ant bites

Contents

Ant bites

Ant bite occurs when an ant bites using their mandibles (insect mouthparts) and mouth to pinch human skin. Ant bite differs from a sting: only female ants have a stinger, near the tail part of their bodies. Fire ants grasp the skin (bite) then inject venom with their stinger (which is immediately painful). Yet other species of ants neither bite nor sting, but instead spray formic acid (from Latin formica ‘ant’) 1.

Ants belong to Hymenoptera insect order, under the family of Formicidae. The order of Hymenoptera includes bees and wasps.

Ants are considered social insects because they live in organized colonies and form complex societies. There are more than 12,000 species of ants. Although they can nearly all bite or sting, few cause significant local and/or systemic reaction in humans. Most ants are too small to effectively bite humans, and their sting is mild. However, the sting from harvester ants and fire ants can cause unpleasant symptoms and may lead to allergic reactions.

Only a very small portion of the population, around 1%, are hypersensitive to ant venom and will experience lethal allergic reactions. Very young and old people and those with suppressed immune systems are most likely to react severely to one or more stings. However, even healthy individuals may experience severe reactions such as anaphylactic shock if they suffer from a multiple stinging incident.

When to see a doctor

Seek emergency medical help if you, your child or someone else you’re with has a severe allergic reaction. Don’t wait to see if the symptoms go away.

Symptoms of a severe reaction (anaphylaxis) may include the following:

  • wheezing or difficulty breathing
  • a swollen face, mouth or throat
  • feeling sick or being sick
  • a fast heart rate
  • dizziness or feeling faint
  • difficulty swallowing
  • loss of consciousness

If you have an attack and you carry an epinephrine autoinjector, administer it right away. Even if symptoms improve after the injection, you still need to go to an emergency room to make sure symptoms don’t recur, even without more exposure to the allergen. This second reaction is called biphasic anaphylaxis.

Make an appointment to see your family doctor if you or your child has had a severe allergy attack or signs and symptoms of anaphylaxis in the past.

The diagnosis and long-term management of anaphylaxis are complicated, so you’ll probably need to see a doctor who specializes in allergies and immunology.

Ant bite symptoms

The typical reaction to many ant bites or stings is a localized urticaria (hives), which are red swellings of the skin that occur in groups on any part of the skin. A fire ant bite or sting causes immediate pain and a red spot, followed a few hours later by a tender, itchy pustule that can last several days to weeks. It is common for bites to be clustered especially under clothing.

Local reaction

Local reaction is the most common presentation following an ant bite or sting. It consists of localized pain, itch, redness, swelling, and swelling. The swelling is usually less than 5 cm in diameter, and is sometimes urticarial (wealing). A local reaction lasts for less than 24 hours.

Large local reaction

A large local reaction of pain, redness, blisters, swelling, and itch is defined as involving a large area of skin greater than 10 cm around the bite/sting site persisting for at least 24 hours. In many cases, the severity peaks after 1 to 2 days, and takes 7 to 10 days to resolve.

Mild systemic reaction

A mild systemic reaction involving the skin and/or gastrointestinal system develops in less than 1% of ant bites or stings. Skin manifestations include flushing, itch, angioedema, urticaria (hives), and redness in areas distant from the bite/sting and/or a generalized distribution. Angioedema is a swelling similar to urticaria, but the swelling is beneath the skin rather than on the surface. Gastrointestinal system symptoms may consist of mild nausea, diarrhea, and/or abdominal cramping. Dizziness, shortness of breath, and nausea occur in moderately severe reactions.

Severe systemic reaction (anaphylaxis)

A severe systemic response or anaphylaxis is a life-threatening allergic reaction to ant venom is marked by clinical manifestations in 2 organ systems distant from the bite/sting, such as angioedema (especially of larynx), flushing, hoarseness, wheezing or bronchospasm, chest pain, hypotension, dizziness, severe abdominal pain, profuse vomiting, or uterine cramping. Anaphylactic shock and loss of consciousness, respiratory and cardiac arrest can occur.

If the person has an emergency kit with an epinephrine autoinjector (EpiPen, Auvi-Q, others), inject it into the muscle of their arm or leg. An epinephrine autoinjector (EpiPen, Auvi-Q, others) is a short-term treatment. The person still should go to the hospital for treatment and care. Certain allergies may require a series of desensitization shots.

Make sure the person is lying down and elevate the legs. Check the person’s pulse and breathing and, if necessary, administer CPR (cardiopulmonary resuscitation) or other first-aid measures.

Ant bite allergy

For people with ant allergy, stings may cause a life-threatening allergic reaction called anaphylaxis (severe allergic reaction). Symptoms of anaphylaxis typically involve more than one part of the body and may include itching and hives, swelling in the throat or tongue, difficulty breathing, dizziness, stomach cramps, nausea or diarrhea. In extreme cases, a rapid fall in blood pressure may result in shock and loss of consciousness. Symptoms of anaphylaxis require emergency medical treatment.

