CHAPTER XV

CHOLERA

DEFINITION AND SYNONYMS

=Definition.=—Cholera is a disease caused by a spirillar type of bacterium, _Spirillum cholerae asiaticae_. The organism multiplies in the small intestines and, undergoing lysis, liberates an endotoxin, which is responsible for the desquamation of the epithelium of the mucosa and other manifestations of the disease. Cholera appears to be endemic in the delta of the Ganges and the various world-wide epidemics can generally be traced to that source. The rice-water stool of cholera teems with the spirilla, and infections of water or food supplies can be traced to such a contamination. The importance of the cholera carrier has been thoroughly demonstrated from the time of the Hamburg epidemic of 1892. The clinical course of the disease is divided into a stage of evacuation, in which we have diarrhoeal discharges of rice-water character along with very painful cramps of the muscles. Following increasing cyanosis we have almost a cessation of circulation often associated with anuria, the algid stage. With the return of activity of circulation and urinary secretion we have the stage of reaction.

=Synonyms.=—Cholera Asiatica.

HISTORY AND GEOGRAPHICAL DISTRIBUTION

=History.=—Although the word χολέρα, meaning flow of bile, is found in the writings of Hippocrates, it certainly does not refer to the disease we now recognize as cholera. The older writers noted the characteristics of bilious discharges in the disease they termed cholera, which could not apply to the bile-free rice-water discharges of what we now term cholera. Koch rather doubted the antiquity of cholera but Susruta, in India, in the 7th century A. D., described a disease in which there were diarrhoea and vomiting, stabbing pains, cyanosed lips and nails, with sinking in of the eyes and weak voice.

Detailed accounts of the presence of cholera in India were published from the 16th to 18th centuries when the Portuguese, English and French were carrying on their wars of conquest in India. These wars naturally spread the disease all over India.

It is thought that true cholera did not exist in China until 1669 when it was carried there from India. It is first described from Japan in 1821 although an epidemic which devastated Tokyo in 1718 may have been cholera.

A great pandemic of cholera started in India, in 1817, extending over Asia but not invading Europe. The second great pandemic is of importance as being the first to invade Europe. It started in India in 1826 and advancing slowly reached Persia in 1829, going thence by way of Astrakhan to Russia, Sweden, Northern Europe and England. By 1832 it had spread over the whole of Europe.

In the same year, 1832, it reached Canada and thence spread to Fort Dearborn where it infected the soldiers who subsequently carried the disease down the Mississippi valley. It was also introduced into New York and spread thence South and West so that by 1836 cholera was present all over the U. S., not disappearing until 1838. It disappeared from Europe in 1839.

The next European outbreak or third pandemic lasted from 1846 to 1862 and was traced to India by way of land and sea, that by land following the caravan route by way of Persia and Russia and that by sea from Indian pilgrims going to Mecca and there causing the infection of Mahommedan pilgrims from Egypt and European Turkey. This pandemic reached the U. S. in 1848, starting at New Orleans and going up the Mississippi valley. Central and South America and the West Indies were also invaded by the third pandemic.

The fourth great pandemic invaded Europe by the usual routes and continued from 1863 to 1875. During its continuance there were two outbreaks in the U. S., one in 1867 and another in 1873.

That in 1873, when it was introduced into three widely separated parts of the country, was the last appearance of cholera in the U. S.

The fifth pandemic began in 1883 and affected particularly the Mediterranean seaports of France, Spain and Italy. It was during this epidemic, in 1883, that Koch, working in Egypt, discovered the cause of cholera, the _Spirillum cholerae asiaticae_.

A very serious outbreak of cholera, which originated in 1891, in pilgrims from the delta of the Ganges, reached Europe in 1892, almost a million deaths occurring in Russia. It was during this epidemic that cholera appeared in Hamburg and gave opportunity for those careful studies as to transmission of the disease to be later referred to.

It is usual to recognize a sixth pandemic which began in 1902 and spread over India, China and the Philippines. This pandemic continuing was a cause of great mortality among the soldiers of the recent Balkan war. During the World War there was much cholera among the Austrian forces in Galicia. It also prevailed in Bulgaria, Greece and Turkey.

=Geographical Distribution.=—Practically every pandemic when studied can be traced back to India and particularly to the delta of the Ganges, which may be considered the enduring focus of the disease.

ETIOLOGY AND EPIDEMIOLOGY

=Etiology.=—The cholera vibrio, _Spirillum cholerae asiaticae_, was discovered by Koch in 1883 and is a short curved organism which, from its shape, is often called the comma bacillus. In addition to single spirilla there may be “S” shapes from attachment of pairs. In cultures in peptone solutions long filamentous forms may be seen which however are exceedingly rare in the rice-water stools. A stained smear from a fleck of mucus gives the fish-in-the-stream appearance. Besides comma-shaped organisms we may have coccoid or rod-shaped forms. In old cultures marked pleomorphism is often seen.

[Illustration: FIG. 72.—Cholera vibrios, short forms. (MacNeal from Kolle and Schurmann after Zettrow.)]

It is Gram-negative and stains best with a dilute (1-10) carbol fuchsin. There is a single terminal flagellum, which endows the organism with great motility, which may best be termed scintillating. It has been estimated that its motility is five times greater than that of the typhoid bacillus. It grows best on media with an alkaline reaction (—0.4%) and it is this tolerance for media of high alkalinity that permits the separation of the cholera spirillum from the ordinary faecal bacteria by the use of Dieudonne’s alkaline blood agar or similar media. This is equal parts of defibrinated ox blood and N/1 NaOH, 3 parts of which are added to 7 parts of nutrient agar. It thus has 15% of normal sodium hydrate, instead of the 1% acid reaction of the usual media. Unfortunately, other spirilla tolerate this high alkalinity.

