The Effect of Bile Flow on Giardia duodenalis Race Simoni in the Intestine of a Laboratory Strain of Rattus norvegicus

Abstract

The rat was used to determine the effect of bile on the survival of Giardia duodenalis race simoni. Using surgical techniques, the flow of bile into the intestines of laboratory rats known to be infected with Giardia was eliminated. Approximately 24 hr after surgery, several locations in the intestines of the altered rats were examined for trophozoites. From the results obtained, it appears bile in the intestine is necessary for survival of Giardia in the laboratory rat. In the past, certain investigators have implied Giardia was either a parasite of the gall bladder and bile ducts or it caused disease of the liver, gall bladder, and bile ducts (Kantor, 1923; Smithies, 1928; De Muro, 1939; Grott, 1939; Gondard, 1952). Others (Goia et al., 1961; Mandoul, 1939; and Cain and Sikorav, 1938) did not believe Giardia was either a parasite of the hepatic system or it caused any disease related to the liver or its ducts. These references all pertained to human Giardia duodenalis race lamblial infections. Hegner and Eskridge (1939), checking for the parasite in a different host, examined the bile ducts of 123 rats and found no Giardia. More recently Karapetyan (1960) made a point of removing the bile by centrifugation from the material used as the inoculum in his in vitro studies on Giardia, so as not to interfere with his results. The only individuals who actually performed in vivo experiments using bile or bile salts were Hegner and Eskridge (1937). They stated sodium glycocholate favored the growth and multiplication of Giardia in rats, sodium Received for publication 25 February 1963. * Paper No. 5050, Scientific Journal Series, Minnesota Agricultural Experiment Station, St. Paul. This work partially supported by the University of Minnesota Graduate School Fund. 1The species designation used in this paper is of Filice (1952) in which he limits the number of species and assigns nontaxonomic race names to differentiate the various forms. taurocholate had no effect, and oleic acid was detrimental to the parasite. The present study was initiated to determine if bile had an effect on the rat Giardia, in vivo, as suggested by the work of Hegner and Eskridge (1937). Goodchild (1958), in his experiments on the effect of bile on Hymenolepis diminuta in the laboratory rat, concluded that bile contains a factor or factors apparently necessary for normal growth and maturation of adult H. diminuta in the rat host. MATERIALS AND METHODS Eighty-seven Sprague-Dawley rats were used in these experiments. They were fed Giardia duodenalis race simoni cysts ad lib. in the drinking water, the same method used in previous studies (Bemrick, 1962). The rats were used singly or in pairs at varying intervals following infection. In each individual, Giardia cysts were demonstrated by the zinc sulfate flotation technique before surgical procedures were initiated. Observations on Giardia-infected rats by Haiba and Williamson (1952) have indicated starvation induced elimination of Giardia from the intestinal tract. To avoid this, the rats were not starved prior to surgery. Rats positive for Giardia were surgically altered in one of seven ways: 1. The bile duct was ligated in two places with number 6-0 silk suture at the anterior one-third, and the duct was severed between the ligatures. 2. The bile duct was cannulated with Intramedic number 10 polyethylene tubing, exteriorizing the bile flow. The cannulae were inserted in the anterior one-third of the duct. The ligatures and cannulae were always placed in this area to try to prevent interference with the flow of pancreatic juices. The technique used was similar to