Signs and symptoms of anaphylaxis include:

  • Skin reactions, including hives and itching and flushed or pale skin
  • Low blood pressure (hypotension)
  • Constriction of the airways and a swollen tongue or throat, which can cause wheezing and trouble breathing
  • Swelling of the throat and tongue
  • A weak and rapid pulse
  • Nausea, vomiting or diarrhea
  • Dizziness or fainting
  • Loss of consciousness

If you’re with someone having an allergic reaction with signs of anaphylaxis:

  • Immediately call your local medical emergency number.
  • Ask if the person is carrying an epinephrine autoinjector (EpiPen, Auvi-Q, others) to treat an allergic attack.
  • If the person needs to use an autoinjector, ask whether you should help inject the medication. This is usually done by pressing the autoinjector against the person’s thigh.
  • Have the person lie face up and be still.
  • Loosen tight clothing and cover the person with a blanket. Don’t give the person anything to drink.
  • If there’s vomiting or bleeding from the mouth, turn the person to the side to prevent choking.
  • If there are no signs of breathing, coughing or movement, begin CPR. Do uninterrupted chest presses — about 100 every minute — until paramedics arrive.
  • Get emergency treatment even if symptoms start to improve. After anaphylaxis, it’s possible for symptoms to start again (recur). Monitoring in a hospital for several hours is usually necessary.

If you’re with someone having symptoms of anaphylaxis, don’t wait to see whether symptoms get better. Seek emergency treatment right away. In severe cases, untreated anaphylaxis can lead to death within half an hour.

An antihistamine pill, such as diphenhydramine (Benadryl), isn’t enough to treat anaphylaxis. These medications can help relieve allergy symptoms, but they work too slowly in a severe reaction.

Ant bite diagnosis

The diagnosis of ant bites or stings is based on clinical findings and relevant exposure, or possible exposure, to ants. Referral for allergy testing is warranted only in cases presenting with severe allergic reaction. For a large local reaction, skin testing is not required because the risk of anaphylaxis after a subsequent ant bite or sting is extremely low.

Ant bite treatment

Treatment for ant bites or stings depends on the type of reaction. First remove the ants from your skin and wash the affected area. Apply a cool compress to sooth the itching and reduce swelling. For most people, ant stings won’t cause any trouble besides some pain that will soon go away.

Treatment for local and large local reaction

Immediate management may include:

  • Oral antihistamines for itch and urticaria. Options include nonprescription cetirizine, fexofenadine (Allegra Allergy, Children’s Allegra Allergy), loratadine (Claritin).
  • Analgesics such as acetaminophen (paracetamol) if painful
  • Apply a cloth dampened with cold water or filled with ice to the area of the bite or sting for 10 to 20 minutes. This helps reduce pain and swelling.
  • Apply to the affected area calamine lotion, baking soda paste, or 0.5% or 1% hydrocortisone cream. Do this several times a day until your symptoms go away.
  • Short-course of oral corticosteroids for large local reaction if inflammation is slow to resolve
  • Education for insect avoidance: remove visible ant nests, avoid walking barefoot, wear trousers and long-sleeve shirt when engaged in outdoor activities.

Long-term management:

  • Education for insect avoidance in areas where venomous ants are prevalent
  • Wear shoes and socks when outdoors
  • Wear work gloves when gardening.

Treatment for mild and severe systemic reaction

During an anaphylactic attack, you might receive cardiopulmonary resuscitation (CPR) if you stop breathing or your heart stops beating.

Immediate management may include:

  • Epinephrine (adrenaline) injection to reduce the body’s allergic response
  • Oxygen, to help you breathe
  • Intravenous (IV) antihistamines and cortisone to reduce inflammation of the air passages and improve breathing
  • A beta-agonist (such as albuterol) to relieve breathing symptoms
  • Immediate referral to emergency room

What to do in an emergency

If you’re with someone who’s having an allergic reaction and shows signs of shock, act fast. Look for pale, cool and clammy skin; a weak, rapid pulse; trouble breathing; confusion; and loss of consciousness. Do the following immediately:

  • Call your local emergency number for medical help.
  • Use an epinephrine autoinjector (EpiPen, Auvi-Q, others), if available, by pressing it into the person’s thigh.
  • Make sure the person is lying down and elevate the legs.
  • If needed, position the person to prevent choking on vomit.
  • Don’t offer anything to drink.
  • Check the person’s pulse and breathing and, if necessary, administer CPR (cardiopulmonary resuscitation) or other first-aid measures.

Using an autoinjector

Many people at risk of anaphylaxis carry an autoinjector. This device is a combined syringe and concealed needle that injects a single dose of medication when pressed against the thigh. Replace epinephrine before its expiration date, or it might not work properly.

Using an autoinjector immediately can keep anaphylaxis from worsening and could save your life. Be sure you know how to use the autoinjector. Also, make sure the people closest to you know how to use it — if they’re with you in an anaphylactic emergency, they could save your life. Medical personnel called in to respond to a severe anaphylactic reaction also may give you an epinephrine injection or another medication.

Consider wearing an alert bracelet that identifies your allergy to bee or other insect stings.

Long-term treatment

If insect stings trigger an anaphylactic reaction, a series of allergy shots (immunotherapy) might reduce the body’s allergic response and prevent a severe reaction in the future.

Unfortunately, in most other cases there’s no way to treat the underlying immune system condition that can lead to anaphylaxis. But you can take steps to prevent a future attack — and be prepared if one occurs.