The cholera organism is strongly aerobic and grows quickly and luxuriantly in the upper part of a tube of Dunham’s peptone solution, this property enabling one to separate it from other organisms of faeces by taking up loopfuls from the surface layer to plate out on agar of about 0 or -0.3% reaction. When grown in peptone solution the cholera spirillum produces a nitroso body so that one obtains an indol reaction (cholera red) by simply adding 5 or 6 drops of concentrated H_{2}SO_{4}.

When this test is employed it is necessary to determine whether the peptone used is suitable for the reaction. As a matter of fact this test is now rather discredited. Blood serum is digested. Recently much discussion has arisen as to the value of the haemolytic power possessed by noncholera vibrios on blood agar plates.

It is true that the digestive action which true cholera has on the red cells of the medium may give the appearance of a zone of haemolysis. Therefore, for the demonstration of this haemolytic

## action of noncholera spirilla, fluid blood media should be used.

The El Tor spirillum, isolated from Egyptian pilgrims without symptoms of cholera, is haemolytic, but gives the immunity reactions of the true cholera vibrios which are not haemolytic.

Gelatine is liquefied and the stab shows an air bubble liquefaction at the summit of the stab. On gelatine plates a powdered glass center with an encircling zone of liquefaction was formerly considered characteristic of cholera, but at the present time gelatine cultures have been almost abandoned in practical work.

As a rule animals cannot be infected by feeding them cholera material unless the acidity of the gastric juice be neutralized and intestinal peristalsis checked by opium (procedure of Koch). Injected intraperitoneally, the cholera vibrio produces a fatal peritonitis. Recently monkeys have been infected after purgation with sulphate of soda and administration of bicarbonate of soda. They died in from one to forty-eight hours with symptoms of cholera.

There have been instances where cholera has been caused in laboratory workers by the accidental ingestion of cholera cultures, thus Orgel was infected from sucking up peritoneal fluid in doing Pfeiffer tests for bacteriolysis and died.

Emmerich and Pettenkofer swallowed cholera cultures, the former experiencing a severe attack of cholera and the latter a diarrhoea in which cholera spirilla were present. On the other hand similar experiments have resulted negatively but this is what should be expected from the epidemiological facts as to carriers.

The virulence of the cholera vibrio can be exalted by passage through guinea pigs—successive culturing of the peritoneal exudate of intraperitoneally infected animals alternating with culture media growth inoculations. Such a fixed virus, the virulence of which cannot be exalted, is the material used by Haffkine in his cholera vaccine. The toxicity of cholera is supposed to be due to an endotoxin which is set free when the vibrios undergo disintegration when lying between the basement membrane and epithelial lining of Lieberkühn’s glands. Others think the vibrios may enter the blood stream, there to be immediately disintegrated with toxin production. The usual idea, however, is that the cholera spirilla never invade the blood stream—they are confined to the alimentary canal. Macfadyen obtained the endotoxin by grinding the frozen spirilla. This toxin was destroyed by a temperature of 60°C.

The spirillum of cholera has but little resistance to disinfecting agents or to drying. It is also rapidly overgrown by putrefactive bacteria and tends to disappear from sewage-contaminated water in a short time. In stools the vibrio dies in about one or two days in summer and in about a week in winter.

The inoculation of animals by cholera cultures tends to produce an immune serum which is remarkable for its high agglutinating power, the titre at times going as high as 1 to 20,000. For agglutination tests in proving spirilla isolated from stools to be true cholera ones we use a serum of at least 1 to 4000 for its specific vibrio. Such a serum should agglutinate any true cholera spirillum in a 1 to 500 or 1 to 1000 dilution. The occurrence of bacteriolysis, when a small loopful of the culture emulsified in 1 cc. of 1 to 1000 dilution of the immune serum and then introduced into the peritoneal cavity of a guinea pig, is the surest proof that a suspected organism is that of cholera.

This is shown when, upon removing a drop of the peritoneal fluid fifteen to twenty minutes afterward, there is noted an absence of motility and disintegration of the spirilla (_Pfeiffer’s phenomenon_).

Complement fixation tests, using the rice-water stools or peptone solution cultures as antigen, are of less value than those above noted. Agglutination is the practical test and is almost as specific as that for bacteriolysis.

=Epidemiology.=—Until recently our attention as to the methods of transmission of cholera was directed almost exclusively to the water and food supply, with a certain degree of consideration of danger from fomites, especially to that connected with clothing soiled by cholera discharges, it having been noted that those who wash such clothing showed a high incidence of infection. Later on the importance of flies in the spread of the disease was strongly insisted upon. At the present time we consider the cholera carrier the most important factor in cholera epidemiology and it is to the detection and isolation of such persons that we now chiefly direct our attention in the keeping out of a country of this dread disease.

It will be remembered that Pettenkofer and Emmerich insisted upon the factors of soil and ground water in the spread of cholera. Emmerich now admits that the spirilla excreted by carriers can produce cholera but that such transference never gives origin to epidemics. For this to take place he thinks that the vibrios excreted by a carrier must come in contact with a soil which has been impregnated with a suitable medium drawn to the surface from the deeper layers of the soil by capillary suction. In such medium the vibrios flourish and acquire the property of actively producing nitrites from nitrates.

Emmerich considers that the symptoms of cholera are those of nitrite poisoning so that only such organisms as possess this nitrite-forming function in high degree can produce virulent outbreaks of cholera.

