PAEASITES 441 



the sick with lime and salt, so as to prevent further 

 infection. 



Parasitic gastro-enteritis of sheep is due to two nematodes, 

 known as Strongylus cei-vicornis and contortus, both found 

 in the fourth stomach and causing heavy mortality. 



The disease principally attacks lambs, but adult sheep 

 do not escape. The question has been dealt with by 

 McFadyean* who first described S. cervicornis. 



The principal symptoms are diarrhoea and muscular 

 wasting ; the disease may last a few hours, or the animal 

 live for several days or weeks. The eggs of the parasite 

 pass away with the fseces and undergo development in the 

 water and soil, but the intermediate host is unknown. 

 The parasites, judging from experiments in ritro, are very 

 difficult to destroy. 



Conditions which favour infection are overcrowding, 

 stagnant ponds, and flooded lands, while the preventive 

 measures are liberal feeding, salt in the food, a supply of 

 good well or running water, and keeping sheep off infected 

 pastures for two or three years. 



Parasitic inflammation of the Fourth Stomach of Ruminants, 

 also described by McFadyean, + is produced by two different 

 species of strongle, the S. gracilis and S. convolutus. In 

 both cases the eggs pass from the stomach into the intes- 

 tines and are there hatched ; through the medium of the 

 fffices they reach the soil, but their further development is 

 unknown. 



The disease lasts a long time, three to six months, and 

 the gradual wasting is so marked that the cases have fre- 

 quently been considered tubercular. The only preventive 

 measure which can be suggested is the destruction of all 

 faeces, for as these contain the embryos it is quite easy for 

 them to find their way into water, or to be carried on to 

 the land with manure. 



Parasitic Enteritis in Horses is produced by the ravages 

 of S. tetracanthus ; outbreaks have been frequent after wet 



* Journal of the Boyal Agricultural Society, vol. viii., 1897 

 t Ihid., vol. Ixiv., 1903. 



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