African eye worm is the common name for Loa loa, a tiny thread-like parasite (a filarial worm) that lives and moves in the soft tissues under the skin and sometimes across the white of the eye. The medical condition it causes is called loiasis. People get infected from the bite of day-biting deer flies (genus Chrysops) that live around shaded, swampy forest edges in parts of West and Central Africa. The fly picks up the parasite when it bites an infected person and then injects the parasite into the next person it bites. Months to years later, the adult worm may travel under the skin, create itchy swellings (often called Calabar swellings), or occasionally pass across the eye, which is dramatic but usually not dangerous for vision. Many people carry the parasite without symptoms for a long time; others have very noticeable skin and eye symptoms.
African eye worm is a parasitic infection caused by a thin, thread-like worm called Loa loa. The worm lives under the skin and sometimes crosses the white of the eye (the conjunctiva), which is why people can literally see the worm move across the eye for a few seconds to minutes. The infection is common in parts of West and Central Africa, especially in rainforest and swampy areas. The worm is spread by day-biting deer flies (also called mango flies or Chrysops).
After a fly bites an infected person, it picks up tiny baby worms (called microfilariae). When it later bites another person, it injects the next stage (larvae) into the skin. These larvae grow into adult worms over months, live under the skin for years, and may wander to the eye or cause short-lived, puffy swellings under the skin called Calabar swellings. The baby worms circulate in the blood mainly during the day, which is why daytime blood tests are used to diagnose the infection.
After a deer fly bite, tiny larval worms enter the skin. Over several months they grow into adults that wander through the soft tissues. Adult females release microscopic baby worms (microfilariae) into the bloodstream, and these microfilariae show their highest numbers in the daytime (a pattern called diurnal periodicity), which matches the day-biting habit of the deer fly. The body’s immune system reacts to the moving worm and its proteins, creating itchy, temporary swellings and sometimes allergic-type symptoms. If a worm travels across the clear tissues over the eye, a clinician may even see and remove it.
Types of loiasis
Asymptomatic loiasis (silent infection). A person has Loa loa in the body but feels fine. Often the only clue is a high eosinophil count (a type of white blood cell linked with allergies and parasites) or microfilariae seen in a daytime blood sample.
Cutaneous loiasis (skin-dominant). The main problem is Calabar swellings—soft, puffy, itchy swellings that come and go, usually on the arms and legs. They last days to a week and then disappear, only to show up in a different spot later.
Ocular loiasis (eye involvement). An adult worm crosses the conjunctiva (the clear covering over the white of the eye). People feel irritation, tearing, and the sense that something is moving. Vision is usually okay, but the experience is alarming.
Microfilaremic loiasis (detectable microfilariae). Blood taken in the middle of the day shows microfilariae. Some people with high levels have few symptoms; others have frequent swellings.
Amicrofilaremic (occult) loiasis. Classic symptoms (Calabar swellings, eye worm) but no microfilariae seen in blood. Other tests (like PCR) or a removed worm confirm the diagnosis.
Imported loiasis. A traveler, migrant, or humanitarian worker returns from an endemic region and develops swellings or an eye worm months to years later.
Endemic loiasis. Lifelong residents in affected parts of West/Central Africa. Many are asymptomatic carriers; some have recurrent swellings.
Mild disease. Infrequent, small swellings and occasional itching; normal daily life.
Moderate disease. Regular swellings, more itching, occasional eye worm; sleep or work is disrupted.
Severe, complicated disease. Rare. Marked inflammation, repeated large swellings, or systemic involvement (e.g., kidney or nervous system issues).
Skin-predominant vs. eye-predominant. A simple clinical way to label the most obvious feature for communication and record-keeping.
Single-worm vs. multiple-worm infection. Not formally a staging system, but it helps explain why symptoms vary—some people harbor more worms and release more microfilariae than others.
Causes
Bites from infected deer flies (Chrysops). This is the direct cause. The fly injects the parasite when it bites in daylight.
Living in endemic forest zones. Rural forest and swamp-edge areas of West and Central Africa have the right environment for the fly to breed and feed.
