This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: parasitology, Subject name: Microbiology
The slender rhabditiform larvae of which of the following helminths move about in water and are ingested by species of cyclops- 
Select and explain. 
A. D. Latum, B. D. Medinensis, C. W. Bancrofti, D. S. Mansoni
B: D. Medinensis
Answer: B: D. Medinensis 
Explanation: . Following ingestion, the copepods die and release the larvae, which penetrate the host stomach and intestinal wall and enter the abdominal cavity and retroperitoneal space . After maturation into adults and copulation, the male worms die and the females (length: 70 to 120 cm) migrate in the subcutaneous tissues towards the skin surface . Approximately one year after infection, the female worm induces a blister on the skin, generally on the distal lower extremity, which ruptures. When this lesion comes into contact with water, a contact that the patient seeks to relieve the local discomfo, the female worm emerges and releases larvae . The larvae are ingested by a copepod and after two weeks (and two molts) have developed into infective larvae . Ingestion of the copepods closes the cycle .