Yellow Fever.

Synonyms.—Typhus Ichteroides; Febris Flava; Black Vomit; Yellow Jack.

Definition.—An acute, infectious, though non-contagious, disease of the tropics or sub-tropics, and characterized by a sadden invasion, a high grade of fever lasting from two to seven days, marked tenderness over the epigastrium, vomiting of black, broken-down blood, albuminous urine, and yellow discoloration of the skin.

History.—The disease, in all probability, has existed for many centuries, although the first authentic report is that of the epidemic which appeared in the Barbadoes, West Indies, in 1647. It made its appearance in this country at Boston in 1693. Since then numerous epidemics have occurred, entailing the loss of thousands of lives and a financial loss of many millions of dollars.

Guiteras has classified the infected areas as follows: I. The focal zone, in which the disease is never absent—Havana, Santiago, Vera Cruz, and other Spanish-American ports. 2. Perifocal zones, or regions of periodic epidemics, including the ports of the tropical Atlantic in America and Africa. 3. The zone of accidental epidemics, between the parallels of 45° north and 35° south latitude.

Epidemic in Havana: that city has been the focus for a century and a half, from which many portions of the civilized world have been repeatedly infected.

Etiology.—While season, age, race, and unhygienic conditions predispose to the disease, the exciting cause has not yet been positively determined, though the bacillus ichteroides of Sanarrelli and the bacillus X of Surgeon-General Sternberg have been found in a number of cases, and believed by many to be the specific cause.

Prophylaxis.—One of the most far-reaching and beneficent discoveries in the history of the medical world was recorded when the medical commission appointed by the Surgeon-General of the United States army completed their work in Havana, proving beyond doubt that the transmission of yellow fever is through the bite of a species of mosquito, the Stegomyia fasciata.

The late Dr. Walter Reed, a major in the United States army, was chairman of the commission, the other members being Assistant Surgeons James Carroll, Jesse W. Lazear, and Aristides Agramonte. As early as 1881, Dr. Carlos Finlay, of Havana, a graduate of Jefferson Medical College, of Philadelphia, had declared his belief that a certain species of mosquito in Havana was the transmitter of yellow fever from person to person. Acting upon this belief, Drs. Lazear and Carroll allowed themselves to be bitten by infected mosquitos. In the case of Dr. Carroll, he became infected and narrowly escaped death. Dr. Lazear, though not infected by the first test, was later accidentally bitten, became infected with yellow fever, and lost his life.

The commission soon determined, by actual experiment, that if a female mosquito of the species Stegomyia fasciata were permitted to bite a yellow fever patient during the first three days of the disease, and then a period of from twelve to twenty clays elapse and a non-immune be bitten by this infected mosquito, he almost invariably developed yellow fever.

The commission also proved, by experiment, that the disease is never transmitted by fomites. A number of immunes slept for twenty consecutive nights in a room in which articles were hung that were soiled by black vomit and bloody fecal discharges from fatal cases of yellow fever. These immunes also packed and unpacked the soiled clothing each day; and a still more severe test was the sleeping in clothing and under sheets that had covered fatal cases of yellow fever, yet not a single case of fever was contracted, though, when exposed to infected mosquitoes later, several contracted the disease.

One of the most practical proofs of their findings is the disappearance of the disease in Havana as soon as the yellow fever patients were protected by mosquito netting, thereby preventing mosquitoes from carrying the infection to others; this, together with the crusade that was inaugurated against the destruction of the larvae of the mosquito, and the removal, as far as possible, of all pools, stagnant ponds, and filthy gutters,—breeding-places of the mosquitoes.

The report of the commission was as follows:

1. The mosquito—Stegomyia fasciata—serves as the intermediate host for the parasite of yellow fever.

2. Yellow-fever is transmitted to the non-immune individual by means of the bite of the mosquito that has previously fed on the blood of those sick with this disease.

3. An interval of about twelve days or more after contamination appears to be necessary before the mosquito is capable of conveying the infection.

4. The bite of the mosquito at an earlier period after contamination does not appear to confer any immunity against a subsequent attack.

5. An attack of yellow fever, produced by the bite of the mosquito, confers immunity against a subsequent attack of the non-experimental form of this disease.

6. Yellow fever is not conveyed by fomites, and hence disinfection of clothing, bedding, or merchandise, supposedly contaminated by contact with those sick with this disease, is unnecessary.

7. A house may be said to be infected with yellow fever, only when there are present, within its walls contaminated mosquitoes capable of conveying the parasite of this disease.

8. The spread of yellow fever can be most effectually controlled by measures directed to the destruction of mosquitoes, and the protection of the sick against the bites of these insects.

Pathology.—The skin and mucous membrane show a varying degree of jaundice, from the light yellow to a dark brownish or orange color, the color deepening over the course of the blood vessels. The liver partakes of the same yellowish color, and at first is hyperemic, though, after death, it is usually anemic. There may be extravasation of blood, giving it a mottled appearance. The parenchymatus changes show fatty or granular degeneration. The gastro-intestinal mucous membrane shows catarrhal lesions with softening of the membrane, at first hyperemic, followed by extravasation of blood.

The stomach contains more or less of broken-down blood, the so-called black vomit. The kidneys undergo diffuse nephritis, with fatty or granular degeneration. The spleen, though dark, soft, and friable, is but little changed in size. The heart is pale, flabby, and shows the same necrotic changes which take place in the other viscera.

The blood is dark and broken down, the disintegration of the red-blood disks is responsible for the hemoglobin found in the blood serum. The meninges and brain are hyperemic, and show the characteristic degenerations.

