Enterobiasis, Anisakiasis, and Ascariasis: Parasitic Infections
Enterobiasis (Pinworm Infection)
Enterobius vermicularis, commonly known as pinworm, often causes infection within families. This infection, called enterobiasis, is characterized by the presence of pinworms in the perianal folds or vagina.
Morphology
Pinworms are small, white, slender nematodes. Adult worms possess a mouth connected to the esophagus, an esophageal bulb, and an intestine that terminates in an anus.
Epidemiology
Pinworm infection is prevalent in overcrowded living conditions. Eggs can survive for extended periods in accumulated dust. Inhalation or ingestion of these eggs leads to infection. There are no known animal reservoirs.
Laboratory Diagnosis
Diagnosis is based on clinical manifestations and confirmed by detecting characteristic eggs in the anal mucosa.
Treatment, Prevention, and Control
The primary treatment is pyrantel pamoate, with mebendazole as an alternative. To prevent reintroduction and relapse, all family members should be treated simultaneously. Good hygiene, including keeping fingernails clean, washing bedding, and prompt treatment, are crucial control measures.
Anisakiasis
Anisakiasis is a globally prevalent disease caused by ingesting larval nematodes of the family Anisakidae, such as those in the genus Anisakis.
Features
Anisakis is a roundworm nematode with several life stages (L1, L2, L3), each requiring a different host. Humans are infected only in the L3 phase.
Reservoir: Crustaceans, fish, and squid.
Clinical Presentation
Symptoms include digestive issues, acute abdominal pain, nausea, vomiting, and diarrhea. Intestinal obstruction may necessitate surgery. Medication often yields good results.
Prevention
Regarding fish, ensure good presentation conditions (unimpaired). For raw or nearly raw consumption (e.g., pickled or salted), freeze fish at -20°C for at least 24 hours.
Treatment
Treatment may involve surgery, immediate medical intervention, and parenteral antihistamines and corticosteroids.
Ascariasis (Ascaris lumbricoides Infection)
Ascaris lumbricoides are large worms, approximately 20 to 35 cm long, with a strong, flexible body. They inhabit the intestine. Females can produce unfertilized eggs. The worms can survive up to two weeks in the soil and are resistant to high temperatures. Humans are the primary reservoir; there is no animal reservoir.
Life Cycle
Infective eggs are ingested and reach the duodenum. They then migrate to the liver and subsequently to the lungs. In the lungs, larvae break through the capillary endothelium, entering the alveoli, bronchioles, and bronchi, ascending to the pharynx. The larvae are then swallowed, returning to the duodenum to complete their maturation. Eggs are passed in the feces, where they can survive even under unfavorable conditions.
Epidemiology
Ascariasis has a higher prevalence in areas with poor sanitary conditions, such as those where untreated human feces are used as fertilizer or where there is inadequate management of wastewater.
Clinical Syndromes
Even a single adult worm can be dangerous.
Symptoms and Complications
This nematode species can cause peritonitis, appendix obstruction, fever, vomiting, and abdominal distension.
Laboratory Diagnosis
Diagnosis is typically made by identifying the oval-shaped eggs in stool samples. Occasionally, adult worms are expelled. A radiograph can visualize worms in the intestine.
Treatment
Mebendazole, pyrantel pamoate, and piperazine are used as alternative treatments.
Prevention
Improving sanitary conditions and avoiding the use of human feces as fertilizer are essential preventive measures.