New Technique for Feeding Sandflies (Phlebotomus) for Experimental Transmission of Kala-Azar.

In the experimental attempts to transmit kala-azar by the bites of sandflies, it has been found desirable to substitute an artificial feeding on blood rich in Leishmann-Donovan bodies for the natural feeding upon infected animals, in order to obtain an abundant growth of flagellates within the flies. This blood is obtained by mixing the blood of a normal animal with the crushed spleen of a hamster heavily infected with kala-azar.For such artificial feeding we used the technique of Hertig and Hertig.1This technique was learned in a few days and in the course of 2 months during the summer of 1928, 565 flies were fed. During this work it became clear that this technique had a number of limitations. The flies had to be fed one by one, making the procedure tedious. During the etherization and handling of the flies, many were injured. A satisfactory engorgement was obtained with P. sergenti, while P. majoronly in rare instances could be fully engorged. In order to feed a larger number of flies with a minimum of injury and a maximum of engorgement, the following technique has been devised.Technique.Etherize a hamster heavily infected with kala-azar, pin its feet on a wooden board, and place its head and neck between the arms of a U-shaped wooden block. Remove the hair over the anterior surface of the neck and chest by pulling and sterilize the skin with alcohol and ether. With aseptic precautions, make a median incision through the skin extending from the anterior end of the lower jaw to the middle of the sternum. Pull apart the skin flaps and pin them to the arms of the U-shaped block, the upper surface of which is slightly raised above the level of the head and neck. Cut the carotid artery on one side and, as the blood wells up, quickly draw it into a sterile pipette. Practically all the blood that is obtained by bleeding can be drawn into the pipette. Defibrinate and centrifuge the blood.