Human subcutaneous dirofilariasis in Assam
A 21-year-old male reported to the surgery out patient department of a teaching hospital with a swelling in the right side of the lower abdomen since 2 months. It started as a small swelling of 1 cm × 1 cm but gradually increased in size to 2 cm × 3 cm with history of periodical itching. On examination, a small movable cystic swelling was found in the right lower quadrant of the anterior abdominal wall. On surgical excision, the cyst was found to be subcutaneous with no attachment to the underlying tissue. On opening the cyst, a live, 12 cm long, white thin worm was found []. The patient was tested for microfilaremia, which was found to be negative.\nThe worms were fixed in formalin and cleared in glycerine for proper viewing of the structures. The worms were white, elongated, 0.5 mm thick and 5 cm to 12 cm in length. The two ends of the intact worms were comparatively thin. The multi layered cuticle showed distinct longitudinal ridges [] and transverse striations []. The cuticle of the first worm was disintegrated at places. The spaces between the ridges were equal to the length of the ridges themselves. The muscle cells were well developed []. The genus Dirofilaria was identified by its thick, multi layered cuticle with ridging and transverse striations, large muscle cells and prominent lateral cord. The paired uteri and the intestinal tube were seen in two of the worms []. Based on size, cuticular and internal morphologic features the second and the third worm were identified as adult female of D. repens while speciation of the first worm could not be done though it was identified as Dirofilaria.