All facts in connection with the spread of cholera by land or water routes can be best explained by the cholera carrier; the individual who is excreting vibrios, while in apparent health, being far more dangerous than the one excreting such organisms in the rice-water stools of a well-recognized case of the disease.

_Water Transmission._—There are two types of outbreaks of cholera according as the general water supply is contaminated or when such contamination is localized to certain wells, cisterns or other nongeneral supplies. In the former the onset is explosive and cases occur almost simultaneously and with equal distribution in all parts of the city, to disappear with almost equal suddenness.

In the latter mode of infection, cases will appear from day to day and often peculiarly localized to certain definite districts of a city or to certain definite users of a particular water supply.

[Illustration: FIG. 73.—An instructive contrast between Altona and Hamburg before the latter filtered its water, having learnt its lesson from a sharp outbreak of cholera. (After G. E. Armstrong.)]

As an example of the first type of outbreak the Hamburg epidemic of 1892 is most instructive.

During a period of only about two months cholera attacked about 17,000 persons causing 8605 deaths in a city with a population of 600,000. This outbreak was attributed to the washing of clothes in the water of the Elbe River by Russian immigrants. These immigrants had come from cholera-infected districts and among them there undoubtedly were cholera carriers.

The water supply of Hamburg was taken directly from the river. The adjoining city of Altona, with a population of 140,000, is further down the river but filtered its water by a slow sand process. Although the water as taken from the river contained the sewage of Hamburg yet there were only 328 deaths or 2.1 per thousand as against 13.4 per thousand for Hamburg. There were many interesting points in connection with the exemption of certain places in Hamburg, of which may be noted the instance of the entire freedom from cholera of a group of houses (Hamburg Hof), with 345 occupants. This was the only section of Hamburg which was supplied with Altona water. As Hamburg and Altona are only separated by the width of a street and hence practically form a single city, the factor of food and contact transmission could easily explain the cases in Altona.

To illustrate the second type of water transmission we have the well-known incident of the Broad Street pump.

This was about the first definitely proven connection between water and cholera. In 1854 it was noted that cholera was about 10 times as prevalent in Golden Square as in other adjacent parts of London. Various factors, such as previous droughts, stagnation of lower strata of the atmosphere, sewerage defects and subsoil drainage were found to be the same in Golden Square as elsewhere. It was noted that the number of cases increased in the neighborhood of the Broad Street well. The employees of a cartridge factory where this well water was used gave a large number of cases while an adjoining brewery, which had a well of its own and served out beer to its employees, did not furnish a single case. Very striking was the case of a lady living at Hampstead, a section of London which was then free from cholera, who had acquired a liking for the water of this well and had brought out to her regularly bottles of water from the well. This lady drank some of the water on August 31 and was seized with cholera the next day. A niece drank of the same water and died of cholera as well as the aunt. A servant also contracted the disease but recovered.

Macnamara has noted the circumstance of a vessel of water, which became contaminated with cholera stools, but which at the time it was drunk by 19 persons did not show anything suspicious in odor, color or taste. One person was stricken one day afterward, two on the third day and two others came down with cholera on the fourth day. It will be noted that only 5 of the 19 were attacked. A similar lack of susceptibility of a certain proportion of people, equally exposed, has been noted in all cholera outbreaks. It is probable that of those of the 19 who did not contract cholera there were developed a certain number of cholera carriers.

_Food Transmission._—Food contaminated by dejecta from cholera patients or carriers is dangerous in proportion to its condition of moisture. Drying and the development of inimical organisms are the two chief factors in destroying the cholera vibrio. Temperature and sunshine are operative in assisting the drying process.

Lettuce and celery are particularly dangerous because of the favorable condition of moisture in their folds and imbrications. Furthermore these vegetables are eaten uncooked and may have been fertilized with night soil (human excrement) which material, if containing cholera dejecta, would infect the plants. Milk is a splendid culture medium for cholera vibrios but, upon becoming acid, sterilizes itself of these vibrios. In sterilized milk, however, they live for extended periods, as long as sixty days and, even when such milk is contaminated by faecal material containing other organisms besides the cholera vibrio, the vibrios live much longer than they do in raw milk.

Milk is liable to be contaminated by flies which have been in contact with cholera stools. Water that has been boiled and food that has been cooked should subsequently be scrupulously protected from flies or other contaminating agents. Uncooked shell fish are peculiarly dangerous in cholera outbreaks.

In India, sun-dried fish, which are frequently covered with flies during the curing process, are a factor in the spread of cholera.

_Transmission by Carriers._—This is now universally recognized as the most important factor in the spread of cholera. Dunbar was the first to draw attention to the presence of virulent cholera spirilla in the faeces of apparently healthy persons during the Hamburg epidemic of 1892.

Since that time these observations have been generally confirmed. In some instances as many as 20% of those who have been in immediate contact with a cholera patient have become carriers, some showing symptoms of cholera but a larger proportion excreting cholera spirilla while continuing in health.

While cholera prevailed in Manila, McLaughlin found from 6 to 7% of carriers among healthy persons living in the infected districts.

Pottevin has recently reported that of 13,000 pilgrims examined 1.7 per thousand carried cholera vibrios. The carriers were especially common among the dysenteric patients. During the Naples epidemic of 1911 it was found that on the average 10% of healthy people in contact with cholera cases became carriers. It was estimated that 90% of the cases in this epidemic were infected by sick or healthy carriers.

Sergeant has recently reported the case of a healthy carrier who continued to excrete cholera vibrios for two months and during this time was in contact with 8 persons, 7 of whom became infected and 4 died. In Manila it was found that many of the children reported as dying of meningitis or infantile beriberi were cholera cases.

