status of our knowledge regarding the transmission of typhoid fever,' by Dr. A. W. Freeman, and the other, "Fly-borne typhoid fever and its control in Jacksonville," by Dr. C. E. Terry. These two papers are of such wide sanitary interest that I would recommend their publication in the Public Health Reports and herewith transmit copies of them for that purpose.

THE PRESENT STATUS OF OUR KNOWLEDGE REGARDING THE TRANSMISSION OF TYPHOID FEVER.

By ALLEN W. FREEMAN, M. D., Assistant Commissioner of Health of Virginia.

With the possible exception of tuberculosis, there is no disease in all the long catalogue of those classed as infectious which has been more studied than has typhoid fever. Both diseases present complex epidemiology, and in both effective practical prevention has come only after long and arduous study. The epidemiology of typhoid fever has become more complex as our knowledge has increased. The infectious agent of the disease can survive for a long enough time and under sufficiently varied conditions to render the study of its transmission difficult in the extreme.

Prior to the discovery of the specific etiological agent of typhoid fever the studies which were made were for the most part fragmentary and unsatisfactory, and until the time of Budd, whose immortal work has never received the recognition which it deserves, nothing of great value in the specific prevention of the disease had been recorded. Budd, whose researches will always remain a model for pure epidemiology, clearly established the infectious nature of the disease, located the infectious agent in the excreta of the patient, and laid the foundation for our modern ideas regarding the disease. The discovery of the infectious agent, coming shortly after the publication of Budd's work, gave great impetus to the prevention of typhoid fever, and from that time to this the history of sanitary science records a continuous series of triumphs over the disease.

At the present time, in summing up our knowledge regarding typhoid fever, we may say without hesitation that it is caused by the Bacillus typhosus of Eberth. The work of Metchnikoff and Besredke, together with the results of antityphoid vaccination, have disproved forever the theory so frequently advanced that typhoid fever is of the same nature as swine cholera, and the typhoid bacillus only a secondary invader, the real infectious agent being a filterable virus to be found in the blood.

We may say, too, with certainty that the typhoid bacillus is of much wider distribution than was thought, even up to a few years ago. It is to be found in the discharges not only of the patient, but of many healthy persons, who may or may not have had the disease, and in

the discharges of many persons who are sick with intestinal fevers so mild as to bear little or no clinical resemblance to true typhoid fever.

We have learned within the past few years that the typhoid bacillus is disseminated, not only as was formerly thought, by water and milk, and occasionally by other foods, but also by flies and fingers and in fact by almost any material object which comes in contact with human filth, and directly or indirectly with human mouths. We have learned by sad experience that the measure of typhoid fever in any community is the measure of the distribution of human filth in that community, and that the dissemination of human excrement will inevitably result in the spread of typhoid fever.

Water has, of course, long been regarded as the great carrier of typhoid infection, and rightly so. Sometimes in epidemics, sometimes in the continuous infection of a large population, sometimes in scattering single cases, water must be held responsible for a considerable proportion of our typhoid. Without adequately protected or purified public and private water supplies, typhoid prevention is impossible.

Milk has, likewise, for many years been regarded as a most important vehicle for typhoid infection. Epidemics without number have been caused by infection of milk supplies. Experience, dearly bought, has demonstrated that even the most rigid inspection of milk supplies can not prevent the occasional infection of a public supply, and that real protection against typhoid fever from infection of milk supplies is to be purchased only at the expense of pasteurization under municipal supervision.

Other food causes of typhoid infection have received much attention, but in spite of much study little has been learned as to their real importance. We have seen much agitation of recent years in regard to the rôle played by shellfish, and particularly oysters, in the transmission of typhoid. A careful study of the evidence would seem to show that while an occasional outbreak of typhoid has been found to be due to infection of oysters, in such cases the pollution has been obvious and inexcusable, such as the fattening of oysters in the harbors of large cities or even at the mouths of sewers. We believe that for the most part the average market oyster is not the cause of any great proportion of our typhoid and is in fact about as safe as any of the foods which we are in the habit of eating uncooked.

TYPHOID FEVER IN CITIES AND TOWNS.

The studies which have been made of the prevalence of typhoid fever in the cities and towns of the United States have revealed much that is of value in the prevention of the disease. The relative value

of water purification, general sanitation, and food protection has been worked out in detail and the practical prevention of the disease has been made almost an exact science.

Everyone knows that frequent explosive outbreaks of typhoid fever have occurred as a result of the infection of public water supplies. From such supplies the typhoid bacillus has been recovered so frequently as to leave no doubt of the accuracy of the results. It has been proved too many times to admit of further question that the use of an impure water supply by a community will result in a continuously high typhoid rate, and that purification of such a water supply will result in a marked and immediate lowering of the rate. In cities in the more northern sections of the United States the purification of a public water supply of a city will result in the reduction of the annual typhoid death rate to a figure usually under 20 per hundred thousand. In the South the purification of the public water supply will in the absence of other measures seldom bring the figure below 50 per hundred thousand. In a southern city, possessing a pure public water supply, the sanitation of the city, and by sanitation. is meant the complete protection from human filth in the community by perfect sewering or by rigid screening and supervision of dry closets. will usually result in reducing the annual typhoid death rate to the figure usually reached by the northern city from water purification alone, namely, 20 per hundred thousand. Unfortunately no figures are available as to the result of the perfect sewering of any southern city of considerable size, as, so far as we are aware, such a city is not to be found.

