Q.What is a Parasites? Add a note on Ascariasis in humans.

Ascariasis is a common parasitic infection caused by Ascaris lumbricoides, often referred to as the common roundworm. This parasite is an endoparasite of humans, meaning it lives inside the human body. Understanding its mode of transmission is crucial for prevention. The eggs of Ascaris are typically excreted along with the faeces of an infected person. These eggs can then contaminate soil, water, vegetables, and fruits. When healthy individuals consume food or water contaminated with these embryonated eggs, they ingest the parasite, leading to infection. This is known as the faecal-oral route of transmission.

Once ingested, the eggs hatch in the intestine, and the larvae mature into adult worms. These adult worms reside in the small intestine, where they can cause a range of symptoms depending on the worm burden and the individual's immune response.

The symptoms of Ascariasis, as described in the NCERT textbook, are quite distinct and primarily relate to the presence and activity of the worms within the digestive system and their systemic effects:

• Internal bleeding: The worms can cause damage to the intestinal lining, leading to internal bleeding.
• Muscular pain and fever: The presence of the worms and the body's immune response can manifest as generalized muscular pain and an elevated body temperature (fever).
• Anaemia: Chronic blood loss from internal bleeding, coupled with the worms competing for nutrients, can lead to anaemia, a condition characterized by a deficiency of red blood cells or haemoglobin.
• Blockage of the intestinal passage: In severe infections, a large number of worms can accumulate in the intestine, forming a tangled mass that physically obstructs the passage of food and waste. This can be a life-threatening complication.

Now, let's evaluate the given options based on these established symptoms:

• (A) Intestinal blockage: This is explicitly mentioned as a severe symptom of Ascariasis, occurring when a large number of worms obstruct the intestinal passage. …