  • Try to stay away from your allergy triggers.
  • Carry self-injection pen of epinephrine (adrenaline). During an anaphylactic attack, you can give yourself the drug using an autoinjector.
  • Allergy specialist referral for skin testing and venom immunotherapy

A generalized urticarial reaction in children < 16 years of age does not need immunotherapy

Allergy shots (venom immunotherapy)

Allergy shots are a form of treatment called venom immunotherapy. Each allergy shot (venom immunotherapy) contains a tiny amount of the specific substance or substances that trigger your allergic reactions. These are called allergens. Allergy shots contain just enough allergens to stimulate your immune system — but not enough to cause a full-blown allergic reaction.

Allergy shots are regular injections over a period of time — generally around three to five years — to stop or reduce allergy attacks.

Over time, your doctor increases the dose of allergens (venom) in each of your allergy shots. This helps get your body used to the allergens (desensitization). Your immune system builds up a tolerance to the allergens (venom), causing your allergy symptoms to diminish over time.

Allergy shots may be a good treatment choice for you if:

  • Medications don’t control your symptoms well, and you can’t avoid the things that cause your allergic reactions
  • Allergy medications interact with other medications you need to take or cause bothersome side effects
  • You want to reduce your long-term use of allergy medication
  • You’re allergic to insect stings

Allergy shots can be used to control symptoms triggered by:

  • Insect stings. Allergic reactions to insect stings can be triggered by bees, wasps, hornets or yellow jackets.
  • Seasonal allergies. If you have seasonal allergic asthma or hay fever symptoms, you may be allergic to pollens released by trees, grasses or weeds.
  • Indoor allergens. If you have year-round symptoms, you may be sensitive to indoor allergens, such as dust mites, cockroaches, mold, or dander from pets such as cats or dogs.

Allergy shots aren’t available for food allergies or chronic hives (urticaria).

Allergy symptoms won’t stop overnight. They usually improve during the first year of treatment, but the most noticeable improvement often happens during the second year. By the third year, most people are desensitized to the allergens contained in the shots — and no longer have significant allergic reactions to those substances.

After a few years of successful treatment, some people don’t have significant allergy problems even after allergy shots are stopped. Other people need ongoing shots to keep symptoms under control.

Allergy shots risks

Most people don’t have much trouble with allergy shots. But they contain the substances that cause your allergies — so reactions are possible, and can include:

  • Local reactions, which can involve redness, swelling or irritation at the injection site. These common reactions typically begin within a few hours of the injection and clear up soon after.
  • Systemic reactions, which are less common — but potentially more serious. You may develop sneezing, nasal congestion or hives. More-severe reactions may include throat swelling, wheezing or chest tightness.
  • Anaphylaxis is a rare life-threatening reaction to allergy shots. It can cause low blood pressure and trouble breathing. Anaphylaxis often begins within 30 minutes of the injection, but sometimes starts later than that.

If you get weekly or monthly shots on a regular schedule without missing doses, you’re less likely to have a serious reaction.

Taking an antihistamine medication before getting your allergy shot can reduce the risk of a reaction, particularly a local reaction. Check with your doctor to see if this is recommended for you.

The possibility of a severe reaction is scary — but you won’t be on your own. You’ll be observed in the doctor’s office for 30 minutes after each shot, when the most serious reactions usually occur. If you have a severe reaction after you leave, return to your doctor’s office or go to the nearest emergency room. Administer epinephrine if recommended by your physician.

Ant bite prognosis

The risk of a severe systemic allergic reaction following an ant bite is greater in adults (especially > 45 years old) than in children. Approximately 85% of adults having systemic allergic response are categorized as severe reaction, while it is only 40% of children. Less than 1% of ant bites result in more severe reaction after a re-bite.

Fire ant bites

Fire-ants (Solenopsis invicta) are aggressive, venomous red-colored stinging insects that have pinching mandibles on the head and a sharp stinger on the rear of the body, which is connected to an internal venom sac. Fire-ant bites can deliver a harmful substance, called venom, into your skin. Fire ant venom contains a chemical called piperidine. Fire ants were first imported accidentally into Alabama from South America around 1930 and have continuously been expanding across the United States, even into Puerto Rico 2. Now there are five times more fire-ants per acre in the United States than in their native South America. The fire ants that came to the United States escaped their natural enemies and thrived in the southern landscape. Fire-ant nests are inhabited by thousands and sometimes hundreds of thousands of tiny red workers (all female — males just hang around for reproductive purposes) and single queens.

Fire ants build dirt nests that form mounds, usually in open, grassy settings. Fire ants bites are typically found in the South/Southeast areas of the United States – from Florida to Texas, and in some parts of the Southwest that do not freeze in winter (see Figure 4). Fire ants are sensitive to vibration or movement and tend to sting when the object they are on moves. For example, when fire ants swarm up a person’s leg, the person jerks or moves. Although fire ants emit communication chemicals, called pheromones, to elicit specific behaviors (alarm reaction, trail formation, queen recognition pheromones have been documented), there is no known pheromone stimulating ants to bite and sting. Usually, whatever causes one ant to bite and stings triggers the other ants to sting to the same response.

Fire ant bites and stings usually occur on the feet or legs after accidentally stepping on a fire ant mound. It is important to be aware that during the summer fire ants obtain the largest amount of venom and therefore the stings are largest and most painful. Fire ants bite and sting causes a burning sensation. Red bumps form at the sting, and within a day or two they become white fluid-filled pustules.

