Note on the classification of the Leishmania sp. responsible for cutaneous leishmaniasis in the East Central Region of Brazil

Leishmania (Viannia) guyanensis in tegumentary leishmaniasis

Leishmania (Viannia) guyanensis is a causal agent of American tegumentary leishmaniasis (ATL). This protozoan has been poorly investigated; however, it can cause different clinical forms of ATL, ranging from a single cutaneous lesion to severe lesions that can lead to destruction of the nasopharyngeal mucosa. L. (V.) guyanensis and the disease caused by this species can present unique aspects revealing the need to better characterize this parasite species to improve our knowledge of the immunopathological mechanisms and treatment options for ATL. The mechanisms by which some patients develop a more severe form of ATL remain unclear. It is known that the host immune profile and parasite factors may influence the clinical manifestations of the disease. Besides intrinsic parasite factors, Leishmaniavirus RNA 1 (LRV1) infecting L. guyanensis can contribute to ATL immunopathogenesis. In this review, general aspects of L. guyanensis infection in humans and mouse models are presented.

2. Mucosal leishmaniasis

Sudanese mucosal leishmaniasis is a chronic infection of the upper respiratory tract and/or oral mucosa caused mainly by Leishmania donovani. The disease occurs in areas of the country endemic for visceral leishmaniasis, particularly among Masalit and other closely related tribes in western Sudan. The condition may develop during or after an attack of visceral leishmaniasis, but in most cases it is a primary mucosal disease. Unlike South American mucocutaneous leishmaniasis, mucosal leishmaniasis in Sudan is not preceded or accompanied by a cutaneous lesion. Pathologically, the lesions show a mixture of macrophages, plasma cells and lymphocytes. An epithelioid granuloma may also be found. Parasites are scanty. Diagnosis is established by demonstration of parasites in smears or biopsies, by culture or animal inoculation, or with the aid of the polymerase chain reaction. Most patients give positive results in the direct agglutination test and leishmanin skin test. Patients respond well to treatment with pentavalent antimony compounds.

Vascular changes in human leishmaniasis: a light microscope and immunohistological study

The study of human cutaneous leishmaniasis from Saudi Arabia (37 cases), and of Sudanese mucosal (52 cases) and visceral (27 cases) leishmaniasis revealed the occurrence of vascular alterations. Vasculitis with or without fibrinoid necrosis and fibrin thrombi were found in both the arteries and veins within the area of inflammation in cutaneous and mucosal leishmaniasis; whereas subendothelial oedema, hyalinosis and intimaproliferation were seen in the small arteries of the various organs in visceral leishmaniasis. Immunoperoxidase staining of the cutaneous leishmaniasis lesions showed the presence of IgG and IgA within the endothelial cells, in the media, and in the perivascular space of the diseased vessels. The formation of immune complexes, locally in cutaneous and mucosal leishmaniasis and circulating in visceral leishmaniasis, is considered responsible for these vascular lesions.

The potential of using recombinant DNA species-specific probes for the identification of tropical Leishmania

Human leishmaniasis is a world-wide public health problem with more than 400000 new reported cases/year (Anon, 1984) in the tropics and subtropics. Were (1985) has estimated that Leishmaniases affect about 20 million people in the Third World. In hospitals where treatment is available, initially all positive cases are treated equally; it is the prognosis and follow-up that varies according to the causative organism. A wide variety of species or subspecies ofLeishmaniamay be present in a small verrucose lesion developing after an infected sandfly bite or appear in lesions as the disease progresses. Depending on whichLeishmaniais present a clinial decision must be made whether to treat with drugs of varying toxicity or not.

An outbreak of cutaneous leishmaniasis in Guyana: epidemiology, clinical and laboratory aspects

An outbreak of cutaneous leishmaniasis reached epidemic proportions among military personnel in Guyana during the period from November, 1977 to March, 1980. As the patients presented from widely separated areas of the hinterland it is likely that cutaneous leishmaniasis is endemic throughout the virgin tropical rain forest of Guyana, although infection is normally sporadic. A striking clinical feature was the 'spirotrichoid' involvement of the draining lymphatics and nodes in half the cases, which histologically all came from the middle region of the spectrum (groups II, III or IV of Ridley's 1980 classification). All the cases tested were serologically positive to a Leishmania braziliensis antigen. One hundred and ten patients were successfully treated with pentamidine, with minimal side-effects, but some required a second course. Four relapsed patients all belonged to the same histological group.

