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PUBLIC RECORD OFFICE

Reference :-

HC.O. 885

23 PUBLIC RECORD OFFICE, LONDON

| ALLY WITHOUT PERMISSION OF THE

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SIE,

190

Enclosure 3 in No. 191.

31st October, 1915. I HAVE the honour to submit the following report on my work during the period fat May, 1915, to 31st October, 1915 :--

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Teaching-During the autumn term the usual course of instruction (both loc- tures and demonstrations) in parasitology (i.e., protozoology and helminthology) is being given by me for students wishing to take the diploma in Tropical Medicine. Five students are in attendance. Help is also given to students of the Veterinary School, and to more advanced workers with research and literature.

Editorial and Literary Work.-As Editorial Secretary I have been respon- sible for the issue of two numbers of the " Annals of Tropical Medicine and Parasit- ology"-namely, Vol. IX., No. 2, June, 1915, and Vol. IX., No. 3, July, 1915. A third number, completing Vol. IX., is in the press.

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It is hoped that the section on protozoa, for which I am responsible, of the book on the "Animal Parasites of Man," now in course of publication, will soon be issued. An appendix thereto, on recent researches, is in active preparation.

As before, have been a sectional editor for the "Tropical Diseases Bulletin," my sections therein comprising general protozoology and the parasites of amœbic, flagellate, and ciliate dysenteries. Flagellate dysenteries are of increasing importance.

Research-Investigations on the experimental introduction into vertebrates of insect flagellates (belonging to the genera Herpetomonas and Crithidia) have been continued. Observations have also been published on the natural occurrence of herpetomonads in mice. These results, mostly obtained in collaboration with Dr. Porter, have been published in a series of three papers which, together with the preliminary paper, are listed in the publications. I have also published a paper, with sixty-eight illustrations, on Spirocheta bronchialis, based on material collected in Khartoum in 1913; also a note on the biology of spirochaetes.

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The main conclusions of these researches may now be given. The flagellates used were Herpetomonas jaculum (Léger), parasitic in the gut of the hemipteron, Nepa cinerea: H. stratiomyia (Fantham and Porter) from the digestive tract of the larva of the dipteron, Stratiomyia chameleon; H. pediculi '(Fantham) from the gut of the body-louse, Pediculus vestimenti; and Crithidia gerridis (Patton) from the alimentary tract of the hemipteron, Gerris paludum. It will be seen that some of these insect hosts are blood-suckers, while others are not.

The vertebrate hosts included sticklebacks (Gasterosteus aculeatus) among the pisces; newts (Molge vulgaris), frogs (Rana temporaria) and toads (Bufo vulgaris), among the amphibia; lizards (Lacerta vivipara), and a grass-snake (Tropidonotus natrix) among the reptilia, and mice (Mus musculus) among the mammalia.

The insect flagellates were introduced into the vertebrates by inoculation or by feeding. No ectoparasites and no hæmatozoa were present on or in the vertebrate bosts at the commencement of the researches.

Full records are given of seventeen experiments on the introduction of the above-mentioned flagellates into two sticklebacks, two frogs, two toads, one newt, three lizards, one grass-snake, and six mice. It may be remarked that relatively few experimental animals can be managed and observed at any one time, as some of the animals used lived for months. The introduced protozoa were pathogenic to the mammals, but not markedly so to the cold-blooded vertebrates. Herpetomonas jaculum, H. stratiomyia, H. pediculi, and Crithidia gerridis proved pathogenic to mice. Frogs became infected with H. jaculum and C. gerridis; sticklebacks, toads, and grass-snakes with H. jaculum, and lizards with C. gerridis. Second and third passages of some of the parasites were obtained. Thus, a mouse became infected by feeding on the liver of another that had died from infection with H. pediculi from human body-lice. Similarly, a lizard died after infection with Crithidia gerridis. A second lizard, fed on the liver of the first, also contracted the infection, and a third one, inoculated with the heart blood of the second, showed leishmaniform parasites. Thus, three passages of the parasite have been accomplished. It is of interest to note, in this connexion, that in cultures of the blood of geckos in Algeria herpetomonads have been found, and that leishmaniasis occurs in this region.

