130 RICKETTSIA 



* 

 4. RICKETTSIA AND TRENCH FEVER 



Our control work with lice in Warsaw demonstrated the 

 common (12 in 148) occurrence of exclusively extracellular 

 rickettsia in lice collected at a public bath-house. Mr. Bacot, 

 of our Commission who collected and worked with these lice 

 between March 31st and April 5th, developed on April 7th a 

 sharp febrile attack and subsequently underwent a course of 

 illness corresponding objectively and subjectively with trench 

 fever. He was carefully studied by ourselves and by Dr. 

 Kruger of the American Red Cross. Mr. Bacot during this 

 period was feeding upon his person the stock of lice brought 

 from England, which were known to be free 1 from rickettsia for 

 a period of over two years before our work and which were 

 carefully controlled by us just prior to Mr. Bacot 's illness. 



On April 27th rickettsia began to appear in Mr. Bacot 's 

 stock lice. They shortly appeared in enormous numbers and 

 study of the lice by serial sections showed that they were always 

 extracellular. Now follows what we regard as the most im- 

 portant observation of all that Mr. Bacot (Brit. Med. 

 Journ., January 29, 1921, p. 156) continued to infect clean stock 

 lice fed upon his person with rickettsia long after his recovery, 

 as late as September, four months after the attack and three 

 months after the disappearance of all symptoms. We have 

 here strong presumptive evidence that Mr. Bacot acquired 

 his infection from the Warsaw lice and that the rickettsia 

 transmitted by him to his own stock of lice were identical 

 with those in the Warsaw lice. We believe that these experi- 

 ences constitute strong evidence for the identity of Rickettsia 

 pediculi and Rickettsia quintana (or wolhynica) as well as for 

 the etiological relationship of rickettsia to trench fever. This 

 belief, of course, predicates that the mass of population in 

 Central Europe is immune to trench fever, and tolerant of 

 Rickettsia pediculi infection. For the present then we must 

 assume that there is but one type of extracellular rickettsia in 



1 Compare Hindle, "Notes on Rickettsia," Parasitology, June, 1921, Vol. 13, No. 2, 

 p. 153. 



