The infection in latent malaria is most often a malignant tertian one. Such cases often develop paroxysms following surgical operations or at time of pregnancy or childbirth. Clark has noted the abundance of parasites in smears from the placenta taken at time of delivery when the peripheral blood showed few or no parasites. Such an examination is of enormous value in differentiating a malarial paroxysm from puerperal sepsis.
Malta Fever.—In this disease, in which the wave-like febrile periods during every three or four weeks are so characteristic as to give it the name of “febris undulans,” there is a very insidious onset. For a week or ten days the temperature climbs up step-ladder-like and then descends in like manner to be followed by a few days of apyrexia with succeeding similar relapses. The case would suggest an attack of typhoid with relapses.
The course of the disease is attended by rather marked anaemia and physical and mental depression. Very characteristic are the fleeting joint pains which involve chiefly the knees, hip, ankle and shoulder joints. There are pain and some swelling but without redness. Neuralgic pains are also common. There is often a bronchitis which, when associated with the rather common night sweats of the disease, is suggestive of phthisis.
The cardiac muscle seems to be especially liable to the toxic effects of the disease so that a weak heart and intermittent pulse are often noted. It has a very protracted course of, on the average, about four months.
An astonishing fact is that so severe and a prolonged fever should give such a slight mortality (2%).
Occasionally, a case shows a high continued or remittent fever and aggravated symptoms, going into a typhoid state. Such cases are often fatal. There is an increase in the lymphocytes but no increase in total leucocytes.
The wave course of the fever, with afebrile intervals and increasing anaemia, is suggestive of kala-azar, particularly when there is a greater enlargement of the spleen than is usual in the disease. Ordinarily the splenic enlargement about corresponds to that of typhoid fever but at times it may be so much enlarged as to suggest the splenic tumor of kala-azar.
Diseases in which Fever is an Important Feature but Gives Little Assistance in Diagnosis
Kala-azar.—This disease has a peculiarly insidious onset because, with a fairly high remittent fever, it may cause but slight feeling of illness in the patient.
Rogers insists upon the importance of taking the temperature every four hours so that one may note the fact of there being two distinct rises in the twenty-four hours instead of the single evening rise of typhoid fever.