What can examination of a 24-hour unpreserved urine specimen help recover?

The examination of a 24-hour unpreserved urine specimen is especially useful for recovering the eggs of Schistosoma haematobium, a parasitic worm associated with urinary schistosomiasis. Unlike other parasitic forms, the eggs of this specific trematode are excreted in urine, which makes urine samples an ideal medium for their detection. Schistosoma haematobium is known to dwell in the blood vessels of the bladder, and as it lays its eggs, they can be found in the urine, allowing for diagnosis through microscopic examination.

Other parasites listed have different modes of recovery; Trichomonas vaginalis typically requires a swab from the vagina or urethra, while Enterobius vermicularis eggs are usually collected from the perianal area using a sticky paddle or tape method. Strongyloides stercoralis larvae are typically found in stool samples rather than in urine. Thus, the 24-hour urine specimen is particularly effective for identifying Schistosoma haematobium eggs, supporting the answer choice identified.