Ascaris Life Cycle

Introduction

Ascaris is a genus that comprises parasitic nematodes commonly known as "small roundworms," affecting mostly mammals. Several species of Ascaris are known, like A. lumbricoides, which affects humans, and another species, A. suums, which affects pigs. Their bodies are fusiform, which means having tapered ends. Their eggs are usually found in impure water that is sometimes ingested by humans while drinking and that results in diseases like ascariasis. Ascariasis is a disease which affects millions of people across the globe, of which 85% show no symptoms. Over the course of time, symptoms increase, which may include fever, abdominal pain, and diarrhoea.

What is Ascaris?

Ascaris is a parasitic worm which comes under the Genus Ascaris, Family Ascarididae, Order Ascaridida, Phylum Nematoda, and Kingdom Animalia. They are parasitic organisms that feed on host bodies to survive. Species of Ascaris exhibit gonochorism, i.e., a sexual system in which only two sexes are present and an individual organism is either male or female. They are differentiated as males by having curved tails and being half the length of females who have straight tails. Both sexes have three “lips” at the anterior end of their bodies. Species of Ascaris, i.e., Ascaris lumbricoides, are infamous for spreading diseases like Ascariasis in humans

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Characteristics

Important characteristics are as follows−

• The body of Ascaris is bilaterally symmetrical and triploblastic

• The body is cylindrical with tapered or pointed ends

• These are dimorphic or unisexual

• The digestive system is present but the respiratory and circulatory systems are absent.

• Fertilization is done internally.

Life Cycle of Ascaris

The life cycle of Ascaris broadly consists of 3 stages−

• Egg Stage- Ascaris lumbricoides are usually present in the gastro-intestinal region or specifically in the small intestine of human beings. In the small intestine, the female Ascaris lays eggs, and each female can produce up to 200,000 eggs in a single day. These eggs later travel to the large intestine and are then removed from the stools of the human body. Unfertilized eggs aren’t infective, but the fertilized ones are, and these undergo subsequent development

• Larvae Stage-Once eggs are ingested, they hatch and larvae have formed that travel to the intestinal layer, invading intestinal mucosa. Larvae usually become harmful after 3 weeks, when they get transported to other parts of the body, like the lungs and throat

• Adult Stage - Larvae when get matured in the intestine, attain their adult form. It takes around three months from ingesting the eggs to completing full development. The lifespan of an average Ascaris is about 1-2 years

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Causes of Ascaris Infection

The major cause of ascariasis is directly linked to the ingestion of its eggs. These eggs, which are produced by female Ascaris inside the host, are later ingested by another host. These eggs are mostly found in areas covered with dirt, basically in non-purified water, non-peeled fruits and vegetables. It can also come from uncooked or half-cooked meat (especially pork)

Symptoms

Some common symptoms of ascariasis are−

• Serious Abdominal or Back Pain

• Nausea, sinusitis, and vomiting

• Diarrhoea, bloody stools, and, in some cases, weight loss

• Worms can be found in stool.

Diagnosis

Ascariasis can be diagnosed by various laboratory testing methods

Stool test− One of the most prominently conducted tests, where the stool would be taken and then later thoroughly examined by the doctor, at least for 40 days. Microscopic eggs or larvae of Ascaris wouldn’t be found in the stool if one is infected by it until 40 days.

X-rays− Worms, are visible in an X-ray of the frontal region of the body. In most cases, it is advised to have a chest X-ray, which can help to reveal the larvae of Ascaris in the lungs.

Ultrasound− An ultrasound is advised to find the worms in the pancreas or liver

CT scans or MRIs− CT scans combine X-ray images taken from different angles. MRI, on the other hand, uses radio waves and a strong magnetic field.

Treatment

Ascariasis which is spread by Ascaris, also known as Aschelminthic infections, is treated by anthelmintic medications. Anthelmintic medications are those types of medications which help in removing parasitic worms such as Ascaris from the human body in the form of faeces. Some common examples of this type of drug are albendazole, mebendazole, and, in some cases, ivermectin. These infections are usually treated for 1-3 days with little or no known side effects

Prevention

Various preventive methods should be taken under consideration to be safe from Ascariasis−

• One should practice safe sex, usually with a condom, to get rid of any chance of getting STDs and also parasitic growth in any of the partners.

• One should wash their hands safely and with a sanitiser or soap so that no parasitic growth can be developed on their palms

• One should cook food (especially non-vegetarian foods). As parasitic worms can grow over uncooked meat or pork and later be ingested

• One should drink clean and well-fetched water and, if possible, RO filtered packaged bottled water, as in the case of impure water, Ascaris eggs can be grown

Conclusion

We can summarise that the life cycle of Ascaris, which is a parasitic worm belonging to the Phylum Nematoda of Kingdom Animalia, starts in the gastrointestinal tract of humans as eggs and then it further develops into larvae and matures into its adult form, which is infectious too. Adult Ascaris have two sexes, males ranging from 0.15m-9.2m in length, whereas females are 0.3m, Ascariasis is a disease predominantly in humans that is caused by its adult form that leads to nausea and vomiting-like symptoms, and it can be tested by examining stool and various chest scans of the patient. This can also be cured by various drugs like albendazole etc

FAQs

Q1. What is the classification of Ascaris?

Ans. It is classified as follows−

• Genus Ascaris

• Family Ascarididae

• Order Ascaridida

• Phylum Nematoda

• Kingdom Animalia

Q2. What is the most important difference between male and female Ascaris?

Ans. Male Ascaris is much shorter in length in comparison to females; also male Ascaris lacks tapering ends while females have much more tapered ends.

Q3. What are some of the preventives that we can take to get rid of Ascaris?

Ans. We can prevent ascariasis by drinking pure water, eating properly peeled fruits and vegetables, avoiding contact with infected soil, and washing hands before consumption or handling of food.

Q4. People of which region are at risk of Ascariasis infection?

Ans. People reside in humid and warm climates and temperate zones during warmer months where hygiene and sanitation are poor.

Q5. Name the organ system that can be affected by Ascariasis infection?

Ans. Some of the well-known, identifiable symptoms are severe abdominal or back pain with nausea, sinusitis, and vomiting. In some cases, diarrhoea, bloody stools, and weight loss are also observed.