LIST OF ILLUSTRATIONS

PLATE: Endocardial Hemorrhage......

..opp. p. 63

CHARTS:

PAGE

No. 1, Respiration, Pulse and Temperature, Case No. 1..

.15

ACKNOWLEDGMENTS

The ranchmen of South Fork and Mound Valleys and certain business men and ranchmen of Elko have given us at all times the most active cooperation and support; have placed their sick animals at our disposal; contributed healthy horses for experimental purposes; paid livery and other bills to a considerable amount; furnished board; fed and cared for experimental animals; furnished men and teams to enable the writer to travel hundreds of miles over the infected district; hauled lumber and other materials; supplied labor and direct assistance liberally; and earnestly and efficiently cooperated with us in many ways. To these we desire to acknowledge our obligation.

We desire especially to express to Messrs. Crane Brothers, J. A. McBride, and A. M. Griswold, our appreciation for their activity and liberality.

Our thanks are also due to Professor Peter Frandsen of the University of Nevada for valuable suggestions and criticisms and for direct assistance in field and laboratory.

EQUINE ANEMIA

AN ACCOUNT OF A RECENT INQUIRY INTO THE NATURE AND CAUSE OF AN OBSCURE AND FATAL DISEASE AMONG HORSES

IN EASTERN NEVADA

By WINFRED B. MACK, D. V. M.
Veterinarian and Bacteriologist.

INTRODUCTION

In September, 1907, the writer was asked to visit Eastern Nevada to investigate an outbreak of virulent disease among horses. In response to this request we visited several ranches in Elko County, examined a number of infected animals, gathered what data were readily obtainable regarding the outbreak, and obtained some material for laboratory study.

On the first ranch visited we found an interesting case in a young horse and remained with him several days, making careful clinical observations and therapeutic experiments. He presented a combination of symptoms with which we were, at the time, altogether unfamiliar. Our text-books contain no description, so far as we have been able to ascertain, of the disease we found there and we were not, at the time, cognizant of anything in current literature bearing upon it. In consequence diagnosis was reserved. Several ranches in the neighborhood were then visited, a considerable number of horses examined, treatment prescribed in several cases, and one autopsy performed. With material from this autopsy we returned to the laboratory, where it was carefully studied, but no diagnosis was attempted.

The losses from this disease are material. Recognizing in it an interesting scientific problem, combined with an important economic question, we decided to undertake a somewhat extended inquiry into its nature, cause, treatment, and the means necessary for its control. We have made many subsequent trips to the affected region, and have spent much time in the field in observation and experiment, having, in fact, devoted practically our entire time since September, 1907, to this problem. The district in question is situated from 335 to 375 miles from Reno, 20 to 50 miles from the railroad. This has involved considerable travel, of which no insignificant amount has Inasmuch as we have no professional assistance

been by team.

there are necessarily many breaks in the continuity of the records and many things, pertinent to an inquiry of this sort, have been left undone. The difficulty of making certain tests under ranch conditions, particularly the examination of blood and urine-manipulations that really demand laboratory conditions for their successful performance as well as the impossibility of having always in the field, so far from the laboratory, the necessary apparatus and reagents, accounts for some of the discrepancies in this report. Furthermore, it is impossible to promptly replace, when in the field, an instrument accidentally broken, as was the case in December, 1907, when the measuring pipette from our blood counting apparatus was broken. For that reason we were unable, at that time, to make certain contemplated blood examinations on both clinical and experimental horses that would have been of considerable value in this investigation.

Our study does not yet warrant any definite conclusions. In fact, but a beginning has been made. Nevertheless, it appears to us that enough has been accomplished to warrant a presentation of the facts already ascertained. It is probable that this disease exists in several States besides Nevada and in certain other countries than the United States. It may prove to be identical with the infectious anemia of Europe and the swamp fever of Manitoba and some of the Middle Western States. In that case we may hope for an earlier solution of the questions involved than otherwise.

HISTORY

In the summer of 1906, a disease appeared among the horses in the region referred to and killed a considerable number. It abated during the cold weather, to reappear, with equal fatality, in the summer of 1907. There is an account of one ranch losing from 7 to 10 head in 1905, and another reports the loss of 15 animals in 1905, or 1906, the owner being uncertain as to the year. At any rate, the disease attracted no particular attention until 1906. At that time, by reason of its occurrence on several ranches, some alarm was felt, and the Agricultural Experiment Station asked to make an investigation. However, when Professor Frandsen reached there, in September, 1906, the disease had already abated, so that he found little to study except its history, as related by those interested. In 1908 there were but a few scattering cases.

There was no veterinarian on the staff of the University of Nevada or the Agricultural Experiment Station prior to January 1, 1907, when the writer undertook the organization of the present department of veterinary science and bacteriology. Previous to the creation of

that department, what work was done in animal diseases was by Professor Peter Frandsen of the department of biology. Professor Frandsen secured the history of the outbreak in 1906, but at the time of his visit saw but one sick animal and had no opportunity for autopsies. He has placed his notes at our disposal, and we quote freely from them.