Epidemiology of cutaneous leishmaniasis in Suriname: a study performed in 2006

Cutaneous leishmaniasis (CL) is a widespread disease in Suriname caused by Leishmania Viannia guyanensis. It is argued that other Leishmania species are also responsible for CL and that the incidence is increasing. This study aimed to identify the species causing the disease and to estimate the annual detection rate of CL in Suriname in 2006. In Paramaribo, 152 patients were registered, of whom 33 were tested in two polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) methods. Twenty-seven patients were infected with L. (V.) guyanensis (complex), one with L. (V.) lainsoni, and one with L. (Leishmania) amazonensis. In the hinterland, 162 CL suspected patients were registered by questionnaires; of these, 24 of 27 tested positive by PCR-RFLP (88.9%; 95% CI, 77.1-100%). With extrapolation of collected data, a detection rate was calculated of 5.32 to 6.13 CL patients per 1,000 inhabitants for the hinterland and 0.64 to 0.74 patients per 1,000 inhabitants for the whole country.

Leukotrienes are essential for the control of Leishmania amazonensis infection and contribute to strain variation in susceptibility

Leukotrienes (LTs) are known to be produced by macrophages when challenged with Leishmania, but it is not known whether these lipid mediators play a role in host defense against this important protozoan parasite. In this study, we investigated the involvement of LTs in the in vitro and in vivo response to Leishmania amazonensis infection in susceptible (BALB/c) and resistant (C3H/HePAS) mice. Pharmacologic or genetic deficiency of LTs resulted in impaired leishmanicidal activity of peritoneal macrophages in vitro. In contrast, addition of LTB4 increased leishmanicidal activity and this effect was dependent on the BLT1 receptor. LTB4 augmented NO production in response to L. amazonensis challenge, and studies with a NO synthesis inhibitor revealed that NO was critical for the enhancement of macrophage leishmanicidal activity. Interestingly, macrophages from resistant mice produced higher levels of LTB4 upon L. amazonensis challenge than did those from susceptible mice. In vivo infection severity, as assessed by footpad swelling following s.c. promastigote inoculation, was increased when endogenous LT synthesis was abrogated either pharmacologically or genetically. Taken together, these results for the first time reveal an important role for LTB4 in the protective response to L. amazonensis, identify relevant leishmanicidal mechanisms, and suggest that genetic variation in LTB4 synthesis might influence resistance and susceptibility patterns to infection.

Cryptic paraflagellar rod in endosymbiont-containing kinetoplastid protozoa

Cilia and flagella are central to many biological processes in a diverse range of organisms. The kinetoplastid protozoa are very appealing models for the study of flagellar function, particularly in the light of the availability of extensive trypanosomatid genome information. In addition to the highly conserved 9 + 2 axoneme, the kinetoplastid flagellum contains a characteristic paraflagellar rod structure (PFR). The PFR is necessary for full motility and provides support for metabolic regulators that may influence flagellar beating. However, there is an intriguing puzzle: one clade of endosymbiont-containing kinetoplastids apparently lack a PFR yet are as motile as species that possess a PFR and are able to attach to the invertebrate host epithelia. We investigated how these organisms are able to locomote despite the apparent lack of PFR. Here we have identified a PFR1 gene in the endosymbiont-bearing trypanosome Crithidia deanei. This gene is expressed in C. deanei and is able to partially complement a pfr1 null mutation in Leishmania mexicana cells, demonstrating that the encoded protein is functional. Careful reexamination of C. deanei flagellar ultrastructure revealed a greatly reduced PFR missed by many previous analyses. This affirms the PFR as a canonical organelle of kinetoplastids. Moreover, although PFR proteins have been conserved in evolution, primary sequence differences contribute to particular PFR morphotypes characteristic of different kinetoplastid species.

Molecular probes and the polymerase chain reaction for detection and typing of Leishmania species in Mexico

Leishmaniasis in Mexico is a public health problem because all the clinical forms have been recorded in most Mexican states. We studied patients showing clinical symptoms of any form of leishmaniasis, from several endemic areas. Bone marrow samples, aspirates or skin biopsies were taken and deoxyribonucleic acid (DNA) was extracted and amplified by the polymerase chain reaction (PCR) with universal primers AJS1 and DeB8, specific for the Leishmania subgenus Leishmania. The PCR products were then hybridized by dot- or Southern blotting and probed with probe 9.2, specific for the L. mexicana complex. If hybridization did not occur, the DNA was amplified with primers D1 and D2, specific for members of the L. donovani complex, and PCR products were hybridized with probe B4Rsa, also specific for the L. donovani complex. DNA was also amplified with primers B1 and B2, specific for the subgenus Viannia, and the PCR products were hybridized with probe B18, specific for the L. braziliensis complex. It was found that in Tabasco and Veracruz, Mexico, localized cutaneous leishmaniasis (LCL) is caused by infection with members of the L. mexicana complex, whereas in the states of Nayarit and Campeche it was due to infection with the L. mexicana and/or L. braziliensis complexes. Visceral leishmaniasis was caused by L. (L.) chagasi, mainly in the states of Chiapas and Guerrero, and by L. (L.) mexicana in one immunocompromised patient from Tabasco.

Use of DNA-based diagnostic methods for human leishmaniasis in Minas Gerais, Brazil

DNA hybridisation was used to type 26 samples from lesions of human patients from the Rio Doce Valley (Minas Gerais, Brazil) clinically diagnosed as having cutaneous leishmaniasis, using kinetoplast DNA (kDNA) cloned mini-circle probes specific for the Leishmania mexicana and Leishmania braziliensis complexes. All samples were found to belong to the L. braziliensis complex. When biopsies were pressed directly onto touch blot membranes 38.5% of the samples were positive. The positivity and specificity obtained were both 100% when cultured blotted parasites were used. The results were confirmed by polymerase chain reaction (PCR) analysis using primers specific for the L. mexicana and L. braziliensis complexes.