No more important addition has been made to our knowledge of the practical prevention of typhoid fever in urban communities than the facts which have come to light regarding the importance of protecting the people of any community against that infection which is not brought in from without the city gates but which is generated within and disseminated from foci close at hand. When we seek to work out a plan of protection for the citizens of any community against typhoid fever we should classify accurately our sources of infection into two groups. We should first consider those sources of exogenous infection without the city, from which infection is brought in, usually in water, milk, or other food, and which are guarded against by water purification and milk and food inspection. We should by no means neglect those sources of endogenous infection within the city, whence typhoid is distributed by an almost infinite variety of means, and which must be guarded against by what we speak of as general sanitary measures, such as sewerage, sanitary inspection, fly prevention, and, in addition, by the very especial supervision of the known cases of typhoid fever.

TYPHOID FEVER IN RURAL DISTRICTS.

It is to be regretted that our knowledge regarding the transmission and prevention of typhoid fever in rural districts is far from being as complete as that regarding urban conditions. The subject is one which has been studied but little in this country, notwithstanding the fact that in many of our States typhoid fever is almost entirely a rural problem. We have learned, however, some facts regarding the transmission of typhoid fever in rural districts which are of value in practical prevention. We know that in most cases water infection has but little to do with the spread of the disease; that existing sanitary conditions in rural districts are utterly inadequate for the proper protection against human filth; and that the general dissemination of fecal matter consequent upon the presence of these insanitary conditions is inevitably followed by the presence of typhoid fever.

We know, too, that the country people at the present time have not learned those precautions which are absolutely necessary to prevent the spread of the disease from the bedside of the patient, and that frequently the disease is spread over large areas of country by contact alone. From our knowledge of the transmission of typhoid fever, taking into account the isolation and lack of intercommunication of the country people, we may confidently expect that an improvement in the sanitary arrangements of our farms, specifically in the building of a sanitary privy for every home and a more careful observance of the precautions of the sick room, will result in a marked decrease in the prevalence of typhoid fever in rural districts.

ANTITYPHOID VACCINATION.

The results already obtained indicate clearly that vaccination with killed cultures of the typhoid bacillus confers upon the individual marked resistance to typhoid infection. In military organizations the great value of this method of protection has already been demonstrated, and results are rapidly accumulating to show that in civil populations the method may also be of great service in the prevention of endemic and possibly of epidemic typhoid.

SUMMARY.

Summing up, we may say that the essential basis for the prevention of typhoid fever has been laid, and that we are now in possession of the information, biological and technical, necessary for the actual eradication of the disease from the urban communities of the United States. The basis for prevention in rural communities, while not complete, is sufficiently certain to insure a great reduction in present rates. The problem is no longer an investigative or scientific problem, but a problem of administration. When the people of the

United States wish to pay for absolute protection against typhoid fever it can be bought with the full assurance that the goods can be delivered.

can.

CONCLUSION.

As physicians and sanitarians, we are most interested in the practical question, Can typhoid fever be prevented? We know that it We know that our methods are certain, that they will yield the desired result in every case where they are properly applied. The problem remaining for solution is how to convince the American people that protection from typhoid fever is something worth spending .oney for.

FLY-BORNE TYPHOID FEVER AND ITS CONTROL IN JACKSONVILLE.

By C. E. TERRY, M. D., City Health Officer, Jacksonville, Fla.

It is not my intention in this paper to present any new facts regarding the carriage of typhoid fever by flies nor to make any valuable contribution to the literature on fly transmission of intestinal diseases, but rather to state an experience which is unique, I believe, in municipal sanitation.

The source of the water supply of Jacksonville, as well as systematic bacteriological examination of this supply, have enabled us, we feel, to completely eliminate it as a factor in the spread of our typhoid fever. The entire absence of open wells, owing to a city ordinance prohibiting them, removes such source of water supply from consideration. The only other water supply that could have been questioned in individual cases are the driven surface wells, and here again local conditions, namely, a perfect sand filter, which our soil furnishes naturally, has enabled us, after repeated examinations for possible sewage contamination of these wells, to disregard them as factors in the spread of this disease.

The city water is artesian from flowing wells of an average depth of a thousand feet. As it issues from these wells it is practically sterile, and outside of contiguous breaks in sewer and water mains there appears no opportunity for its contamination. No facts connected with any of our cases of typhoid fever would indicate that such an accident had ever occurred. Below is a table of the bacterial counts taken from reservoirs and taps in different portions of the city for the past three years. It will be seen from a perusal of this table that our supply is of unusual purity.