen dies, no longer produces eggs, or does not produce workers, leading to the eventual death of the colony. There are now fast-acting baits that cause colony death in three days or less, as compared with the older baits that took two weeks or longer [18].
Broadcast bait applications eliminate the need to locate individual ant mounds, instead depending on foraging ants to take the bait back to the rest of the colony. In addition, there is no colony relocation, because the mound is not disturbed and most bait applications eliminate the colony queen. Because large areas can be treated, this method can result in slower reinfestation by colonies migrating from untreated areas.
Granular insecticides are generally not used for broadcasting, with the possible exception of fipronil, which is available in both a granular form for broadcasting and also as a bait [16]. In one study, fipronil granules were broadcasted over several acres containing high IFA densities, resulting in over 96 percent control that was maintained for over 30 weeks [19]. In contrast to fipronil, most other chemicals used in IFA baits are only efficacious as baits.
Individual mound treatments — Individual IFA mounds can be treated by application of an insecticide or by nonchemical means (hot water, physical removal). The chemicals used are formulated as baits, drenches, granules, dusts, aerosols, or liquid fumigants and should be specifically labeled for use on IFAs (table 3).
Ideally, contact insecticides should kill worker ants quickly, as slower-acting chemicals may cause the ants to relocate. Other difficulties of this method are locating and treating barely visible small colonies and assuring that the queen is killed. If the queen is not destroyed, she will continue to lay eggs, and the colony will recover. Even if the queen dies, surviving workers may rebuild a mound and live for over one month.
When treating multiple-queen colonies, which may contain hundreds of queens, all must be killed, thus making effective individual mound treatments extremely difficult. However, if the queen(s) is successfully killed, colonies treated individually may be eliminated faster than colonies treated with broadcast bait applications. This is important if IFA mounds are located in areas where humans are at immediate risk, such as around homes, school yards, athletic fields, nursing homes, medical facilities, or other such areas.
The nonchemical methods of treating individual mounds, such as the use of hot water (190 to 212°F or 88 to 100°C) and nest removal, may work if colonies are small but usually are not successful with large, mature colonies.
Combination treatments — Broadcast baiting can be combined with individual mound treatments. Baits should always be broadcast first to efficiently reduce IFA populations. After one or two days, the worker ants have spread the bait through the colony, which can then be treated with an individual contact insecticide to quickly eliminate the stinging worker ants.
Barrier and spot treatments — Barrier and spot treatments contain active ingredients that kill IFAs on contact and are usually sold as sprays or dusts, while some are mixed into latex paint. They may be applied in wide bands on and around building foundations, equipment, and other areas to create ant barriers. Barrier and spot treatments do not eliminate colonies but can prevent IFAs from foraging indoors or infesting electrical and electronic equipment (table 3) [12].
INDOOR TREATMENTS — A few bait-formulated insecticides and some sprays, dusts, and aerosols are registered for use indoors. On occasion, colonies can be located indoors by following foraging ant trails back to nesting areas. If an entire colony is found indoors, it should be exterminated as soon as possible by applying a spray or dust onto the colony. Use of a bait alone is too slow for this situation. However, if baits are used in conjunction with spot treatments, then the bait should be applied one or two days before. If the entire colony is not located, then spot treating infested areas or spraying ant trails with registered products may not eliminate the colonies but can at least kill foraging ants, thus keeping them from attacking. If fire ants are entering the home from outdoor colonies, apply barrier insecticides to the outside around the base of the structure and chemically treat nearby mounds using individual mound treatments. In addition, bait applications should be made when needed, usually two to three times per year, around the perimeter to maintain control (table 3).
IFAs are attracted to electrical equipment (see 'Indoor infestations' above). Thus, indoor equipment with wires, contact points, fuses, or switches should be inspected if an IFA infestation is suspected.
Another approach for controlling IFAs inside buildings is the use of an "inside-outside" treatment. This is being used more frequently in homes and also may be useful for some medical facilities. The treatment consists of using nonrepellent residual insecticides that can be transferred by IFAs that walk across treated areas. Treatments are applied indoors where foraging trails are located, as well as outdoors. A spray band should be applied one foot up and one foot out from the base of the building. IFAs that cross this band will not die immediately but will take the insecticide back to the nest on their bodies and spread the insecticide around, causing, in many cases, complete elimination of the nest.
