E. R. Stitt

“ It is a well recognized fact in the tropics that the natives seem to have an immunity to malaria yet may carry parasites in their circulation and serve as carriers. The native children to a striking degree harbour parasites and to them malaria is a prime cause of death. After repeated infections, if not fatal, a temporary immunity is acquired. Many localities in the tropics owe freedom from malaria to an absence of anophelines, as for instance Barbadoes. Again malaria-bearing mosquitoes may acquire the habit of feeding on animal blood other than that of man. ”

“ In such people a definite finding of a cause sufficient to account for an illness is usually the key to the diagnosis. With those from the tropics, however, it is different. A single individual may be found upon examination to have amoebiasis, malaria, filariasis and syphilis, yet none of these infections prevent him from following his usual occupation. When such a patient comes to a ward it requires a correlating mind to eliminate four or five definite diagnoses, and fix upon some disease which is common to both tropics and temperate climates, as for example, typhoid fever. ”

“ Everyone taking up the study of tropical disease should first study the geographical distribution of such diseases and those practising in temperate climates should remember that the first question to be asked a man suspected of having a tropical disease is “Where have you been during the past months and years?” ”

“ Definition.—Plague is primarily a disease of rats or other rodents and is caused by a bacterium of the haemorrhagic septicaemia group, Bacillus pestis. The disease exists in the rodent in both an acute and chronic form. Acute plague of the rat is apt to be septicaemic, so that when certain species of fleas which infest the rat feed on the blood of their host they ingest plague bacilli. These seem to multiply in the region of the proventriculus and cause thereby an obstruction to the stomach. As a result the flea makes vigorous and repeated but ineffectual efforts to feed. ”

“ It should be remembered that lesions of joints may accompany or follow almost all infectious diseases, and that it is often impossible to ascertain if the lesions be due to the actual presence of organisms within the joint or to the action of toxic substances elaborated elsewhere; so that infectious arthritis is broadly defined as arising from the presence within the body of a focus of infection. ”

“ Not only is it important to understand that elephantiasis and other manifestations of filarial infection may and usually do exist without there being embryos in the peripheral blood of the patient, but also, that a high percentage of a population may show filarial embryos in their blood and yet never or with extreme rarity show any of the signs of filarial disease. These people, with abundant embryos in their blood, usually show no disturbance of health. In the Philippines one may rarely see a case of chylocele but usually there is nothing clinical to note. ”

“ This probably explains the endemic rather than the epidemic characteristics of the spread of amoebic dysentery because, if the innumerable vegetative amoebae in dysenteric stools were equally operative with the more sparsely eliminated cysts, there would be epidemics of amoebic dysentery similar to those of bacillary dysentery. The old idea that water, fruit or vegetables, from which one can isolate amoebae on culture, are sources of infection must be abandoned, as such cultural amoebae are known to have no pathogenic relation to man. ”

“ When we consider that a knowledge of malaria, blackwater fever, amoebic dysentery, bacillary dysentery, liver abscess, pellagra and hookworm disease is just as important for the medical man in the Southern States of the United States as for the physician in tropical colonial possessions, it will be realized that there is more of a practical side to tropical medicine than is usually admitted. ”

“ In epidemics of beriberi it has been observed that those who eat most rice are more often attacked, thus men more frequently than women. A temperature of 120°C. destroys the vitamine. Owing to the absence of rice as a constituent of other than slightest importance in the dietary of Brazilian cases of beriberi, as well as from numerous reports of the occurrence of the disease in nonrice-eating persons, the view that is now entertained is that not only polished rice, but any predominating carbohydrate article of diet, which is deficient in the neuritis-preventing substance, can produce beriberi. ”

“ In diagnosis in the tropics it is necessary to have at one’s fingers’ ends the various physical signs and subjective symptoms more or less characteristic of every disease of man as well as the laboratory findings. It is only when one has at hand all obtainable information that the solution of the medical problem becomes possible. ”

“ It is just as easy to give quinine to a man in the tropics as it is in temperate climates, but when one considers the propositions of draining tropical swamps and shutting off circulation of air on a torrid night with fine wire gauze in the windows and closely woven mosquito nets around the bed, the question is decidedly different. In consequence, the tendency is for the average man to despair of accomplishing anything in the way of mosquito destruction and screening and to seize eagerly on the inferior alternative, that of quinine prophylaxis. ”

