What is paragonimiasis?
Paragonimiasis is an infection with parasitic worms. It is caused by eating undercooked crab or crayfish.
Paragonimiasis can cause illness resembling pneumonia or stomach flu. The infection can last for years.
How common is paragonimiasis?
Paragonimiasis is extremely common, especially in Asia, West Africa, and South and Central America.
It can affect patients at any age. It can be managed by reducing your risk factors. Please discuss with your doctor for further information.
What are the symptoms of paragonimiasis?
Paragonimiasis causes no symptoms during initial infection. Many people with paragonimiasis never experience any symptoms. When paragonimiasis symptoms do occur, they result from the worms’ location and activity in the body, which change over time.
In the first month or so after being infected, paragonimiasis worms spread through the abdomen, sometimes causing symptoms that can include:
- Belly pain
- Itching and hives
Worms then travel from the belly into the chest. There they can cause respiratory symptoms, such as:
- Shortness of breath
- Chest pain (made worse by deep breathing or coughing)
Without treatment, paragonimiasis becomes chronic. It can continue for decades.
The most common long-term paragonimiasis symptom is a cough with bloody sputum (hemoptysis) that comes and goes. Other chronic paragonimiasis symptoms may include:
- Belly pain
- Bloody diarrhea
- Lumps or bumps on the skin of the belly or legs that come and go over time
Some people with chronic paragonimiasis have no noticeable symptoms.
In less than 1% of people with paragonimiasis, the worms infect the brain. Symptoms can include:
- Double vision
There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.
When should I see my doctor?
If you have any signs or symptoms listed above or have any questions, please consult with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.
What causes paragonimiasis?
Paragonimiasis is caused by infection with a flatworm. That’s a parasitic worm also called a fluke or lung fluke because it can also infect the lungs. Usually, infection comes after eating undercooked crab or crayfish that carry immature flukes.
Once swallowed by a person, the worms mature and grow inside the body. Over months, the worms spread through the intestines and belly (abdomen). They penetrate the diaphragm muscle to enter the lungs. Once inside the lungs, the worms lay eggs and can survive for years, causing chronic (long-term) paragonimiasis.
What increases my risk for paragonimiasis?
There are many risk factors for paragonimiasis, such as:
- Travelling to or living in developing countries and countries such as Japan, China, Taiwan, South Korea, Vietnam, the Philippines, and Thailand. Other species affect people from Africa as well as Central and South America.
- Have preference for diet for crab or crawfish
Diagnosis & Treatment
The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.
How is paragonimiasis diagnosed?
Diagnosing paragonimiasis can be difficult or delayed. That’s because its symptoms are often mild and overlap with more common conditions.
Most often, a person with symptoms has multiple tests before a doctor makes the diagnosis of paragonimiasis. Exams and tests used to make a diagnosis include:
- Patient history. Your doctor will get clues about possible paragonimiasis by looking at the pattern in which your symptoms appeared. Your doctor will ask about your past eating of undercooked crab or crayfish.
- Physical examination. Abnormal breath sounds or belly tenderness observed with a doctor’s examination of the chest or belly can suggest a problem and direct further testing.
- Blood tests. A high number of a specific type of white blood cells can suggest parasitic infection. Antibodies against flukes may be present in the blood.
- Sputum microscopy. Fluke eggs can be detected during examination of coughed-up sputum under a microscope.
- Chest X-ray. Nodules (spots) in the lungs, hollowed-out areas (cysts or cavities), or fluid around the lungs (pleural effusions) may be present.
- CT scan. High-resolution images of the lungs may show more detailed information than a chest X-ray. Also, CT of the head or abdomen may be abnormal if paragonimiasis involves the brain or liver.
- MRI. Very high-definition images of the brain can identify cysts or brain swelling caused by paragonimiasis.
- Bronchoscopy . A doctor can put an endoscope (flexible tube with a camera on its tip) through the nose or mouth into the lungs. Flukes or their eggs are collected from lung fluid samples. The flukes or eggs may be seen under a microscope.
- Thoracentesis. A doctor puts a needle through the chest wall to sample fluid around the lungs (pleural effusion).
- Stool studies. Fluke eggs may be seen in stool samples when examined under a microscope.
A definite diagnosis of paragonimiasis is made when fluke eggs are detected in an infected person’s sputum or stool. But the flukes may not lay eggs until two months after you are infected. That makes early diagnosis difficult.
How is paragonimiasis treated?
In most people, paragonimiasis can be cured with oral anti-parasite medications. The recommended treatment is praziquantel (Biltricide). It is taken three times daily for two days.
In the rare cases of paragonimiasis with brain involvement, other treatments may be necessary, such as anti-seizure medications or surgery to reduce brain swelling.
Lifestyle changes & Home remedies
What are some lifestyle changes or home remedies that can help me manage paragonimiasis?
The following lifestyles and home remedies might help you cope with Paragonimiasis:
Never eat raw freshwater crabs or crayfish. Cook crabs and crayfish for to at least ~63°C. Travelers should be advised to avoid traditional meals containing undercooked freshwater crustaceans.
If you have any questions, please consult with your doctor to better understand the best solution for you.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Parasites - Paragonimiasis (also known as Paragonimus Infection). https://www.cdc.gov/parasites/paragonimus/prevent.html. Accessed Mar 12, 2017.
Paragonimiasis. http://www.webmd.com/a-to-z-guides/paragonimiasis#1-2. Accessed Mar 12, 2017.
Review Date: March 12, 2017 | Last Modified: April 17, 2017