32 THE BROWN EAT IN THE UNITED STATES. 



Experiments were made with two species of rat fleas, both of 

 which were found to carry the infection. Probably all kinds of rat 

 fleas transmit plague, while those that commonly infest dogs, cats, 

 and man do not. 



The conclusions of the Plague Commission had already been prac- 

 tically accepted by medical men in most parts of the world, and 

 recent outbreaks of plague were followed by active measures for the 

 destruction of rats. In India, as early as 1905, the authorities of the 

 United Provinces (Agra and Oudh) began a persistent war upon the 

 animals. Rewards were offered for killing rats, and traps were given 

 to the people. In the four centers of population — Agra, Allahabad, 

 Bareli, and Badaun — a total of 416,403 rats were killed before the 

 close of the first year. a In Athens, Odessa, Oporto, Glasgow, and 

 other European cities systematic, but on the whole unsuccessful, 

 efforts were made to exterminate these animals. 



Similar attempts to get rid of rats have been made since Septem- 

 ber, 1907, in some of the Pacific ports of our own country, particu- 

 larly in San Francisco, where up to February, 1908, 77 deaths from 

 plague occurred. Traps, poisons, bounties, and other means were 

 employed to reduce the number of rodents. During the first four 

 months of warfare under the direction of the United States Marine- 

 Hospital Service about 130,000 of the animals were destroyed in San 

 Francisco and vicinity. In the early months of 1908 the work of de- 

 struction was stimulated by increased bounties, and for a time the 

 number of rats killed averaged about 7,000 per week. Up to May, 

 1908, 278,000 rats were captured in the city and it was estimated 

 that half a million had been poisoned. 



From May, 1908, to January 1, 1909, 115,869 rats were trapped and 

 9,797 were found dead in San Francisco. On an average, over 140,000 

 poisoned baits per week were placed, but as a matter of course the 

 number of dead rats discovered was only a small percent of the 

 total number killed by poison. The last rat found infected with 

 plague bacillus was taken October 23, 1908, but no human cases of 

 the disease have occurred in the city since January, 1908. 



In Honolulu, Hawaii, active operations against rats have been 

 reported since May 23, 1908. During the 30 weeks ending December 

 12, 1908, 20,288 rats were trapped and 3,528 shot from trees in the 

 city. None of those examined was infected with plague bacillus. 



But rats disseminate diseases other than bubonic plague. Trich- 

 inosis among swine is probably perpetuated entirely by rats. The 

 occurrence of trichinse among herbivorous animals is very rare, and 

 in the hog can result only from its eating the flesh of animals infested 

 with the parasite. The only two animals of the farm known to be 



« Report on Plague in the United Provinces by Maj. Chator White, 1906. 