“ Epidemiology.—There seems to be a consensus of opinion that when malaria is kept in check by proper and persistent quinine prophylaxis or by other antimalarial measures blackwater fever becomes mild in character or even nonexistent. It is those who are careless about quinine prophylaxis or those who expose themselves to depressing influences as cold, wet, excessive fatigue or alcoholic debauches in whom blackwater shows itself.
Overexertion leading to fatigue and chilling seem to be the most common exciting factors. Those in bad health from disease or lack of proper diet seem more susceptible. ”

“ Definition.—Cholera is a disease caused by a spirillar type of bacterium, Spirillum cholerae asiaticae. The organism multiplies in the small intestines and, undergoing lysis, liberates an endotoxin, which is responsible for the desquamation of the epithelium of the mucosa and other manifestations of the disease. Cholera appears to be endemic in the delta of the Ganges and the various world-wide epidemics can generally be traced to that source. The rice-water stool of cholera teems with the spirilla, and infections of water or food supplies can be traced to such a contamination. ”

“ Just as with the material from a puncture of a bubo or the sputum from plague pneumonia we should employ animal inoculation as well as cultural procedures with the blood.
We usually have a marked leucocytosis due to a great increase in the polymorphonuclears. The white count may exceed 50,000. Just as septicaemic plague may so overwhelm the organism that it does not respond with fever so may the leucocytosis be absent. Bubonic and pneumonic plague tend to become septicaemic, so that in such types of the disease we may obtain results with blood cultures. ”

“ In the disease we have a fever suggestive of typhoid fever and oedema about the face. A marked eosinophilia is characteristic. Another helminthic parasite which may invade the muscles of man is the larval Taenia solium. This must be of extreme rarity because infection with the adult T. solium is most rare and it is only accidental that the embryonic stage would occur in man. It is a fact that the common tapeworm of man, Taenia saginata, is found in the human host only as a sexually mature parasite in the intestines; there is never a cysticercus stage in the muscles. ”

“ Again, it has been shown that where the wild animals on which tsetse flies feed may show an infection of from 16 to 50% yet not more than 2 out of every 1000 tsetse flies, caught and tried out on susceptible animals, show themselves infective.
Both of the human trypanosomes of Africa have been cultured by using the N.N.N. medium in which rat’s blood was substituted for that of the rabbit. Human blood will also serve as a substitute. Growth however is not constant.
Epidemiology.—Practically the only method of transmission of the disease is by the bite of infected tsetse flies. ”

“ Natives seem to suffer severely from tick fever in childhood but in adult life possess a sufficient degree of immunity so that the disease shows itself in a very mild form in those harboring spirochaetes.
The immunity conferred by an attack is not lasting and a second infection may occur within a year. Such second attacks, however, do not present the relapses so important in a clinical diagnosis. As a matter of fact there may be no symptoms and such cases with spirochaetes in their blood make ideal carriers for the infection of ticks or lice. Ticks can be infected by these carriers. ”

“ The rise of temperature in benign tertian and quartan malaria takes place in about one-half the cases somewhat early in the day, while the daily rise in tuberculosis, septic conditions and liver abscess, is more apt to occur in the evening, the evening rise being almost the rule in such diseases. Hectic fevers generally show a less distinct cycle of chill, hot stage and sweating than do the benign malarial paroxysms. At the same time the enlarged spleen, presence of parasites in the peripheral circulation and response to quinine are diagnostic points in malaria which must always be thought of. ”

“ It has been suggested that if the surface lesions are allowed to develop to maturity, the skin, which is the great elaborating center for antibodies, will produce enough adequately to protect the whole body; whereas, if the surface lesions are aborted, there is a diminished stimulus with consequent diminished elaboration of protective bodies. The brain is then liable to parenchymal invasion, since chemicals, owing to difference in their physical properties, cannot replace natural antibodies in controlling the disease in this location. ”

“ The old idea that tropical life produced an anaemia is no longer held, the view now being that such anaemic conditions are almost invariably due to some well recognized cause, the most important of which is malaria. Natives of the tropics may appear bleached out but show a normal red count and haemoglobin percentage. Chamberlain’s observations have shown that a residence in the tropics of approximately two years has no appreciable influence on the red cell count or haemoglobin content of the blood of white men and that the actinic rays do not seem to be operative in producing anaemia. ”