The vibrios are rarely excreted in the faeces of the cholera patients longer than seven to ten days. Frequently they disappear in three or four days.

With healthy cholera carriers the period of the continuance of vibrio excretion is equally short but cases have been reported where periods of from three weeks to two months have been noted. It is usually stated that 97% of carriers become vibrio free within a month.

Greig has found infection of the bile of the gall bladder or ducts in 80 cases in 271 cholera autopsies. When living organisms are injected into the ear vein of a rabbit they pass into the bile. An examination of the epithelial layers of the gall-bladder of such a rabbit shows destruction of the cells and the presence of vibrios in the underlying tissues. While cholera spirilla are soon crowded out by intestinal bacteria, thus explaining the short period during which cholera spirilla are excreted by convalescents, this is not true when the cholera vibrio gets into the bile ducts or gall bladder. Greig found one cholera convalescent excreting cholera vibrios forty-four days after the attack. Of 27 persons who had been in contact with cholera patients 6 were excreting cholera vibrios although apparently well.

A very important matter is that persons who fail to show cholera vibrios may begin to excrete such organisms after the administration of a purgative or following some intestinal disorder. In fact purgatives may set up an attack of cholera in a cholera carrier.

The spread of cholera is intimately connected with the great religious festivals and pilgrimages of Oriental people. Not only do those of India keep up the dissemination of the disease there but pilgrims going from the delta of the Ganges to Mecca carry the infection and transmit it to their fellow pilgrims from Egypt and Algiers. Greig examined a number of cholera convalescents who were about to return to their homes in India and found 30 per cent of these pilgrims excreting cholera vibrios in their stools.

In India cholera accounts for about 1 to 1.5 deaths per 1000 of population. Malaria and plague are other great causes of death.

The intimate commercial relations between Europe and Egypt and Algiers make the introduction of the disease into European ports an easy matter. Of particular importance is the fact that so many sick people make pilgrimages, these being peculiarly liable to act as carriers.

Excesses in eating, often of badly prepared or decomposing food, following periods of religious fasts, predispose the natives of India to cholera.

Lowered resistance, as from disease or from gastric disorder, increases the susceptibility to cholera. Errors in diet and in

## particular the effects of alcoholic excesses markedly predispose to

infection.

PATHOLOGY

The cholera spirillum does not produce a soluble toxin, the toxic principle being intracellular. The organism rarely penetrates more deeply than just under the epithelial layer of the glands of Lieberkühn. As a result of the outpouring of the fluid into the lumen of the gut we have an increase in the red cells (7,000,000 per cu. mm.) and leucocytosis of from 12,000 to 50,000. The specific gravity of the blood is greatly raised, 1073 to 1078, and the alkalinity diminished. The blood pressure is markedly lowered, 60 mm. in very severe cases and 75 mm. in less severe ones.

The lower portion of the small intestines is the favorite location for the action of the endotoxin of cholera. Early and marked postmortem rigidity is a striking characteristic of the cholera cadaver. Muscular contractions, causing odd positions of the limbs, have at times given a basis for the idea that the victim had been buried alive.

Besides marked rigor mortis the emaciation, leaden hue of skin and shrivelled hands are noteworthy.

In opening up the body there is a striking dryness of all the structures. The dry and dark-red muscles stand out prominently. The lungs are dry and shrunken. The right heart is full of a dark, jelly-like, viscid blood. The leading changes are found in the abdomen. The omentum is dry, sticky and shrivelled looking. The intestines have a ground glass appearance with a lilac-pink color of the small intestines which is in contrast with the normal color of the large intestines.

There is congestion of the affected intestinal mucosa and the lumen is filled with the alkaline rice-water material. If the case is of some days standing we have a rather brownish, foul-smelling bowel content. There is usually a parenchymatous nephritis and on section the medullary portion is much congested.

Crowell gives the following points as indicating cholera upon autopsy: (1) Cyanotic finger nails, (2) dry tissues, (3) dry and sticky peritoneum with pink serosa of ileum, (4) contracted and empty urinary bladder, (5) shrunken dry spleen and liver, (6) rice-water intestinal contents and (7) prominence of lymphoid tissues in the ileum.

In his studies of the pathology of cholera Greig drew attention to the frequency of the involvement of the gall-bladder. He also noted the presence of small areas of consolidation in the lungs of those developing pneumonia during the early days of convalescence. In the exudates of such areas cholera vibrios could be seen thus showing their penetration of the lung. Although rare instances of recovery of the cholera spirillum from the blood have been reported Greig was unable to accomplish this in any instance. In his opinion the spirilla travel by way of the lymphatic system. In eight cases out of fifty-five cases he recovered the spirilla from the urine.

SYMPTOMATOLOGY

=A Typical Case of Cholera.=—The so-called prodromal or premonitory diarrhoea is not a feature of the onset of _cholera gravis_, the type of the disease which characterizes the cholera epidemic.

The period of incubation is usually from one to five days. Longer periods are possibly explained by some exciting intestinal disorder in a cholera carrier. The course of the disease is conveniently divided into a stage of evacuation, an algid one and a stage of reaction.

_The Stage of Evacuation._—A profuse and frequent diarrhoea comes on without colic or tenesmus. In fact the stools are voided with a sense of relief as when an enema is gotten rid of.

The striking feature, however, of these movements is the sensation of prostration which accompanies them.

The faecal character of these diarrhoeal stools is soon lost and the typical rice-water stool is now passed. This designation is very apt and the flocculi of intestinal epithelium, in a watery, slightly opaque fluid, suggests rice-water. The odor is slightly albuminous.

