Trichinosis: Symptoms, Causes, Diagnosis and Treatment — What You Need to Know
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD | Last reviewed: October 7, 2026
Quick Answer
Trichinosis (trichinellosis) is a roundworm infection caught by eating raw or undercooked meat containing trichinella larvae, most often pork or wild game [1]. Digestive symptoms start 1 to 2 days after eating it, and muscle pain, fever and facial swelling follow weeks later [1]. Most cases improve within a few months [2]. Cooking meat to 160°F (71°C) prevents it [1].
What the research says
Severe infection can reach the nervous system, and treatment combines an antiparasitic with a corticosteroid. A clinical review of neurotrichinellosis, one of the most serious complications of severe trichinellosis, found that brain involvement (encephalopathy) was the presentation most responsible for deaths, that albendazole and mebendazole are the anthelmintics of choice and should be used with corticosteroids to prevent allergic reactions, and that only a muscle biopsy gives absolute certainty of infection (Bruschi et al., Handbook of Clinical Neurology, 2013) [3].
Diagnosis rests on the exposure history, and education alone is a weak safeguard. An expert review concluded that laboratory tests are not sensitive enough to diagnose individual patients reliably when an outbreak is suspected, so a likely diagnosis depends on identifying a shared source of exposure supported by antibodies in more of the exposed people than expected. It also judged public education probably not a reliable way to prevent trichinellosis on its own, recommending mandatory testing of potentially infected meat where feasible (Shimoni & Froom, Expert Review of Anti-infective Therapy, 2015) [4].
When Should You See a Doctor?
If you have mild trichinosis with no symptoms, you might not need medical care [1]. But if you have digestive problems or muscle pain and swelling about a week after eating pork or wild-animal meat, talk with your healthcare professional [1].
Tell your healthcare professional you recently ate raw or undercooked meat. It is key information that points them toward the right diagnosis.
What Is Trichinosis?
Trichinosis (trik-ih-NO-sis) is a type of infection caused by a roundworm parasite. Roundworm parasites use a host body to live and breed more roundworms. These parasites, also called trichinella worms, infect animals such as deer, bears, moose, walruses, wild boars and pigs [1].
The infection, also called trichinellosis (trik-ih-nuh-LOW-sis), spreads when animals eat the young forms of the roundworm in raw meat. These young forms are called larvae [1].
Trichinosis happens throughout the world [1]. Medicine exists to treat the adult worms that cause the condition, but not everyone needs medicine. The best defense is making sure food is cooked to the recommended temperature.
How Do Roundworm Larvae End Up in Meat?
People get trichinosis when they eat infected meat that hasn’t been cooked enough. The larvae grow into adult worms in the small intestine within about a week. The adult worms make more larvae that travel through the bloodstream. They then make a home in muscle tissue [1].
Each larva either forms a cyst around itself or buries itself in the muscle without a cyst. The larvae can live for months to years inside the muscle tissue [1].
You Can’t Catch It From Another Person
You can’t get the infection from another person or give it to another person. Wild animals become infected when they feed on other infected animals. Domestic animals could be infected by their feed or contact with meat scraps [1].
What Are the Symptoms of Trichinosis?
Symptoms of trichinosis infection, and how bad they are, can vary. They depend on the number of larvae eaten in the infected meat [1], and symptoms sometimes get worse as the roundworm larvae travel through the body.
Can You Have Trichinosis With No Symptoms?
Yes. Trichinosis with only a small number of parasites in the body may not cause symptoms at all [1].
Early Symptoms (Days 1–2)
People eat meat infected with roundworm larvae in tiny sacks, called cysts, that hold the parasite. During digestion, the larvae are released. The larvae then enter the wall of the small intestine, where they grow into adult worms and mate. Digestive symptoms can begin 1 to 2 days after infection [1]:
Early symptom | What it looks like |
Loose stools | Changes in bowel habits shortly after eating the infected meal |
Belly pain | Abdominal discomfort during the digestive stage |
Tiredness | Unusual fatigue appearing early in the infection |
Upset stomach and vomiting | Nausea and vomiting during the first days |
Later Symptoms (About 2–8 Weeks)
About a week after infection, the adult female worms make larvae. The larvae go through the wall of the intestine and enter the bloodstream. They travel around the body and bury themselves in muscle tissue. Symptoms caused by roundworms in muscle tissue most often start 2 to 8 weeks after infection [1]:
Later symptom | What it looks like |
High fever and chills | Fever with chills once larvae reach muscle |
Muscle pain and tenderness | Aching, sore muscles |
Aching joints | Joint pain accompanying muscle symptoms |
Swelling of the eyelids or face | Puffiness around the eyes or face |
Weakness | Reduced strength and stamina |
Headache | Head pain during the muscle stage |
Sensitivity to light | Discomfort in bright light |
Eye pain or pink eye | Pain or conjunctivitis |
Itchy skin | Skin itching |
How Long Do Symptoms Last?