Working outdoors during the day. Farming, logging, road work, or river-related activities increase fly contact.
Travel to endemic regions without protection. Even short trips can be enough if bites occur repeatedly.
Rainy seasons and humid months. More breeding sites for flies means more bites and higher transmission risk.
Shaded, muddy, or slow-moving water nearby. Deer flies like these areas for resting and breeding.
Lack of protective clothing. Short sleeves and shorts leave skin exposed for bites.
Skipping insect repellent. Not using repellents on skin or clothing allows flies to feed more easily.
No window screens or poor housing barriers. Flies can enter homes in daytime and bite people indoors.
Sleeping or napping outdoors in the day. Even brief dozing can lead to unnoticed bites.
Activities that attract flies. Working near livestock or using bright objects that draw flies can increase encounters.
Multiple bites over time. Infection risk rises with repeated exposure, not just a single bite.
Human reservoir of infection. In endemic areas, many people carry microfilariae, so local flies frequently become infected.
Limited vector control. Few community-level efforts to reduce deer fly populations means ongoing transmission.
Environmental changes. New roads, logging, or irrigation may expand fly habitats.
Lack of awareness. Not recognizing the importance of daytime protection against biting flies increases risk.
Protective gear not suited to heat. In hot climates, people may avoid long sleeves or treated clothing because they’re uncomfortable.
No access to repellents or treated clothing. Cost or availability can be barriers.
Staying for years in endemic regions. The longer you remain, the greater the cumulative exposure.
Community exposure patterns. If neighbors, family, or coworkers are heavily exposed, personal risk also rises because local flies often carry the parasite.
Common symptoms and signs
Calabar swellings. Soft, puffy, itchy swellings that appear suddenly, often on the arms or legs, then fade and recur elsewhere. They are allergic-type reactions to a moving worm.
Itching (pruritus). Generalized or in patches, often worse around the swellings. Scratching marks are common.
Hives or rashes. Raised, itchy welts can come and go with the immune response to worm proteins.
Eye worm episode. A clear, thread-like worm crosses the white of the eye. People feel tearing, burning, or a crawling sensation; vision typically remains okay.
Red, irritated eyes. From the worm’s passage or from rubbing due to irritation.
Tearing and light sensitivity. The eye reacts to irritation with watering and photophobia.
Localized pain or tenderness. The skin over a swelling may be sore; the area can feel warm.
Migrating discomfort. As the worm moves, discomfort and swelling shift to a new spot over days or weeks.
Fatigue and malaise. The immune system is “on,” which can make people feel tired or unwell.
Low-grade fever. Some people get periodic fevers during active inflammatory phases.
Joint or muscle aches. Inflammation around tissues can cause soreness, especially near swellings.
Swollen lymph nodes. The immune response in nearby nodes may make them feel enlarged and tender.
Cough or chest tightness (occasional). Rare, transient lung irritation can occur when the immune system reacts to microfilariae.
Skin thickening or subtle tracks. With repeated episodes, skin may show faint lines or chronic changes where worms have moved.
Anxiety or sleep disturbance. The surprise of seeing or feeling a moving worm—especially near the eye—can be distressing.
Diagnostic tests
Important idea: Diagnosis rests on (a) recognizing the typical symptoms and signs (Calabar swellings, eye worm), and (b) proving the parasite with tests (seeing the worm, finding microfilariae in daytime blood, or detecting its DNA). Doctors often use several methods together.
A) Physical exam
Direct visualization of a conjunctival worm. A clinician looks carefully at the eye and may actually see the slender, white worm moving under the clear membrane. This is a clinching sign when present.
Inspection and palpation of Calabar swellings. The clinician examines puffy, non-pitting swellings (often on arms/legs) that appear and resolve over days, matching the classic pattern for loiasis.
Skin examination for scratch marks and migrating changes. Generalized itching, excoriations, and shifting areas of tenderness hint at a moving subcutaneous worm.
Lymph node check. Enlarged, tender nodes near affected limbs support an active immune response to a local parasite.