Early in this stage cramps of the muscles set in. The muscles of the legs, especially the calf muscles and those of the feet, are

## particularly liable to these very painful contractions which may

cause the patient to cry out for relief. The muscles of the abdomen and back may also be involved as may at times the muscles of the entire body.

Vomiting, at first of the contents of the stomach and later of rice-water material, is a distressing feature to the patient and by reason of the manner in which it often gushes from the patient’s mouth is liable to contaminate the attendants.

Along with the excessive loss of fluid the tissues, especially of the face, become shrunken, the eyeballs with their congested conjunctivae sink back in the orbits, and the nose becomes pinched. The pulse becomes more and more feeble and there is a steady diminution in the secretion of urine. An increasing duskiness of the skin, which is cold and clammy to the touch, denotes the setting in of the algid stage.

_Algid Stage._—In this stage there is almost complete cessation of circulation, even the incision of a vein is only followed by a drop of black tarry blood. Anuria is practically complete.

The vomiting, purging and cramps may or may not subside and in the patient, with his great thirst, intense exhaustion and cadaveric appearance, with mental faculties fairly well preserved, we have an example of a living death. The temperature of the sodden, inelastic, clammy skin is markedly depressed, even below 90°F., while the rectal temperature may approximate normal or be elevated.

Some authorities consider a marked difference between the superficial and rectal temperatures as of bad prognosis.

The voice becomes husky and finally so feeble that the patient can only whisper and the breath feels cold.

The sodden shrivelled hands, as those of a washerwoman, are very characteristic. Thirst is intense.

The patient now falls into a listless, motionless state in which, however, the apathy is more apparent than real. The algidity may deepen and death ensue or the stage of reaction may set in. The algid stage may last from a few hours to two or three days.

Collapse and uraemia are the two most frequent causes of death.

_Stage of Reaction._—The pulse returns, urine is again secreted and the duskiness and coldness of the skin give way to normal conditions and a favorable convalescence sets in. At other times, however, the rise of surface temperature and restoration of the circulation are not attended by urinary secretion.

In such cases a typhoid state ensues with accelerated respiration, dry, brown tongue and muttering delirium.

It is customary to divide the types of cholera cases into:

1. _Cholera gravis._ The type above described.

2. _Cholerine._ In this there is a more or less marked stage of evacuation with possibly the appearance of rice-water stools. The urine, however, does not become suppressed and the algid stage is not entered upon.

3. _Cholera sicca._ This type of the disease is more apt to be seen in old or debilitated people. The patient dies of collapse without showing symptoms of vomiting or diarrhoea. At the autopsy one may find the bowels distended with rice-water contents.

The so-called _cholera ambulans_ is simply another designation for the more or less ill cholera carrier.

=Sequelae.=—Following an attack of cholera we may have abscess of the parotid gland or gangrene of various parts of the body. There may be ulceration of the cornea. In pregnant women the disease almost invariably causes abortion. Post-choleraic pneumonias and renal inflammations are to be considered.

Symptoms in Detail

_General Appearance._—A typical case of cholera, with its cyanosed, drawn, pinched face, cold, clammy skin and the eyes deeply sunken in the orbits, makes a picture rarely seen in other conditions. The washerwoman’s hands appearance should always be looked for.

_Temperature Record._—The temperature of the skin surface is lowered from the normal while that of the rectum may be normal or even elevated. There may be a difference of 10° or more between rectal and surface temperature. In the stage of reaction the temperature may continue to rise to high fever points and this so-called hyperthermic type is very fatal.

_Circulatory System._—The pulse is rapid and feeble in the stage of evacuation to become imperceptible in the algid stage. The circulation is practically at a standstill so that only a few drops of black tarry blood, which does not coagulate readily, flow from a wound of a vein when giving an intravenous injection. The blood is concentrated and has a specific gravity of 1072 to 1078. The systolic pressure falls greatly, even to 60 mm. of mercury in a severe, or 75 mm. in a less serious case. The red cell count is increased to 7 or 8 million red cells per c.mm. and the leucocyte count reaches 15,000 to 50,000.

_Nervous System._—The mind is clear, even when the patient seems profoundly apathetic. The muscle cramps are characteristic of the disease.

DIAGNOSIS

=Clinical Diagnosis.=—It is customary to state that cholera nostras and infections with virulent meat poisoning bacteria of the paratyphoid group show bile in the intestinal discharges and not the typical rice-water stools of true cholera. It must be remembered that these affections can at times show as marked muscular cramps, emaciation, cyanosis and weak voice as cholera so that only the bacteriological examination can differentiate.

Algid pernicious malaria generally shows a rather high axillary temperature and the stools are rarely so profuse as in cholera.

In ptomaine or mushroom poisoning the vomiting usually precedes the diarrhoea—the opposite of the order in cholera.

Acute intestinal obstructions may simulate but here we have faecal vomiting and constipation.

With irritant poisons as arsenic or antimony there is the metallic taste and the pains are chiefly colicky rather than muscular and the stools rather dysenteric.

I have seen severe cases of bacillary dysentery which could not be differentiated clinically from cholera, and it is interesting to note that many cases of cholera occurring in the Balkan war were diagnosed as bacillary dysentery. In children cerebral manifestations are very common so that in the Philippines many such cholera cases were diagnosed as meningitis.

