An early history of attacks of fever, with marked fluctuation of temperature, associated with rapid pulse, even with the apyrexial morning fall, is suggestive. Then with the glandular enlargements we think immediately of laboratory examinations. As with pellagra the history is very important in the diagnosis of trypanosomiasis.
For the laboratory diagnosis we may use peripheral blood with some thick film method. The examination of preparations from the peripheral blood is usually very discouraging. Very much better results (in fact some prefer this method to any other) can be obtained by taking 10 to 20 cc. of blood in about 25 cc. of citrated salt solution, centrifuging 2 or 3 times and examining the sediment of the third centrifugalization. Dutton and Todd prefer to centrifuge citrated blood and to collect the leucocyte layer for examination as is done in opsonic work.
Gland Puncture.—The English workers usually prefer the gland puncture method, using a sterile but dry hypodermic needle. Water in the needle distorts both leishman bodies and trypanosomes.
In the sleeping-sickness stage trypanosomes can almost constantly be found in the cerebro-spinal fluid.
In a diagnostic study of 336 cases Broden obtained 87% of positives from gland puncture, 80% from centrifugalizing the supernatant fluid left from the second centrifugalization of the blood and 4.5% from spinal fluid examinations.
Some prefer to inoculate susceptible animals, particularly the guinea pig or monkey, with blood or gland juice from the suspected case. A very satisfactory material is an emulsion from an excised gland which may be inoculated intraperitoneally into white rats. The further course, after animal inoculation, is the examination of the blood of these animals for trypanosomes. Usually at the time the guinea pigs die we find numerous trypanosomes.
Other tests are: (1) Trypanolysis, when unheated suspected serum and trypanosomes are incubated together for one hour. Normal serum may occasionally cause disintegration and treated cases give it in only about 45% of cases. Unfavorable untreated cases give it in about 80% of cases.
(2) The so-called auto-agglutination test is not of much value. In this the red cells of the blood of a trypanosomiasis case come together in clumps when one makes a wet preparation. It is not a rouleaux formation. (3) The attachment test is made by making a mixture of inactivated serum, leucocytes and trypanosomes and allowing them to be in contact for 20 minutes. A positive test shows attachment of the trypanosomes to the leucocytes.