Infection of birds with Proteosoma by the bites of mosquitoes / by Major Ronald Ross.

  • Ross, Ronald, Sir, 1857-1932.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Infection of birds with Proteosoma by the bites of mosquitoes / by Major Ronald Ross. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    none contained proteosoma, one of the crows and all the weaver birds showed a copious pro- teosoma infection within nine or ten days of being bitten by grey mosquitoes fed previously on sparrows with the latter parasite. Lastly, out of five sparrows which originall}' contaUied a vei-y few proteosoma, four showed a new and much more copious infection a week after being subjected to a similar experiment. I failed, however, to transmit the proteosoma of sparrows to mainas and some other birds. In all the birds in which the parasites appear- ed after the experiment, the invasion presented such constant and unmistakable characters that no possible room for doubt was left as to the infection being due to the mosquitoes. The blood of the birds experimented with was examin- ed both before the experiment and on several occasions afterwards. The course of events was always as follows. The blood would remain entirely free from proteosoma (except in the case of the five sparrows which originally con- tained a few of them) until the fifth, sixth, seventh or eighth day after the experiment, when one or two parasites oidy would be found in an entire specimen. Next day it would invariably be seen that the number of parasites had largely increased; and this increase would continue until in a few days, in almost every case, the parasites become so exceedingly numerous that from ten to sixty and even more could be count- ed in almost every field of the oil-immersion lens, while I often observed as many as seven distinct parasites in a single corpuscle. The only ex- ceptions were the case of the crow and that of the five originally infected sparrows, in which the number of parasites did not exceed about