Roundworm Parasitic Infection in Humans

Roundworms or Nematodes are long, thread-like parasitic worms that cause infections of the digestive tracts in humans. Infections caused by these worms are very common the world over, and in very severe cases, can prove fatal. The infection is mainly spread by a lack of adequate hygienic and sanitation methods.

For example, failing to wash hands before eating or before touching the mouth, failing to wash fruits and vegetables before eating, eating raw or uncooked meat or seafood, playing or working in soil that is contaminated, or having pets that are infected with roundworms. Following are different types of infections caused by nematodes in humans:

It is caused by anisakid roundworms, which infest fish, squid, and other sea creatures. You stand to get infected, if you eat raw or improperly cooked seafood. The ingested larvae attach themselves to the intestinal tissue, and induce nausea, vomiting, diarrhea, and severe abdominal pain in the infected person.

Ascariasis, the most common and possibly the most dangerous of all the roundworm infections, is caused by Ascarid roundworms, parasites that can grow up to 12 to 14 inches. Once ingested, Ascarid eggs reach the digestive tract, and release the larvae.

These larvae perforate the intestinal wall, enter the liver and bloodstream, and migrate towards the lungs. Symptoms of Ascariasis usually manifest themselves when the larvae reach the lungs.

This, known as Loeffler's Syndrome, is when the infected person experiences chest pains and inordinate coughing bouts, sometimes accompanied by bloody sputum. He or she may also have trouble breathing due to inflammation of the lungs.

From the lungs, the larvae move into the upper lung passages and airway. They are swallowed and returned to the intestine, where they now mature, reproduce, and release up to 20,000 eggs a day. The infected person suffers from stomach pain, cramps, and nausea. The overgrowth of the worms can lead to intestinal blockage or rupture.

The patient may require nasogastric suction to deal with the intestinal blockage, followed by a course of anthelmintic drugs. In severe cases, surgery may be required.

Toxocariasis is caused by the Toxocara canis and Toxocara cati parasites, which are found in the intestines of cats and dogs, especially ones that are not regularly dewormed. Every time these household pets defecate, the soil is contaminated with the parasites and their eggs.

The eggs are quite hard, and can survive in the soil for a very long time. They are sticky, and easily transfer themselves to anyone coming in contact with the soil where they lie. Children playing in sandboxes or mud are especially vulnerable.

The Toxocariasis eggs are ingested and the larvae hatch inside the intestines; this is why this infection is also called visceral larva migrans (VLM).The hatched larvae then travel through the bloodstream to other parts of the body. They can infect not just the lungs, but also the heart, the brain, the liver, and the eyes.

The signs of infection are coughing bouts, skin rash, high fever, and tissue swellings called granulomas. There may be complications from a swollen liver, inflammation of the lungs, and infection of the eyes leading to ocular larva migrans (OLM).

Trichuriasis, caused by the Trichuris trichuria parasite, is common in warm, humid climates. The parasite is also known as Whipworm, and over 800 million people are affected by it, annually. The ingested eggs hatch into larvae in the small intestine, and move to the large intestine where they attach themselves to the intestine wall.

A mild Trichuriasis infection generally doesn't have too many visible symptoms, but a heavy infection produces abdominal cramps and dysentery. It is more dangerous for children, in whom it can produce anemia and developmental retardation.

Roundworm infection is mainly detected by the symptoms produced, from the presence of worms in vomit and in the anus, from stool and tissue tests, and from X-ray and ultrasound scans.

Once detected, depending upon the degree of infestation and the condition of the patient, the doctor may prescribe a course of anthelminthic medication like Albendazole and Mebendazole (which prevent the worms from feeding or paralyze them), surgery, or both. The treatment does not prevent reinfection, so proper hygiene should be maintained.

Disclaimer: This story is for informative purposes only, and should not be used as a replacement for expert medical advice.