general pains; nausea and vomiting may occur and sweating is common.
The temperature rises rapidly and may reach 104° F. (40° C.) upon the
first day. In children the disease may be ushered in by a convulsion.
The pulse is rapid (no to 130). Jaundice is not infrequent and severe
nausea and vomiting and cerebral symptoms may be observed. The spleen
32 THE INFECTIOUS DISEASES.
is enlarged and, rarely, may rupture. There may be herpetic vesicles upon
the lips and petechias or mottling of the skin may be noted.
The liver may be palpable. During the paroxysm the blood contains the
spirochaete. The leucocytes are often increased in number.
After the fever has lasted about seven days it falls by crisis in a few hovurs
to normal or below this point and with this fall there is profuse perspiration,
sometimes diarrhoea or nose-bleed, and a general amelioration of the symp-
toms. Within a few hours or at most a day or two the patient is apparently
well. The crisis may occur as early as the third day or as late as the
tenth. In the aged or in weak individuals it may be associated with collapse.
After about one week and usually on the 14th day from the invasion, the
paroxysm is repeated, being ushered in by one or more chills, the fever recurs
and the other symptoms reappear. The relapse is, as a rule, shorter than
the primary paroxysm and is terminated by crisis in the same manner. After
another afebrile interval there may be a second, and following this, a third
relapse. Rarely has a fourth been observed. Each succeeding relapse is
shorter than its predecessor. At times there is no relapse, the patient recover-
ing after the first crisis. Convalescence, while usually rapid, may be much
protracted in patients who have been weakened by severe types of the infec-
tion.
Complications such as nephritis with hsematuria, haematemesis, rupture
and infarct of the spleen, paralyses and obstinate ophthalmia may occur.
In females, if pregnant, abortion usually takes place.
The disease is not very fatal; death, however, may take place during the
paroxysm in aged and feeble patients or as a result of a complication.
The differential diagnosis from enteric fever and from malaria, the two
diseases with which relapsing fever is most likely to be confounded, may be
made by examination of the blood. Specimens should be taken from a
finger-prick, spread thinly and may be examined fresh or stained with various
aniline colors.
Treatm.ent. No drug has yet been found which exerts any influence upon
this disease; a serum has, however, been elaborated from the blood of infected
horses, the use of which has been attended with good results. The treat-
ment in other respects is symptomatic. The patient should be kept in
bed during the paroxysms and should be exposed as little as possible during
the intervals lest a relapse be induced. At the onset a mercurial purge should
be given and followed by a saline. Throughout the disease the bowels
should be kept open and the kidneys active. The temperature should be
controlled by hydrotherapeutic measures and the pains by small doses of the
coal tar analgesics. Patients in whom the pain is marked and distressing
may be allowed small quantities of powder of ipecac and opium or morphine.
In enfeebled patients the early exhibition of stimulants, especially alcohol
YELLOW PEVER. 33
and strychnine is necessary. Emesis may be controlled by pellets of cracked
ice, sips of iced champagne, small doses of cocaine or the hypodermatic
administration of morphine should this become unavoidable.
The diet during the febrile paroxysm should be entirely of fluids, while
during the remissions easily digestible and nourishing soHds may be allowed.
During the progress of convalescence the patient should receive general
tonic treatment.
YELLOW FEVER.
Synonyms. Febris Flava; Bilious Remittent Fever; Typhus Icteroides;
Typhus Tropicus.
Definition. Yellow fever is an acute infectious disease characterized by
a febrile paroxysm which is followed by a short remission which in turn is
succeeded by a relapse. It is often accompanied by jaundice and a tendency
to haemorrhages, especially into the stomach.
.etiology. This disease prevails endemically in certain tropical cities
and according to Guiteras these zones of infection may be recognized: a.
The focal zone, from v/hich yellow fever is never absent, including Vera Cruz,
Rio de Janeiro and other Spanish American ports, h. The perifocal zone
or region of periodic epidemics, which includes the tropical ports of the
Atlantic coast of America and Africa, c. The zone of accidental epidemics,
between the parallels of 45° north and 35° south latitude.
Yellow fever is seldom seen far from the sea-coast or at an altitude greater
than 1000 feet. It is a disease of the summer months, disappearing with the
incidence of frost and is prone to attack cities, especially in their most thickly
populated and unsanitary districts. Males seem to be more subject to infec-
tion than females, "and the disease attacks all ages except young infants.