The parasites, whether herpetomonas or crithidia, were present in the verte- brate hosts in either the non-flagellate or the flagellate form, or usually both. They were more abundant in the internal organs of the host, particularly in the liver, spleen, and bone-marrow. In all experiments where C. gerridis was used the para- No transition site invariably retained the crithidial facies in the vertebrate host.

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It is noted that infections obtained in the adult to a trypanosome was ever seen. experimental animals were not heavy, thereby differing from those recorded in young animala in our previous paper. Doubtless the parasites are more virulent in young hosts, as is the case with Mediterranean kala-azar in children.

That H. ctenacapkali (Fantham) can infect dogs was also shown experimentally. The conclusions are as follows:-

Herpetomoniasis can be induced in various warm- and cold-blooded verte- brates when the latter are inoculated or fed with herpetomonads occurring in the digestive tracts of various insects. The infection produced and the protozoal para- sites found in the vertebrates resemble those of human and canine leishmaniasis.

An infection can also be induced in certain vertebrates when they are fed or inoculated with Crithidia gerridis, and both flagellate and non-flagellate stages occur therein, but no transition to a trypanosome was found.

I believe that leishmaniases are arthropod-borne herpetomoniases, and that these maladies have been evolved from flagellates of invertebrates (especially herpe- tomonads of insects) which have been able to adapt themselves to life in verte- brates. (Herpetomoniases are, by some, termed leptomoniases).

In areas where leishmaniases are endemic an examination should be made of all insects and other invertebrates likely to come into contact with men or dogs or rats and mice, in order to ascertain if these invertebrates harbour herpetomonads. Preventive measures should be directed against such invertebrates, especially arthropods. Further, it is likely that certain vertebrates, such as reptiles and amphibia (especially those that are insectivorous) may serve as reservoirs for leish- maniases or, as they should preferably be termed, herpetomoniases. From such reservoirs the herpetomonads may reach man by the agency of ectoparasites or flies, especially such as are sanguivorous.

The natural occurrence of herpetomonads or leptomonads in mice formed the subject of a second paper, illustrated by seven text figures. I first saw these flagel- lates in the blood of mice in Cambridge in 1909. The infection was scanty and the parasites were examined in the fresh state, and were stained intra vitam. Similar parasites were also seen in 1911 and 1912, but again the infections were scanty. The mice were kept in laboratories where rats and rat-fleas, Ceratophyllus fasciatus and Ctenophthalmus agyrtes were present. It is highly probable that the former such fleas in England flea was infected with Herpetomonas pattoni, as are known to harbour scanty infections of this flagellate, and this flagellate has been found in fleas both in Cambridge and Liverpool. Reference is made in the paper to the interesting remarks published by Dutton and Todd in 1903 in Memoir XI. of this School. Dutton and Todd found a natural infection of house mice with herpetomonads at McCarthy Island, Gambia River. It is concluded that Herpetomonas pattoni, which occurs naturally in the gut of rat-fleas, can, probably also live in dog-fleas and human-fleas, and that it can adapt itself to life in the blood and internal organs of such vertebrates as rats and mice.

A third paper deals with the general subject of insect flagellates and the evolu- tion of disease, especially in relation to leishmaniasis, and points out the great need for the use of comparative methods in the study of protozoology. The significance of the herpetomonad stage of leishmania is pointed out, and the early work of Christophers, Mesnil, Novy, and others, on the root of the flagellum in the non- flagellate stages of the various species of leishmania is referred to. In this connexion also, the importance of the early work of Patton on the complete life-cycle of a herpe- tomonad is again pointed out. Stress is laid on the existence of herpetomonad stages of leishmania, more especially of L. tropica, in man, as recorded by Escomel, La Cava, Splendore, and others, while the discovery of herpetomonad parasites by Franchini, in man, is recalled. Flagellate stages of L. donovani have recently been That herpetomonada may occur in the seen in subinoculated dogs by Wenyon. latex of certain plants and cause disease therein should also be remembered in this connexion. It is concluded that leishmaniasis is a flagellosis, and treatment and preventive measures along these lines should accordingly be undertaken, as has been suggested by Vianna, by the use of tartar emetic in treatment, and by Dodds Price and Rogers in the removal of coolie lines from an infected area as a successful preventive measure.

It may be remarked that various birds, some of them insectivorous; have been successfully infected with insect flagellates, such as Herpetomonas culicis, and that a paper on the same is in course of publication.