ASCARIASIS

ASCARIASIS is a disease of humans caused by theparasitic roundworm Ascaris lumbricoides. Perhaps as many as one quarter of the world's population are infected, with a prevalence of 45% in Latin America and 95% in parts of Africa.^[1] Ascariasis is particularly prevalent in tropical and sub-tropical regions wherehygiene is poor. Other species of the genus Ascaris can cause disease in domestic animals, such as Ascaris suum which infects pigs. Some genes have been identified in humans that may increase susceptibility to infection.^[2]

Infection occurs by swallowing food contaminated withAscaris eggs from feces. The larvae hatch in theintestine, burrow through the gut wall, and migrate to thelungs through the blood system.^[3] There they break into the alveoli and pass up the trachea and oesophaguswhere they are coughed up and swallowed. The larvae pass through the stomach for a second time into the intestine where they mature into adult worms. They maintain their position by swimming against the intestinal flow caused by peristalsis.^[3] Adult worms have a life-span of 1-2 years which means that individuals may be infected all their lives as worms die and new worms are acquired. (WIKIPEDIA)

Prevention

Prevention includes: use of toilet facilities; safe excreta disposal; protection of food from dirt and soil; thorough washing of produce; and hand washing.

Food dropped on the floor should never be eaten without washing or cooking, particularly in endemic areas. Fruits and vegetables should always be washed thoroughly before consumption.

[edit]Treatment

Main article: Ascaricide

Pharmaceutical drugs that are used to kill roundworms are called ascaricides and include:

• Mebendazole (Vermox) (C₁₆H₁₃N₃O₂). Causes slow immobilization and death of the worms by selectively and irreversibly blocking uptake of glucose and other nutrients in susceptible adult intestine where helminths dwell. Oral dosage is 100 mg 12 hourly for 3 days.
• Piperazine (C₄H₁₀N₂.C₆H₁₀O₄). A flaccid paralyzing agent that causes a blocking response of ascaris muscle to acetylcholine. The narcotizing effect immobilizes the worm, which prevents migration when treatment is accomplished with weak drugs such as thiabendazole. If used by itself it causes the worm to be passed out in the feces. Dosage is 75 mg/kg (max 3.5 g) as a single oral dose.
• Pyrantel pamoate (Antiminth, Pin-Rid, Pin-X) (C₁₁H₁₄N₂S.C₂₃H₁₆O₆) Depolarizes ganglionic block of nicotinic neuromuscular transmission, resulting in spastic paralysis of the worm. Spastic (tetanic) paralyzing agents, in particular pyrantel pamoate, may induce complete intestinal obstruction in a heavy worm load. Dosage is 11 mg/kg not to exceed 1 g as a single dose.
• Albendazole (C₁₂H₁₅N₃O₂S) A broad-spectrum antihelminthic agent that decreases ATPproduction in the worm, causing energy depletion, immobilization, and finally death. Dosage is 400 mg given as single oral dose (contraindicated during pregnancy and children under 2 years).
• Thiabendazole. This may cause migration of the worm into the esophagus, so it is usually combined with piperazine.
• Hexylresorcinol effective in single dose, mentioned in : Holt, Jr Emmett L, McIntosh Rustin: Holt's Diseases of Infancy and Childhood: A Textbook for the Use of Students and Practitioners. Appleton and Co, New York,11th edition
• Santonin, more toxic than hexylresorcinol, mentioned in : Holt, Jr Emmett L, McIntosh Rustin: Holt's Diseases of Infancy and Childhood: A Textbook for the Use of Students and Practitioners. Appleton and Co, New York, 11th edition
• Oil of chenopodium, more toxic than hexylresorcinol, mentioned in : Holt, Jr Emmett L, McIntosh Rustin: Holt's Diseases of Infancy and Childhood: A Textbook for the Use of Students and Practitioners. Appleton and Co, New York, 11th edition

Also, corticosteroids can treat some of the symptoms, such as inflammation. In some cases with severe infestation, the sudden death of the worms may cause bowel obstruction, requiring surgical intervention.^[13]

Native Americans have traditionally used epazote (Chenopodium ambrisioides) for treatment, which was not as powerful as pharmaceutical compounds, but spontaneous passage of Ascarids provided some proof of efficacy.

[edit]Roughly 1.5 billion individuals are infected with this worm, primarily in Africa and Asia.^[14][1] Ascariasis is endemic in the United States including Gulf Coast; in Nigeria and inSoutheast Asia. One study indicated that the prevalence of ascariasis in the United States at about 4 million (2%)

(WIKIPEDIA)