There are three types of skin manifestations that can occur after a fire ant bites:

  1. A local reaction is the most common reaction to fire ant bites and is characterized by an instant sense of burning that is followed by itching and a raised, red welt on the skin that lasts for approximately four to six hours. After the welt subsides, the following day a pustule usually forms with blistering, and resolves over a week. Victims are often prone to scratching these lesions as they are intensely itchy, however it is recommended that you refrain from doing so as an infection in the skin might occur.
  2. A small percentage of people who are stung develop a large local reaction. This is where a large welt appears on the skin at the site of the bite, and over 6 to 12 hours swelling occurs with extreme itching that later becomes painful. Usually in one to two days the swelling becomes increasingly large and reaches its maximum size becoming hot and painful.
  3. In a rare group, anaphylaxis can occur from a fire ant bite. This is a severe allergic reaction that usually coincides with a previous fire ant or wasp bite history. The signs of anaphylaxis present within 30-40 minutes of the bite and are life threatening if not treated immediately and properly. Symptoms of anaphylaxis typically involve more than one part of the body and may include itching and hives, swelling in the throat or tongue, difficulty breathing, dizziness, weakness, stomach cramps, nausea or diarrhea. In extreme cases, a rapid fall in blood pressure may result in shock and loss of consciousness. Symptoms of anaphylaxis require emergency medical treatment. Patients who develop anaphylaxis and have a significant history of systemic reactions to fire ant stings should be checked for a venom allergy antibody called V-IgE by doing a skin test at an allergist’s office.

There are many toxic reactions that have been associated with fire ant bites and one must be wary of these systemic reactions. They are: serum sickness, seizures, mononeuritis, nephrotic syndrome, and worsening of preexisting cardiopulmonary disease.

Only a very small portion of the population, around 1%, are hypersensitive to ant venom and will experience lethal allergic reactions. Very young and old people and those with suppressed immune systems are most likely to react severely to one or more stings. However, even healthy individuals may experience severe reactions such as anaphylactic shock if they suffer from a multiple stinging incident.

When you first identify the fire ant you should kill it by slapping it off your body and consequently washing the sting site with soap and cold water.

I get stung by fire ants there isn’t much you can do, except watch the affected area for excessive swelling, itching or redness, or other symptoms like shortness of breath, thickening of the tongue, sweating, that could indicate a severe systemic allergic reaction (anaphylaxis). If this occurs, seek medical attention. Otherwise treat stings as you would stings of other insects and keep them clean and intact to avoid secondary infections.

In regards to the itching, it can last for hours and an oral antihistamine can be taken or a topical steroid ointment applied such as hydrocortisone. This same treatment is effective for a local reaction and a large local reaction. The hydrocortisone ointment can be covered with first aid tape to increase absorption of the steroid. Very large local reactions are treated with a prescription steroid ointment and/or an oral corticosteroid such as prednisone. If the patient develops anaphylaxis they should be treated emergently and also evaluated by an allergist. The allergist can administer desensitizing injections in the event the patient is stung again by a fire ant.

Identifying Fire Ants

The shape and size of the fire ants nest depends on soil type and ant colony size. Fire ants build nests of dirt in the ground, often on the edges of sidewalks or roads. In moist, clay-type soil, the dome-shaped mounds can be quite tall, up to 18 inches. In dry, sandy soil the mounds may be entirely flat and look like a small patch of disturbed soil. All nests have no obvious entry or exit holes. Since fire ants do not remove vegetation from the area around their mounds, they may be very hard to see.

Fire ant nests are often found in open areas such as lawns and pastures and along roadsides and unused cropland. They can also be found next to or under other objects on the ground, such as timber, logs, rocks, pavers or bricks.

Fire ants enter and leave the mound via underground tunnels which radiate outwards from the nest. These tunnels can be up to 30 meters long. Internally, nests consist of many interconnecting galleries, which have a honeycomb appearance. If a nest is disturbed, the workers may very quickly move the queen and the brood (eggs, larvae and pupae) to a new location.

Fire ant colonies are made up of three groups. Each group carries out specific tasks within the community and their role is determined by their age, size, colony type and needs.

  1. Workers
    • Worker ants are sterile and are responsible for building the nest, caring for the queen and the brood. As worker ants age, their role changes to that of colony maintenance, sanitation and defence. The oldest workers function as foragers, leaving the colony to search for food.
    • When a fire ant nest is disturbed it is the worker ants that rush to the surface to defend the colony.
    • Small workers will live up to 2 months, medium up to 3 months and large up to 6 months.
  2. Alates
    • Mature colonies produce a number of winged, fertile males and females called alates. These are cared for by workers until they leave the colony to begin their mating flights.
    • Females mate with a male in flight. She will then find an appropriate site for a nest, shed her wings and proceed to build her own fire ant colony.
    • The mated male will eventually die, and the female will start her new life as a queen.
  3. Queens
    • Fire ant queens are the only reproductive females in a fire ant colony. Their primary function is reproduction. Queens also produce chemicals called pheromones, which affect the behavior of the workers and alates in the colony.
    • There are two kinds of red imported fire ants — the single queen and multiple queen forms. Workers in single queen colonies are territorial. Workers from multiple queen colonies move freely from one mound to another, which has resulted in a dramatic increase in the number of mounds per acre. Areas infested with single queen colonies contain 40 to 150 mounds per acre (rarely more than 7 million ants per acre). In areas with multiple queen colonies, there may be 200 or more mounds and 40 million ants per acre.
    • A newly mated queen lays about a dozen eggs. When they hatch 7 to 10 days later, the larvae are fed by the queen. Later on, a queen fed by worker ants can lay up to 800 eggs per day. Larvae develop 6 to 10 days and then pupate. Adults emerge in 9 to 15 days. The average colony contains 100,000 to 500,000 workers and up to several hundred winged forms and queens.
    • Fire ant queens can live up to 7 years.

