The diagnostics and treatment of tropical diseases

by E. R. Stitt

As regards scarlet fever, statistical reports from various parts of the tropical world fail to show cases.

In a report from Shanghai, which can hardly be considered as a tropical city, there is a statement that this disease first made its appearance in 1900, since which time it has spread among the Chinese, exhibiting marked virulence. Again in a Basutoland report there were quite a number of cases reported (67), but as this colony is in the extreme south of Africa it could hardly be called tropical.

Typhoid Fever.—When reliance for diagnosis rested almost solely on clinical manifestations, it was held that typhoid fever was rare or unknown in the tropics.

Since the advent of laboratory methods of diagnosis it has become known that typhoid and the paratyphoid fevers are quite common. The paratyphoid infections are more common in the tropics than in the temperate regions. The fever course and clinical picture of typhoid in the tropics are distinctly atypical. It was formerly common to consider cases of typhoid as malaria and in the southern states of the United States it was a common thing to diagnose typho-malarial fever.

Of course, latent malaria is apt to flare up in a person sick with typhoid, but the idea that there was a symptom-complex partaking of the characteristics of typhoid fever and malaria is now classed with historical data.

It is a remarkable fact that in many of the cities of the Orient conditions favoring infection with typhoid fever, such as neglect of the most elementary measures of disposal of faeces and lack of safeguarding of water supplies, exist and yet the natives seem to have an immunity to organisms causing alimentary tract diseases. It must be that such immunity is acquired by attacks of the disease in childhood. Certainly, Europeans in such communities have no protection unless they are vaccinated. It must be remembered that the protection from vaccination against the enteric group of bacteria can be relied on for not longer than a period of two years.

It would seem that typhoid fever in tropical countries is more serious than in temperate climates—thus the death rate in India is about twice as great.

In the absence of laboratory tests the chief reliance in the clinical diagnosis of typhoid should rest in the rather gradual onset of a continued fever, with a rather apathetic toxaemia. Of course atypical cases may have a fairly abrupt onset. An important point in the diagnosis is the rather slow pulse rate for the temperature elevation.

Marris Atropine Test.—Manson-Bahr regards the Marris atropine test as of the utmost value in the diagnosis of the enteric group of fevers. In this test one gives a hypodermic injection of grain 1/50 of atropine sulphate. Should the case be typhoid or paratyphoid the pulse rate is practically uninfluenced during the period from 25 to 50 minutes after the injection. In other infections or in normal individuals, the pulse rate drops at first but after 10 or 15 minutes rises to exceed the pulse rate before the injection by 30 or 40 beats during the period of 25 to 50 minutes following the injection.