=Laboratory Diagnosis.=—Agglutination is the practical aid in diagnosis. The serum from cholera convalescents, or those vaccinated against cholera, show agglutinins. It has been stated that properly vaccinated cases show a titre of from 1 to 2 thousand in about 70% of cases. Normal human serum does not agglutinate in a higher dilution than 1 to 20. Greig has found that fatal cholera cases rarely give higher than 1 to 40. In cases recovering he found well-marked agglutinating power by the 6th day, titres of 1 to 500 or 1 to 1000 being frequently obtained. Janoue and Watanabe found the agglutinating power of the sera of convalescents to fall rapidly after the third week. As a rule the titre varied from 1 to 100 to 1 to 400. The highest titre noted was 1 to 10,000.

It is well to first make a microscopical examination of the stool by taking one of the whitish epithelial flakes from the rice-water material and making a straight smear which is then dried and fixed with heat. This may be stained best by a dilute carbol fuchsin (1 to 10). Methylene blue makes a good stain, or more differential is that by Gram’s method which shows the Gram-negative spirilla stained by the bismarck brown counterstain, giving the appearance of fish parallel to one another in a stream. According to Koch a diagnosis can be made in this way of one-half the cases during an epidemic.

The scintillating motility of cholera spirilla may strike one in the examination of the stool in hanging drop.

Dunbar has a quick diagnostic method in which epithelial flakes from the stool are emulsified in peptone solution. Then on a slide, according to the method to be later described, is deposited a drop of 1 to 50 normal serum dilution and on the same slide a second drop of 1 to 500 dilution of cholera serum. A loopful of the suspected stool emulsion is rubbed up in each of these serum dilutions and we should have cessation of motility and clumping in the cholera immune serum provided the organisms in the stool are true cholera spirilla.

In case of an autopsy on a suspected case of cholera one should tie off, between double ligatures, at least two 5-inch sections of small intestines, one just above the ileo-caecal valve and one taken from about the middle of the ileum. These portions of gut should be dropped into sterile salt mouth bottles, well stoppered and sent to a bacteriological laboratory as soon as possible. As the cholera spirilla, when associated with faecal bacteria, tend to die off within twelve to twenty-four hours it would probably be advisable to inoculate an agar or blood serum slant with material from the ileum at the same time the sections of gut are removed. For diagnosis of a cholera carrier with a normal stool or a cholera suspect with a diarrhoeal one inoculate 2 or 3 tubes of peptone solution with 2 or 3 loopfuls of material from the stool. With suspected carriers who are constipated and to whom one should not give purgatives we may insert into the rectum a rubber tube or a throat swab in order to obtain material immediately. The cholera spirilla grow rapidly and being strong aerobes, they grow on the surface of the fluid so that by taking a loopful from the surface, we may in three to eight hours obtain a pure culture. Should there be a pellicle present, this should be avoided in transfer by tilting the tube slightly, so that the material near the surface be obtained without touching the pellicle. Inoculate a second tube from the surface of this first and, if necessary, a third (_enrichment method_).

Smear the three-hour surface growth of a peptone culture on a dry agar surface in a Petri dish. From colonies developing make agglutination and, if desired, cultural tests. It is by immunity reactions and not by cultural ones that we identify cholera spirilla. The surface moisture of plates is best dried by the filter-paper top.

The cholera colony is easily distinguished from the ordinary faecal bacterial colonies by its transparent, bluish gray, delicate character.

A practical quick method is to make smears from suspicious colonies, stain for one minute with dilute carbol fuchsin and if vibrios are present to make 2 vaseline rings on a single slide allowing ample space at one end for handling the preparation safely. Inside of one ring deposit with a platinum loop a drop of salt solution and inside the ring nearest the end which is to be held by fingers or forceps deposit a loopful of 1 to 500 or 1 to 1000 dilution of cholera serum. The emulsion in the salt solution remains uniformly turbid and under a low power of the microscope (⅔-inch) shows a scintillating motility. The emulsion made into the drop of serum quickly shows a curdy agglutination and upon examination with the ⅔-inch objective shows clumping and absence of motility. Cover-glasses placed over the two vaseline rings assist in the study of the preparation.

The best-known selective medium for plating out cholera material is that of Dieudonne which is referred to under etiology. Apparently a more satisfactory medium is that proposed by Goldberger, this medium being transparent.

First prepare a 100% meat infusion by treating 500 grams of finely chopped lean beef with 500 cc. water and after three hours strain the infusion, adjust reaction to neutral with 5.3% anhydrous sodium carbonate, then add to each 100 cc. 2½ cc. of the 5.3% anhydrous sodium carbonate, sterilize in Arnold for one-half hour and filter. Next prepare a 3% meat extract agar and mix one volume of the alkaline meat infusion with 3 volumes of the hot melted 3% meat extract agar. Pour plates and cover with a piece of filter-paper and place in incubator for one-half hour until they are quite dry. The necessity for a surface without moisture applies to Dieudonne’s and Krumwiede’s alkaline egg media as well as this one. On this medium cholera grows well while faecal bacteria are restrained.

The cholera colony is clear, round and shows a brownish center but is without that striking bluish opalescence shown on ordinary agar plates.

While peptone solution is a more favorable enrichment medium and answers perfectly when cholera organisms are fairly abundant yet, when scarce, selective enrichment media may be desirable. Of these the best known is Ottolenghi’s alkaline bile. Goldberger prefers an alkaline egg peptone solution made as follows:

Shake up an egg with an equal quantity of water and add to this egg solution an equal quantity of a 5% solution of anhydrous sodium carbonate. Steam one hour. Then add 1 part of this alkaline egg medium to 9 parts of peptone solution, filter and sterilize. Recent reports on _Aronson’s cholera medium_ would indicate its great value in stool examination for cholera. The organisms taken from such plates emulsify easily and there is no interference with their agglutinability. To prepare it add to 100 cc. of 3% nutrient agar, 6 cc. of 10% solution of exsiccated sodium carbonate and steam in Arnold sterilizer for fifteen minutes. Then add 5 cc. of 20% saccharose solution, 5 cc. of 20% dextrin solution, 0.4 cc. saturated alcoholic basic fuchsin and 2 cc. of 10% sodium sulphite. A precipitate forms which quickly settles and plates can be poured from the supernatant fluid. Cholera colonies develop in twelve hours and show as red colonies in fifteen to twenty hours.

