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THE PHILIPPINE '•^^iiis^nsi^ 



Journal of Science ^ «« 



B. Tropical Medicine 



Vol. IX FEBRUARY, 1914 No. 1 



COCKROACHES AND ANTS AS CARRIERS OF THE VIBRIOS 

 OF ASIATIC CHOLERA ^ 



By M. A. Barber 

 (From, the Biological Laboratory, Bureau of Science, Manila, P. I.) 



Cockroaches, especially of the species Perivlaneta amencana 

 Linn., are very common in dwelling houses in Manila at all 

 seasons of the year. They are voracious feeders on all kinds 

 of organic matter, and at night time, especially, creep over any 

 unprotected human food and discharge their faeces there. Since 

 they have ready access to human faeces in closets not provided 

 with sanitary plumbing, they may become the carriers of in- 

 fective material from the closets to human food. This is the 

 more probable, since these insects not only creep rapidly, but also 

 fly from place to place. In the following experiments, it was 

 purposed to test the faeces of cockroaches which had previously 

 ingested cholera cultures and human faeces containing cholera 

 vibrios, with the purpose of determining if these insects may 

 not become carriers of Asiatic cholera. 



The cockroaches used in these experiments were all Peripla- 

 neta americana and all winged adults. The method of experi- 

 mentation was simple. The insects were caught and kept in a 

 jar for a day or more until they had become hungry. They were 

 then distributed in wide-mouthed bottles, one insect to a bottle. 

 Cultures of cholera or liquid human faeces were introduced into 

 the bottles by means of a pipette. Some powdered carmine was 

 added to the faeces or cultures so as to make it possible to identify 

 a faeces sample with a given feeding. Liquid faeces obtained 



' Received for publication December 8, 1913. 



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