It is common for individual fire ant nests to contain thousands of ants, with a year-old colony having as many as 10,000 workers. By 3 years of age, a colony could contain as many as 100,000 individual ants — comprised of three distinct groups that have very different functions.

Colonies frequently migrate from one site to another. The queen needs only half a dozen workers to start a new colony. They can develop a new mound several hundred feed away from their previous location almost overnight. Flooding causes colonies to leave their mounds and float until they can reach land to establish a new mound. Colonies also can migrate to indoor locations.

Fire ants bite with their jaws while they sting. This allows them to pull the stinger out, rotate and sting again. A single ant can inflict several stings in a matter of moments.

The venom in a fire ant sting will kill bacteria and some of your skin cells. This results in the formation of a blister that fills with a cloudy white material in about 24 hours. While this looks like a pus-filled lesion that should be drained, it is really sterile, and will heal quickest if left alone.

Figure 1. Fire ant

Fire ant

Figure 2. Fire ants

Fire ants

Figure 3. Fire ants lifecycle

Fire ants lifecycle
[Source 3 ]

Figure 4. Fire ants geographic distribution

Fire ants geographic distribution

How long do fire ant bites last?

In regards to the itching, it can last for hours and an oral antihistamine can be taken or a topical steroid ointment applied such as hydrocortisone. This same treatment is effective for a local reaction and a large local reaction. The hydrocortisone ointment can be covered with first aid tape to increase absorption of the steroid. Very large local reactions are treated with a prescription steroid ointment and/or an oral corticosteroid such as prednisone.

Are fire ants as lethal as killer bees?

Both fire ants and killer bees attack en masse and can both cause fatal allergic reactions, but that’s where the similarities end. Africanized bees can overwhelm and kill even healthy non-allergic people, but encounters are rather rare. Fire ants can’t overwhelm a healthy, mobile person and even hundreds of stings are rarely fatal. But, fire ant mounds are extremely common. The chance of being killed by bees is higher if you encounter them, but the chance of being killed by fire ants is greater only if you are highly allergic, or cannot quickly get away from them. The chance of either is small.

Where do fire ants come from?

Red fire ants (Solenopsis invicta) and black imported fire ants (Solenopsis richteri) are native to South America 4. They were accidentally introduced into the U.S. around the 1930’s through the port of Mobile, Alabama; probably in soil used for ships’ ballasts and have been spreading since 4. There are several Solenopsis fire ant species native to the U.S.

Are fire ants still moving west and north?

Yes, and south, too. They have spread west to eastern New Mexico (Donna Anna County) and have crossed the Rio Grande River into northern Mexico. Their northward spread has reached the middle of Oklahoma where their survival depends on freezing soil temperature conditions. Cold winters tend to push them back. Western spread is largely dependent on availability of surface or ground water. However, with human assistance they have begun to infest parts of California where they are found mostly in urban areas, creek bottoms and irrigated land.

Can I tell the difference between fire ants and native ants?

Some uncertainty comes from the fact that red imported fire ants vary in size (1/16 to almost 1/4 inch long, with the largest workers 2 or 3 times larger than the smallest. Red imported fire ants are an exotic invasive species and in many areas of Texas they have displaced other species of fire ants native to the state. Solenopsis geminata, the tropical fire ant, is the most common native fire ant species encountered. To the unaided eye, they are almost identical to red imported fire ants. However, Solenopsis geminata will have a few larger workers with large, square-shaped bi-lobed heads. These ants specialize in collecting and milling seeds, but build mounds similar to red imported fire ants.

What is the difference between single queen and multiple queen forms of the red imported fire ant?

There are two genetically distinct forms or the red imported fire ant, Solenopsis invicta: The single queen or monogyne form and the multiple queen or polygyne form.

  • Single queen (monogyne form): only one queen (reproductively active wingless female) per colony or mound; slightly larger worker ants; members of colonies are territorial; mounds generally larger in size; mound densities usually less than 300 mounds per acre; fewer ants per acre.
  • Multiple queen (polygyne form): more than one and up to hundreds of unrelated queens per colony; smaller average worker ants; worker ants move freely from one mound to another and share resources; mound densities greater than 300 mound per acre; more ants per acre.

Can fire ants be eradicated completely?

Red imported fire ants cannot be eradicated completely with methods available today in large areas of infestation like in the southeastern United States. But with proper control methods, they can be reduced or eliminated temporarily from small areas. Their biology and spread make it economically, technically and ecologically impossible to eradicate them from larger areas. However, recent efforts have been made to eradicate red imported fire ants species from small isolated infestations in California and around Brisbane, Australia. To date, these efforts have not been documented to be a success.