General exam with travel/exposure mapping. The clinician documents recent or past time in West/Central Africa, daytime outdoor work, and fly exposure—critical context that turns a “mystery swelling” into a likely parasite diagnosis.
B) Manual/bedside tests
Basic vision testing (visual acuity). Reading an eye chart confirms that the dramatic eye event rarely harms sharpness of vision; changes suggest another eye problem that needs attention.
Color vision and confrontation visual fields. Simple in-office checks to ensure the retina and optic nerve are okay; these help rule out other eye diseases when the eye is irritated.
Penlight and lid eversion exam. Gently flipping the eyelid and shining a light helps look for a moving worm in the conjunctival tissues or trapped under the lid.
Measurement and photography of swellings. Using a tape measure and phone/camera documents size and timing. Photos over days help show the “migratory, on-off” pattern typical for loiasis.
C) Laboratory and pathological tests
Daytime thick and thin blood smears (Giemsa-stained). A blood sample drawn in the middle of the day is examined under a microscope for microfilariae. Seeing Loa loa microfilariae confirms infection.
Microfilaria count (quantification). Counting how many microfilariae are present per milliliter helps describe intensity of infection. It also guides safety planning if treatment is considered later.
Concentration methods (e.g., Knott’s test or membrane filtration). Special lab techniques filter or spin the blood to increase the chance of finding microfilariae when they are few.
PCR for Loa loa DNA. A molecular test that detects the parasite’s genetic material in blood. PCR helps when smears are negative but suspicion is strong (so-called occult loiasis).
Serology (filarial antibodies, often IgG4-based). Blood antibody tests can support the diagnosis but may cross-react with other filarial worms; a positive result is helpful but not definitive by itself.
Eosinophil count and total IgE. A complete blood count often shows eosinophilia; total IgE (an allergy-linked antibody) may be elevated. These are supportive clues, not proof.
Urinalysis and kidney function tests (supportive). Rarely, immune reactions can affect the kidneys. Checking urine protein/blood and blood creatinine provides a baseline picture.
Pathology of an extracted worm or tissue. If a worm is removed (for example, from the eye), a pathologist can identify Loa loa by its structure (cuticle, body features) under the microscope.
D) Electrodiagnostic tests
Electrocardiogram (ECG) only if complications are suspected. Loiasis itself usually does not require electrodiagnostic testing. An ECG is used only for broader medical assessment if a clinician is evaluating chest symptoms or planning therapies in a complex case. It is not a routine diagnostic tool for loiasis.
E) Imaging tests
Slit-lamp biomicroscopy (eye microscope). An eye-care professional uses a special microscope to examine the front of the eye in detail and may directly see the worm. This is more an “optical exam” than radiology, but it is a key visual imaging step for ocular loiasis.
High-resolution soft-tissue ultrasound (selected cases). An ultrasound probe over a swelling or eyelid can sometimes show a thin, moving structure in the subcutaneous tissues, helping confirm a live worm when it isn’t visible to the naked eye. Brain or chest imaging is not routine for loiasis and is reserved for unusual, complicated cases.
Non-pharmacological treatments
These are therapies and practical measures that help with comfort, safety, and procedures. They do not kill the parasite by themselves, but they support recovery and reduce risk.
Professional removal of a visible eye worm (minor procedure).
What it is: An eye doctor numbs the surface, makes a tiny nick in the conjunctiva, and gently lifts out the worm with fine forceps.
Purpose: Immediate relief from irritation and to reduce local inflammation.
How it helps: Removes the adult worm causing symptoms. It doesn’t cure the whole infection (others may still be in the body), but it helps the eye heal.Removal of a worm from under the skin (office procedure).
What: A clinician numbs the skin and extracts the moving worm through a small cut.
Purpose: Reduces pain and swelling at that spot and provides a specimen for confirmation.
How: Physical removal lowers local inflammation and confirms the diagnosis.Cold compresses for Calabar swellings.
What: Cool, clean cloth on the swollen area 10–15 minutes, a few times daily.