BIOLOGIC CONTROL AGENTS — IFA population densities are more than five times greater in the United States than in their native South America, where competition with many parasites, pathogens, and predators controls their numbers [20]. Successful IFA biologic control agents could potentially reduce the dominance of IFAs, allowing native ants to better compete. IFA populations in the United States could then be reduced to lower-density levels, similar to those found in South America, thus minimizing their contact with humans and animals. Therefore, an integrated approach of biologic control agents for long-term suppression combined with specific chemicals for immediate relief would be both more effective and also reduce human exposure to pesticides.
Research on natural enemies of IFAs is being conducted by the United States Department of Agriculture, Agricultural Research Service (USDA-ARS) in Florida and in some universities in the United States. Biologic control agents that have been developed against IFAs are small, decapitating flies belonging to the genus, Pseudacteon and a microsporidian pathogen, Kneallhazia (formerly Thelohania), and Solenopsis virus 3. More in-depth reviews have been published [21,22]. Decapitating flies have been released in the United States. Kneallhazia solenopsae is being used in field studies in several areas. Other biologic control agents are in various stages of development.
Decapitating flies — There are approximately 20 species of decapitating flies that prey on IFAs in South America. These flies are host specific, attacking only IFAs, and pose no known threat to other organisms.
The decapitating fly hovers over an IFA worker (picture 2) and then quickly dives down to deposit an egg in the IFA's thorax. In a few days, the larva hatches and moves toward the head region. Once reaching the head of the IFA, the larva eats the IFA's glands and muscles and releases an enzyme that causes the head to fall off (picture 3). The larva then pushes the mouthparts out of the way and seals itself into the head capsule for pupation. Depending on temperature, the total developmental time from egg to adult is between 30 and 90 days. Once the adult fly emerges, it has only a few days to look for a mate and repeat the attack cycle again.
IFAs quickly learn to avoid the attacking flies and will hide under any available object or leave the area. Therefore, a single fly can stop the foraging of many workers, and a few flies in and around an IFA mound are sufficient to stop foraging by an entire colony of IFAs. If enough flies are established in a large area, decreased foraging by IFAs could cause a major shift in the use of food resources in favor of other ant species, reducing the total IFA density.
The decapitating flies, P. tricuspis, P. obtusus, and P. curvatus, have been released in several states (Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, and Texas) and have successfully reproduced and expanded in most of them (Alabama, Florida, Louisiana, Mississippi, South Carolina, Tennessee, Oklahoma, Georgia, and Texas) [22,23]. Three other species of decapitating flies have also been released and established in the United States [24].
Decapitating flies offer promise as a biologic control agent of IFAs because of their:
●Specificity for only IFAs
●Ability to adapt to the climate and geography of the affected areas
●Disruptive effects on IFA behavior
The total impact that decapitating flies will have on IFA populations in the United States over time remains to be determined.
Pathogenic fungi — The microsporidium, K. solenopsae (Microsporidia, Thelohaniidae), is a pathogen that causes the slow demise of an IFA colony. It is one of the most common pathogens of IFAs in Brazil and Argentina.
During a survey in the United States in 1996 for pathogens in IFA colonies, K. solenopsae was discovered in IFA workers in Florida, Mississippi, and Texas. A field study in Florida showed a 63 percent reduction in IFA populations infected with K. solenopsae, and the pathogen had spread to over 85 percent of IFA nests. The true field impact of this disease on IFA populations may be difficult to study because healthy, uninfected IFAs may move in and colonize areas as infected colonies decline [20].
K. solenopsae is transmitted transovarially (vertically) from the queen to her offspring. Horizontal transmission (colony to colony) also occurs and has been accomplished both in the laboratory and field by inoculating uninfected colonies of IFA with brood from infected colonies. The major effect of this disease on IFA colonies is weakening of the queens so that they slow or stop production of offspring. Infected queens weigh 50 percent less than uninfected ones. The advantages of K. solenopsae as a biologic control agent include debilitation of queens, specificity for IFA, self-sustaining infections, and lower relative tolerance to chemical pesticides.
IFA colonies have been inoculated with K. solenopsae in 11 states (Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, and Tennessee) [25]. The widespread utilization of K. solenopsae could result in a long-term suppression and environmentally safer control of IFA populations.
Yellow head disease — Another naturally occurring disease of IFA was discovered in 2002 while examining IFA colonies in Florida. The disease is caused by a protozoan, Mattesia spp, and was named yellow head disease (YHD) due to the yellow-orange color of the heads of infected ants. The disease was identified in 8 percent of the IFA colonies surveyed and was found throughout Florida in both multiple-queen and single-queen fire ant colonies.
