Abstract
Herein is described a method for the removal of adult S. mansoni worms from experimentally infected rabbits. The method has been used with good results in rabbits although there is no apparent reason why it could not be applied to other experimental animals susceptible to schistosomiasis.
The animal is tied to a board and a large dose (100 mg) of Heparin (Abbott-10 mg per cc) in 30 to 40 cc of physiological saline is injected very slowly into the heart or intravenously. Between 15 to 30 minutes are allowed to elapse at which time the animal is sacrificed in any desired fashion, the abdomen opened and the portal vein exposed. An 18-gauge needle with attached 50-cc syringe is inserted into the portal vein with the point of the needle directed towards the liver. The heparinized blood in the portal vein is aspirated while the syringe and needle are rotated to direct the bevel of the needle toward the worms which will be seen flowing into the syringe with the blood. About 15 to 20 cc can thus be aspirated before the portal vein collapses.
An additional 10 to 15 cc of blood can be aspirated by exerting a gentle squeezing pressure on the lobes of the liver-this will force more blood into the portal vein, and the liver will be seen to blanch slightly. The syringe is disconnected from the needle and put aside without fear of the blood clotting. A clean dry syringe may be attached to the needle and additional aspirations carried out in the manner described.
If it is desired to keep the worms alive, the aspirated blood is poured into a solution of 0.5% saponin in physiological salt solution (0.85%)-this will lake the blood cells but have no apparent effect on the worms.
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