Test for _cholera red_ reaction. Add from three to five drops of concentrated chemically pure sulphuric acid to the first or second peptone culture after eighteen to twenty-four hours growth. Some specimens of peptone do not give the reaction. At times we only get the cholera red when we have a pure culture of cholera.

PROGNOSIS

There is the greatest variation in the mortality in different epidemics as is true of most other epidemic diseases. At any rate 50% may be considered an average mortality.

Young children and old people give a very high mortality rate as is also true of alcoholics and those with kidney disease.

PROPHYLAXIS AND TREATMENT

=Prophylaxis.=—Of all the quarantinable diseases cholera is the one in which personal prophylaxis is apparently of greatest influence in protection from infection.

In the presence of cholera one should not only drink recently boiled water, which has been protected from the contaminating influence of flies, but all forms of uncooked food should be avoided. In the first rank of prohibited foods should be raw shell fish and uncooked salads. Such articles as lettuce and celery are

## particularly dangerous on account of the moisture retained. Fruits

such as bananas and oranges can be made safe by covering them with boiling water for two or three minutes and subsequently peeling. Care must be taken that native servants do not put fish, which may have been contaminated with cholera-infected water, on the ice in an ice box and through such a source to have the butter, etc., infected. The most scrupulous attention should be given the matter of the care of the ice-box in the tropics.

If conditions are such that boiled water cannot be obtained the water may be treated with good quality chlorinated soda. As a stock solution we use 1 teaspoonful of chlorinated soda to 1 pint of water and of this 1 teaspoonful to 2 gallons of the water to be disinfected. Pottevin recommends six hours contact with hypochlorite of soda, 1 mg. per liter.

Besides care of the food and water ingested particular attention should be paid to the washing of the hands before eating and if in contact with cholera cases careful disinfection of the hands.

Experience in cholera epidemics has shown the importance of avoiding anything which might lower resistance. In particular are fatigue, excesses in alcohol or the taking of any kind of indigestible foods to be avoided. It must be remembered that the use of purgatives may set up cholera in a cholera carrier so that this possibility should be thought of.

Tea has been recommended as a prophylactic, as has also eucalyptus oil, 10 minims twice daily.

As acids have an inimical effect on the cholera spirilla some have recommended the use of acid drinks but as a matter of fact the best prophylactic is the normal gastric juice and there is a possibility that the use of such acid drinks might upset the digestion and thus defeat the object desired.

As to municipal measures for the control of a cholera outbreak the most important one is to diagnose cholera carriers, such cases often occurring in those associated with a cholera case. Such carriers should be isolated and their stools disinfected until at least 2 negative examinations show them to have ceased being cholera carriers. Of course a cholera case should be isolated and kept in a fly-screened room.

For disinfection of stools one requires an equal amount of a 5% compound cresol solution which when mixed with the same amount of stool becomes a 2½% solution. This should be in contact with the stool at least one hour before emptying the container. Chlorinated lime, 1 pound to 4 gallons, makes a splendid disinfectant for stools—equal parts of this 1 to 16 chlorinated lime solution and stool.

Bed clothing or other material contaminated by vomitus or faeces should be immersed in a 2½% compound cresol solution. All food utensils should be disinfected by boiling.

Persons attending cholera cases should wear gowns and remove the same upon leaving the room. Particular care should be exercised in hand disinfection after attending a cholera case.

There is no danger from aerial conveyance of infectious material other than the possibility of one’s coming within the danger zone of a vomiting patient. Therefore, for disinfection of a room occupied by a cholera patient we need not use formaldehyde gas but washing of floors and lower part of walls with 2½% compound cresol solution is sufficient. The stock solution of chlorinated lime, 1 pound to 4 gallons, is suitable for mopping floors and walls.

_Vaccination prophylaxis_ against cholera has been less used than has been the case with plague or typhoid fever. The anti-cholera sera have no practical value prophylactically and the same statement applies to the use of such sera in treatment of cholera.

Ferran, in 1885, was the first one to use cholera vaccines in prophylaxis. Haffkine, in 1893, adopted the use of a preliminary subcutaneous injection of an attenuated cholera organism to be succeeded later by one, the virulence of which had been exalted by passage through animals to a fixed virulence. (Pasteur’s anthrax method.) He now only uses the fixed virulence vaccine. This vaccine is not killed by heat.

The statistics indicate quite a reduction in susceptibility on the part of vaccinated persons (probably 8 to 1) but only slight lessening of mortality rate. Of 5549 nonvaccinated 198 contracted cholera and 124 died. Of 5778 vaccinated 27 contracted cholera and 14 died.

In the recent Balkan war (1913) Kolle’s vaccine was employed with considerable success. This vaccine is killed by exposure to 58°C. for one hour. It was found that this vaccine was not only of value prophylactically but diminished case mortality as well. With 91,224 persons vaccinated and 8,968 not vaccinated, the case rate among the inoculated was 0.7% and the death rate 10.2%, while among the noninoculated the case rate was 9.3% and the death rate 27.5%.

Ottolenghi prefers to sterilize with a temperature of 53°C. He gives 500 million at the first injection and 2 billion at the second.

