Trichuris trichiura Tliis worm is also knowu as the whipworm because the anterior end is highly atlenuatl'<l and the posterior end i. s thicker and more fleshy. 1t is another common intestinal worm nnd is usua Uy found together "ith Asca. ris. Trichuris eg_i:s that are passed Ollt by the female wonn embryonate in the soil in two to three we.-ks. "·hen these infecti\'e eggs are ingested, larvae are released. They then migrate to the large intestine$ particularly the caecum. where they de,·elop i1lto the adult worm:; (See l Uus. 15. 4). The attenuated anterior end penetrates the intestina l mucosa. In light infection, the patient i~ usually asymptomatic. lo cases ofhea\'y worn, burden, the patkul may suffer from abdominal discomfort and blood-streaked diarrheal :;tools. Bleeding sites h:n·e been observed at tl1e site of attachment. There are available e,idences in the cases ofhea\'y worm infection, anemia may develop. Heavy infection may, likewise, re,,-ult to rectal prolapse. The direct fecal smear, Kato thick and Kato-Katz techniques are very useful in the reco,-ery of Trichuris eggs during stool examination in the laboratory. Like J\scaris, Trichuriasi scan be controlled and prevented through periodic treatment, use of sanitary toilet facilities and proper hygienic practices. Hookworms These are blood sucking roundworms, because they can get attached into the intestinal mucosa of the small intestines through their b11ccal capsule. This buccal capsule ii; provided 1dth a definite dental pattern, which can he Jp is species identification. The two common species of hookworm are Necator ame. rica. n us and Ancylostoma duo<lenale. lo the Philippines, Necator americanus has a wider distribution compared to Ancylostoma duodenale. Animal hook,vonns are also existent namely: Ancylostoma brazilie11se of cats and A11cylostom a ca11inum of dogs. The eggs of these two parasites are very difficult to diffcreatint e. When these eggs reach the soil through indiscrimina te defecation, they rapidly embryonate and after 24-48 hours, the rhabditifrom larva is released. In about 7-10 days, the rhabditiform larva develops into the infective filariform larva. Human infection occurs when the filariform larvae penetrate the sk-in. After skin penetration, the patient develops some form of dermatitis commonly called ground or dew itch. The larvae then migrate to the lungs and the patient manifests pulmonary symptoms like coughing and v. ihee7. lllg. Then the parasites proceed to the small intestines where tl1ey develop into the adult worms (See Illus. 15. 5). The presence of adult worms in the intestines may result to abdomina l pain. Because of the buccal capsule, the parasite is able to bite into the intestinal mucosa and while biting is able to suck out blood from the hos L For as long as the worm is attached, the patient suffei-s from a conslilnt blood loss which may resolt to microcytic bypochromic anemia. Development of anemia, however, is determined by the·worm burden and the iron status of the patient. 362 