Chapter XL: Trench Fever

DEFINITION AND SYNONYMS

=Definition.=—Trench fever is a specific, acute infectious disease, probably caused by _Rickettsia quintana_, acquired usually through the agency of the body louse, characterized by an abrupt onset, a febrile period of about five days often followed by one or more relapses, and ending in complete recovery.

Trench fever was one of the most widespread diseases occurring in the forces of the World War. It is transmitted by contamination of a skin abrasion or of a louse-bite wound with the faeces of an infected louse, although Strong and his colleagues reported the bite of an infected louse as a demonstrated method of infection.

Clinically, it shows an abrupt onset, with fever, headache, pain on moving the eyeballs, soreness of the muscles of the legs and frequently hyperaesthesia of the shins. As a rule the initial fever is followed after a few days by a single short rise but there may be a fever course of many relapses with apyretic intervals. Recovery is complete, death practically never occurring; but convalescence may be protracted, and incapacitating after-effects, such as neurasthenia, cardiac disturbances and myalgia, may be noted.

=Synonyms.=—Pyrexia of Unknown Origin (P. U. O.), Meuse fever, Volhynian fever, Shin fever, Quintan or five-day fever.

HISTORY AND GEOGRAPHICAL DISTRIBUTION

=History.=—It is remarkable that so striking and communicable a
disease as trench fever should have been an unrecognized entity
prior to the recent war. While resembling dengue in some respects,
and relapsing fever in others, as well as various well-recognized
exotic fevers, there is no satisfactory account of the prior
existence of such a type of fever. Werner was of the opinion that a
quintan fever of the Middle Ages might have been trench fever, and
it has been suggested that a quintan fever described by Hippocrates
may have been of this nature, but the evidence is not convincing.
Some have thought that the miliary fever reported in France from
1821 to 1855 might have been a type of trench fever since it had no
mortality.

=Geographical Distribution.=—During the war, trench fever was
reported not only in Flanders, but also among the troops fighting
in Macedonia and Mesopotamia, and in the forces of the Central
Powers on the German and Austrian fronts. It is remarkable that
since the war this louse-borne disease seems to have disappeared,
although other diseases transmitted by lice, as typhus fever and
relapsing fever, continue to occur widely in Poland, Russia and the
Balkans.

ETIOLOGY AND EPIDEMIOLOGY

=Etiology.=—It now seems rather definitely settled that trench fever belongs to the group of diseases caused by Rickettsia bodies, and this species has been named _Rickettsia quintana_. Like the other organisms of the group, these bodies are very small (0.3 to 0.5 by 1.5 to 2 microns), Gram-negative, nonmotile and stain best by Giemsa’s method. As these bodies with their coccal or bipolar staining characteristics, when observed in the eggs of ticks infected with the virus of spotted fever of the Rocky Mountains, showed the so-called chromatin staining, Ricketts regarded them as chromatin-staining bacteria. Since, however, they are transmitted by an arthropodan host, we believe now that they are probably protozoal in nature.

Bradford and his colleagues stated that they were able to culture
these organisms by Noguchi’s method for culturing the organism of
syphilis, but Strong failed to obtain growth. As the organism of
typhus fever has recently been cultured by the same method, it
would appear that the trench fever organism also is cultivable.
The virus is present in the whole blood, in the plasma and in
the washed erythrocytes; it is nonfilterable, and withstands a
temperature of 56°C. for 20 minutes but not one of 80°C. for 10
minutes. These organisms in the alimentary tract of the louse are
extracellular, and not contained within the cells of the epithelium
of the gut of the louse. The trench fever bodies differ from those
of typhus in that they are plumper and stain more deeply with
ordinary aniline dyes.

=Epidemiology.=—The ordinary method of transmission is by the agency of infected lice, but the disease can be produced artificially by the injection of the blood of an infected person. It is probable that urine also may be a factor in transmission, as Strong brought about infection by smearing skin abrasions with urinary sediment from trench fever cases.

It is now considered that the bite of the louse is noninfectious,
although Strong succeeded in transmitting the disease by this
means in five cases. The accepted explanation of the mechanism
of infection is that it takes place through contamination of an
abrasion or wound of the skin with louse faeces or with the juices
from the crushed bodies of infected lice. In this connection,
excoriations of the skin resulting from the scratching of
scabies-infested areas makes a scabies patient peculiarly liable
to trench fever infection. The louse faeces become infective only
after seven days from the time of feeding on trench fever cases,
this fact indicating a developmental cycle in the louse.

PATHOLOGY

As the disease of itself is never fatal, there have been no opportunities for studying the pathological changes.

SYMPTOMATOLOGY

The period of incubation is usually given as from two to three weeks. In the experimentally produced cases of the American Red Cross Commission, the incubation period varied from five to thirty days; thus with intravenous injection of blood it varied from five to twenty days, and with inoculation of scarified areas with louse faeces the period was between seven and eleven days.

The onset is quite abrupt with headache, dizziness and pain on motion of the eyeballs. There is pain also in the back and limbs. The conjunctivae are injected. The fever rises rapidly to 102°-104°F. and falls rather abruptly to normal at about the fourth day. In most of the cases a secondary rise occurs so that we may have a saddle-back type of temperature chart.

The temperature charts tend to be grouped in three classes: (1)
Those with a short febrile course of a few days, followed by a
fall to normal, with or without a subsequent rise; (2) those with
a more or less sustained type of fever, extending over five or six
weeks without distinct relapses, and (3) those more typically of a
relapsing type, with five or six distinct febrile periods.

In more than one-half of the cases there occurs an eruption
of small (2 to 4 mm.) erythematous spots, which disappear on
pressure. They are usually located on chest, back or abdomen,
appear on the second day of the fever, and fade out by the fourth
day. Constipation and anorexia are usually noted. The spleen is
often somewhat enlarged. There is frequently a trace of albumin
in the urine, but it is not accompanied by casts. The cutaneous
hyperaesthesia over the shins is a prominent feature, but the same
disturbance of sensation may be complained of over the ulna or
fibula. Usually we find a leucocytosis but many cases show a normal
white count or even a slight leukopenia. During the apyrexia there
is an increase in mononuclear percentage. The pulse is rather slow
for the temperature.

DIAGNOSIS

Notwithstanding the intensive study given this disease during the war, we do not seem to have any constant or reliable laboratory test.

In some of the cases where muscle pains of the neck are marked there may be a stiffness of the neck that is suggestive of cerebro-spinal fever. Similarly, pain of the abdominal muscles may cause a suspicion of appendicitis and lead to an unnecessary operation.

The onset of trench fever is very like that of dengue or influenza.

In epidemic jaundice, the occurrence of the jaundice and marked
albuminuria should differentiate.

PROGNOSIS

This is most favorable as to ultimate complete recovery, but some cases show a prolonged convalescence with manifestations of irritable heart or neurasthenia.

PROPHYLAXIS AND TREATMENT

Prophylaxis consists in attacking the louse problem, although attention should be given to the disinfection of the urine.

Acetylsalicylic acid may be given to relieve the headache and the muscle pains; and some laxative for the usual constipation. There is no specific treatment.