style="font-size:15px;"> 5. Wood’s lamp may be used to reveal the scolices if the patient has been given quinacrine dyes; the worms will have absorbed the dye, and they fluoresce at a wavelength of 360 nm. Also, after the use of quinacrine, tapeworm proglottids appear yellow.
Procedure Limitations for the Tapeworm Scolex Search
1. Niclosamide or praziquantel therapy leads to dissolution of the tapeworm. Therefore, the scolex and other proglottids may be difficult to recover unless the patient receives a saline purge soon after taking the medication.
2. It is often difficult to identify proglottids without staining. Identification may be achieved by staining with India ink.
India Ink Injection Procedure for Tapeworm Proglottids
Identification of adult worms usually involves examination of a tapeworm proglottid. A Taenia proglottid must be gravid, containing the fully developed uterine branches. Using a syringe (1 ml or less) and a 25-gauge needle, India ink is injected into the central uterine stem of the proglottid, filling the uterine branches with ink, or into the uterine pore. The proglottid can then be rinsed in water or saline, blotted dry on paper towels, pressed between two slides, and examined. After the identification has been made, the proglottid can be left between the two slides (place a rubber band around the slides), dehydrated through several changes of ethyl alcohol (50, 70, 90, and 100%), cleared in two changes of xylene, and mounted with Permount for a permanent record. After the xylene step, the proglottid will be stuck to one of the two slides; do not try to remove it (it is very brittle and will crack) but merely add the Permount to the proglottid and then add the coverglass (Fig. 4.9).
Figure 4.9 Taenia gravid proglottids after India ink injection of the uterine branches. (Left) Taenia fresh gravid proglottid prior to India ink injection. (Middle) Taenia saginata gravid proglottid. (Right) Taenia solium gravid proglottid. doi:10.1128/9781555819002.ch4.f9
It is important to remember that even when submitted in fixative, the tapeworm eggs within the branched uterine structure may not be killed and may remain infective. Since this procedure is usually limited to tapeworms in the genus Taenia, if eggs of Taenia solium (pork tapeworm) are present, they present a potential danger in terms of possible egg ingestion/inhalation/swallowing leading to cysticercosis. This becomes a possibility when performing the actual ink injection. If the needle accidentally pokes through the tapeworm proglottid, an aerosol can be created that may contain infectious eggs. ONE SHOULD WEAR A MASK, GLOVES, AND LABORATORY COAT AT ALL TIMES WHEN PERFORMING THIS PROCEDURE.
Procedure for the Tapeworm India Ink Injection (MASK, LABORATORY COAT, AND GLOVES MUST BE WORN AT ALL TIMES WHEN PERFORMING THIS PROCEDURE)
1. Using a 1-ml syringe and a 25-gauge needle, fill the syringe with approximately 0.5 ml of India ink.
2. Rinse the proglottid with tap water, and blot it dry on paper towels.
3. To prepare for the injection, hold the proglottid between your thumb and first finger or on the surface of the counter (harder to do).
5. Very carefully, penetrate either the central uterine stem at the end where the proglottid has become unattached from the chain or penetrate the side uterine pore with the end of the needle.
6. GENTLY inject some India ink; it should penetrate the uterine branches very quickly. IF THE INJECTION DOES NOT IMMEDIATELY OCCUR, DO NOT FORCE THE INJECTION.
7. You can try the other entry location, again GENTLY injecting the ink.
8. After the injection, rinse the gravid proglottid with tap water, blot dry on paper towels, and place the proglottid between two microscope slides separated at the edges by thin pieces of cardboard.
9. Fasten the preparation by placing rubber bands at each end of the slides so that the segments become somewhat flattened.
10. Observe the number of uterine branches on ONE SIDE ONLY where they come off the main uterine stem; generally Taenia saginata has 12 or more branches, while Taenia solium has approximately 8 or fewer branches.
11. After the identification has been made, the proglottid can be left between the two slides (place a rubber band around the slides), dehydrated through several changes of ethyl alcohol (50, 70, 90, and 100%), cleared in two changes of xylene, and mounted with Permount for a permanent record.
12. After the xylene step, the proglottid will be stuck to one of the two slides; do not try to remove it (it is very brittle and will crack) but merely add the Permount to the proglottid and then add the coverglass.
Results and Patient Report from the India Ink Injection Procedure
Tapeworm proglottids may be recovered (either singly or several attached together).
1. Report as:
Example: Taenia saginata gravid proglottid present
Procedure Notes for the India Ink Injection Procedure
1. Remember that T. solium eggs are infective (cysticercosis). The identification to the species level may not be possible until after the ink injection is completed.
2. Wear mask, laboratory coat, and gloves when performing this procedure.
3. Fresh, unpreserved proglottids are recommended; preserved proglottids can be used, but they are harder to inject.
4. Make sure the proglottid is blotted dry prior to the injection; otherwise, it may be difficult to hold onto the proglottid—it can slip through your fingers.
5. DO NOT FORCE THE INK INJECTION. If the ink does not easily flow into the branches, it may be because the proglottid is not gravid, but only mature. Also, the needle may not be in the right place.
6. IF THE INK INJECTION IS FORCED, it is more likely you may create an aerosol, thus increasing the danger for exposure to viable T. solium eggs.
7. Remember that after the xylene step, the proglottid will be stuck to one of the two slides; do not try to remove it (it is very brittle and will crack) but merely add the Permount to the proglottid and then add the coverglass.
Procedure Limitations for the India Ink Injection Procedure
1. If the proglottid is fresh, it may have begun to disintegrate, thus making the ink injection more difficult.
2. If the proglottid is mature AND NOT YET GRAVID, the branches may not inject properly.
3. If the ink injection is not successful, one can try some of the mounting methods found in chapter 9.
Qualitative Test for Fecal Fat
The microscopic examination of stool with the addition of Sudan III is a very simple, quick, and widely used technique to screen the specimen for fat. Fresh, unpreserved fecal material is required. If there is a time delay prior to testing, the specimen should be refrigerated. Specimens collected more than 48 h earlier or specimens that are dried out should be discarded, and fresh specimens should be collected. Although this technique
