Typhus Fever (Gr. typhos, 'mist,' 'stupor') has probably had an important place among the pestilences attending upon war and famine in all ages; it can be traced back with some definiteness to the 11th century, and from the 16th at least has been a frequent epidemic. It is generally regarded as the pestilence of the 'Black Assize' (q.v.), and has been known as jaill fever or camp fever at various times.
Symptoms and Course.—Typhus occurs at all ages, but most frequently between ten and thirty. The period of incubation (see MEASLES) is most commonly about twelve days, but may be as long as three weeks, or may be absent, the symptoms beginning immediately after infection. The onset is generally definite, sometimes quite sudden; severe headache, with pains in the back and limbs, shivering, prostration, and loss of appetite are generally the early symptoms. The prostration rapidly increases; the face is flushed and dusky, and the expression dull; the temperature generally rises to 104° or 105°, without much remission, and the pulse to 100 or 120 per minute. The tongue is at first white, but generally, except in very mild cases, becomes dry and brown. Vomiting and diarrhoea are only exceptionally present. Generally about the fourth or fifth day the characteristic rash, called by Sir W. Jenner the mullberry rash, appears, and after two days or so no fresh spots come out. The rash consists of rounded or irregular spots, which may be at first bright red, but may be from the beginning, or if not soon become, livid or dusky, owing to minute hemorrhages (Petechiæ, q.v.) into the skin, of which they are the seat. The rash is rarely absent, except in children; and its copiousness and lividity are generally in direct proportion to the severity of the case; when very dark, it constitutes the so-called black typhus. It generally remains visible till the crisis. About the end of the first week the headache gives place to delirium, generally of a quiet type; and during the second week this often passes into partial or complete unconsciousness. The pupils are generally much contracted. Towards the end of the second week the patient becomes more and more feeble and prostrate; tremors of the muscles, with jerkings of the limbs, or picking at the bedclothes are almost always present. But about the fourteenth day, if the patient live so long, a rapid change takes place called the crisis. Within from twelve to thirty-six hours the temperature falls to normal or lower; the pulse is slowed in proportion, intelligence returns, and the patient feels no discomfort but weakness. In a few days the appetite becomes ravenous, and convalescence is rapid and uninterrupted. Relapses are almost unknown, and complications infrequent. In fatal cases death usually takes place in the second week, either by coma, by failure of the heart, or by asphyxia from congestion of the lungs; but it sometimes occurs after a few days' or even a few hours' illness. The death-rate in hospital cases is usually from 15 to 25 per cent.; but under unfavourable circumstances—e.g. in wars or sieges—it has sometimes been 50 per cent. or even higher. In children typhus is hardly ever fatal; its danger increases in a very marked degree with the age of the patient.
Post-mortem Appearances.—If the patient die while the rash is present, it remains visible after death. The internal organs present no distinctive changes, the fluidity of the blood and softening of tissues present are also met with in other rapidly fatal febrile diseases.
Treatment.—No means is known of cutting short the disease. Good nursing, a plentiful supply of fresh air, administration of abundant liquid nourish- ment, in many cases free stimulation are required. Sleeplessness is often a serious symptom, and requires to be met by opiates.
Causation.—Typhus is a disease specially associated with filth and overcrowding. It is generally met with, therefore, in the squalid parts of large towns. Epidemics are very frequently associated with want and privation, as in war and famine. It is extremely contagious; but there is abundant evidence that the virulence of the poison is much reduced by abundant dilution with fresh air, hence the special importance of free ventilation in its treatment. In the great majority of cases it can be traced to infection from a previous case; instances to the contrary are so few that its origin de novo, strongly maintained by Murchison, must be regarded as extremely improbable. No characteristic organism has been discovered. The infection can be conveyed by clothes, &c., but much less readily than some other infectious diseases—e.g. scarlet fever and smallpox. It is rare for a person not himself infected to convey the disease to one who has not been in contact with the sick.
It is a disease for the most part of temperate climates. At the present day Ireland, Russia, Italy, Persia, and North China are its chief seats.
See Murchison's Continued Fevers; Hirsch's Geographical and Historical Pathology.