﻿22 The Philippine Journal of Science 1914 



SUMMARY 



After an absence of six years in human beings and five years 

 in rats, a case of human plague was found in the Philippines 

 on June 17, 1912. There have been a total of 68 cases and 58 

 deaths up to October 1, 1913, in Manila, and 9 cases and 9 deaths 

 in Iloilo. During April, 1913, several cases of pneumonic plague 

 were detected on vessels that came from Hongkong and Amoy. 

 A careful investigation of these cases and of all subsequent 

 arrivals failed to show any connection between them and the 

 first cases of plague on June 17 in Manila. The disease waa 

 probably introduced by plague rats or insects present in cargo 

 from infected ports which was not unpacked until it was distrib- 

 uted in the city. Rat catching was done in Manila during the 

 entire time that plague was absent, but no case of rat plague 

 was found until August 31, 1912, this in spite of the fact that 

 over 14,000 rats had been caught in districts in which human 

 cases had occurred since June 17. Plague was found in rats 

 and cats and in bedbugs and fleas. An explosive human outbreak 

 occurred in October in which 21 cases were traced to the goods 

 warehouse at the Azcarraga railway station. The gray rats 

 were found to be the commonest. The percentage of plague 

 among rats has been very small, less than 0.002, whereas it is 

 the common experience in cities in which plague occurs that at 

 least 2 per cent of the rats are plague infected. Another most 

 striking incident was the fact that of the total 48 plague rats 

 which were encountered, a rat sick of plague was only found once 

 and a rat that died of plague was only found once. The remain- 

 ing rats in which plague was detected were caught in spring 

 traps, died as a result of poison, or were clubbed to death. The 

 transmission of plague by fleas was definitely shown by guinea 

 pigs contracting plague from the bed of a human victim and by 

 finding infected fleas in the desk of a human victim. Multiple 

 house infection occurred only three times, and all of the cases 

 were within the incubation period of the disease. Rat nests 

 were frequently found in hollow bamboo, and the experience 

 had in Java was fully confirmed. Seasons apparently had no 

 influence upon the number of cases, whereas in the near-by ports 

 of Hongkong and Amoy seasonal prevalence is most marked. 

 The only place in the Philippines in which plague occurred outside 

 of Manila was Iloilo. The sanitary measures employed consisted 

 in the isolation of the plague victim in a plague hospital. The 

 rat-catching and rat-proofing measures were begun at the pe- 

 riphery of a zone which extended three blocks on each side of 



