Sparganosis is a condition that occurs when the larvae of a certain kind of tapeworm take up residence inside a human host. The disorder is considered a zoonosis, which means it is an infection that affects all vertebrates and can thus be transmitted to humans. It is a type of tapeworm infection (a kind of helminthiasis and parasitic infection).
Definition & Facts
Sparganosis refers to infestation by a particular kind of tapeworm called Spirometra. The tapeworm is very similar to one that infects crustaceans and fish. Proliferative sparganosis is a fatal type of the infection.
To date, the countries with the most cases of Sparganosis in humans include Korea and Japan. It is most common in North America and Asia. Travelers who visit these regions and eat the local cuisine can become infected and return home with cases of Sparganosis. Sparganosis can be spread or transmitted via contaminated water, undercooked meat, and close contact with infected snakes and frogs. It is most common for people between the ages of 20 and 50.
According to the National Institutes of Health (NIH), currently more than 1,600 infections in human hosts have been reported. With the increase in global travel, tourism and raw/natural food culture, cases are continuing to be reported worldwide.
Symptoms & Complaints
Some of the most commonly reported major symptoms of sparganosis include the following:
- Obstruction in the intestines as the worm grows.
- The presence and growth of nodules that are painless at first.
- Eye pain and irritation, including swelling of the eyelids that can lead to blindness.
- Central nervous system symptoms including seizures, coma, fever, headaches, memory loss, confusion, fatigue, weakness, loss of motor skills, and eventual hemorrhage in areas of the cerebellum and cerebrum (brain).
- The presence of tumor or tumors under the skin (typically beginning in the neck, thigh, or shoulder) that eventually open and spread to other areas of the body. The infection may progress for up to 25 years before becoming severe.
Sparganosis is primarily contracted by eating raw or undercooked freshwater fish, frogs, snakes, and other infected vertebrates. The worm can also be transmitted by having contact with infected food during preparation, drinking water that is infested with the larvae, or having contact with animals that are infected with the worm.
In some countries, it is common practice to consume raw tadpoles, snakes and other freshwater aquatic life or use their raw parts over open wounds and orifices, particularly the eyes. It is thought that this is medicinally valuable and that it reduces inflammation, but such poultices of amphibian skin can cause infection through transmission of the worm larvae instead.
Diagnosis & Tests
Diagnosing sparganosis begins with taking an individual's medical history and family history as well as his or her travel and food history. Because the infection can progress over a long period of time, it is necessary to go back into the individual's past travel and food history for a period of time as well.
A physical examination that focuses on areas where symptoms are being felt is the next course of diagnostic action. The physician will inquire about and compile a complete list of symptoms to date and do a physical body examination to look for presentation of nodules, swelling, inflammation, pain, and other diagnostic symptoms. From this point, there are various tests that may be ordered to confirm the diagnosis as follows:
- CT (computed tomography) scan or magnetic resonance imaging (MRI) scan. With this test, the goal is to identify whether there are tissue changes over time (this will indicate whether or not the parasite is still living) and try to identify the location of the the worm for surgical removal.
- Serum or cerebrospinal fluid analysis. Testing for the presence of the parasite in and around the brain.
- Tissue sample analysis. Testing for the presence of the parasite in the tissue via biopsy.
Treatment & Therapy
There are only two known treatments that have delivered success to date with treating sparganosis, and neither treatment has been effective if the condition advances to the proliferative stage where the parasite has invaded multiple organs and tissue areas. The two treatments that are currently prescribed include these:
- Medication. Drugs can include anthelmintics such as praziquantel, mebendazole, and albendazole. Sometimes medication alone or medication combined with surgery have been successful. At other times, the results have been mixed.
- Surgical removal of the parasite. So long as sparganosis has not reached the proliferative stage, it remains possible to locate and surgically remove the parasite itself. If this can be accomplished, the recovery outlook is very positive.
Prevention & Prophylaxis
If one does come into contact with freshwater aquatic animals and potential host animals, one should wash hands thoroughly after doing so.
Individuals who are planning to travel to areas where sparganosis is more common should be particularly cautious about swimming, drinking the local water, eating local cuisine and practicing safe hygiene while on their trip.
Because there is no preventative vaccine, only by taking these precautionary measures can a potential infection be prevented. Most importantly, because the worm can incubate for many years before causing symptoms, it is never safe to assume infection has not occurred and let precautionary measures lapse.