Symptoms.—Incubation.—This varies from twenty-four hours to two weeks with the usual prodromal symptoms; viz., languor, listlessness, loss of appetite, partial arrest of secretions, with pain in head and back.

Invasion.—The invasion is abrupt; the chill, though not long, is well defined, and followed by febrile reaction, the temperature rapidly reaching 103°, 104°, or 105°; the skin becomes hot, dry, and harsh; the urinary secretion is arrested, and the bowels are obstinately constipated. The patient suffers severely with pain in the back, limbs, and head, and is extremely restless and uneasy. Much irritation of the stomach exists from the first, with pain and sense of oppression in the epigastrium; in a majority of cases vomiting speedily comes on, and continues through this stage, the retching and ejection from the stomach being painful and difficult.

The eyes are generally suffused, reddened, and very sensitive to light, presenting the appearance that would follow exposure to wood-smoke; this has been looked upon as almost a pathognomonic symptom by some.

The pulse, varies greatly in different cases; in many it is hard, quick, and irregular; in others small, corded, and oppressed; and, again, not different from what it would be in a simple remittent. The tongue hardly ever presents the same appearance; sometimes clean, again broad, flabby, and covered with a thin white coat; or reddened at tip and edges, pointed and coated in the center; and again presenting a thick, yellowish, or yellowish-brown coat. As before remarked, this stage varies in duration, and there is just as much variation in its intensity.

Stage of Remission.—The febrile action gradually abates; the vomiting ceases, or is less constant; the pains are much ameliorated; the skin becomes softened, and frequently covered with perspiration- The patient feels comparatively well, though exceedingly debilitated, and has hopes of speedy recovery; and yet, even now, may be noticed that yellowish discoloration, manifesting itself in the conjunctiva and the skin of the forehead and breast, the precursor of that third stage from which it is so difficult to recover.

This remission, sometimes so complete, can hardly be noticed at others, but the first rapidly passes into the third stage; or collapse. It is always of short duration, not more than from two to ten hours.

Third Stage.—In this stage the pulse becomes very feeble, and the prostration is excessive; the yellow appearance of the skin, which gives the disease its name, becomes plainly visible, and continues to deepen as the disease advances. The irritability of the stomach is excessive; nothing can be retained, but the vomiting now is easy. The material ejected from the stomach is peculiar, being very dark colored, and hence known by the name of black vomit. This dark-colored material has been determined to be broken-down blood.

Diarrhea frequently ensues, the discharges from the bowels resembling' those ejected from the stomach. The respiration is hurried and difficult, with frequent sighing, and the patient complains of an intolerable oppression and distress at the precordia.

The powers of life rapidly fail; slow delirium or coma comes on, and death soon eases the patient from his intense suffering. During this stage there is very little, if any, urine secreted, and it is highly albuminous. In some cases febrile reaction occurs during this stage, and in favorable cases terminates by lysis, or assumes a typhoid type, which rapidly proves fatal.

Diagnosis.—According to the statements of all authorities, it is extremely difficult, if not impossible, to distinguish yellow fever from the severer forms of remittent fever, in the first stage. Yet the prevalence of the disease as an epidemic in that locality is considered sufficient cause to adopt a treatment suitable for its arrest, in every case presenting the symptoms named.

The subsidence of the fever, after the exacerbation has continued more than twenty-four hours, is a prominent symptom of the disease; the commencing yellow discoloration of the skin, great prostration, and finally vomiting of dark-colored material, renders the diagnosis beyond cavil.

Prognosis.—We are always to bear in mind that yellow fever is one of the gravest of diseases; yet the prognosis varies, depending upon the character of the epidemic and the stage in which treatment is begun. In some epidemics the toxemia is intense and the mortality reaches an alarming per cent, while at other times all the cases seem more or less mild, the mortality dropping as low as five per cent.

Treatment.—Prophylaxis.—Quarantine must be rigidly enforced in individual cases as well as in the infected districts. The excreta should be thoroughly disinfected and buried: all clothing and bedding of a fever patient should be either disinfected or burned. When possible, those not immune should leave the infected area at the earliest moment, seeking a cooler place in a higher altitude. During an epidemic excesses of all kinds should be studiously avoided.

The medicinal treatment for yellow fever has largely been a failure, and physicians with little or no experience have been about as successful as those who have passed through the various epidemics; hence it is not presumptuous for one who has never seen a single case to outline a course of treatment.

Remembering that the blood is very early influenced by the toxin, causing its disintegration, we would suggest the remedies which would antidote or check this destruction,—antiseptics, such as baptisia and echinacea, in full doses, would most likely influence this process. The first-named remedy has been used extensively by our Southern physicians for this purpose.

Realizing that just in proportion as we control the fever will we retard the necrotic processes, the wet-sheet pack or spirit vapor bath would be among our best auxiliary measures to produce sedation. Internally, aconite or veratrum in the small dose would assist the above measures. Where there is great nervous irritability, with flushed face, bright eyes, and contracted pupils, gelsemium would likely prove of benefit. For gastric irritation, ipecac and rhus tox. would most likely be useful agents; for depression, camphor has been used successfully; for the stage of collapse, the treatment would be similar to the same stage in cholera; viz., hypodermic injections of strychnia and large injections, sub-cutaneously, of warm saline solution.

In the earlier stages, the bowels should be emptied by large enemas of warm water. For the intense thirst, acidulated waters would do no harm, and might afford some relief. During convalescence great care should be taken not to give anything but the blandest kind of diet, such as sherry whey, koumiss, malted milk, clam and chicken broths, etc.

The Eclectic Practice of Medicine, 1907, was written by Rolla L. Thomas, M. S., M. D.