234 Arthropods as Essential Hosts of Pathogenic Protozoa 
Other Types of Relapsing Fever of Man —In addition to the three 
types of human relapsing fever already referred to, several others 
have been distinguished and have been attributed to distinct species 
of spirochastes. The various spirochastoses of man are: 
African, caused by 5 . duttoni; European, caused by 5 . recur- 
rentis; North African, caused by 5 . berbera; East African, caused 
by 5 . rossi; East Indian, caused by 5 . carteri; North American, 
caused by 5 . novyi; South American, caused by 5 . duttoni {?) 
Nuttall (1912) in his valuable resume of the subject, has em¬ 
phasized that “in view of the morphological similarity of the sup¬ 
posedly different species of spirochaetes and their individual variations 
in virulence, we may well doubt if any of the ‘species’ are valid. 
As I pointed out four years ago, the various specific names given to 
the spirochaetes causing relapsing fever in man may be used merely 
for convenience to distinguish strains or races of different origin. 
They cannot be regarded as valid names, in the sense of scientific 
nomenclature, for virulence and immunity reactions are not adequate 
tests of specificity.” 
North African Relapsing Fever of Man -The type of human 
relapsing fever to be met with in Algeria, Tunis, and Tripoli, is due to 
a Spirochceta which does not differ morphologically from Spirochceta 
duttoni, but which has been separated on biological grounds as 
Spirochceta berberi. 
Experimenting with this type of disease in Algeria, Sergent and 
Foly (1910), twice succeeded in transmitting it from man to monkeys 
by inoculation of crushed body lice and in two cases obtained infec¬ 
tion of human subjects who had received infected lice under their 
clothing and who slept under coverings harboring many of the lice 
which had fed upon a patient. Their results were negative with 
Argas persicus, Cimex lectularius, Musca domestica, Hcematopinus 
spinulosus and Ceratophyllus fasciatus. They found body lice 
associated with every case of relapsing fever which they found in 
Algeria. 
Nicolle, Blaizot, and Conscil (1912) showed that the louse did 
not transmit the parasite by its bite. Two or three hours after it 
has fed on a patient, the spirochaetes begin to break up and finally 
they disappear, so that after a day, repeated examinations fail to 
reveal them. They persist, nevertheless, in some unknown form, 
for if the observations are continued they reappear in eight to twelve 
