THE EXTERMINATION OF THE MOSQUITO

ALVAH H. Doty, M.D.

Formerly Health Officer of the Port of New York

The indifference on the part of the public regarding the extermination of mosquitoes is due largely to the fact that the danger of these insects as media of infection is not known or not fully understood. The bite which they inflict is generally accepted as unavoidable, and the possibility of eliminating this source of annoyance is looked upon with considerable skepticism. This feeling is encouraged by the results which often follow ordinary attempts to destroy the breeding places. of mosquitoes for the work is either improperly done or it is confined. to a few premises or a very small part of the infested territory; in the latter instance, good results are not forthcoming, for breeding places in the immediate vicinity which have not been treated or disturbed furnish sufficient mosquitoes to perpetuate the nuisance.

Prior to 1900, the southern part of the United States, the West Indies, Mexico and South America were often visited by outbreaks of yellow fever, involving great loss of life as well as serious injury to commerce. In the United States these outbreaks often led to very unpleasant interstate disputes. This condition will probably never occur again for it has been proved that yellow fever is transmitted only by a certain kind of mosquito known as the "Aedes," or more commonly, the "Stegomyia," and that if proper means are employed, this disease may be prevented or quickly and successfully dealt with.

Malaria is found in almost every part of the world, and in the past certain sections have been almost depopulated by this disease. Malaria is also transmitted by a variety of mosquito, the "Anopheles," and the extermination of this insect means the prevention of malaria.

Unfortunately, so far as the protection of the public is concerned, the extent to which mosquitoes act as media of infection is unknown, although indisputable evidence has been presented that diseases other than yellow fever and malaria are transmitted from one person to another in this way, and it is not improbable that future investigation will show that some of the more common forms of infection are contracted through this source. At least, there is abundant evidence that the danger of mosquitoes as media of infection is serious enough to demand the most active cooperation on the part of the public in the work of extermination. The means by which this is accomplished are not difficult to carry out, and under ordinary conditions do not involve very great expense. I refer to the destruction of breeding places.

throughout the entire infested territory. There is no other way by which this important sanitary problem can be successfully dealt with. For practical purposes it may be said that there are two classes of mosquitoes in the United States the inland or so-called "freshwater" mosquitoes of which there are many varieties, including the "Aedes," and the "Anopheles"; and the Atlantic coast or " salt-water " mosquitoes also commonly known as the "striped-legged" mosquitoes. There is a distinct line of demarkation between the breeding place of these two classes, for the Atlantic coast mosquitoes will not breed inland, and the inland mosquitoes will not breed in the salt water swamps. along the Atlantic coast. This knowledge renders valuable aid in the identification and extermination of these insects.

The salt water swamps referred to consist of vast areas, frequently miles in extent, and in certain sections of the coast forming one continuous breeding place; and the mosquitoes which propagate here can be exterminated only by the proper drainage of the swamp land.

The extermination of inland mosquitoes requires a different procedure, for this variety not only breeds in small pools of water, rich in vegetation which furnish plenty of food for the larvae to feed upon, but they will breed in almost any exposed receptacle containing water, and it is not difficult to understand why so many mosquitoes are found about premises which are not kept in good sanitary condition. Unsuccessful attempts to exterminate mosquitoes are usually due to the fact that their breeding places escape detection, for they occur in the most unsuspected places, yet they may be found if care and patience is observed, and the time expended in this way is quite sure to be rewarded.

Mosquitoes are perpetuated from one year to another by females which late in the fall seek some warm and protected place, the house or barn for instance, and pass into a stage of stupor, or "hibernation " and remain in this state until the spring returns, when they become active again, seek a breeding place, lay their eggs and die. This teaches an important lesson, for if the breeding places are destroyed early in the season and the hibernating females do not find a place to deposit their eggs, there will be no mosquitoes during the following. months.

It seems strange that with the knowledge we now possess regarding the danger of mosquitoes as media of infection, and the certainty. with which they may be exterminated if proper means are employed, greater progress has not been made in eliminating these very formidable agents of infection; yet experience has shown that successful results in this direction have been accomplished only in instances where the work

has been done under some form of official control. This not only insures the employment of proper methods, but requires that every part of the infested territory shall be subjected to the most careful inspection and the breeding places destroyed.

It is evident that the successful extermination of mosquitoes rests in the hands of the Federal, State or Municipal government, for any action which may be taken must include all the area where these insects may propagate.

