Spirochcetosis of Fowls 
235 
days. These new forms are virulent, for a monkey was infected 
by inoculating a single crushed louse which had fed on infected blood 
fifteen days before. 
Natural infection is indirect. Those attacked by the insect 
scratch, and in this act they excoriate the skin, crush the lice and 
contaminate their fingers. The least abrasion of the skin serves for 
the entrance of the spirochastes. Even the contact of the soiled 
fingers on the various mucosa, such as the conjunctive of the eye, 
is sufficient. 
As in the ease of Spirocheeta duttoni, the organism is transmitted 
hereditarily in the arthropod vector. The progeny of lice which 
have fed on infected blood may themselves be infective. 
Spirochaetosis of Fowls —One of the best known of the spirochaetes 
transmitted by arthropods is Spirocheeta gallinarum, the cause of a 
very fatal disease of domestic fowls in widely separated regions of 
the world. According to Nuttall, it occurs in Southeastern Europe, 
Asia, Africa, South America and Australia. 
In 1903, Marchoux and Salimbeni, working in Brazil, made the 
first detailed study of the disease, and showed that the causative 
organism is transmitted from fowl to fowl by the tick Argas persicus. 
They found that the ticks remained infective for at least five months. 
Specimens which had fed upon diseased birds in Brazil were sent to 
Nuttall and he promptly confirmed the experiments. Since that 
date many investigators, notably Balfour and Kindle, have contri¬ 
buted to the elucidating of the life-cycle of the parasite. Since it 
has been worked out more fully than has that of any of the human 
spirochaetes, we present Hindle’s diagram (fig. 143) and quote the 
brief summary from his preliminary paper (19116). 
“Commencing with the ordinary parasite in the blood of the fowl, 
the spirochaete grows until it reaches a certain length (16—1991.) and 
then divides by transverse division. This process is repeated, and 
is probably the only method of multiplication of the parasite within 
the blood. When the spirochaetes disappear from the circulation, 
some of them break up into the coccoid bodies which, however, 
do not usually develop in the fowl. When the spirochaetes are 
ingested by Argas persicus, some of them pass through the gut wall 
into the coelomic fluid. From this medium they bore their way into 
the cells of the various organs of the tick and there break up into a 
number of coccoid bodies. These intracellular forms multiply by 