Purpose: Comfort and swelling control.
How: Cold slows local blood flow and calms histamine-driven puffiness.Rest and limb elevation during flare-ups.
Purpose: Reduces pressure and throbbing discomfort in swollen areas.
How: Elevation helps fluid drain out of tissues.Gentle eye protection and light avoidance after an eye episode.
What: Sunglasses outdoors; avoid bright screens for 24–48 hours if the eye is irritated.
How: Less light equals less pain and faster surface healing.Artificial tears (non-medicated lubricants).
Purpose: Soothe scratchiness after a worm has crossed the eye or after removal.
How: Lubrication reduces friction and supports the surface barrier.Strict hand/eye hygiene.
What: Clean hands, avoid rubbing the eye, and keep the eye area clean if there was a small incision.
How: Cuts infection risk while the surface heals.Stop wearing contact lenses until cleared.
Purpose: Prevents irritation and secondary infection after eye events or procedures.Itch-control habits.
What: Keep nails short, use cotton clothing, and try not to scratch.
How: Prevents skin breaks that can become infected.Symptom diary.
What: Track timing of swellings, eye events, and any fevers or headaches.
How: Helps your clinician time tests (like daytime blood tests) and plan treatment.Daytime scheduling for blood sampling.
Purpose: Loa loa baby worms peak in the blood midday; a correctly timed sample increases test accuracy.Travel clinic consultation (before, during, after travel).
Purpose: Risk assessment, repellent advice, and post-travel screening if needed.Insect bite avoidance—repellents on skin.
What: Use DEET (20–50%) or picaridin (20%) on exposed skin when in endemic areas.
How: Fewer bites mean lower infection risk.Permethrin-treated clothing and bed nets.
What: Treat clothes and nets with permethrin.
How: Kills or repels deer flies on contact; nets also block other biting insects.Long sleeves, trousers, and light-colored clothing.
How: Physical barrier; deer flies are attracted to movement and dark colors, so lighter clothing helps a bit.Avoid high-risk places at peak times.
What: Deer flies bite in the daytime, especially near shaded streams and swamps.
How: Plan activities away from these locations when possible.Window screens and fans.
Purpose: Mechanical deterrents; moving air makes it harder for flies to land and bite.Community vector control participation.
What: Local projects to reduce breeding sites (standing water, dense brush near homes).
How: Fewer flies lowers everyone’s risk.Prompt medical review after mass-drug-administration (MDA) if in endemic areas.
Why: People with very high Loa loa levels can have bad reactions to certain deworming campaigns aimed at other parasites. Early evaluation helps keep you safe.Health education for families and workers.
What: Teach the signs (Calabar swelling, eye worm), timing for blood tests, and the need for supervised care.
How: Earlier diagnosis and safer treatment.
Drug treatments
Important safety note: The main curative medicine for loiasis is diethylcarbamazine (DEC). Albendazole is often used as a pre-treatment or an alternative in certain situations. Ivermectin can temporarily lower baby worms but is risky in loiasis if the microfilaria count is high; it must be used only with expert guidance after proper testing. Other medicines below are adjuncts to control inflammation, pain, or secondary infection. Always use these under a clinician’s direction.
Diethylcarbamazine (DEC)
Class & purpose: Filarial antiparasitic; the primary drug for loiasis.
Typical dose & time: ~8–10 mg/kg/day split into 3 doses for 21 days (doctors may start low and increase to reduce reactions).
How it works: Kills microfilariae and has activity against adult worms.
Key side effects: Itching, fever, swelling (Mazzotti-type reaction), rash; in people with very high microfilariae, rare serious neurologic reactions can occur if therapy is not carefully staged. Clinicians often add antihistamines or short-course steroids to reduce reactions.Albendazole
Class & purpose: Benzimidazole antiparasitic; used as pre-treatment to lower microfilariae or as an alternative if DEC cannot be used immediately.
Typical dose & time: 200–400 mg twice daily with food for 21–28 days (regimens vary).
