Many nematode infections are symptomless, particularly if the person has only a few adult worms (low worm burden). With the exception of Strongyloides, the nematodes cannot complete their life cycle within the host, so the number of adult worms is limited to how many a person was originally infected with. Here is a brief overview of disease symptoms and treatments for each of the roundworms that we covered:
Ascaris lumbricoides
Symptoms range from none to malnutrition and stunted growth in children with high worm burdens. If the numbers of worms are particularly high, intestinal obstruction can occur. Also, cases of intestinal perforation and migration of adult worms occasionally occur. Treatment includes oral albendazole or mebendazole, which are effective within a few days and have few side effects.
Enterobius vermicularis
Infections range from symptomless to fairly intense perianal pruritis (itching), which occurs when the female migrates to the anus to deposit eggs. Occasionally worms can get to the genital tract and cause vaginitis or other genitourinary problems, or they can be found in the appendix and cause appendicitis. Treatment is with oral albendazole, mebendazole, or pyrantel pamoate; a second dose should be given two weeks later to kill any worms that may have hatched from previously deposited eggs.
Hookworm Ancylostoma duodenale and Necator americanus
Patients with hookworm infection can be asymptomatic if only a few worms are present. Attachment to the intestinal wall by the worms via their hooks can lead to pain, nausea, and anorexia. Heavy infections can cause bleeding (occasionally resulting in anemia) and protein malnutrition. When the larvae originally penetrate the skin, it can cause itching and a rash (known as "ground itch). Pulmonary symptoms can occur when the larvae are migrating. Treatment is the same as with Ascaris, using oral albendazole or mebendazole. Anemia is usually treated with iron supplements.
Strongyloides spp.
Patients can experience diarrhea, constipation, and anorexia with heavier infections. As with hookworm, larvae can cause itching and rash at the site of skin penetration. Migrating larvae can cause various pulmonary and tracheal symptoms. Autoinfection can sometimes lead to hyperinfection, especially in patients that are immune suppressed. Hyperinfection can disseminate to other parts of the body, including the central nervous system. Strongyloides infections can be fatal to newborns and people with disseminated larvae. Treatment is with oral ivermectin; alternatively, albendazole is used if the patient cannot have ivermectin.
Trichuris trichiura
Patients are often symptomless with this infection. However, heavy infections can cause abdominal pain and diarrhea. Occasionally, especially in children, these whipworms can cause a prolapsed rectum because the worms attach to the lower part of the colon. Growth retardation has also been seen in children. Treatment is the same as Ascaris infection, with a few days of oral albendazole.
