INSECTS AND HUMAN DISEASE 149 



The disease is characterised by fever, anaemia, and prostration, 

 the anaemia is always rapid and profound, the reduction of 

 the red blood corpuscles being almost incredible, and accom- 

 panied by a corresponding increase of the white corpuscles. 

 In certain severe cases, patients become perfectly indifferent 

 and immovable, and the slightest movement produces 

 vertigo. Unless the disease ends fatally at an earlier 

 date, the high fever lasts from fifteen to thirty days ; after 

 that it falls, and the eruptive phase begins. Although 

 verruga is caused by a blood parasite, the only organisms 

 found in the blood of patients are exceedingly minute, 

 rod-like structures, called Barton's ^-bodies or Bartonia 

 bacilliformis, after their discoverer Dr A. L. Barton of 

 Lima. Continued observations of the blood of sufferers 

 from verruga show that, if the patient is destined to 

 recover, the ^-bodies will become distorted, break up, and 

 ultimately disappear, and that their disappearance coincides 

 with the outbreak of the eruption; should the ^-bodies 

 reappear, the disease terminates fatally. 



As showing the virulence of this disease, we may quote 

 two examples from the pen of Mr C. H. T. Townsend, 

 entomologist to the Peruvian Government: "In 1906, at 

 San Bartolome, which is in the verruga district, on the 

 Central railway, two thousand men were employed in 

 tunnel work during the year. Among these there 

 occurred two hundred known deaths from verruga, and it 

 is practically certain that still further deaths occurred 

 among the many labourers who left the works and whose 

 history was not followed up. The general experience with 

 labourers on the Central railway has been that five or six 

 nights passed successively within the verruga district causes 

 the fever to appear in seventy-five per cent, to eighty per 

 cent, of the workmen in a camp. In a week or so nearly 

 all are certain to contract the disease. No animals of any 

 kind were employed by the labourers in any of this work. 

 Mosquitoes and buffalo gnats (Simulidce) in abundance, as 



