Which parasitic infection can cause weight loss and malnutrition in humans?

Ascariasis is caused by the Ascaris lumbricoides worm, which is one of the largest intestinal parasites in humans. This infection can lead to significant weight loss and malnutrition due to several factors associated with the presence of these worms in the gastrointestinal tract. The adult worms can consume nutrients directly from the host's diet, leading to deficiencies. Furthermore, the inflammation and disruption of intestinal function caused by the parasites can impair nutrient absorption, compounding the effects of malnutrition.

Chronic infections with Ascariasis can also result in a reduced appetite and gastrointestinal distress, further contributing to weight loss. This combination of factors emphasizes the impact of Ascariasis on a person's nutritional status, specifically in vulnerable populations such as children in areas with poor sanitation. The other conditions, while they may cause discomfort or other health issues, are less directly associated with significant weight loss and malnutrition.