The Nodular Worm. 4:5 



The disease may be desoi ibed to be of a wasting nature ; lambs 

 simply do not thrive, they lose condition, look thin and miserable, 

 and die in great numbers. On posl-mortem the presence of an anaemia 

 and hj^draemia is markedly pronounced, the carcases are bloodless, 

 the organs and tissues pale, and the fat has completely disappeared, 

 and its place is taken by watery substance. The collection of liquid 

 is also pronounced in the connective tissue of the muscle. The cause 

 of the trouble is found in the alimentary canal, both in the end of the 

 small intestines and the commencing portion of the large ones (caecum 

 and the first part of the colon). In the walls of the small intestines 

 nodules are present which are more numerous towards the end. They 

 are not always equally frequent ; sometimes they are fairly scanty, in 

 other cases they occupy practically the whole wall. Invariably, 

 however, the lesions are most pronounced in the caecum. The wall of 

 this intestine is thickened and is almost rigid. The mucous membrane 

 has a corrugated rough appearance ; the different layers are infiltrated 

 with watery liquid, which is most pronounced in the submucous 

 portion of the wall. On closer observation it will be found that the 

 thickening of the wall is caused by the presence of nodules sometimes 

 so closely packed that frequently they touch each other. The surface 

 of the mucosa is covered with a viscid, sometimes milky deposit, 

 occasionally tinged with blood. Attached to the mucosa are small 

 conspicuously white worms which are usually curved and reach about 

 half an inch in length. 



Different types and sizes of nodules are noted, their characters are 

 most easily recognized in the small intestines, where they are more 

 frequently solitary, although a number of them may be crowded 

 together. 



Arbitrarily we may distinguish three principal and pronounced 

 types, viz., the reddish nodule, the greenish nodule, and the hard 

 nodule. Thej vary in size from a kaffir corn seed to that of a pea or 

 more. They are sometimes quite hidden under the mucosa and can 

 only be found on palpation or else stand out prominently over the 

 surface forming a small hemisphere; others bulge out into the outer 

 M^all of the intestines, the serosa, and are easily recognized. All the 

 nodules show on or near the summit, bulging into the intestinal lumen, 

 a small pit. It is through this pit that the entry of one of the larval 

 stages of the worm in the mucosa has taken place which led to the 

 formation of the nodule. The red nodules are the initial stages and 

 still show injection of the vessels of the areas involved, on section they 

 are moist and glistening. The Jarvae being very small, cannot be 

 seen by the naked eye. Their presence produces the accumulation 

 of white corpuscles (Eosinophile leucocytes) which undergo disintegra- 

 tion around the larva and so form a greenish abscess. Pus in this 

 stage escapes through the pit when a slight pressure is applied to the 

 nodule. The hard nodules are calcified, they have an irregular shape. 

 They are most frequently seen bulging out in the outer wall. They 

 are the old nodules, from which the larvae have escaped at an earlier 

 stage or in which the larvae have succumbed. The oldest nodules are 

 the hardest ones and have a tendency to decrease in size and become 

 angular tlie older they are, but they will never entirely disa,ppear. 

 The content is a hard concrement resistant to the knife, sometimes it 

 is as hard as a stone. In the caecum of lambs the nodules are rarely 

 found in this last stage, they are usually in the first and second 



