INFLUENZA has the same importance in childhood as in adult life and it is worthy of special study because it exhibits a number of char acteristic and important modifications.
Influenza is known to have been prevalent in the fourteenth century, but a clinical and scientific knowledge of the disease was not obtained until the epidemics of 1S30 and 1S40. A great advance in our knowledge of the disease was made during the great pandemic of 1SS9 to 1S91.
Influenza (epidemic grippe) is an acute contagious and infectious disease occurring mostly in epidemics and its cause is a specific organ ism, the bacillus of influenza.
R. Pfeiffer discovered this bacillus in 1SS9 after a number of false observations had been published. His work has been verified by re peated investigations so that to-day the importance of Pfeiffer's bacillus of influenza is no longer in question. It is a small, rod-shaped bacillus, strongly anaerobic, with very slight resistive power and short-lived out side the body. Its vitality is soon destroyed in water and in earth, and for cultivation it must be grown on blood haemoglobin at a temperature between C. (76°-106° F.). The contagion is spread from the secretions of the mucous membranes. The bacillus is found in vast numbers in the nasal secretions, while in an ordinary coryza very few bacilli are present. At first the bacilli are found free in the secretion, but later inside the pus cells. For a rapid bacteriological diagnosis it is best to make smears from the nasal secretion and stain with a weak carbol-fuchsin solution. In children the bacillus has been found in the blood, various secretions, cerebrospinal fluid, in pus from the ears, etc.
The incubation period according to different authorities from one to eight days.
The ninny variations in the clinical picture of this disease are clue to the fact that there is an infectious inflammation of dissimilar organs and tissues.
The parts most affected arc the respiratory mucous membranes, through which the bacillus gains entrance into the system, the alimen tary tract, and the nervous system as a result of toxic irritation.
The predominance of various symptoms depends on the part spe cially affected. The symptoms may be loosely grouped into those of catarrhal, gastric and nervous (rheumatoid) influenza and at times into a combination of all three.
In a widespread epidemic no age escapes, although it is compara tively rare in early infancy. It occurs most frequently from fifteen to forty years of age. The ages of 47,000 cases treated by physicians in Bavaria in 1SS9 and 1S90 were as follows: Epstein's statistics show 1.6 per cent. in the first year, 12.5 per cent. from one to ten years, and 36 per cent. from ten to twenty years. Strassmann has reported cases occurring in the newborn.
The source of infection in the newborn and young infants is the mother, yet nursing babies acquire a relative immunity through the mother's milk as is observed in other infectious diseases.
The younger the child the more marked are the intestinal symptoms, with secondary involvement of the central nervous system, which gives it more the nature of a general infection or intoxication. The symptoms on the part of the respiratory apparatus become more pronounced as the child grows older.
The onset of the disease is usually sudden. Children first complain of feeling tired and indisposed and on examination appear depressed and listless, complain of headache and show some fever. There is a marked distaste for food; the facial expression is anxious; cyanosis is frequent; the eyes are watery and sensitive to light; and herpes cornefe is not uncommon. The pulse is rapid and there is tenderness of the neck, back and legs. The younger the child, the more indistinct is the clinical picture. In very young children the disease may be ushered in by vomiting and convulsions and other symptoms of meningeal irrita tion, also intestinal disturbance, constipation, diarrhoea, coryza and a dry, hacking cough.