DIAGNOSIS OF AFRICAN TICK FEVER. 233 



fevers, but sball merely record the results of some experiments carried on 

 in relation to the diagnosis and differentiation of the African tick variety 

 of the disease. Boss and Milne, 15 in examining eases of spirillum fever 

 in Uganda, Africa, found that the organism might be exceedingly rare in 

 the blood, even when the examination was made at the height of the 

 fever and from cases which from a clinical standpoint were well marked. 

 Sometimes it was necessary to spend several hours before finding a single 

 spirillum, and in some instances only two or three were found in the 

 whole blood film. In one case of tick fever out of eight which were 

 studied, about one spirillum was found in every thirty fields, in the other 

 seven very few spirilla were present. These authors refer to the fact that 

 Daniels examined a case of the disease in the second week with negative 

 results. Dutton and Todd, TL Koch and Manson all agree that the 

 parasites in tick fever are much more scanty than in European relapsing 

 fever. I observed a patient in Africa who was in approximately the 

 second week of fever, in whom no spirochasta 3 could be found in the 

 circulating blood in a single, but careful and prolonged examination of 

 the fresh film and of one stained preparation. However, a small amount 

 of blood collected at the same time that the microscopic specimens were 

 examined, was inoculated into a mouse and three days later spirocliEeta? 

 were found in its blood. Therefore, it is clear that in some cases of tick 

 fever, during its active periods, a diagnosis may not be arrived at from a 

 study of the blood with reference alone to the presence of spirochsete. 

 Moreover, in both the European and African varieties of the disease, 

 the parasites may be entirely absent from the blood during the relapses 

 or in the later stages, and then even animal inoculations may fail as a 

 means of diagnosis. It is also true in relation to the emp]o}'ment of 

 animal inoculations as a means of diagnosis, white or gray mice, or white 

 rats, the animals which are most valuable for use in this connection, are 

 usually very scanty or impossible to obtain in most tropical or subtropical 

 countries. I have recently been able to show that wild mice captured in 

 these districts are not sufficiently susceptible to infection with the African 

 species of spirochsetse to be of value for use in diagnostic purposes. In 

 addition, neither of these means permits of a differentiation of the 

 species of spirochetal and of the separation of tick fever from the 

 other forms of relapsing fever. Hence, other methods of diagnosis are 

 desirable. 



As long ago as 1896 and 1897 Gabritschewsky 10 and Loventhal 1T 

 suggested and employed the serum for diagnostic purposes in cases of 

 relapsing fever. They recommended that a drop of serum of the patient 

 to be tested and which contained no visible spirochastaj be added to a drop 



15 hoc. tit. 



10 Ann. Inst. Past. (1896), 10, 630. 



17 Deutsche med. Wchnsch. (1897), 23, 500. 