Negroes and mixed races seem to be less prone to the affection than whites
possibly because during their continued residence in regions where the disease
is endemic they may have suffered from an abortive and unrecognized type
of infection. Immunity is usually but not always conferred by one attack.
The specific cause of yellow fever, which is in all probability a micro-organism
has not yet been isolated; several observers have described bacteria which
they have considered to be the specific germ but their observations have not
been confirmed.
The chief and very probably the only mode of transmission of yellow
fever is through the bite of a species of mosquito, the stegomyia jascmta.
Rigid experiments have shown that the disease is not conveyed by means of
fomites. That the infection may be transmitted to a non-immune by injec-
tion of blood drawn from yellow fever patients has also been proven.
Pathology. The skin is of icteroid hue although jaundice may not have
3
34 THE INFECTIOUS DISEASES.
been evident ante mortem and subcutaneous extravasations of blood may be
present. The blood-serum contains haemoglobin resulting from the destruc-
tion of the red blood cells. The heart may be the seat of fatty degeneration.
The Uver is enlarged and congested, later it undergoes fatty changes and is
yellowish-brown in color. Spots of necrosis are usually present. The
kidneys are enlarged, congested and the seat of acute inflammation. Areas
of necrosis may occur in these organs as well as in the liver. The gastric
mucosa is congested and swoUen, there may be submucous haemorrhages
and the organ may contain blood-serum and degenerated blood pigment (black
vomit). There may be general enlargement of the lymph nodes, particularly
those of the peritonaeum, of the neck and axiUae. Changes characteristic of
yellow fever alone have never been noted.
Symptoms. The incubation period is from three to four days, rarely
over five days. Prodromata are rare, the invasion being usually sudden
with chilly feelings or by convulsions, in the case of children, followed by head-
ache, general pains, prostration and fever. The onset usually takes place
between midnight and dawn. The temperature soon reaches 102° to 105° F.
(38.9° to 40.5° C). The face is flushed, the eyes are injected and watery and
photophobia is present. The pulse is weak and at first rapid in proportion
to the height of the temperature, after a day or two, even though the fever is
higher than before, the pulse rate begins to decrease and gradually continues
to do so until it may become slower than normal before the fever declines.
This lack of proportion between the pulse rate and the height of the tem-
perature is characteristic of this disease and is an important diagnostic point.
The skin is hot and dry, the tongue is red and cracked and the throat and
gums may be sore. Slight jaundice may appear early in the disease. Nausea
and vomiting may appear at the invasion but are more likely not to occur
until the second or third day. In severe infections thevomitus may be of
coffee-ground material, tar-like or even of unchanged blood, while in milder
forms it consists merely of blood particles, mucus and bile. The bowels are
usually constipated but the stools are not clay colored. With slight varia-
tions in temperature this, the first stage of the disease, lasts three or four days
and is terminated by the return of the temperature by lysis to normal.
At this time the second stage or stage of calm begins, the symptoms dis-
appear and in mild cases convalescence becomes established. In the severe
infections this stage, after lasting from a few hours to a day or two, merges
into the third stage.
In this stage, although rarely there may be no fever, the temperature rises
again while the pulse rate may decrease to even as low as 60. The jaundice
becomes more pronounced, the tongue is dry, brown and cracked, and nausea
and vomiting return. Haematemesis with abdominal pain is frequent, there
may be tarry stools and haemorrhages from the nose, gums, uterus, kidneys
YELLOW FEVER.
35
and into the skin. There may be suppression of urine and death from uraemia
or the patient may grow progressively weaker and die of the profound toxaemia,
the fever remaining elevated until this has occiirred. In more favorable cases
after a secondary fever of two or three days, the temperature falls by lysis,
the symptoms amehorate and the patient goes on to a protracted convalescence
during which jaundice may be persistent.
Albuminuria is a feature of this disease, appearing in mild cases even on the
OAY OF
DISEASE
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Fig. 4. — Clinical chart of yellow fever^showing the pulse typically slow in comparison
to the height of the temperature.
second or third day. It may be merely transitory but in severe infections
it is present in large amounts and accompanied by casts. At times the neph-
ritis may result in anuria and death from urasmic poisoning.
