DURATION OF THE INFECTIVENESS OF VIRULENT RINDERPEST 



BLOOD IN THE WATER LEECH, HIRUDO 



BOYNTONI WHARTON ' 



By William Hutchins Boynton 

 (From the Veterinary Division^' Bureau of Agriculture, Manila, P. I.) 



This investigation was suggested by the fact that in the cam- 

 paign against rinderpest in the Philippines particular difficulty 

 is experienced in ridding low swampy districts of the disease. 

 On numerous occasions such localities have been apparently 

 free from rinderpest, but in four or five weeks the disease has 

 reappeared. In most instances the movement of animals was 

 apparently controlled, and it did not seem possible that the dis- 

 ease was introduced from other districts. 



Consideration of these apparently spontaneous outbreaks with 

 reference to the localities in which they appeared to be most 

 frequent led me to examine leeches, to determine if they could 

 maintain the virus of rinderpest alive for any length of time. 

 Leeches subsist on blood, and consume large quantities at one 

 feeding. Cattle sick with rinderpest are apt to seek cool places 

 and water holes during the febrile stage of the disease, while 

 carabaos do so normally. This gives the leeches ample oppor- 

 tunity to feed upon them. Persons engaged in field work have 

 repeatedly observed leeches attached to carabaos immediately 

 after they emerged from carabao wallows. These facts indicate 

 that leeches may be a factor in the rinderpest problem. 



On examining the literature on leeches, I have found that 

 Bass and Johns cite the statement of Sakharov, Rosenbach, 

 Blumer, Hamburger, and Mitchel(i) that they kept malaria 

 Plasmodia alive for several days in leeches that had been allowed 

 to draw the blood of malaria patients. 



Laveran and Mesnil (2) state: 



Various trypanosomes which were found by Brumpt in fresh-water 

 fishes, can be divided into several g-roups accordinj? to their mode of evolu- 

 tion in the bodies of leeches (Hemiclipsis). 



* To be published as Bulletin No. 29, Bureau of Agriculture of the 

 Government of the Philippine Islands. 

 'Archibald R. Ward, Chief. 



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