How it works: Disrupts parasite cell microtubules; slower kill lessens sudden inflammatory reactions.
Key side effects: Upset stomach, liver enzyme elevations (rare); avoid in early pregnancy unless specialist advises; check for drug interactions.Ivermectin (specialist-guided only in loiasis)
Class & purpose: Antiparasitic that quickly lowers microfilariae.
Typical dose & time: 150–200 µg/kg as a single dose or repeated—only after testing shows it is safe and with specialist oversight.
How it works: Paralyzes microfilariae, letting the body clear them.
Critical warning: In high Loa loa microfilarial loads, ivermectin can trigger severe neurologic events (encephalopathy); never self-treat. It is often avoided or used only after counts are safely reduced (e.g., with albendazole or other specialist measures).Prednisone (or prednisolone)—adjunct
Class & purpose: Corticosteroid to control inflammation and allergic-type reactions during treatment or severe Calabar swellings.
Typical dose & time: Often 0.5–1 mg/kg/day for a few days, then tapered; individualized.
How it works: Calms the immune response to dying parasites.
Side effects: Mood changes, high blood sugar, blood pressure rise, stomach upset; avoid long, unsupervised use.Cetirizine (second-generation antihistamine)—adjunct
Class & purpose: H1-antihistamine to reduce itching and hives-like rashes.
Typical dose: 10 mg once daily.
How it works: Blocks histamine receptors in the skin.
Side effects: Usually mild; occasional drowsiness or dry mouth.Hydroxyzine (first-generation antihistamine)—adjunct, helpful at night
Dose: 25 mg at night (varies).
Purpose & how: Stronger itch control and helps sleep; blocks H1 receptors centrally and peripherally.
Side effects: Drowsiness, dry mouth; avoid driving if sleepy.Acetaminophen (paracetamol)—adjunct for pain/fever
Dose: Adults commonly 500–1000 mg every 6–8 hours (max per local guidance).
Purpose & how: Lowers fever and eases aches triggered by inflammation.
Side effects: Liver risk if overdosed or mixed with alcohol; follow labels and clinician advice.Ibuprofen (NSAID)—adjunct for pain/inflammation (if safe for you)
Dose: 200–400 mg every 6–8 hours with food; avoid if you have ulcers, kidney disease, or are on blood thinners.
How: Blocks prostaglandins to reduce pain and swelling.
Side effects: Stomach irritation, bleeding risk; use only if your clinician says it’s okay.Topical antibiotic eye drops (e.g., moxifloxacin) after worm extraction—if prescribed
Purpose: Prevent secondary bacterial infection of the small eye incision.
How: Kills common surface bacteria while the eye heals.
Side effects: Local irritation; use only as directed and for the full course.Short-course steroid eye drops (e.g., loteprednol) after extraction—if prescribed
Purpose: Reduce post-procedure eye inflammation.
How: Local steroid effect on the conjunctiva.
Side effects: Can raise eye pressure if used too long; must be short and supervised by an eye doctor.
Not recommended: Doxycycline is helpful for some other filarial infections because those worms carry Wolbachia bacteria. Loa loa does not, so doxycycline is not useful for loiasis.
Dietary, “molecular,” and supportive supplements
Important: No food or supplement cures loiasis. These ideas support general recovery, reduce inflammation, or protect the eye/skin. Always check for interactions with your medicines.
Hydration (water)—goal 2–3 liters/day unless your doctor says otherwise.
Supports circulation and comfort during inflammatory flares.Protein-rich foods—eggs, fish, beans, dairy.
Protein supplies amino acids for tissue repair after procedures or swelling.Vitamin A (from food; supplements only if deficient)—carrots, sweet potato, spinach.
