Gambar halaman
PDF
ePub

quito. Life history of mosquito. Breeding places in stagnant water. Importance of destroying breeding places by drainage, etc., or when this is impossible by covering the surface of the water with a film of oil. Past malaria campaigns. Legal machinery provided, but depends on each community to enforce it.

Recommendations:

1. That mosquito control districts be formed which shall cover all malaria infected areas in California and that this be done as rapidly as possible.

2. That if by the end of the year 1916 this plan be found ineffectual or unsatisfactory, the legislature should appropriate funds to be used by the State Board of Health to employ a sufficient number of inspectors to undertake the field work of malaria extermination under the present authority of the State Board of Health.

Dr. Wilbur (page 12)-Malaria is part of the price we have paid for introducing the African into the Southern States and part of the price we pay for finding gold in California. To get rid of the problem is merely a matter of dollars and cents. Compared to tuberculosis it is a very simple problem. Waste of water in irrigation one cause for frequency of mosquitos. Problem of the carrier of malaria. In Italy it was found that the only practical plan was to administer quinine in quantities sufficient to kill the malaria parasite in the whole population. The same system could be used in California without difficulty. Measures for control of mosquitos and human malaria carriers by which disease could be obliterated.

Professor Herms (page 15)-Malaria control practically synonymous with mosquito control. Need for survey to determine kinds of mosquitos and their distribution. Anopheles quadrimaculatus the most dangerous mosquito. Two hundred thousand dollars needed from state for campaign of cradication. Local campaign. Oil for preventive. Right and wrong kinds; 28 to 32 rees Beaumé correct; treated stove oil. Drainage of breeding pools important. Waste of irrigation water favors the mosquito. Need for county ordinances. Danger from the quinine treatment by which parasite may become resistant to the remedy. Quinine can be made effective where mosquito control impracticable. Mosquito does not acquire malaria in swamps, but only from afflicted human beings. Changes undergone by parasite in human and insect host. Malaria propagated only when conditions are favorable to it.

Dr. Meyer (page 22)—Methods used in a survey of malarial conditions in California through examination of school children. Results in Chico and Gridley. Need for educating public and extending the survey. Different treatment for city and malarial districts. Infection of city dwellers usually takes place in country districts. Reduction by quinine treatment. Lack of appreciation of problem by medical profession an obstacle to campaign against malaria. Treatment of malaria carriers.

Dr. Whipple (page 27)—Sanitary conditions on Isthmus of Panama. Favorable conditions of campaign: Finding of General Gorgas, ample authority, and financial support. Getting things done by persuasion rather than force. No time for education at Panama. Control of carriers of yellow fever easy because patient knows he is sick and can be guarded. Malaria carriers not disabled and won't stand for treatment. Difficulties in eradicating anopheles mosquito. Breeding places: hoof prints in wet soil, knot holes in trees, etc. Mosquito traps in houses and daily mosquito patrol to catch insects in houses. Brush and grass cleared for one hundred to two hundred yards about houses. Mosquito rarely flies over one-fourth mile.

Mr. Grunsky (page 30)-Organization of health department in Canal Zone in 1904. Problem of the water supply. Rain barrel customary source and favorite breeding ground for stegomyia mosquitos. First step to screen barrel. Water supply brought in by pipes July, 1905, and rain barrel abolished. Since May, 1906, there has been no case of yellow fever originating in Canal Zone. Sanitation work on Canal Zone made construction of canal possible with small loss of life.

Meeting of March 8, 1916 At the conclusion of the dinner and business meeting of the Club at the Hotel St. Francis on the evening of March 8, 1916, President Hodghead called the meeting to order with the following statement:

Remarks by President Hodghead THE PRESIDENT: On all questions of scientific research in which the Club has been interested from time to time, we have been very dependent on two great universities of the state, as we are tonight in this subject on which this committee is to report.

Last year a general section was appointed upon the comprehensive subject of the public health of the state. Dr. Wilbur, as you know,

chairman, and Dr. Lucas, of the University of California, is vicechairman. The committee organized by resolving itself into a number of sub-sections. We had a report last year from one of those committees on the County Hospital problem in California. The report this evening is the second one of the series from this committee of the section and will cover the subject of malaria, which, as you well know, has been one of the scourges of this state for many years. As it has been conquered in other regions, less fortunate than ours in other respects, it certainly could be conquered here. It will be interesting to have the report of the committee appointed to consider this question. The Chairman is also President of the State Board of Health. The first number this evening will be the report of the committee by its chairman, Dr. George E. Ebright.

Report of the Committee on Malaria

Delivered by Dr. George E. Ebright To the President and Members of the Commonwealth Club of California:

Your committee upon the malaria problem in California respectfully submits the following as its report:

Before 1850 malaria was unknown in California. It was introduced in the early 50's during the great influx of population into the state, probably from three sources: The Mississippi valley, the Isthmus of Panama and the shores of the Mediterranean. During the period following the discovery of gold and the building of the great continental railroads, emigrants arrived from the malarial-infected regions of the Mississippi by way of the transcontinental emigrant routes, also arriving by way of the Isthmus of Panama, there becoming infected with malaria and introducing it chiefly, probably, through the region of Sacramento and its vicinity. Again, many laborers were employed upon railroad construction who came from the malarial-infected districts of Italy. These carriers, arriving in a country already the home of the anopheline mosquito, readily established foci of malaria in the great valleys and along the foothills of the western slope of the Sierras, until at the present time it is to be found generally in Placer, Shasta, Sacramento, San Joaquin, Butte, Tehama, Fresno, Tulare and Kern counties, which nine counties show seventy-five per cent. of the total deaths from malaria in the state.

