On the biology of the infective Larva ofMonodontus trigonocephalus(Rud.) of Sheep

Abstract

The biology of the infective larva of the Sheep Hook-wormMonodontus trigonocephaluswould be expected on general grounds to resemble that ofAncylostoma duodenale, to which it is closely related. Two facts in the biology of the adults must, however, be borne in mind. In the first place, the normal temperature of man is about 37° C, while the normal temperature of the sheep is 39°–40° C. Secondly, both Looss (forA. duodenale) and Hesse (forM. trigonocephalus) have shown that the pre-infective larvæ feed actively on faecal matter. Looss has drawn attention to the fact that cultures of Ancylostomes made from the fæces of a host living on an exclusively herbivorous diet, were very much poorer in the resultant crop of larvae than those made from fæces of a host living on a partly carnivorous diet. Now the adultMonodontuslives in a host which is purely herbivorous, and the larvæ are reared in fæces entirely of a vegetable nature. One might therefore expect differences in the biology of the ensheathed stage.