On the role of insects, arachnids and myriapods, as carriers in the spread of bacterial and parasitic diseases of man and animals. A critical and historical study / by George H. F. Nuttall.
- George Nuttall
- Date:
- 1900
Licence: In copyright
Credit: On the role of insects, arachnids and myriapods, as carriers in the spread of bacterial and parasitic diseases of man and animals. A critical and historical study / by George H. F. Nuttall. 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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![ful what they died of—1ST.] In another experiment he placed 20 fleas (obtained from a cat) in a bell-jar with a rat dying of plague. He then placed a healthy rat in a cage into the bell-jar, but also allowed the cadaver of the first rat to remain 36 hours in the vessel. The second rat died on the fifth day of plague. This experiment was repeated three times, once with mice, the result being positive, twice with rats, the result being negative. Simond attributes the negative result to the rats catching and devouring the fleas which attacked them. He had never observed plague pass from diseased to healthy animals when the former were free from fleas, in sup- port of which statement lie, however, only cites a single experiment in which a flealess cadaver of a plague-rat remained 24 hours in a cage occupied by 7 healthy rats. (He does not state how long these were kept under observation.) Simond does not directly claim that fleas inoculate the bacilli by means of their proboscides, but he certainly implies it. He observes that he has noticed fleas voiding their dejections on the skin whilst in the act of sucking blood, and thinks if bacilli were in their excreta these might readily gain an entrance into the wound produced by the insect and thus give rise to infection. He believes that the different forms of spontaneous plague in man and animals are usually attributable to the agency of parasites, chiefly fleas, and thinks his hypothesis, for such it must still be called, explains the prevalence of plague, especially in filthy dwellings. Simond believes that infection from man to man takes place but in an insignificant number of cases as compared to those where fleas carry the infection from rat to man. In conclusion, he suggests among other prophylactic measures the advisability of throwing scalding water on dead rats so as to kill the fleas on them prior to removing the carcasses. He regards rats as the main cause in the spread of plague among human subjects, and would appear to have made some observations, which show that rats continue to die throughout the duration of plague epidemics, though it is only when the mortality is great amongst them that it is especially noticed. Simond also believes that Cimex may convey infection from man to man. Simond does not seem to have been aware of the experiments made by Huttall with fleas and bugs, or he would not have stated that the virulence of the bacilli may be increased in the body of the flea. The fact that various germs were seen to die off in](https://iiif.wellcomecollection.org/image/b24764127_0028.jp2/full/800%2C/0/default.jpg)