How do I eliminate fire ants from my yard?

There is no single, easy answer for every situation. Most people with more than a handful of mounds (5 ant mounds per ¼ acre yard or 20 per acre) will be satisfied with just a bait or the “Two Step Method”, which can provide 80 to 90% reduction of ant mounds in the treated area and works best on larger landscapes such as city blocks, neighborhoods or homeowner associations, school grounds and parks. Other methods may more suitable for smaller lots, where greater control is required or where fewer ants occur and native ant preservation is desired. Remember, no method is 100% effective all the time, though some come close, and no method is permanent. The ants will re¬invade, with new colonies probably appearing after the next rain, and certainly within a year.

What is the “Two- Step Method” for controlling imported fire ants?

The Two Step is a proven method of reducing imported fire ant populations in heavily infested home lawns and ornamental turf. Briefly, it is the:

  1. Once or twice per year broadcast application of a bait product, and
  2. Treating unwanted active nuisance mounds at any time between these broadcast treatments using an individual mound treatment such as a dust, granule, bait, drench insecticide or home remedy such as use of very-hot water as a drench.

By allowing for the bait treatment to take effect this method reduces the over-reliance on use of individual mound treatments and is suitable for treating larger areas. This approach is more cost-effective and environmentally friendly than most other chemical approaches, and “organic” options for the products selected are available.

Why tackle fire ants in the fall?

An ideal time to apply bait-formulated fire ant insecticides is from late August through October to allow the baits to reduce fire ant populations over the winter. Many bait products are somewhat slow-acting. Bu applying the in late summer or early fall, ant mound numbers will already be suppressed by early spring. Because bait product performance depends on foraging ants to retrieve the bait particles, applying them too early in the spring in cool weather (below 65°F) will be ineffective. Also, early spring application of slower acting products will not produce maximum effects until later in the spring or early summer. Fall applications are especially good for agricultural sites such as hay pastures where the first cutting is the most valuable.

Which bait should I use? How long does it take for baits to work?

The key to using baits is patience. Applied properly and using a fresh bait product, a broadcast application will give 80% to 90% control, rarely 100%. For instance, products containing the active ingredient, indoxacarb (Advion®), are the fastest-acting, providing maximum control within about 2 weeks, while baits containing hydramethylnon (Amdro® and others) give maximum control in 3 to 6 weeks. Products containing ingredients known as insect growth regulators (IGR’s) such as Extinguish® (methoprene), Distance® or Esteem® (pyriproxyfen) or Award® (fenoxycarb), when applied late in the year, may take several months to provide maximum control, but will suppress ant colonies for a months. One approach, for example, for heavy imported fire ant infestations is to treat with Amdro® first for fast knockdown, then come back with Award® for longer duration control as ants start to reinfest the area some months later. One product, Extinguish Plus is actually a blend of hydramethylnon and methoprene that provides rather quick suppression that lasts longer due to the insect growth regulators ingredient.

I tried using baits, but they don’t seem to work.

Baits work well if they are used properly. The thing to remember is the ants collect the bait as a source of food. Putting the bait out at the right time of day, and at the correct rate (usually 1 to 1 1/2 lb/acre but varies by product and formulation) is critical. If the ants are not actively foraging, they will not pick up the bait. The best times to apply bait applications occur between 65 and 95°F – generally mid-morning after the dew has evaporated, or late afternoon on hot days when the air begins to cool. Apply a small amount of bait or other food lure such as a potato chip in the area to be treated. If ants are all over it within 45 to 60 minutes, the bait is fresh and the ants are foraging! Always read and follow closely the directions provided on the product label before using any pesticide.

When and how often should I reapply the bait?

The fall application is important because it will help suppress ants by the following spring. Reapply when imported fire ant mounds begin to appear again. Generally, if you make a spring application, suppression should last until that fall, when the next application should be made. Re-infestation depends on size of area treated and frequencies of mating flights. Larger areas experience less colony immigration from untreated adjacent properties. During favorable colony development conditions and wet years, mating flights may be more frequent and intense, resulting in more newly formed colonies that appear one to two months following a successful mating flight.

How much does it cost to treat for fire ants?

If you have a 1/4 acre lot (100 x 100 feet, 70 X 150, etc.) you would need less than 1/2 pound of a bait product. A pound costs around $10 and yields two applications, with some to spare. Go here https://fireant.tamu.edu/controlmethods/products , for cost comparisons among products. It’s really not that expensive, if done right.

Within a month or so, it would likely get ants down to a level you wouldn’t notice. For faster control, treat individual nuisance mounds after broadcasting a bait product.

Is there anything I can use that isn’t a pesticide?

A pesticide is anything that kills pests. However, some options do not rely on chemicals formulated to kill insects. Using very hot water is somewhat effective for individual mounds. Approximately 3 gallons of very hot water poured onto mounds will eliminate ants about 60% of the time. Drench mounds on cool sunny mornings when the ants are close to the surface. However, you will risk damaging plants, grass, and even burning yourself. Some home remedies such as instant grits thought be eaten by ants and swell in their stomachs and cause death when placed on the mound, have demonstrated to be ineffective, in this case because worker ants cannot ingest particles larger than 2 microns.

