Which whipworm infection is often asymptomatic or causes loose stools?

• A. Trichuris trichiura
• B. Enterobius vermicularis
• C. Ascaris lumbricoides
• D. Ancylostoma duodenale

Answer: (A)

Infections with whipworms tend to be mild or even asymptomatic, especially when worm burden is low. The whipworm, Trichuris trichiura, lives in the large intestine and irritates the mucosa just enough to cause loose stools in milder cases. When the infection is heavier, it can lead to more noticeable symptoms like persistent diarrhea and abdominal discomfort, and in children, rectal prolapse can occur. The other parasites listed are not whipworms and present differently: pinworm mainly causes perianal itching; Ascaris lumbricoides can cause obstruction or respiratory symptoms with heavy infection; hookworms (Ancylostoma duodenale) commonly cause iron-deficiency anemia and fatigue due to blood loss.