The organism was probably imported with the negroes from Africa and is one of the legacies of slavery.
The diseases of animals are in many ways closely linked with those of man.

In the case of the larger parasites, such as the tapeworms and the trichina, there is a direct interchange of disease with animals, certain phases of the life cycle of the organisms are passed in man and others in various of the domestic animals.

A small inconspicuous tapeworm inhabits the intestine of dogs and seems to produce no ill effects.

The eggs are passed from the dog, taken into man, and result in the formation of large cystic tumors which not infrequently cause death.

Where the companionship between dog and man is very close, as in Iceland, the cases are numerous.
Most of the diseases in animals caused by bacteria and protozoa are not transmitted to man, but there is a conspicuous exception.