Symptoms may last for several months, but they ease when the larvae form cysts. Even after the infection is gone, tiredness, mild pain and weakness may last for months or years [1].
Having many parasites can cause bad muscle pain and weakness. This can make it hard to move, breathe and speak [1].
What Causes Trichinosis?
People get trichinosis when they eat raw or undercooked meat that is infected with the larvae of a trichinella roundworm parasite [1].
Source of infection | How animals or food become infected |
Wild animals (deer, bears, moose, walruses, wild boars) | Infected when they feed on other infected animals [1] |
Domestic pigs | Infected by their feed or contact with meat scraps [1] |
Pork in the U.S. | Less common source today due to better pork feed and product management; pigs raised or killed on non-commercial farms may still be infected [1] |
Wild-animal meat | Source of most trichinosis in the U.S. [1] |
Beef | Rarely a source, because cows don’t eat meat, but infection has been linked to beef mixed with infected pork [1], or meat ground in a grinder that processed infected meat |
What Are the Risk Factors?
Eating raw or undercooked food is the main risk factor for trichinosis [1]. Food also can be infected by grinders or other equipment [1].
Risk factor | Why it raises risk |
Eating raw or undercooked meat | Larvae survive when meat isn’t cooked to a safe temperature |
Eating meat from wild animals | Wild-animal meat is the source of most U.S. cases |
Animals raised or processed outside a commercial facility | Pigs on non-commercial farms may be infected |
Shared meat grinders | Grinders that processed infected meat can contaminate beef or other meat |
What Are the Complications?
Complications linked to trichinosis are rare. But if many roundworm larvae move through the body to muscle tissue in and around organs, this may cause harmful complications. Some may be fatal [1].
How Is Trichinosis Diagnosed?
Your healthcare professional can diagnose trichinosis by asking about your symptoms and doing a physical exam [2]. Tell your healthcare professional if you’ve eaten meat that was raw or not cooked to a safe temperature. You also might have these tests:
Test | What it looks for |
Blood tests | A blood sample can show signs of trichinosis: a high number of white blood cells called eosinophils, or, after a few weeks, antibodies formed against the parasite [2] |
Muscle biopsy | Removing a small piece of muscle to study under a microscope for roundworm larvae. A blood test most often is enough, but a biopsy may also be done [2] |
How Is Trichinosis Treated?
Trichinosis most often gets better on its own [2]. If you have a mild or moderate number of larvae, most symptoms go away within a few months. But you may have tiredness, mild pain, weakness and loose stools for months or years [2]. Infection with a lot of larvae can cause worse symptoms that need treatment right away [2]. Your healthcare professional may prescribe different medicines based on what you need.
Antiparasitic Medicine
This is the first line of treatment [2]. Early on, albendazole or mebendazole can kill the worms and larvae in the small intestine [2]. Side effects may include upset stomach, vomiting, loose stools and stomach pain [2].
If the larvae have buried themselves in muscle tissues, the antiparasitic medicines may not kill all the parasites [2]. But you may take an antiparasitic medicine if you have inflammation (pain and swelling) of the brain, heart or lungs due to larvae in these organs.
Pain Relievers
After the larvae are in the muscles, your healthcare professional may prescribe pain relievers to help ease muscle aches and inflammation [2]. Over time, the larvae cysts in the muscles tend to harden into calcium, called calcify. Then the larvae die, and the muscle aches and weakness most often go away [2].
Steroid Medicine
Sometimes trichinosis can cause an allergic reaction. This may happen when the parasite enters muscle tissue or when dead or dying larvae release chemicals in the muscle tissue. A steroid medicine may control pain and swelling [2].
How Do You Prevent Trichinosis?