Are there organic methods to control fire ants?

Fire ant control methods considered to be “organic” usually include cultural, physical, mechanical and biological control techniques, but some chemical treatments such as plant-derived (botanical, such as pyrethrins or d-limonene) and microbial-produced (such as spinosad) insecticides are considered to be “of natural origin,” or organic. Some products are certified as organic by OMRI (Organic Materials Research Institute). Regardless of chemical origin or preparation, the Texas Fire Ant Project promotes the use of the least toxic methods. OMRI (Organic Materials Research Institute) certified organic products such as bait and mound treatments using products containing spinosad or mound drenches using products containing pyrethrins or d-limonene can be used with the Two Step method.

Are there any biological controls for fire ants?

The University of Texas and the United States Department of Agriculture (USDA) have been conducting research on fire ant parasitic phorid fly species as one of several potential biological control agents for helping to control fire ants. Three species have been released and established in parts of Texas and are spreading naturally to adjacent areas. However, documentation about their impact on fire ant population levels has been published to date. Even in South America where the imported fire ants and parasitic fly species come from, the flies only affect about 3% of the worker ants in a colony. Some biological control agents that have already been marketed include predaceous mites, parasitic nematodes, and the fungus called Beauveria bassiana. Scientific studies continue to be being conducted to evaluate the effectiveness of some of these natural enemies, but others remain untested or have not been shown to be highly effective.

Why don’t we use Mirex?

Mirex was an effective ant killer, but it was one of the most persistent compounds ever made. Mirex belongs to a group of chemicals that have mostly been banned from sale or use. Their ingredients, or their degradation products, accumulated in biological systems.

What is the safest product for my children, pets, chickens, etc.?

Always follow the directions provided on the product’s label. For insecticides registered by the Environmental Protection Agency (EPA), labeled products pose minimum risk to people and the environment when applied as directed. You can use a less toxic material and apply it so that there will be little contact. The main concern is to not put a contact insecticide in high concentrations where children and animals can contact it, including storing insecticides where they are inaccessible. Bait products, when broadcast applied, not only have very low toxicity, but are scattered very thinly and fall down in the grass where few things other than ants can encounter them. Granular and dust products will remain on the soil surface where potential contact can occur unless the material is watered in after application. Drenches may be a better individual mound treatment choice. Keep animals and kids away from treated areas as directed or until vegetation and the soil surface are dry.

What are some considerations when using insecticides around water and well heads?

Much of the same information holds true as for ant management around children and animals, but there is also the danger of ant mound drenches containing contact insecticides running off either immediately or after a rain. Selecting products with ingredients known to be less toxic to aquatic organisms can help. Some product labels, such as products containing fipronil, specify how far from the edge of a body of water a chemical can be applied. When broadcast-applying a bait product, make sure not to get bait particles in surface water as they may be eaten by fish. Contact the manufacturer for answers to questions about their products.

What are some options for controlling fire ants inside the home?

The most important step is to identify the ant species and locating the nesting site. For ants nesting indoors, some products labeled for indoor use can be applied, including bait formulations, which foraging worker ants collect and take back to the colony to feed the queen. Trails of foraging ants can be sprayed with a contact insecticide, but these treatments do not directly affect the colony and may cause colonies to divide into a number of smaller colonies. Read and follow the directions on the product label for best results. Be sure to keep products away from small children and pets. Treating ants in the landscape outside will also help control some ant species, particularly imported fire ants that foraging inside from outdoor colonies or occasionally migrate indoors to nest. Finally, a band of contact insecticide can also be applied around the perimeter of your house to provide a barrier against invasion.

Fire ant bites prevention

You should take the following steps to prevent fire ant stings and bites:

  • First, stay away. Fire ants, like other insects, are most likely to sting if their homes are disturbed. Unfortunately, since some mounds are flat, they may be stepped on accidently. This can result in hundreds of ants swarming out, coming to the defense of the mound.
  • Do not disturb or stand on or near ant mounds. If you find or accidently disturb a mound, move away quickly. The longer you stay near a mound, the more stings you may get.
  • Be careful when lifting items (including animal carcasses) off the ground, as they may be covered in ants.
  • Fire ants may also be found on trees or in water, so always look over the area before working or playing in the area.
  • Wear closed-toe shoes and socks outdoors; avoid going barefoot outside. When working in the garden or yard, wear work gloves. Shoes and gloves allow you to get away from the mound and to remove the shoes, socks and gloves with the attached stinging fire ants before they can reach your skin.

Removing mounds requires killing the queen ant. Commercial products are available but take several weeks to make the mounds disappear.

Fire ant bites symptoms

Symptoms of a fire ant sting may include:

  • Swelling, redness, itchiness, and pain around the site of the bite
  • Pus-filled blisters that last 3 to 8 days
  • Possible scab at the area of the bite that lasts 3 to 10 days

Those allergic to fire ant venom may also have:

  • Difficulty breathing
  • Rapid heart rate
  • Throat swelling

Symptoms of a Serious Reaction

For people with fire ant allergy, fire ant bites may cause a life-threatening reaction called anaphylaxis. Symptoms of anaphylaxis typically involve more than one part of the body and may include itching and hives, swelling in the throat or tongue, difficulty breathing, dizziness, stomach cramps, nausea or diarrhea. In extreme cases, a rapid fall in blood pressure may result in shock and loss of consciousness. Symptoms of anaphylaxis require emergency medical treatment.

