386 Special Procedures II (chap. 23) 



and then into fixative; place them horizontally in 95% alcohol vapor: 

 1 minute. Then fix. This coagulates the embryos and attaches them. 



Animal Parasites 



Animal organisms parasitic in or on man include protozoans, platy- 

 helminths, nemathelminths, and arthropods. Clinical parasitology is 

 extensive and therefore only a few methods which can expedite a tissue 

 technician's work are incorporated here. Since the Romanowsky-type 

 stains are used on blood parasites (malaria, trypanosomes, filaria, etc.) 

 the preparation of smears is included in the section on hematologic ele- 

 ments (p. 218). Tissue sections can be stained in a similar manner. 

 Parasitic roundworms (pinworms, Trichuris, Ascaris, hookworms), flat- 

 worms (lung, intestinal, bile duct and blood flukes, tapeworms) and 

 arthropods (ticks, lice, mites) are discussed in the sections on inverte- 

 brates and whole mounts in this chapter. Methods given there can be 

 adapted in most cases of parasitic helminths and arthropods. Sections 

 of tissue parasitized by protozoans or helminths are effectively stained 

 by hematoxylin methods, also by periodic acid-Schiff; protozoans and 

 worms are strongly PAS positive due to stored glycogen in both forms, 

 and PAS-positive cuticle in the helminths. The scolices hooks in hydatid 

 disease [Echinococcus), however, do not show with PAS and are better 

 demonstrated against a hematoxylin backgroimd. Ova and larvae can 

 be handled according to directions given on page 374. Intestinal proto- 

 zoa (amoebae, flagellates, ciliates, and coccidia) require the following 

 special methods, both for smears and tissue sections. 



Only permanent slide mounts are described. Consult clinical labora- 

 tory manuals for temporary and rapid examination methods for imme- 

 diate diagnosis. Gradwohl (1936) is comprehensive. 



Intestinal Protozoa: Smear Technics 



Preparing Concentrate Smears (arensburger and markell, 1960) 



procedure: 



1. Add 1 ml. of feces to 10-15 times its volume of tap water. Mix well 

 and strain through 2 layers of wet gauze in a funnel. Collect in a 

 small centrifuge tube. Add 1-2 ml. of ether. Using a cork or thumb 

 for a stopper, cautiously shake the tube. Fill with water to 1 cm. 

 from top. 