The best way to prevent trichinosis is to cook food well [1]. Follow these tips:
Prevention step | What to do |
Cook meat to a safe temperature | Don’t eat meat that’s raw or not cooked to a safe temperature. Cook cuts of meat until brown. Cook pork and meat from wild animals to 160°F (71°C) at the center, using a meat thermometer [1] |
Freeze pork | Freezing pork that is less than 6 inches thick at 5°F (-15°C) for three weeks kills roundworm parasites [1] |
Know what freezing can’t do | Roundworm parasites in wild-animal meat won’t die by freezing, even over a long period [1] |
Know what processing can’t do | If meat is infected, smoking, curing and pickling won’t make it safe to eat. Neither will cooking it in a microwave [1] |
Clean meat grinders | If you grind your own meat, clean the grinder well after each use [1] |
Wash your hands | After handling raw meat, wash hands well with soap and water for 20 seconds [1] to prevent spreading parasites to other food |
How should you prepare for a trichinosis appointment?
You’re likely to start by seeing your family healthcare professional. Sometimes, you may see an infectious disease specialist [2]. Make a list of:
Your symptoms and when they began, including those that don’t seem linked to the reason you scheduled the appointment
Key personal information, including major stresses or recent life changes, and whether you’ve eaten any raw or rare pork or wild-animal meat lately
All medicines, vitamins, herbs and supplements you take, including dosages
Questions to ask your healthcare team
Some questions to ask: What is likely causing my symptoms or condition? What are other possible causes? What tests do I need? Is my condition likely to clear up or last? What treatments are there? Are there brochures or other printed material I can have? What websites do you suggest? Be sure to ask all the questions you have.
Your healthcare team may ask you:
Question | Why it matters |
Have you eaten raw or rare pork or wild-animal meat lately? | The key exposure question |
Have your symptoms stayed with you or do they come and go? | Helps place the infection stage |
How bad are your symptoms? | Determines whether treatment is needed |
What makes your symptoms better? What makes them worse? | Guides symptom management |
What should you do next about trichinosis?
If you recently ate raw or undercooked pork or wild-animal meat and are having digestive problems or muscle pain and swelling, don’t wait for the symptoms to move to the muscle stage. Talk with your healthcare professional and mention exactly what you ate, because it is the fastest way to the right diagnosis. In the meantime, keep track of your symptoms and when they began, and cook all pork and wild-game meat to 160°F (71°C) at the center.
Take action today: bookmark this guide, share it with anyone who hunts, forages or cooks wild game, and schedule a visit if your symptoms match the later-stage checklist above.
Frequently Asked Questions
What is trichinosis?
Trichinosis is an infection caused by a roundworm parasite. The parasites, also called trichinella worms, infect animals such as deer, bears, moose, walruses, wild boars and pigs, and people get infected by eating undercooked meat containing the parasites’ young forms, called larvae.
Is trichinosis the same as trichinellosis?
Yes. Trichinellosis is simply another name for the same infection caused by trichinella roundworm larvae.
How do people get trichinosis?
People get trichinosis when they eat raw or undercooked meat that is infected with the larvae of a trichinella roundworm parasite. The main risk factor is eating raw or undercooked food.
Can you get trichinosis from another person?
No. You can’t get the infection from another person or give it to another person.
What happens inside the body after eating infected meat?
The larvae grow into adult worms in the small intestine within about a week. The adult worms make more larvae that travel through the bloodstream and make a home in muscle tissue, where each larva forms a cyst around itself or buries itself in the muscle.
How soon do symptoms start?
Digestive symptoms can begin 1 to 2 days after infection. Symptoms caused by roundworms in muscle tissue most often start 2 to 8 weeks after infection.
What are the early symptoms of trichinosis?
Early digestive symptoms include loose stools, belly pain, tiredness, and upset stomach and vomiting.
What are the later symptoms of trichinosis?
Later symptoms include high fever and chills, muscle pain and tenderness, aching joints, swelling of the eyelids or face, weakness, headache, sensitivity to light, eye pain or pink eye (conjunctivitis), and itchy skin.
Can trichinosis cause no symptoms at all?
Yes. Trichinosis with only a small number of parasites in the body may not cause symptoms.
How long do trichinosis symptoms last?
Symptoms may last for several months but ease when the larvae form cysts. Even after the infection is gone, tiredness, mild pain and weakness may last for months or years.
Can trichinosis make it hard to move, breathe and speak?
Yes. Having many parasites can cause bad muscle pain and weakness that can make it hard to move, breathe and speak.
What are the serious complications of trichinosis?
Complications are rare, but if many larvae move to muscle tissue in and around organs, they can cause inflammation of the heart muscle layer (myocarditis), the brain (encephalitis), the tissue protecting the brain and spinal cord (meningitis) or the lungs (pneumonitis). Some complications may be fatal.
How is trichinosis diagnosed?
