The Local Points of Defense and the Passive Transfer of Acquired Immunity to Nippostrongylus Muris in Rats

Abstract

The life cycle and morphological development of Nippostrongylus muris in the rat were worked out in detail by Yokogawa12 who first described the parasite. The bisexual adult worms, 4 to 6 mm. in length, are found as small, barely visible, coiled red threads in the upper part of the small intestine. Eggs are passed in the feces of the rat and develop into infective larvae within 4 to 5 days. The larvae, after actively penetrating the skin of the rat, are carried by the blood stream to the lungs and invade the alveoli. Here, they undergo a brief period of development before migrating up the trachea, down the esophagus and through the stomach to the intestine where they reach maturity. The females begin to lay eggs 6 to 7 days after infection. The fact that rats after recovery from an initial infection are relatively resistant to subsequent infections was first reported by Africa3 and by Schwartz, Alicata and Lucker4 and has been repeatedly confirmed by the more extensive studies of Chandler56-7'8 Spindler910 Graham11 and Porter12 .