Relapses sometimes take place; complications are not very common; such
sequelae as parotitis and multiple abscesses have been observed.
The diagnosis of the disease may at times be difficult. Malarial fever
of the remittent type may be differentiated from yellow fever by the earlier
incidence of the remission, the longer duration of the chill and the presence
36 THE INFECTIOUS DISEASES.
in the blood of the malarial parasite in the former disease. Here also the
three salient characteristics of yeUow fever are aids, these being the typical
facial expression, slow pulse and early occurrence of albuminuria. These
points are serviceable in the separation of the disease from dengue as are also
the haemorrhages and the early occurrence of jaundice in yellow^ fever in con-
tradistinction to the absence of the former and the possible later incidence
of the latter in dengue.
The prognosis in yellow fever is grave, the severer forms of the infection
being particularly fatal. In weak, poorly-nourished and alcoholic subjects
the chances of recovery are less than in those in whom the opposite conditions
obtain. Of patients who exhibit the "black vomit" by no means all die,
but those profoundly poisoned and in whom mental and kidney symptoms
occur seldom recover.
The prevention of yellow fever consists in the guarding of patients suffering
from the disease from the bites of mosquitoes, in the obstruction of ways of
ingress of the mosquito to the house, of the destruction of these insects within
dwellings and of the employment of means with a view to prevent their prop-
agation. How effectually the disease may be prevented is evidenced by its
rarity in Havana, where it formerly prevailed largely, since proper steps have
been taken in prophylaxis. Mosquitoes in dwellings may be destroyed by
means of sulphur fumigation and may be prevented from entering by means
of screens. Patients suffering from the disease should be surrounded by
netting. Although the most recent observers believe that yellow fever is not
transmitted in any other way than by the mosquito and that disinfection of
clothing, bedding and the like is unnecessary it may be wise to employ the
usual disinfection methods of the sick-room and its contents after the patient's
recovery.
Preventive inoculation has not been employed with success.
Treatment. The patient should be isolated and screened. He must be
strictly confined to bed from the onset and should be moved as little as possible.
The bowels and bladder must be evacuated while in the recumbent position
and, should it be impossible to urinate under these circumstances, catheter-
ization must be undertaken. AU body and bed linen must be kept scrupu-
lously clean and when these are changed the utmost care not to disturb the
patient to the least degree must be observed. Food and medicines when
taken by mouth should be given by means of a spouted cup or through a
tube so that the head need not be raised.
At the onset of the disease the bowels should be opened by fractional doses
of calomel followed by a saline laxative; here magnesium, in the form of
the effervescing citrate, or sodium sulphate is to be preferred. The kidneys
should be mildly stimulated by one of the alkaline diuretics and the skin
kept active by means of tepid sponge baths. During the febrile stages it is
YELLOW FEVER. 37
wise to feed entirely per rectum and to administer medication by means of
this channel or hypodermatically. For the temperature and nervous symp-
toms hydrotherapeutic measures are indicated. Cool sponging is perhaps
best and the baths shoiild be given with great care so as to disturb the patient
as little as possible. The pain may be reheved by means of smaU doses
— gr. V (0.33) — of acetphenetidine (phenacetine) combined with caffeine
sodio-benzoate if there is the slightest tendency to cardiac weakness. While
most authorities advise the hypodermatic administration of morphine if
this symptom is severe, certain observers, whose experience of the treatment
of yellow fever has been considerable, consider this drug contraindicated at
all stages of the disease; quinine given per rechcm — gr. xx (1.33) — is useful
in this affection. Formerly this drug was extensively employed in yellow
fever and while it is probable that it exerts no specific effect its administration
does no harm. Vomiting is difficult of control and should be treated by
pellets of cracked ice. Small doses of cocaine — gr. \ (0.016) — of hydro-
cyanic acid, of creosote or of carbolic acid have been recommended but ice
alone usually accomplishes all that is possible. Haemorrhage may be com-
bated by the hypodermatic administration of ergot or by means of calcium
chloride, gr. xl (2.66) per rectum. The latter drug is said to cause an increased
coagulability of the blood. Lead acetate and iron perchloride have been
advocated but are probably better omitted.