Diagnosis starts with a symptom discussion and physical exam. Blood tests can show a high number of white blood cells called eosinophils or antibodies against the parasite, and a muscle biopsy may also be done to look for larvae under a microscope.
Does trichinosis go away on its own?
Most often, yes. With a mild or moderate number of larvae, most symptoms go away within a few months.
What medicines treat trichinosis?
Antiparasitic medicines such as albendazole or mebendazole are the first line of treatment early in infection. Pain relievers can ease muscle aches and inflammation, and steroid medicine may control pain and swelling from allergic reactions.
Why doesn’t antiparasitic medicine always kill all the parasites?
If the larvae have buried themselves in muscle tissues, the antiparasitic medicines may not kill all the parasites. They may still be used when inflammation affects the brain, heart or lungs.
What happens to the larvae left in the muscles?
Over time, the larvae cysts in the muscles tend to harden into calcium (calcify). Then the larvae die, and the muscle aches and weakness most often go away.
Why do some people with trichinosis take steroid medicine?
Trichinosis can cause an allergic reaction when the parasite enters muscle tissue or when dead or dying larvae release chemicals in the muscle. A steroid medicine may control the resulting pain and swelling.
What is the safest temperature to cook pork?
Cook pork and meat from wild animals to 160°F (71°C) at the center, using a meat thermometer.
Does freezing meat kill trichinella parasites?
Freezing pork that is less than 6 inches thick at 5°F (-15°C) for three weeks kills the parasites. But roundworm parasites in wild-animal meat won’t die by freezing, even over a long period.
Do smoking, curing or pickling make infected meat safe?
No. If meat is infected, smoking, curing and pickling won’t make it safe to eat, and neither will cooking it in a microwave.
Is beef a common source of trichinosis?
No. You can’t get trichinosis from beef most of the time because cows don’t eat meat. But some cases have been linked to beef mixed with infected pork or ground in a grinder that processed infected meat.
What is the main source of trichinosis in the U.S.?
Wild-animal meat is the source of most trichinosis in the U.S. Pigs have become a less common source due to better management of pork feed and products.
How do you prevent trichinosis when grinding your own meat?
Clean meat grinders well after each use, since grinders that processed infected meat can contaminate beef or other meat.
When should you see a doctor for trichinosis?
See your healthcare professional if you have digestive problems or muscle pain and swelling about a week after eating pork or wild-animal meat. Mild trichinosis with no symptoms might not need medical care.
What should I tell my doctor at the appointment?
Tell your healthcare professional if you’ve eaten meat that was raw or not cooked to a safe temperature, and bring a list of your symptoms and when they began, key personal information, and all medicines and supplements you take.
Related Reading
Roundworms: Symptoms, Causes, and Prevention Guide covers the roundworm infections people can catch and how to prevent them.
Eosinophilia: Symptoms, Causes, Related Disorders, Diagnosis, Treatment and When to See Your Provider — What You Need to Know explains high eosinophil counts, a common blood finding in parasitic infections.
Food Poisoning (Foodborne Illness): Symptoms, the 16 Common Causes, and How to Recover Safely at Home covers common foodborne illnesses and how to recover safely at home.
Parasitic Infection: Types, Symptoms, and Prevention Strategies outlines the main types of parasitic infections and how to avoid them.
Sources
Mayo Clinic Staff. Trichinosis - Symptoms and causes. Mayo Clinic. December 24, 2025. https://www.mayoclinic.org/diseases-conditions/trichinosis/symptoms-causes/syc-20378583
Mayo Clinic Staff. Trichinosis - Diagnosis and treatment. Mayo Clinic. December 24, 2025. https://www.mayoclinic.org/diseases-conditions/trichinosis/diagnosis-treatment/drc-20378587
Bruschi F, Brunetti E, Pozio E. Neurotrichinellosis. Handb Clin Neurol. 2013;114:243-249. PMID 23829915. https://doi.org/10.1016/B978-0-444-53490-3.00019-4
Shimoni Z, Froom P. Uncertainties in diagnosis, treatment and prevention of trichinellosis. Expert Rev Anti Infect Ther. 2015;13(10):1279-1288. PMID 26243167. https://doi.org/10.1586/14787210.2015.1075394
Medical disclaimer
This article provides general health information for educational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare provider with any questions about a medical condition. If you believe you have trichinosis, especially after eating raw or undercooked pork or wild-animal meat, consult a healthcare professional. Emergency signs such as severe inflammation of the heart, brain or lungs require immediate medical attention.
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