Ascaris is a genus of parasitic nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...

 worms known as the "giant intestinal roundworms". One species, A. suum
Large roundworm of pigs
-Introduction:Ascaris suum, also known as large roundworm of pigs, is a parasitic nematode that causes ascariasis in pigs. Until recently it was believed that Ascaris suum could also infect humans; however, it has now been established that humans are affected by a related parasite, Ascaris...

, typically infects pigs
PIGS is a four letter acronym that can stand for:* PIGS , Phosphatidylinositol glycan anchor biosynthesis, class S, a human gene* PIGS , the economies of Portugal, Italy , Greece and Spain...

, while another, A. lumbricoides
Ascaris lumbricoides
Ascaris lumbricoides is the giant roundworm of humans, belonging to the phylum Nematoda. An ascarid nematode, it is responsible for the disease ascariasis in humans, and it is the largest and most common parasitic worm in humans. One-sixth of the human population is estimated to be infected by this...

, affects human populations, typically in sub-tropical and tropical areas with poor sanitation. A. lumbricoides is the largest intestinal roundworm and is the most common helminth infection of humans worldwide, an infection known as ascariasis
Ascariasis is a human disease caused by the parasitic roundworm Ascaris lumbricoides. Perhaps as many as one quarter of the world's people are infected, with rates of 45% in Latin America and 95% in parts of Africa. Ascariasis is particularly prevalent in tropical regions and in areas of poor...

. Infestation can cause morbidity, and sometimes death, by compromising nutritional status, affecting cognitive processes, inducing tissue reactions, such as granuloma, and provoking intestinal obstruction or rectal prolapse.


  • Adult: cylindrical shape, creamy white or pinkish in color.
  • Male: average 15–31 cm and is more slender than female.
  • Female: average 20–35 cm in length..


  • Bloody sputum
  • Cough
  • Low-grade fever
  • Vomiting worms
  • Passing of worm in stool
  • Gallstone
    A gallstone is a crystalline concretion formed within the gallbladder by accretion of bile components. These calculi are formed in the gallbladder, but may pass distally into other parts of the biliary tract such as the cystic duct, common bile duct, pancreatic duct, or the ampulla of...

  • Liver abscesses
  • Pancreatitis
    Pancreatitis is inflammation of the pancreas. It occurs when pancreatic enzymes that digest food are activated in the pancreas instead of the small intestine. It may be acute – beginning suddenly and lasting a few days, or chronic – occurring over many years...

  • Pulmonary eosinophilia

Lung phase

A.lumbricoides is known as Ascaris pneumonitis. In the lung it causes hemorrhage, inflammation, bacterial infection. It also causes allergy in areas with seasonal transmission. Typically occurs at 6–15 days after initial exposure.

Intestinal phase

The intestinal phase causes malnourishment, intestinal blockage, verminous intoxication. A.lumbricoides will move around in the body in response to chemotherapy or fever. Typically occurs at 6 to 8 weeks after initial exposure.


Early diagnosis can be performed by examination of stool for the worm eggs. The spread or infection of A.lumbricoides can be controlled by proper disposal of faeces and proper washing of food. Control of helminthiasis is based on drug treatment, improved sanitation and health education.

Defense Mechanism

As part of the parasite defense strategy, Ascaris roundworms secrete a series of inhibitors to target digestive and immune-related host proteases, which include pepsin, trypsin, chymotrypsin/elastase, cathepsins, and metallocarboxypeptidases (MCPs).
Ascaris inhibits MCPs by releasing a enzyme known as Ascaris carboxypeptidase inhibitor (ACI). This enzyme binds to the active site of MCP and blocks the cleavage of its own proteins by the host MCP (Sanglas et al., 2008)


Infections with A.lumbricoides are easily treated with a number of anthelmintic drugs:
  • pyrantel pamoate
    Pyrantel pamoate
    Pyrantel pamoate or Pyrantel Embonate , is used as a deworming agent in the treatment of hookworms and roundworms in domesticated animals such as horses, cattle, sheep, pigs, cats, dogs, and many other species. It is a combination of pyrantel and pamoic acid...

     given as a single dose of 10 mg/kg
  • levamisole
    Levamisole is an anthelminthic and immunomodulator belonging to a class of synthetic imidazothiazole derivatives. It was discovered at Janssen Pharmaceutica in 1966...

     given as a single dose of 2.5 mg/kg
  • mebendazole
    Mebendazole or MBZ is a benzimidazole drug developed by Janssen Pharmaceutica and marketed as Vermox, Ovex, Antiox, and Pripsen...

     given as a single dose of 500 mg
  • albendazole
    Albendazole, marketed as Albenza, Eskazole, Zentel and Andazol, is a member of the benzimidazole compounds used as a drug indicated for the treatment of a variety of worm infestations. Although this use is widespread in the United States, the U.S. Food and Drug Administration has not approved...

     given as a single dose of 400 mg.sup

The drugs' main target is the absorbing cells of the worm. The drugs prevent the worm from absorbing sugar in the intestine which is essential for its survival. This process leads to depletion of energy in worm and its eventual death within few days. The dead worm is then excreted from the gut in the stool. Albendazole is not well absorbed by the intestines and a high fat food or meal should be consumed with each dose.

Many parasitic disease specialists are seeing increased initial incidence and recurrence of roundworm in the U.S. and are thereby increasingly recommending follow up courses of medication to treat internal eggs which have not yet hatched, in addition to the initial treatment period as above. This consists of sporadic treatment with albendazole or similar for a period of three days each month for up to five months after the initial treatment period.

More severe cases, blockage of intestine or pancreatic ducts require surgical removal of worms.

Some, including parasitologist Dr. Hulda Clark have advocaated a diet high in Jalepeno peppers, citing the low incidence of Ascaris infection in Mexicanos.

See ascariasis
Ascariasis is a human disease caused by the parasitic roundworm Ascaris lumbricoides. Perhaps as many as one quarter of the world's people are infected, with rates of 45% in Latin America and 95% in parts of Africa. Ascariasis is particularly prevalent in tropical regions and in areas of poor...

for more information.
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