Our Vanishing Wild Life: Its Extermination and Preservation

by William T. Hornaday

The life history of that parasite is not well known, but it may easily develop that the cycle of its maximum destructiveness is seven years, and therefore it may be accountable for the seven-year plague among the hares and rabbits of the northern United States and Canada.

Possibly Strongylus strigosus is all that stands between Canada and a pest of rabbits like that of Australia. Just why this parasite is inoperative in Australia, or why it has not been introduced there to lessen the rabbit evil, we do not know. Mr. Seton declares that the rabbits of his park were "subject to all the ills of the flesh, except possibly writer's paralysis and housemaid's knee."

Parasitic Infection Of Wild Ducks. —The diseases of wild game, especially waterfowl, grouse and quail, have caused heavy losses in America as well as in European countries, and scientists have been carefully investigating the cause and the general nature of the maladies, as well as probable methods of prevention and cure. Mr. Geo. Atkinson, a well-known practical naturalist of Portage la Prairie, Manitoba, writes as follows to a local paper on this subject, which I find quoted in the National Sportsman:

The question which has developed these important proportions during the past year is that of the extent of the parasitic infection of our wild ducks and other game, and the possibilities of the extended transmission of these parasites to domestic stock, or even humanity, by eating.

The parasites in question are contained in small elliptical cases found underlying the surface muscles of the breast, and in advanced cases extending deeper into the flesh and the muscular tissues of the legs and wings. They are not noticeable in the ordinary process of plucking the bird for the table, and are not found internally, so that the only method of discovering their presence is by slitting the skin of the breast and paring it back a few inches when the worm-like sacs will be seen buried in the flesh.

These parasites have come to my notice periodically during the process of skinning birds for mounting during the past number of years, but it was only when they appeared in unusual numbers last fall that I made inquiries of the biological bureaus of Washington and Ottawa for information of their life history and the possibilities of their transmission to other hosts.

Replies from these sources surprised me with the information that very little was known of the life history of any of the Sarcosporidia, of which group this was a species. Nothing was known of the method of infection or the transference from host to host or species to species, and both departments asked for specimens for examination.

Authorities are a unit in opinion that the question is one of great importance to game conservation, and although opinions of the dangers from eating differ somewhat, a record is given of a hog fed upon affected flesh developing parasites in the muscles in six weeks' time, while a case of a man's death from dropsy was found to be the result of development of these parasites in the valves of the heart.

The ability of these low forms of life to withstand extremes of heat makes it necessary for more than ordinary cooking to be assured of killing them, and since their presence is unnoted in the ordinary course of dressing the birds for the table, there is little doubt that very considerable numbers of these parasites are consumed at our tables every season, with results at present unknown to us.

The species I have found most particularly infected have been mallards, shovellers, teal, gadwall and pintails, and the birds, outwardly in the best condition, have frequently been found loaded with sacs of these parasites and only the turning back of the breast skin can disclose their presence.