Given the severity of a potential reaction, an accurate diagnosis for fire ant allergy is key to being prepared for an emergency. An allergist / immunologist has specialized training and skills to test for stinging insect allergy and develop a plan to manage allergies.

Fire ant bite treatment

Fire ant sting treatment is aimed at preventing secondary bacterial infection, which may occur if the pustule is scratched or broken. Clean the blisters with soap and water to prevent secondary infection. Do not break the blister. If a blister is accidentally opened, careful attention to keeping the area clean with soap and water should still prevent infection. Topical corticosteroid ointments and oral antihistamines may relieve the itching associated with these reactions.

First Aid

If you have a history of severe allergic reactions to insect bites or stings, you should consider carrying an epinephrine auto-injector (EpiPen) and should wear a medical identification bracelet or necklace stating your allergy. Learn how to administer the epinephrine, and replace the device before the labeled expiration date.

Epinephrine is a rescue medication only, and you must still go to an emergency room immediately if you are stung.

You should take the following steps if you are stung or bitten by fire ants:

  • Rub off ants briskly, as they will attach to the skin with their jaws.
  • Antihistamines may help.
    • Follow directions on packaging.
    • Drowsiness may occur.
  • You should go to an emergency medical facility immediately if fire ant bites cause severe chest pain, nausea, severe sweating, loss of breath, serious swelling, or slurred speech.

If you have had a serious adverse reaction to a fire ant sting you should be evaluated by an allergist / immunologist. With proper testing, your allergist can diagnose your condition and determine the best form of treatment.

Allergy shots (immunotherapy) may be effective long-term treatment for stinging insect allergy. Your allergist will give you shots containing small doses of your allergen, allowing your body to build a natural immunity to the trigger.

Home remedies for fire ant bites

Home treatment depends on the location of, and your reaction to fire ant bites.

Wash the exposed area with plenty of soap and water. DO NOT use alcohol to wash the area. Wash the eyes with plenty of water if any venom gets in them.

For mild stings, place ice (wrapped in a clean cloth) on the bite area for 10 minutes and then off for 10 minutes. Repeat this process. If the person has problems with blood circulation, decrease the time to prevent possible damage to the skin.

Some people are allergic to fire ant venom. If the reaction is severe, seek medical help right away and call your local emergency number (such as 911) or poison control.

Those who have an allergy to insect bites or stings should carry a bee sting kit and know how to use it in an emergency. These kits require a prescription.

Fire ant sting allergy treatment

Fire ant sting allergy is treated in a two-step approach:

  1. The first step is the emergency treatment of the symptoms of a serious reaction when they occur.
  2. The second step is preventive treatment of the underlying allergy with whole body extract immunotherapy, which contains the entire body of the fire ant, not just the venom, as is the case with other stinging insects. It is a highly effective program administered by an allergist-immunologist, which can prevent future allergic reactions to fire ant stings. At this time, scientists are not able to isolate venom from fire ants.

Life-threatening allergic reactions (anaphylaxis) can progress very rapidly and require immediate medical attention. Emergency treatment usually includes administration of certain drugs, such as epinephrine, antihistamines, and in some cases, corticosteroids, intravenous fluids, oxygen and other treatments. Once stabilized, these patients sometimes require close observation in the hospital overnight.

Injectable epinephrine is often prescribed as emergency rescue medication for treating an allergic reaction. People who have had previous allergic reactions and rely on epinephrine must remember to carry it with them at all times.

Also, because one dose may not be enough to reverse the reaction, recent guidelines recommend keeping two doses of injectable epinephrine available and to activate emergency medical services if used. Even if symptoms improve after a single dose of epinephrine, immediate medical attention following an insect sting is recommended.

The long-term treatment of fire ant sting allergy is called whole body extract immunotherapy. Whole body extract immunotherapy involves administering gradually increasing doses of extract to decrease a patient’s sensitivity to the fire ant sting. This can reduce the risk of a future allergic reaction to that of the general population. In a matter of weeks to months, people who previously lived under the constant threat of severe reactions to fire ant stings can return to leading normal lives.

If you think you might be allergic to fire ant stings, see an allergist. Based on your history and certain tests, the allergist will determine if you are a candidate for skin testing and immunotherapy.

Fire ant bites prognosis

Minor reactions have an excellent prognosis. The sooner appropriate treatment is started, the better the outcome. People who are not allergic to fire ants should be fine in a few hours to a few days. People with severe allergic reactions may need to stay in the hospital. However, fire ants are becoming an increasingly important public health concern in the United States. More than 80 fatalities have been reported from fire ant-induced anaphylaxis.

References
  1. Formic Acid. https://pubchem.ncbi.nlm.nih.gov/compound/Formic-acid
  2. Fire ants invade and evolve. https://evolution.berkeley.edu/evolibrary/article/_0_0/fireants_01
  3. Fire ants lifecycle. https://www.fireants.org.au/look/biology-and-ecology/lifecycle
  4. Fire Ant Frequently Asked Questions. https://fireant.tamu.edu/manage/faq
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