292 SANITARY ENTOMOLOGY 



No definite organism has been finally fixed on as the cause of typhus 

 fever although several have been described. Plotz (1914) and others, 

 with excellent reasons, regard Bacillus typhi exanthematici as the cause. 

 Bodies called Rickettsia prowazeki Da Rocha-Lima (1916), are described 

 by Da Rocha-Lima, Noeller (1916), and others, as the causative organ- 

 ism, and it is claimed that they undergo multiplication in the cells of the 

 midgut of infested lice. Whether Rickettsia is the cause of the disease or 

 a product of the contagium is still uncertain. Stempell (1916) describes 

 a Protozoan, Strickeria jiirgensi, which he suspects to be the cause of 

 typhus, and claims that it undergoes part of its development in the in- 

 testines of Pediculus corporis, and is sometimes transmitted to man in 

 large numbers. Rabinowitch (1914!-1916) regards Diplobacillus exantJie- 

 maticus as the cause; Penfold (1916) describes a Micrococcus; Proescher 

 (1915) describes minute Diplococci and Diplobacilli as present in the 

 endothelial cells of the human subject. Finally Futaki (1917) has 

 described Spiroschaudvrmia exanthematotyphi from the liver and urine of 

 patients dying of typhus and has found the same organism in lice. Brumpt 

 (1918) discusses Rickettsia prowazeki Da Rocha-Lima, the so-called 

 cause of typhus fever, and claims that it is a coccobacillus and that he 

 found it in 73.6 per cent of the lice (Pedictdus corporis) from healthy 

 prisoners in France. He found that these lice infected with this organism 

 remained infective all their lives and therefore concludes that Rickettsia 

 cannot be the cause of typhus fever, even though it may be transmitted by 

 the lice to men and again taken up by them. In experiments on himself, 

 with infected lice he did not produce any infection. Brumpt perhaps 

 found the Rickettsia pediculi which is associated with normal lice. 



TRENCH FEVER. — This disease has only recently been recognized, 

 having passed even in the early days of the war under the initials P. U. O., 

 or pyrexia of unknown origin. Many of the greatest investigators in the 

 various armies concentrated attention on this baffling disease of the 

 trenches which stood among the highest of the disabling diseases of the 

 Western front. The first records of the connection of the louse were 

 contained in statements of Davies and Weldon (1917, 1918) that one of 

 them had produced the disease in himself by permitting infected lice 

 (Pedictdus corporis) to bite him. The incubation period was 12 days. 

 Early in 1918 two separate committees, the British under Sir David 

 Bruce and Major W. Byam, and the American under Dr. R. P. Strong, 

 succeeded in proving louse transmission. The English committee (Bruce 

 1918) in an experiment in which lice were crushed on a scarified area 

 of skin of volunteer patients incubated the disease in eight and ten days. 

 In experiments with the feces of lice fed on trench fever patients, a small 

 amount of dried excreta rubbed on a scarified area of skin, incubated the 

 disease in three men on the sixth, seventh and eighth days. Blood from 