Among 72,653 soldiers, having 2 inoculations of this vaccine, the incidence of cholera was about 13 times less than among 14,332 who were not vaccinated.

Of 2897 Greek sanitary corps men inoculated 0.45% were attacked while of 114,805 combatants, not inoculated, about 2% were attacked by cholera. One would naturally consider the greater exposure of the sanitary forces.

Cholera vaccines made from killed cultures are the ones now generally used.

During the World War a Roumanian regiment numbering 4,500 soldiers, had 386 cases of cholera develop in the course of six days, with 166 deaths. Vaccination was commenced and during the interval between the first and second injections, new cases continued to appear. Two days after the second injection the epidemic ceased. In another regiment the commandant refused to have his men vaccinated. A group of Jewish soldiers, 200 in number, insisted on being vaccinated, which was done. Later the regiment was stricken by cholera and 450 cases developed. None of the vaccinated Jewish soldiers contracted the disease.

Some prefer sensitized living cultures for prophylaxis but such vaccines are less practical.

There is much to indicate that Strong’s cholera autolysate is of value prophylactically. In this cholera cultures are killed at 60°C. The killed culture is then allowed to digest itself in the incubator at 37°C. for three or four days (peptonization). The preparation is then filtered and from 2 to 5 cc. of the filtrate is injected.

=Treatment.=—Many of the older authorities recommended the use of various astringent medications for the checking of suspicious diarrhoeas and most of these prescriptions contained opium in some form, such as lead and opium pills or aromatic sulphuric acid and laudanum. In view of the fact that for the infection of animals Koch had to employ opium for checking peristalsis in addition to neutralization of gastric juice it would seem very undesirable to use opium by mouth. Calomel in divided doses and continued over one or two days, but not exceeding 7 or 8 grains, has been recommended.

At present the treatment which is thought to give the best results is the permanganate one proposed by Rogers. In this the patient is given calcium permanganate water ad libitum and 2-grain pills of potassium permanganate every half hour until the stools become more faecal in character. These pills are made up with vaseline and coated with a mixture of a 1 part salol and 5 parts of sandarach varnish.

Reports as to the use of kaolin in treatment and as a prophylactic have been favorable. The suspension in water is given as a drink and as an enema.

Rogers has recently been administering 1/100 of a grain of atropine sulphate morning and evening. His statistics would indicate a reduction in mortality of about one-half. Cases treated with atropine also rarely show collapse. Injections of adrenalin solutions have been recommended.

A great objection to any form of oral medication is the tendency to vomiting. This can in a measure be controlled by cracked ice or by a small hypodermic of morphia. The latter drug also relieves the very painful cramps.

One danger which must always be borne in mind in giving more than one dose of any drug subcutaneously is that with the slowing or cessation of circulation, coming on with the algid state, we have no absorption but, when the stage of reaction sets in and the drug, whether morphine or toxic stimulant, begins to be taken up, there may ensue a fatal poisoning.

However the views of authorities may conflict as to special forms of treatment, there is universal acceptance of the employment of intravenous injections of fluid to combat collapse. Normal saline is the fluid usually used, but Rogers recommends his hypertonic solution which consists of 120 grains of sodium chloride, 6 grains of potassium chloride and 4 grains of calcium chloride to the pint of water.

In the Philippines the normal saline seemed to answer as well as the hypertonic solution.

Sellards had success in combating anuria, which is one of the most dangerous conditions encountered in cholera, and at the same time answered equally well with normal saline in relieving collapse, by giving 2% sodium bicarbonate injections.

There is a marked acidosis in cholera and this form of treatment seems indicated.

The objection to using sodium carbonate is that the salt has a lytic action on red cells in vitro and furthermore Sellards found that it tended to cause convulsions in one of his cholera cases. Sodium bicarbonate, even in 4 or 5% concentration, does not have any haemolysing effect on the red cells. Of course it is true that in sterilization the bicarbonate tends to be converted into carbonate but Sellards found that by sterilization in an autoclave connected with live steam, at 7 pounds pressure, this was minimized, only about 25% of the bicarbonate being converted into carbonate after 1 hour.

If the temperature by rectum is about normal or slightly below, the temperature of the fluid should be 102° to 104°F. and one usually gives about 2 quarts.

Owing to the collapse of the veins it is usually necessary to cut down on them instead of inserting the needle through the skin as for salvarsan injections. The same apparatus as for salvarsan injections is suitable but with a somewhat larger container as we give from 1 to 2 quarts of fluid. At least fifteen minutes should be taken up for the introduction of 1 quart of fluid.

To determine the necessity for intravenous infusion in cholera Rogers has recently recommended the employment of small bottles containing aqueous solution of glycerine with specific gravities varying from 1048 to 1070, increasing the specific gravity in each successive bottle by 2°.

Drops of blood from the cholera patient are deposited at the center of the surface of the fluid in the bottles from a capillary pipette. If the specific gravity of the blood is 1062 at least a liter of saline or sodium bicarbonate solution is needed. If 1066, at least 2 liters. Formerly he estimated the indications by blood pressure, considering a pressure of 80 in Europeans or of 70 in natives as indicating intravenous injections.

On the whole the reports from the use of anti-cholera sera are not very encouraging. Savas, however, was favorably impressed by such treatment during the Balkan war. It should be administered intravenously and early in the attack and given in doses of 50 cc. Of 61 severe cases, so treated, the mortality was 55.7%. Of 17 severe cases, not receiving serum treatment, all died.

Hot water bottles should be used to keep up the body heat. No food should be given during the first thirty-six hours but after that time we may give broths or albumin water.

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