Cost of Malaria in California

It has been estimated by the California State Board of Health that the cost each year to the state from malaria directly and indirectly to health, labor and property values is $2,820.000. Quoting from the January, 1916, report of Dr. James G. Cumming, Director of the Bureau of Communicable Diseases of the State Board of Health dealing with malaria in one of the badly infected districts:

“The physicians of one of the valley cities agree that the malarial practice amounts to fifty per cent. of their total. Sixty-two individuals of this community were questioned regarding the number of laboring days lost each year on account of malaria. This was found to be an average of 20 days per individual. There is a total population of 3,000 and if the number infected is figured at the conservative estimate of fifty per cent, and there is allowed a $2.00 a day wage, the economic loss in wages alone is $60,000. annually. It is also stated that in the great majority of cases of severe injury or shock such as the breaking of a leg, or after childbirth, the latent malaria becomes evident. In fact, the prevalence of the disease is so well recognized that quinine treatment is given preliminary to all major operations. The charts of six out of nine cases of typhoid fever strongly indicate the co-existence of malaria and typhoid infection. The onset of the illness simulates malaria, and this is followed by the typical febrile chart of typhoid fever."

Dr. Cumming's estimate puts the economic loss from malaria in this particular community at at least $100,000. Loss to property values is more difficult to estimate. It is not difficult to imagine, however, that a prospective settler having in contemplation the purchase of one of two ranches, other things being equal, would decide against a malaria infected district, for two reasons: First, the danger to his own life and that of his family; second, the economic loss in laborers the subjects of a disease which interferes with their efficiency.

Types of Malaria Malaria may be acute or chronic. In acute malaria there are chills. and fever at regular or irregular intervals, depending upon the type of the disease. The common forms found in California are the tertian malaria in which the paroxysm of chills and fever comes on every other day, and the estivo-autumnal malaria which is irregular in its manifestations. Quartan malaria exists, but is very rare. An attack of acute malaria may be so mild that the patient is not necessarily taken from his work nor confined to the house. Without treatment he may apparently recover in a short time, but may become a sufferer from chronic malaria in the sense that from time to time he may suffer an exacerbation of the symptoms over a long period of years. Conditions which otherwise interfere with his general health, such as a surgical operation or any intercurrent illness, even a change of climate, are likely to be attended with a recurrence of the malarial symptoms. Chronic malaria, however, does not necessarily follow an acute attack, and an individual may become infected and harbor within his system the malaria parasite, the presence of which may only be evidenced by a greater or less impairment of general health, and possibly the occurrence of an acute attack under conditions which cause a temporary lowering of the individual's resistance. Malaria carriers

are also recognized who never show any definite evidence of the disease, and this is particularly true of children who are the chief carriers in mosquito infested districts. On the coast of west Africa it has been found that 100 per cent. of children in certain badly affected localities showed the malarial parasite in their blood, while in the less badly affected regions the per cent. ranged from ten per cent. to twenty per cent. The children showed no clinical manifestations of malaria at the time of examination. In other words, the disease was latent. Investigators in a certain region of Alabama found that eight per cent. to nine per cent. of the children were infected and that but three and one-half per cent. of them developed malarial symptoms within five months after the parasites had been discovered. Malaria is essentially a disease of childhood in those localities where the disease is endemic, and only those children survive who offer the greatest resistance to the malarial poisons.

How Malaria Is Maintained Human malaria carriers are the agencies by means of which malaria as an endemic disease is carried over from one mosquito season to another. In other words, if all the people in a malarial district could be removed from that district during the winter time when mosquitos are not seen and no other malarial patients brought into that district, the spring crop of young mosquitos would have no means of becoming infected with malaria, nor could they, by biting or otherwise, cause malaria in the malaria-free human individuals in that district.

The life cycle of the malarial parasite requires two hosts, one of which is man, and the other the anopheline mosquito. The transmission of the parasite from the anopheline mosquito to inan, and from man again to the anopheline mosquito, and the various changes undergone in each case, are so well known as not to require elaboration in this report. It is sufficient to say that in the absence of either host, either man or the anopheline mosquito, malaria cannot be propagated; so that the solution of the problem of malaria in any district depends, from a practical standpoint, upon the destruction of the malaria carrying mosquito.

Water is absolutely necessary for mosquito breeding. The female mosquito deposits her eggs on the surface of the water. The eggs hatch in from twelve to forty-eight hours. The larvae are called wrigglers which are very small at this time and hardly visible to the naked eye, but in a few days they become fairly conspicuous objects. The wrigglers feed on small plant life growing on the sides and the bottom of the water, or by eating smaller organisms at or near the surface of the water. The development of the wrigglers is greatly influenced by the temperature and food supply; when conditions are unfavorable the larval stage is lengthened. During the summer this stage lasts as a rule from seven to eight days, but may be as long as six weeks in the early spring or the late autumn. The wriggler is an air breather, and if prevented from having access to the air on the surface of the water it will die. For this reason a film of oil upon the water is fatal to the mosquito in this stage. The larval or wriggler stage is followed by the pupa or tumbler which is also aquatic and lasts only two to four days. The pupa then rises to the surface, the skin splits along the back permitting the winged insect to emerge.

The anopheline mosquito requires at least fifteen to eighteen days for the complete development from egg to adult. In cold weather the time is correspondingly longer. The newly hatched female insect lives as a rule from thirty-five to forty days during the summer; the male lives on an average only three or four days even under the most favorable conditions, and does not leave the breeding place, nor does he bite. During the winter, mosquitos commonly hibernate and may pass several months in this state, appearing in the spring to propagate as fishes. Still, fresh water is necessary as a breeding place for the

« SebelumnyaLanjutkan »