“ The possibility of carriers of plague bacilli in those who might go on to convalescence need not be considered, as practically all cases of plague pneumonia die. Other material from the patient than sputum does not seem to be a source of danger in the spread of plague, so that there is no need for the disinfection of urine and feces. There has recently been an outbreak of septicaemic plague in Ceylon in which there was an absence of plague in the rats. The infection was possibly transferred directly through bedbugs or human fleas. ”

“ It is only a white count or a differential count or an examination for malaria that is required.
As a practical point it is very rare that a red count is indicated. There is one point not sufficiently recognized by physicians and that is that a routine blood examination is not apt to be as carefully conducted as one calling for a specific feature. Without disparaging the necessity of routine examination of urine as well as blood it is a fact that the internist who knows what he wants gets better results from the laboratory man. ”

“ Just as children bear the brunt of malaria in old malarious districts and adults suffer in places in which the disease has been more recently imported, so by analogy we may consider the disease as of more recent introduction in India. We now know that visceral leishmaniasis is widely distributed in China, north of Yangtse, as well as in the Sudan, and quite recently a case of kala-azar has been reported from South America, in an Italian, who had lived in Brazil from 1897 to 1910. ”

“ In blackwater fever the pulse is rapid and soon becomes weak and of low tension.
Plague shows a striking toxic action on the heart muscle so that we soon get a soft, dicrotic pulse, rapid from the first and soon becoming thready. Patients with plague may die from cardiac failure upon getting up from bed.
A rapid pulse, especially in the morning, is thought to be a feature of active leprosy.
In cholera the pulse is rapid and feeble during the stage of evacuation and with the onset of the algid stage we practically have a cessation of the circulation. ”

“ We do not understand why in one case sporulating parasites should plug the capillaries of the central nervous system, with the production of conditions resembling well-recognized nervous diseases, while in another case the damage is done the intestinal mucosa, pancreas or lungs. At any rate these pernicious manifestations of malaria should always be kept in mind when a case of sudden cerebral involvement or acute abdominal disease shows itself in a patient in a malarious country and a blood examination should be promptly made. ”

“ When employing a native interpreter it is always well to keep in mind the fact that such assistants will rarely admit of ignorance of the language of the medical man and, furthermore, they try to twist the answers of the patients to make them agree with what they may think is in accordance with the desire of the examiner. Again in carrying out the physical examination it is difficult to be certain that the findings as to location or degree of pain, sensations, or time of appearance of lesions, as well as data as to pulmonary, renal and alimentary tract disorders, are correct. ”

“ The gastro-intestinal infections, typhoid fever, dysentery, diarrhoea, probably serve as a barometer of the sanitary conditions of a city.
But there are many other diseases whose importance from an economic standpoint may not be fully appreciated from mortality tables. Notable among these are venereal diseases, malaria, filariasis, yaws and hookworm diseases. Further it may be noted that many diseases without being the direct cause of death have a distinct bearing on the mortality. ”

“ Rare cases may run an acute course and show a high death rate. The fever course resembles that of a typhoid fever with two or more relapses, in that a step-like rise of fever for ten or twelve days is followed by a similar fall during the succeeding week or ten days, an afebrile interval of a few days then ensuing, to be followed by a second or third or even tenth febrile wave with the separating days of apyrexia. The course of the disease may last for a year or more attended with progressive anaemia and manifestations of neurasthenia. ”

“ Definition.—Blackwater fever is a disease of disputed etiology but recently there has seemed to be rather general agreement that it is connected with repeated attacks of malaria. It is prone to affect the old European residents of parts of the tropics where malignant tertian is rampant.
On the basis of lowered integrity of the red cells, by reason of repeated attacks of malaria, we may have extensive lysis of the red cells following the administration of a dose of quinine or as the result of refrigeration, excessive exposure to the sun or great fatigue. ”

“ In the tropics and in temperate climates where the Shiga type bacillus is the infecting organism the onset is usually rather sudden with malaise, abdominal pain and a diarrhoea, which only temporarily relieves such pain. This initial diarrhoea is soon followed by the characteristic dysentery stool and the pains, which latter tend to centre about the umbilicus and to become continuous. There is usually loss of appetite and slight nausea and the patient may at times show a very slight tendency to flightiness. The mind however is usually clear. ”