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Description:Under a magnification of 128X, this photomicrograph revealed some of the morphologic ultrastructure of a hookworm rhabditiform larva. Rhabditiform (L1) larvae that hatch from eggs are 250-300µm long, and approximately 15-20µm wide. They have a long buccal canal, and an inconspicuous genital primordium. Rhabditiform larvae are usually not found in stool, but may be found there is a delay in processing the stool specimen. If larvae are seen in stool, they must be differentiated from the L1 larvae of Stronyloides stercoralis.
Clinical Features:Iron deficiency anemia (caused by blood loss at the site of intestinal attachment of the adult worms) is the most common symptom of hookworm infection, and can be accompanied by cardiac complications. Gastrointestinal and nutritional/metabolic symptoms can also occur. In addition, local skin manifestations ("ground itch") can occur during penetration by the filariform (L3) larvae, and respiratory symptoms can be observed during pulmonary migration of the larvae.

Laboratory Diagnosis:Microscopic identification of eggs in the stool is the most common method for diagnosing hookworm infection. The recommended procedure is as follows:

1.- Collect a stool specimen.

2.- Fix the specimen in 10% formalin.

3.- Concentrate using the formalin–ethyl acetate sedimentation technique.

4.- Examine a wet mount of the sediment.

High Resolution: Click here for hi-resolution image (6.55 MB)
Content Providers(s):CDC/ Dr. Mae Melvin
Creation Date:1979
Photo Credit:
Links:CDC – Div. of Parasitic Diseases: Hookworm
CDC Organization
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Copyright Restrictions:None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.