Supports eye surface health; avoid high-dose pills unless prescribed.Vitamin C (supplement 200–500 mg/day)
Antioxidant that helps neutralize inflammation byproducts; gentle on stomach.Vitamin E (low-dose, 100–200 IU/day if used)
Antioxidant; do not combine with blood thinners without medical advice.Zinc (10–20 mg/day total intake)
Helps skin and immune function; long-term high doses can deplete copper—don’t exceed guidance.Selenium (50–100 mcg/day)
Antioxidant cofactor; stay within safe limits to avoid hair/nail issues.Omega-3 fatty acids (EPA+DHA 1–2 g/day)
Shift inflammatory mediators toward a calmer profile; may reduce post-flare soreness.Probiotics (per label, e.g., Lactobacillus/Bifidobacterium daily)
Modest immune-modulating effects; can help if antibiotics are used after a procedure.Curcumin (turmeric extract 500–1000 mg/day with piperine)
Anti-inflammatory properties; avoid with anticoagulants or gallbladder disease unless cleared.Quercetin (250–500 mg/day)
Mast-cell stabilizing effects; may ease itch tendencies; check for interactions.Bromelain (200–400 mg/day)
Proteolytic enzyme from pineapple; may support swelling control; avoid if allergic.Lutein + zeaxanthin (10 mg + 2 mg/day)
Supports retinal/ocular surface antioxidants—eye-health supportive, not a cure.Mixed colorful vegetables and fruits daily
Polyphenols act as gentle antioxidants; “eat the rainbow” is a safe, food-first approach.Avoid excess alcohol
Protects liver while on antiparasitic therapy and reduces dehydration that worsens headaches.
Regenerative, stem-cell drugs”—a reality check
There are no approved “regenerative” or stem-cell drugs for loiasis, and none are recommended. If you see such claims online, be skeptical. What clinicians actually use—only as adjuncts and for specific reasons—are medicines that temper immune reactions caused by dying parasites:
Prednisone/prednisolone (short course)—damps severe inflammatory reactions during DEC or after extraction.
Methylprednisolone (brief IV use in hospital)—for rare, severe reactions; specialist only.
Epinephrine (emergency use)—for anaphylaxis-like reactions (very uncommon); life-saving only in emergencies.
Second-generation antihistamines (e.g., cetirizine, fexofenadine)—reduce itch and hives.
First-generation antihistamines (e.g., hydroxyzine)—help itch and sleep.
Leukotriene blockers (e.g., montelukast)—occasionally used off-label for stubborn swelling/itch; modest benefit.
These do not kill Loa loa. They only control the body’s reaction so antiparasitic therapy is safer and more comfortable.
Surgeries/procedures
Conjunctival worm extraction (eye).
Procedure: Numbing drops → tiny surface nick → worm gently removed → brief antibiotic +/- steroid drops.
Why: Relieves irritation, prevents surface damage, and provides a specimen.Subcutaneous worm extraction (skin).
Procedure: Local anesthetic → small incision → worm teased out → closure with a stitch or strip.
Why: Reduces discomfort and confirms diagnosis.Incision & drainage if secondary infection occurs.
Procedure: Open and drain a pus pocket; short antibiotic course if needed.
Why: Treats bacterial complications from scratching or skin breakdown.Repair of conjunctival laceration or persistent granuloma.
Procedure: Ophthalmologist tidies and sutures tissue if a tear persists.
Why: Restores smooth eye surface and comfort.Apheresis (very rare, specialist centers).
Procedure: A machine filters blood to lower microfilariae counts before giving antiparasitic drugs.
Why: To reduce risk of severe reactions in people with extremely high Loa loa levels.
Ways to prevent African eye worm
Use DEET (20–50%) or picaridin (20%) on exposed skin during the day.
Wear long sleeves, trousers, and light-colored clothes; treat clothes with permethrin.
Avoid shaded streams and swampy areas during peak daytime biting.
Use window screens and fans; keep vehicle windows closed in rural areas.
Sleep under insecticide-treated nets (helps against other vectors too).
Plan fieldwork to minimize exposure at known hotspots.
Participate in local vector control efforts around homes and work sites.
Seek pre-travel counseling if visiting endemic regions; learn symptoms.
Get tested (daytime blood) if you develop Calabar swellings or see a worm in your eye.
During community deworming campaigns, tell health workers if you live in or traveled to Loa loa areas—it affects which medicines are safe for you.
