A definitive diagnosis of ascariasis can be made by observing which of the following: (A) An adult worm passed during a bowel movement, (B) Larvae in x-ray of lungs, (C) Motile larvae in a stool sample, (D) An eosinophilia in a differential white blood cell count
Answer is A. Identification of adult worms passed by an individual can ensure a definitive diagnosis. Although an eosinophilia accompanies ascariasis, this condition can be caused by other infections and by various allergic conditions. Motile larvae in a stool are indicative of infection with Strongyloides stercoralis. Nematode larvae cannot be seen in an x-ray.