Mon. May 23rd, 2022

Hookworm is found worldwide, especially in tropical areas. The global prevalence of hookworm how to clear a cloudy pool with baking soda infection is greater than the past estimate of nearly 500 million, so therefore, its effect to the human health should not be ignored.

Trichinella spiralis
This causes trichinosis. It occurs worldwide, especially in Sastern Europe and West Africa. The Adult female worms are up to 3-4 X 0.6mm; the adult male worms are up to 1.5 X 0.04mm. The incysted larvae (1mm) is enclosed in a fibrous cyst wall. It is localized in the small intestine (adult worms) and straited muscles (larvae). Any mammal (rat, bear, fox) can be infected, but pigs are the most important reservoirs of human disease. The infective stage of the Trichinella spiralis is the Larva. It is transmitted through the alimentary (eating raw or undercooked meat, usually pork, containing larvae encysted in the muscle) route.

The larvae excyst and mature into adults within the small intestine of host. Male worms die after fertilization, female worms lay larvae. They are released and distributed via the bloodstream to striated muscles (diaphragm, tongue, m.deltoideus, m.pectoralis, m.intercostalis). Larvae encyst in the muscles within fibrous capsule and can remain viable for several years. Humans are end-stage hosts, because the infected flesh is not consumed by other animals.

Clinical manifestations are as follows: initially diarrhea, abdominal pain followed by 1-2 weeks later by fever, muscle pain, periorbital edema and eosinophilia. Death, which is rare is usually due to congestive heart failure or respiratory paralysis.

Laboratory diagnosis involves muscle biopsy which would reveal larvae within striated muscle; serologic test (become positive 3 weeks after infection). Treatment therapy includes anti-parasitic drugs such as Thiabendazole, Albendazole, mebendazole, prednisone, depending on what the doctor prescribes. Prevention is done by properly cooking pork and by feeding pigs only with cooked garbage: pork inspection in slaughter houses using a trichinoscope.

Ancylostoma duodenale and Necator americanus (hookworms)
They cause ancylostomiasis (hook worm infection). Disease occurs primarily in children and construction workers who are exposed to infected soil.

Adult worms are 1cm in length; Eggs are translucent, oval with blunt poles, 40-60 micrometer in size. The rhabditiform larva is about 0.25-0.5 micrometer with rhabditiform oesophagus (1/3 body length), pointed tail end; the filariform larvae is about 0.6-0.7 micrometer with cylindrical esophagus (1/4 body length), sharply pointed tail. Its host is the humans; mode of transmission is by penetration of the skin by filariform larva. Its infective stage is the filariform larva.

Filariform larvae penetrate the skin, usually of feet or legs after exposure to infected soil. They are carried by the blood to the lungs, migrate into the alveoli and up the bronchi and trachea, and then are swallowed. Larvae develop into adults in the small intestine, attach to the wall with either cutting plates (Necator) or teeth (Ancylostoma). They feed on blood, up to 0.1-0.3ml per worm can be lost per day. Immature eggs pass in the feces about 2 months after infection. The eggs develop into rhabditiform larvae and then into filariform larvae (infective stage) in warm, moist soil.

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