YHD has been observed in Florida and Mississippi, although it probably occurs in other states as well. The actual impact on IFA has not been determined, although there have been cases where demise of infected ants has been observed. Therefore, this disease has promise as a biologic control agent [21].
Parasitic ants — Solenopsis daguerrei (Santschi (algorithm 2)) is a small ant that parasitizes IFA colonies in South America and does not sting or interact with humans. This ant produces no worker caste, only reproductive males and females, and therefore is totally reliant on its fire ant host colony for its care and survival.
S. daguerrei enter IFA colonies, attach themselves to IFA queen(s), and divert resources from the IFA colony. The IFA workers mistakenly feed and maintain the immature stages of S. daguerrei.
Field studies of the impact of S. daguerrei on IFAs have been conducted in Argentina and have shown that S. daguerrei reduces IFA colony growth, the number of sexual reproductives produced by the colony, and the number of host queens in multiple-queen colonies. However, a major problem still exists with trying to utilize this parasite as a biologic control agent for IFAs because attempts to propagate it have been unsuccessful [26].
Viruses — Viruses have been shown to be effective against several insect populations, and several viruses have been identified infecting IFAs [27]. In cases where colonies with the virus were collected in the field and returned to the laboratory, all of the immature stages for the colony died within three months [28]. This virus, called S. invicta virus 3, is being developed as a potential biopesticide [29].
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or email these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient education" and the keyword(s) of interest.)
●Beyond the Basics topic (see "Patient education: Imported fire ants (Beyond the Basics)")
SUMMARY
●Background – The imported fire ant (IFA) is an aggressive, stinging ant originally native to South America that has become a formidable pest to humans and livestock in the Southeastern United States, some of the Caribbean islands, and Asia. Both red IFAs and black IFAs exist, with the red IFA being the most widespread and damaging species in the United States. Regularly updated maps of IFA territory are available. (See 'Species' above and 'Territory' above.)
●Stings – The various clinical sequelae that can result from IFA stings are discussed separately. (See "Stings of imported fire ants: Clinical manifestations, diagnosis, and treatment".)
●Natural behaviors – IFAs live within earthen mounds, each of which may contain up to 500,000 ants plus one or more queens (picture 1 and figure 1). The worker ants are highly aggressive and will sting anything they encounter as they forage for food. IFAs feed on a variety of food sources, including insects, small animals, and plant tissues. Workers find food and take it back to the colony to feed the rest of the colony. This behavior is exploited in different control strategies. (See 'Medical entomology' above.)
●Indoor infestations – Indoor infestation of homes and medical facilities is a significant problem. Aside from the obvious risk to residents from stings, IFAs are attracted to electrical equipment and can cause mechanical failures and fires as a result of short circuits. (See 'Indoor infestations' above and 'General medical impact' above.)
●Policies for institutions – In parallel with professional pest control services, clinicians in endemic areas may be asked to assist with institutional management plans for IFA control. Some suggestions for prevention of outdoor and indoor IFA infestations have been developed (table 1 and table 2), as well as an algorithm for responding to the sighting of ants indoors (algorithm 1).
●Evaluation of debilitated patients with possible IFA stings – Clinicians can also help devise a medically oriented plan for how to proceed when IFAs are encountered in rooms or on patients. Our approach for patient assessment is designed for facilities serving debilitated residents (algorithm 2). (See 'Invasion of health care facilities' above.)
●Chemical pesticides – Chemical pesticides are the only effective method for control of IFAs (table 3). There are no methods that permanently control IFAs in an area and none that can eradicate them. (See 'Control of imported fire ants' above.)
•Outdoor pesticides – Broadcast baiting is the best approach for treating a large outdoor area. Individual mound treatments are designed to eradicate a colony that is posing an immediate threat. Barrier and spot treatments contain pesticides that kill ants on contact and are applied in wide bands on and around building foundations and equipment. (See 'Outdoor treatments' above.)
•Indoor pesticides – Indoor pesticides contain low levels of active ingredients and require regular applications to be effective. (See 'Indoor treatments' above.)
●Biologic controls – A variety of biologic control organisms may be used in the future to curtail further spread of IFAs and reduce the dependence on pesticides. Promising agents include several species of predatory flies, pathogens that either cause impaired fertility or death, and other ant species that parasitize IFA colonies and compete for resources but do not interact negatively with humans or livestock. (See 'Biologic control agents' above.)
ACKNOWLEDGMENTS — The UpToDate editorial staff acknowledges David F Williams, PhD, and Robin Rockhold, PhD, who contributed to earlier versions of this topic review.
آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