During the course of the disease the kidneys and the circulatory system
may be stimulated and the toxaemia lessened by high rectal irrigations of hot
— 110° to 116° F. (43.5° to 46.5° C.) — normal sahne solution. Two of these
may be given daily and the quantity should be at least i gallon (4 litres).
The ursemic symptoms respond very favorably to this means of treatment;
here also hot baths and packs are useful. If at any time there are symptoms
of cardiac weakness free hypodermatic stimulation by means of alcohol, strych-
nine, digitalis, camphor and aether, or camphor and oil are indicated. Collapse
may be treated by this means, by the hypodermatic or intravenous adminis-
tration of considerable quantities of normal salt solution and by enemata
of strong black coffee.
During the stage of remission the patient's strength must be supported
by means of stimulants and tonics.
The following treatment of the disease has been recommended. Sodium
bicarbonate gr. vii ss (0.5) and mercury bichloride gr. J-^ (o.ooi) are given
dissolved in ice water every one or two hours depending upon the severity of
the infection; the sodium bicarbonate tends to lessen the excessive acidity
of the gastric juice and urine and by rendering the latter alkahne the tendency
to nephritis and aniiria may be diminished. At the invasion the patient is
given a hot mustard foot bath and for the following three or four days cool
sponges are given, an ice bag is applied to the head and a sinapism to the
38 THE INFECTIOUS DISEASES.
epigastric and lumbar regions. No food is given during the first three days
of the disease.
The serum treatment of yellow fever, although the subject of much exper-
imentation, has as yet yielded no very favorable results.
During convalescence the patient should be kept in bed or at any rate until
the profound prostration which is a feature of yellow fever has disappeared
and the heart and kidneys have retmrned to their normal action, he should
be kept at rest. Tonics such as iron, strychnine and quinine should be pre-
scribed.
The food during the febrile stages should be administered wholly per
rectum, nutrient enemata such as those suitable in gastric ulcer being indicated
(see p. 353); during the remission fluids may be given by mouth and after con-
valescence has become established the greatest caution must be observed in
feeding. No solids should be given for at least ten days after the symptoms
have subsided and too large quantities at a time must be avoided. The
first foods allowed by mouth are peptonized milk, milk, milk and vichy,
kumyss or matzoon, one drachm (4.0) every hah hoiu*, later beef juice may be
given, then the whites of eggs, the proprietary infant foods, broths and gruels.
Gradually the various semi-solids, junket, cereals, milk toast, etc., may be
added until finally the patient is able to tolerate solid diet.
INFLUENZA.
Synonyms. Epidemic Catarrhal Fever; Grip.
Definition. An acute infectious disease, generally endemic and from
time to time occurring in widespread epidemics^ characterized by catarrhal
inflammations of the various mucous membranes, prostration and a tendency
to involvement of the nervous system.
iEtiology. At various periods of the world's history since the sixteenth
century widespread epidemics of this disease have occurred, the last of these
in 1889, when within a year it had prevailed in most parts of the civilized world.
Since this epidemic in most American cities there are seen yearly a number
of cases of epidemic influenza. Epidemics remain in a locality from one to
two months and the affection is prone to attack a very large proportion of the
population. Epidemics differ greatly in severity and in liability to com-
plications.
The specific factor in the causation of this disease is the influenza bacillus
which was discovered by Pfeiffer in 1892. It occurs in great numbers in the
nasal, tracheal and bronchial secretions of patients affected and may be
easily demonstrated.
Epidemic influenza is markedly contagious and rapid in its spread, and occurs
with its greatest degree of severity in the colder seasons of the year. Unhy-
INFLUENZA. 39
gienic surroundings do not seem to affect its incidence; it attacks all ages
and both sexes and those who have suffered from one infection seem more
prone than others to a second.
Authorities differ as to the portal of entry of the contagium, probably,
however, it reaches the organism upon the inspired air and the infection takes
place through the respiratory tract. It is asserted that the primary lodgment
of the bacillus may be either the gastro-intestinal tract or the conjunctiva.
Pathology. This disease is characterized by no typical lesions; only those
due to the complications are found post mortem. In the abdominal type
of the infection there may be enlargement of the solitary and agminated
follicles of the intestine.
Symptoms. The incubation period is from one to three or four days,
although at times the interval between the entrance of the contagium into the
body and the manifestation of symptoms may be longer.
The onset is usually sudden with a chill followed by a rise in temperatiu-e —