Worm Diseases While Traveling: Sucking and Roundworms

Bilharzia is particularly dangerous: it is transmitted by sucking worms, also called schistosomes (flukes); these live in stagnant waters in Asia, Africa, Central as well as South America and can be transmitted by even brief contact. According to WHO estimates, more than 200 million people worldwide are affected. The Bernhard Nocht Institute for Tropical Medicine in Hamburg explains that schistosomiasis can only occur where the intermediate hosts of the pathogens, which are certain freshwater snails, are found. Humans become infected on the shores of inland waters, through the larvae, which can penetrate the skin. Here, a skin rash occurs.

Via the lymphatic and blood systems as well as the lungs, the larvae reach the liver, where they grow into sexually mature worms within about six weeks. They then settle in the blood vessels of the intestinal tract or urinary tract, depending on the type of pathogen, to produce their eggs, which in turn cause inflammation, bleeding and tissue damage.

About 20 to 60 days after infection, fever, chills, headache, cough, swelling of the liver, spleen, and lymph nodes may occur; usually these symptoms disappear after several weeks, but the most severe courses have been reported, resulting in death. After about six months to several years after infection, the chronic stage begins.

Organ damage after worm infestation

In the case of minor worm infestation, there are usually only mild symptoms. With massive worm infestation, on the other hand, organ-specific complaints may occur. Intestinal bilharzia may be manifested by lassitude, weight loss, indigestion, abdominal pain, and bloody-mucous diarrhea.

Liver bilharzia is the most severe form: Swelling of the liver and spleen is followed by blood stasis with water retention in the abdomen and swelling of veins in the abdominal skin and esophagus. Bursting of the veins leads to life-threatening blood loss.

Bladder bilharzia can cause various symptoms in the bladder and urinary tract, and in late stages the urine is often bloody. The best known complication is bladder cancer. Diagnosis is made with the help of specialized laboratories. With early treatment with medication, schistosomiasis heals properly.

Roundworms very common

In the tropics and warm regions of Europe live the 15 to 40 centimeters long, white roundworms: the eggs of this parasite are found in the stool, in sewage sludge or even on fertilized vegetables. They enter the body with food. They settle in the small intestine, their maggots pierce the intestinal wall and enter the heart with the bloodstream, then the lungs.

Roundworm infestation is one of the most common intestinal worm infections – the World Health Organization estimates that about a quarter of the world’s population is affected. There are allergic reactions and bronchitis when worm maggots pass through the lungs.

Complaints in the intestines occur only when the infestation is severe: Colic, nausea, malnutrition and anemia. Rarely, a roundworm cluster leads to small intestinal obstruction. Eggs excreted in the stool remain capable of development for months if conditions are favorable. However, there is no direct transmission from person to person. The eggs can be detected in the stool about two months after infection.

Infestation with roundworms is treated with mebendazole, a drug that is effective against a variety of worm species. Mebendazole kills the worms, with treatment lasting three days.