The author describes the first cases of spontaneous leishmaniasis in guinea-pigs, as verified for the first time, in Curitiba, at the Institute of Biology and Technological Research. Studying the inoculability of Paracoccidioide brasiliensis in guinea-pigs, he found animals which presented tumoral lesions in the ears and peritesticular skin. The examination of these tumors, mixed with a small drop of Giemsa's original solution, plus the exam of the rubbings of the same material, coloured by the May-Grunwald Giemsa after fixation by Heidenhein's solution and the histological exams of the cuts in the tumoral lesions revealed the presence of elements which possessed the same morphology and aspect of the LEISHMAN-DONOVANI corpuscles. In the meanwhile, a parasitosis by protozoarians of the Leishmania variety might have been suspected, because large macrophagi could be seen in the histological cuts, all parazitized, identical with those which are found in other cutaneous leishmaniosis. The author then proceeds to the experimental study of the sickness, first by endeavouring to obtain material for the inoculation and cultures, by means of punctures in the tumors. Part of the product of the punctures was sown in N. N. N. medium and part inoculated in other guinea-pigs. After the third day the cultures presented the flagellated forms of the parasite, free or grouped in rosettes in the culture liquid. All the guinea-pigs inoculated with part of the material obtained by puncturing and with the liquids of the cultures, reproduced the tumors found in the animals spontaneously infected. With a view to reproducing the same features of generalization which were observed in other experimental animals, with other strains of leishmania, new animals were inoculated after having been tarred and blocked in order to attempt the breaking down of possible natural resistences, which proved unnecessary, however, for the generalization went on of itself naturally and without artifice. Inoculations were made by the subcutaneous, intraperitonial, intrasplenic, intramedular, intracerebral and endovenous channels and by instillation in the conjunctive, in those guinea-pigs which received subcutaneous inoculations, the incubation period varied between 11 and 15 days, this period being longer when the internal channels were used, when it was generally one or two months before the lesions appeared. When the lesions are on the skin or when the inoculation is done there, the first manifestations of lesions are characterized by a slight thickening of the subcutaneous tissue, which, little by little, becomes more consistent, giving place to a tumoral growth which attains great volume and characterizes the most developed phase. The lesions, when metastatic, are localized mostly in the tegumentary extremities and periarticular zones, having the same appearance as the lesions observed by other researchers who have studied the infection of hamsters, mice and dogs infected by L. donovani, L. infantum and L. tropica. The experiments carried out in all the tumoral lesions in guinea-pigs, were positive for leishmania, where they were found free in the tissues or parasitizing large macrophagi. At times the tumors ulcerate and become covered with a crusty layer, easily detachable, covering a rosy surface of granulomatosis aspect. The spleen and lymphatic ganglia are the internal organs which most react, hypertrophy always being present, and it has been possible to re-isolate the parasite of these organs as well as those of the liver, suprarenal, testicle, medulla of the bones and cardiac blood. A series of sixty guinea-pigs were inoculated in the skin of the nose and sacrificed within anything from a few minutes' up to twenty-four hours' interval. The material obtained from these animals was fixed in Bouin-Hollande, included in paraffin and coloured by hematoxilin-eosine and Maxinow's hematoxilin-azur II-eosine. The study of the histological cuts in the different periods of evolution showed that the inflammatory process passes through a series of modifications which start by an acute inflammatory phase followed by a simple granulomatosis phase, finally followed by another characterized exclusively by large parasitized macrophagi - the macrophagi phase. During the period of evolution of the inflammatory lesion, the infiltrative phenomena are constant and are at first constituted of granulocited neutrophils, eosinophils and mononuclear cells, followed by a preponderance of monocytes and lastly by the sole presence of large parasitized macrophagi. The author compares his findings in the guinea-pigs with those in other animals inoculated with different strain of Leishmania, calling attention to a real dermatropism of the parasite under study to its dissemination through the lymphatic channels and to the histologycal lesions identical to those other leishmaniosis, principally by those produced by L. tropica.
Leishmaniasis; guinea-pig