HEALTH CONDITIONS ON PICNIC GROUNDS

W. B. MAY, M.D.

Medical Expert, Division of Communicable Disease

Frequent trips to nearby recreation grounds by those who are compelled on account of thin pocketbooks to remain in the cities during the hot summer months are the only vacations afforded many of our urban people, and great care should be taken to avoid the possibility that these pleasure seekers may incur the danger of contracting typhoid fever or other disease through the impurity of the drinking water supplied to the patrons of the picnic grounds.

In many instances this water is pumped through pipes from the pond, river and lake on the borders of which the recreation grounds are located.

No effort, as a rule, is made to filter or purify the water notwithstanding the fact that garbage and in many instances excretions of the patrons are deposited in the stream or carried in open drains to the pond or lake.

The latrines are often situated in some secluded part of the grounds and as a general rule are simply open sheds which soon become foul and offensive both to the sense of sight and smell, owing to the fact that no pit or vault is excavated and no tight box or care provided.

The health officer should carefully inspect all picnic grounds located within his jurisdiction, and insist on some means for providing a safe drinking water and should force the owners to provide decent fly-proof toilet facilities and means for incineration or other proper disposal of the wastes.

QUALIFICATIONS OF HEALTH OFFICERS PRESCRIBED BY PUBLIC HEALTH COUNCIL

On July 6, the Public Health Council held a public hearing to which all health officers and many others had been invited for the purpose of expressing their views on proposed qualifications for local health officers.

Eleven health officers appeared. The general sentiment as expressed by these gentlemen and by the letters received at the Department were strongly in favor of the proposed qualifications. After going over them again very carefully, the council duly adopted the following regulation:

Resolved, That it is the sense of the Council that the following qualifications should be required of Health Officers hereafter appointed:

I. They shall be physicians of several years' standing;

II. They shall when appointed be not less than twenty-four nor more than sixty-five years of age;

III. They shall have complied with one of the following require

ments:

1. A course of at least six weeks including practical laboratory and field work with lectures and reading, at an educational institution. Such courses to be approved by the Public Health Council. Examination and certificate.

2. Correspondence course of one year followed by at least one week. of practical demonstrations in laboratory and field work. Both correspondence course and demonstrations to be given under conditions approved by the Council, with examination and certificate for each.

3. Evidence satisfactory to the Public Health Council of special training and practical experience in public health work. Such evidence. to be afforded if required by successful examination.

Provided, that under special conditions specified in writing by the local board of health or other appointing power these qualifications may be waived by the Public Health Council.

The following resolution was also adopted at the same meeting: Resolved, In view of the qualifications to be required of local health officers to be appointed after November 1, 1916, the Public Health Council recommends to local health boards and other appointing officers called upon to make such appointments previous to November 1, 1916, when these requirements become effective, that they specify that the health officer to be appointed shall agree to conform to the requirements within the first year of the new term.

THE NEW YORK UNIVERSITY COURSES IN PUBLIC

HEALTH

The Public Health Commission appointed by ex-Governor Sulzer made a recommendation that "Medical colleges in New York State introduce courses in sanitary science leading to a degree, which ultimately might be required of all health officers." The Public Health Council in June, 1915, added a strong recommendation that the universities also give two shorter courses so that the majority of health officers would have at least some additional training to that which they now possess. Three such courses have been developed at New York University in which laboratory work, lectures and field work will be combined. One of the most important of the courses, consisting of field work, laboratory work, lectures and conferences, will cover six weeks. The course leading to the degree of Doctor of Public Health begins with the six weeks' course and continues, with optional work, for a further six months to complete the first year, the second year being devoted to original work and the writing of a thesis.

There will also be an extension course covering three hundred hours of home reading and written examinations with a final week in the laboratories at the University. Both the shorter and longer courses given in the University began on July 15. The extension

course begins October 1.

The extension course will cover the same subjects as those prescribed for the six weeks' course in the University. It is supposed that those taking the course will devote on an average of one hour a day throughout the year. The course of study will be prescribed and questions will be sent on each of the subjects. The answers to these questions. will be corrected and discussed. At the end of the course, one week's sojourn at the University will be required, in which a certain amount of laboratory work will be combined with examination.

Those who take the long course and pass the practical and written examinations will receive a certificate of efficiency in Public Health. Those having the degree of Doctor of Medicine, upon the completion of the course and the presentation of a satisfactory thesis showing evidence of nine months' original work on some problem connected with public health or sanitation, will receive the degree of Doctor of Public Health. The fee will be fifty dollars for the six weeks' course and fifty dollars for the extension course.

The fee for the course leading to the degree of Doctor of Public Health will be two hundred dollars for the first year and twenty-five dollars for the second year.