When to see a doctor—don’t wait if you notice these
You see a worm cross your eye or feel movement under the skin.
You have repeated, migrating swellings, especially with itch.
You recently returned from West/Central Africa and have eye irritation, unusual swelling, or daytime fevers.
You were given ivermectin for another reason and now have severe headache, confusion, weakness, or vision changes—seek urgent care.
You develop signs of infection at an extraction site (increasing redness, warmth, pus).
You are pregnant, breastfeeding, or have liver disease and were told you may need antiparasitic medicine—discuss the plan with a specialist first.
Simple diet do’s and don’ts
Do:
Drink plenty of water daily.
Eat lean protein (fish, eggs, beans) for tissue repair.
Choose colorful vegetables and fruits for antioxidants.
Include healthy fats (olive oil, nuts, omega-3 fish).
If your clinician prescribes albendazole, take it with food to limit stomach upset (many regimens prefer with a meal).
Avoid / be cautious:
- Grapefruit and large amounts of grapefruit juice (can alter levels of some drugs—ask your clinician).
- Alcohol, especially while on antiparasitic medicines or steroids (liver and stomach protection).
- Very spicy or acidic foods if they trigger stomach irritation with medicines.
- Supplements you haven’t cleared with your clinician, especially if you’re on steroids or blood thinners.
- Raw or unsafe foods/water during travel that can add other infections on top of this one.
Frequently asked questions
1) What exactly is African eye worm?
A parasitic infection caused by Loa loa, a thin worm that lives under the skin and sometimes crosses the eye surface. It’s picked up from day-biting deer flies in West and Central Africa.
2) How do people get it?
By being bitten in the daytime by an infected Chrysops (deer) fly. It doesn’t spread from person to person directly.
3) Where is it found?
Parts of West and Central Africa, especially rainforest and swampy regions in countries such as Cameroon, Gabon, Republic of the Congo, and neighbors.
4) What are Calabar swellings?
Short-lived, soft puffy swellings under the skin caused by the immune system reacting to a moving adult worm. They can last hours to days, then disappear and reappear elsewhere.
5) Can it make me blind?
The worm can cross the eye and cause irritation, light sensitivity, and tearing, but permanent vision loss is uncommon. Proper removal and care protect the eye.
6) How is it diagnosed?
By seeing a worm in the eye or skin and/or finding microfilariae in a daytime blood smear (since the baby worms are most numerous during the day). Sometimes PCR tests or serology are used. Doctors also look for eosinophilia (a type of white blood cell increase).
7) Why are daytime blood tests important?
Loa loa baby worms follow a daily rhythm, peaking in the day. Testing at the right time makes the test more sensitive.
8) What is the best treatment?
Diethylcarbamazine (DEC) is the main medicine. Albendazole is often used first to lower microfilariae if needed, and ivermectin is used only with caution and specialist oversight because of safety concerns in loiasis.
9) Why is ivermectin risky here?
If you have a lot of Loa loa baby worms in your blood, ivermectin can kill them too quickly, which has, in rare cases, led to severe neurologic reactions. That’s why careful testing and planning are critical.
10) How long does treatment take?
Typical DEC courses last about 3 weeks. Some people need staged or repeated treatments, especially if counts were high.
11) Is doxycycline helpful like in other filarial infections?
No. Loa loa does not depend on the Wolbachia bacteria that doxycycline targets, so it doesn’t help here.
12) Can children or pregnant people be treated?
Yes, but drug choice and timing need specialist judgment. Always involve a clinician experienced with tropical medicine.
13) What if I also have onchocerciasis or other worms?
Co-infections complicate treatment plans. Specialists will sequence or combine therapies in a safe order.
14) I’m a traveler—what should I do to avoid it?
Use repellent, permethrin-treated clothing, and long sleeves during the day, and avoid shaded streams where deer flies bite.
15) Is there a vaccine?
No vaccine exists yet. Bite prevention and early diagnosis are the keys.
Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.
The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members
Last Updated: August 11, 2025.
