Ascaris lumbricoides is a roundworm that comes under the phylum Nematoda. They infect humans. Ascaris is an endoparasite that infects the gastrointestinal tract. It is characterised by its large size. The males are 2 to 4 mm in diameter, 15 to 30 cm long, and females are 3 to 6 mm in diameter and 20 to 50 cm long. The males are slightly curved from the posterior end. It is estimated that it infects one billion people over a year. The infection is common in Africa, America, East Asia and China. .
Characteristics of Ascaris Lumbricoides
- Ascaris is a long, slender giant worm. The males are shorter than the females.
- The length of the female is 20 to 50 cm, and that of the males is 15 to 30 cm.
- The male worm is curved from the posterior end.
- Their body is elongated, cylindrical, smooth and unsegmented.
- Their body is tapered, and the end is round and pointed.
- Their body is covered with a noncellular, highly resistant cover called a cuticle, which helps them not get digested in the stomach of humans.
- They have a fully developed digestive system and distinctive digestive parts.
- Male and female are separated. Sexual dimorphism is present.
Lifecycles
Ascaris lumbricoides life cycle completes in seven stages:
First stage: It starts in the small intestine of humans. The adult Ascaris release their fertilised and unfertilised eggs into the intestine, which mix with the faeces and are released into the environment.
Second stage: The unfertilised eggs do not develop further. The fertilised eggs undergo further development. This is the infective stage. The eggs are converted into larva.
Third stage: The embryonated eggs are ejected out from the anus of the host with faeces into the external environment. They live freely in soil or water. By coming in contact with the soil and water containing egg or larva, the eggs go into the host’s stomach.
Fourth stage: The embryonated egg is ingested by the host, human or pig.
Fifth stage: The eggs hatch in the body of the host, and the larvae invade the intestinal mucosa. They circulate and migrate to the lungs.
Sixth stage: After entering into lungs, the larva starts maturing further. It takes 10 to 14 days to penetrate the alveolar wall. The matured larva now moves the bronchial tree upward into the throat, gets swallowed, and goes into the host’s stomach.
Seventh stage: This is the last stage of the life cycle of Ascaris. On reaching the small intestine, they start to develop into adult worms which takes 2 to 3 months. It also takes 2 to 3 months to oviposition the egg by an adult female.
The lifespan of adult worms is one to two years. When the adult female lays eggs, the eggs migrate into the intestine and are then removed into the external environment, and the whole life cycle starts again.
Infections
Ascariasis is the infection caused by this roundworm. These infections are very common. It occurs due to poor sanitation. The infection also occurs from human faeces because it contains eggs of the Ascaris. When the faeces containing Ascaris eggs are used as fertilisers and manure, the eggs with the vegetable and fruits go into the stomachs of animals and humans. Eating pork can also be the reason for Ascaris infection in humans.
Symptoms
The body only starts showing symptoms only in case of large infections. The symptoms are abdominal pain, ulcers in the intestine, fever, cough, bloody sputum, and sometimes long worms pass down through the anus.
Loeffler’s syndrome is the most common disease caused by ascariasis. This is a lung disease that is caused due to infection of any parasite in the lung. The symptoms include pulmonary infiltration, asthma and allergic reactions. This disease also sometimes increases fertility in women.
Preventions
- The worms are usually present in the faeces and dirty water, So by maintaining hygiene, we can prevent parasitic infections.
- If we properly dispose of faeces, the infection rate will reduce because if we kill the egg present in the faeces, the chances of infections are low.
- The eggs of the Ascaris survive 1 to 3 years. When we use human faeces as manure, the eggs present in the faeces go into the vegetables and from vegetables, the egg goes into the body of humans. Washing vegetables properly and cleaning hands are necessary to prevent parasitic infections.
- The eggs can be killed by alcohol, some special chemicals, iodine, cooking the food properly, acetic acid also effective in killing the acts of Ascaris.
Conclusion
Ascaris is a round parasitic worm that infects the human intestine. It is a common worm that can infect humans and swine. They are present in the soil, water. Humans get infected when they drink river water or dirty water. They are the most prevalent worms found worldwide. The infection caused by it is ascariasis. Generally, it does not show any symptoms, but it can cause malnutrition in children. Prevention from the infection is to maintain proper hygiene and a proper faeces disposal system. Its eggs can be removed by alcohol, vinegar and iodine etc.