170 



KAI.A-AZAli COMMISSION 



Probability of 

 an ' ' insect " 

 vector 



4. The Loishman-Donovan parasite was fminfl in the peripheral Wood in 86"6 per cent, 

 of the cases. 



5. The ordinary grey monkey of the Sudan {Cfrcopitliecnn sabieim) can be infected with 

 kala-azar. 



G. It can he infected by intraperitoneal inoculation and by subcutaneous inoculation. 



7. Natural infection, from an infected to a healtliy animal, can occur provided the 

 animals are kept in close contact. 



8. The Leishman-Donovan parasite is present in the peripheral blood of infected monkeys. 



9. So far we have found that the best method of infecting tlie monkey is by injecting 

 into the peritoneal cavity the contents of a spleen puncture taken during life. 



10. So far we have not succeeded in infecting dogs nor have we foimd spontaneous 

 Leishmaniosis in the dog. 



11. The parasite can he cultivated readily on artiticial media, development into flagellate 

 forms being obtained in 10 per cent, citrate, on Novy and MacNeal's medium and on 

 Nicolle's modification of that medium. 



12. The parasite appears to degenerate quickly after the death of the host. Post 

 mortem examinations and post mortem spleen punctures for diagnostic purposes 

 should be done immediately after death. 



PossiBLK Mkthods of Infection' in Kala-azah 



From the evidence obtained it appears likely that some insect acts as the transmitting 

 agent of kala-azar in the Sudan. You can take unaltered parasites from one monkey, inject 

 them subcutaneously into anotlicr monkey, and the latter becomes infected with the disease, 

 so that presumably the disease can be conveyed without any extracorporeal development 

 into the flagellate stage. Further, a healthy monkey kept beside an infected monkey can 

 contract the disease, and in the case recorded in this paper the infection was a rapid and 

 fatal one, and was contracted from a monkey which was not heavily infected with the 

 disease. How then did this monkey become infected? If an insect, the bed-bug {Cimex 

 lectulariits) is unlikely, as these monkeys were kept in a metal cage and no bed-bugs were 

 found, so that some other insect transmitter must be looked for, and furtlier experiments will 

 be carried out to elucidate this point. Possibly also, if an insect is the transmitting agent, 

 only a small percentage of the feeding or biting animals become infected (owing to the small 

 number of parasites in the peripheral blood) and this would account for the absence of 

 epidemics and the apparently wide-spread distribution of the disease. The presence of 

 a flagellate form also suggests an intennediate host and a developmental stage outside the 

 human body. 



The other possible source of infection is an intestinal one, the flagellate form occurring 

 free outside the body and entering the body again by water or by food. If so, in the 

 naturally infected monkey, tlu; monkey must have eaten food contaminated l)y the excreta 

 of the infected monkey. 



We beg to acknowledge our indebtedness to Captain .\rchibal(l, 1\..\.M.C'., of the 

 Wellcome Tropical Research Laboratories, Khartoum, for so kindly carrying on our 

 experiments during our absence on leave. 



LlTERATrnK 



Alv.ircz and Pcreira da Silva (1910). — "Sobre a e.xistencia do kala-azar ospontanuo no caocin Lisbo:i." 



Mfilieiint ronfempiinttira, 22 itf nuiio 1910, p. 1C2. 

 Basile (1910). — "Sulla Leislinianlosi del eane e siiU'ospite interniedio del kala-azar infantile." 



Itemcoiil! ilfllii It. Afniihuiiii ilii Lineel, vol. xi.x., nrrir 5a, 2°*<'i/i. fuse. 1U°. Nov. 20, 1910, ji. .'i2.3. 