Leishmaniasis in Brazil: XV. Biochemical distinction of Leishmania mexicana amazonensis, L. braziliensis braziliensis and L. braziliensis guyanensis--aetiological agents of cutaneous leishmaniasis in the Amazon Basin of Brazil

Enzymic profiles of the three known agents of human cutaneous leishmaniasis in the lower Amazon region are compared. Of 14 enzymes, 10 (ASAT, ALAT, GPI, G5PD, MDH, ACON, PEP, HK, MPI and ACP) differentiate Leishmania mexicana amazonensis from L. braziliensis braziliensis or L. braziliensis guyanensis: this supports their taxonomic status as distinct species. In contrast, only slight mobility differences of four enzymes (ASAT, ALAT, PGM, MPI) separate L. b. braziliensis and L. b. guyanensis, which are distinguished biochemically for the first time: this indicates that they are closely related. Four stocks of L. b. panamensis correspond with L. b. guyanensis on mobilities of 10 enzymes (ASAT, ALAT, PGM, GPI, G6PD, MDH, PK, HK, MPI, ACP), although these two subspecies are known to be separable by kinetoplast DNA buoyancies and the enzyme 6PGDH. The generation of practical, regional biochemical keys to the medically important leishmanias is discussed.

Some methods for the enzymic characterization of Latin-American Leishmania with particular reference to Leishmania mexicana amazonensis and subspecies of Leishmania hertigi

30 Brazilian stocks of Leishmania mexicana amazonensis and 13 stocks of subspecies of Leishmania hertigi were characterized by starch-gel electrophoresis, using 18 enzymes selected from a total of 36 investigated. L. m. amazonensis was separable from subspecies of L. hertigi by enzymic profiles of 11 enzymes. The L. m. amazonensis stocks, which were from a wide range of hosts in a large geographical area, were enzymically extremely homogeneous, and could only be subdivided on two enzymes; sub-groups did not relate to each other or to any differences in epidemiological characters, including the clinical form of the human disease. 12 stocks regarded as L. hertigi deanei, that were isolated from Coendou prehensilis prehensilis and Coendou sp. in Pará State, Brazil, were separable into two sub-groups by three enzymes. A single stock of L. hertigi hertigi from Panama was separable from both enzymic sub-groups of L. h. deanei, in each case by three enzymes. The significance of these and other characters of diversity is discussed, together with the use of enzymes for the identification of the leishmaniae.

Isoenzyme characterization of Leishmania species from Iraq

Leishmaniasis in Iraq takes both the visceral and cutaneous forms. The causative organisms are identified according to the electrophoretic variation of the enzymes MDH, GPI, 6PGD, PGM and IDH. The 37 visceral stocks investigated fall into two groups which differ only with respect to GPI. The six cutaneous stocks were divided into three groups. Group 3 represents Leishmania major, while groups 4 and 5 refer to L. tropica showing intraspecific variation with regard to 6PGD.

Epidemiology of dermal leishmaniasis in the Rio Doce Valley, State of Minas Gerais, Brazil

Dermal leishmaniasis is prevalent in the predominantly settled agricultural areas in the Rio Doce Valley in the eastern part of the State of Minas Gerais, Brazil. The disease has been recorded almost equally in both sexes. Cases have been confirmed in all age groups but youths aged ten to 14 years form the population segment at greatest risk to infection. Cases of single cutaneous lesions, multiple cutaneous lesions and muco-cutaneous lesions have been recorded in the area. Isolates of parasites include representatives of the Leishmania mexicana and L. braziliensis complexes and at least one parasite that does not fit into either category. Infections have not been detected in small mammals (mainly rodents) but about 3% of dogs are infected. The phlebotomine fauna includes no species (or close relatives of species) previously incriminated as vectors of mexicana and braziliensis infections in Brazil. In the complex and confusing epidemiological situation in the Rio Doce Valley it seems unwise to apply traditional specific names to Leishmania of the area.