Typhoid and the paratyphoids are best differentiated clinically by the presence of a continued fever, the absence of a double daily rise and the existence of a more marked apathy.
The recent statements that hookworm disease may show enlargement of the spleen would make this a condition to differentiate. Hookworm ova and an eosinophilia indicate ancylostomiasis but there is always the question here as with malaria as to the existence of kala-azar and some other affection.
Laboratory Diagnosis.—The leukemias can be easily differentiated by the blood picture, an important matter because the spleen of spleno-myelogenous leukemia is very friable and the danger from splenic puncture is far greater in this condition than in kala-azar. Banti’s disease with its leucopenia shows a rather similar blood picture and can only be surely differentiated by the finding of leishman bodies in kala-azar.
While malaria may at times show a leucopenia below 4000, a polynuclear percentage below 50 and a large mononuclear one of 20 or more, yet the simultaneous appearance of all three is rare in malaria while common in kala-azar.
Malta fever, typhoid and the paratyphoids are best differentiated by blood cultures or agglutination tests.
Until recently it was recommended that for diagnosis our best procedure was to make a splenic puncture. Manson and others have pointed out the dangers from splenic puncture in kala-azar and have rather preferred puncture of the liver, although recognizing that the chances of obtaining parasites from a liver puncture, are less than from a splenic one.
Statistics have been given where a mortality approximating 1% has followed spleen puncture. Bousfield, however, using an all-glass syringe with a 1½ inch needle did not have a fatality in 120 spleen punctures.
For diagnosis the spleen or liver juice, rather than pure blood, is smeared on a slide and stained by some Romanowsky method, preferably that of Giemsa.
Cultures on N. N. N. medium can also be made.