Leishmania mexicana mexicana: genetic heterogeneity of mexican isolates revealed by restriction length polymorphism analysis of kinetoplast DNA

Leishmania mexicana mexicana isolates from 23 patients with localized, diffuse, and an atypical "pseudodiffuse" form of cutaneous leishmaniasis were obtained in various endemic regions of Mexico. Restriction fragment length polymorphism analysis of kinetoplast DNA was done with nine different endonucleases in addition to an in vitro growth pattern analysis. We found that the 23 L. mexicana mexicana isolates could be consistently classified into six groups, according to the endonuclease digestion patterns obtained with HaeIII, HpaII, and MseI. Whereas localized cutaneous leishmaniasis isolates could have any of five patterns, diffuse cutaneous leishmaniasis showed only two patterns and pseudodiffuse cutaneous leishmaniasis consistently showed only one pattern. Thus, a clear correlation among digestion pattern, clinical disease, and geographical localization was obtained for the pseudodiffuse cutaneous leishmaniasis group. Additionally, the L. mexicana mexicana isolates could be differentiated into fast- and slow-growing groups. Diffuse cutaneous leishmaniasis isolates were found to be fast growing, whereas localized cutaneous leishmaniasis isolates fell into both categories. In contrast, all pseudo diffuse cutaneous leishmaniasis isolates were slow growing. Here we report the first study in which distinct and persistent genotypic characteristics of kinetoplast DNA heterogeneity within the L. mexicana mexicana species could be directly correlated with clinical disease and its growth behavior, suggesting that a distinctive restriction pattern could have important biological implications. Additionally, this study sheds new light on the biological significance of parasite kinetoplast DNA, since the heterogeneity seems not to be random but to form a distinct pattern.

Lectin-binding properties of different Leishmania species

Carbohydrate cell-surface residues on stationary promastigotes of 19 isolates of Leishmania were studied with a panel of 27 highly purified lectins, which were specific for N-acetyl-D-glucosamine, D-mannose, L-fucose, D-galactose, N-acetyl-D-galactosamine, and sialic acid. The specificity of the cell-surface carbohydrates was analyzed by agglutination and radioiodinated lectin-binding assays. L. (L.) amazonensis and L. (L.) donovani were agglutinated by 12 and 10 of the 27 lectins used, respectively. Artocarpus integrifolia lectin (Jacalin) was incapable of agglutinating the tested species of the donovani complex, and this result was confirmed by radioiodinated Jacalin-binding assays. Jacalin had an average of 3.8 x 10(6) receptors/L. (L) amazonensis promastigote and bound with an association constant of 5 x 10(6) M(-1).

Identification of Mexican Leishmania species by analysis of PCR amplified DNA

Leishmania parasites isolated into culture from patients with LCL or DCL from four different Mexican states were characterised using polymerase chain reaction (PCR), hybridisation with specific probes, and isoenzymes. PCR of the parasites showed that 10 of 11 of those isolates were members of the mexicana complex. This was confirmed in seven cases by isoenzymes. Restriction enzyme digests of PCR products of Mexican isolates showed the isolates to be different from the L.(L.) mexicana reference strain BEL21. Two (C2 and AM) of the isolates were shown to be a possible mixed infection between mexicana and braziliensis complex members. With a second set of samples from different patients from Campeche state, PCR of 14 biopsies indicated the presence of braziliensis complex members in six of the samples. The results showed that most of our isolates of Leishmania which come from the states of Tabasco and Veracruz are members of the Leishmania mexicana complex, but they seem to be different from the L.(L.) mexicana BEL21 reference strain. By hybridisation most of the biopsies (seven out of 14) from Campeche belong to the L. braziliensis complex and two out of 14 to L. mexicana complex and three out of 14 hybridised with both complexes, and two biopsies were negative. In Campeche, which is very close to Tabasco state and has border with Guatemala, we found members of the L. mexicana and L. braziliensis complexes.

A new focus of cutaneous leishmaniasis due to Leishmania amazonensis in a Sub Andean region of Bolivia

We detected a new outbreak focus with high incidence of cutaneous leishmaniasis in the Sub Andean region of La Paz. This area was never considered previously as an endemic zone of leishmaniasis. Leishmania stocks from human lesions were isolated: three stocks were explored by pulse field gradient electrophoresis, showing evidence for their affiliation to the L. mexicana complex. Eight stocks were submitted to isoenzyme electrophoresis and compared with five reference strains: L. amazonensis, L. braziliensis, L. chagasi, L. mexicana and L. pifanoi. Close genetic proximity was evidenced between newly isolated parasites and the reference stock of L. amazonensis, whereas high divergence was observed between them and either the L. pifanoi, L. mexicana, L. braziliensis and L. chagasi reference strains.

Isoenzyme characterization of Leishmania isolated from human cases with localized cutaneous leishmaniasis from the State of Campeche, Yucatan Peninsula, Mexico

Seventy-five isolates from the State of Campeche, Mexico, an area endemic for localized cutaneous leishmaniasis (LCL), were characterized by isoenzyme markers (glucose phosphate isomerase, mannose phospate isomerase, nucleoside hydrolase, phosphoglucomutase, 6-phosphogluconate dehydrogenase, and glucose-6-phosphate dehydrogenase). Seventy (93.3%) were identified as Leishmania (Leishmania) mexicana and 5 (6.7%) as L. (Viannia) braziliensis. This is the first report of authochthonus human LCL caused by L. (V.) braziliensis in the State of Campeche, Yucatan Peninsula, Mexico.

Coexistence of two species of Leishmania in the digestive tract of the vector Lutzomyia ovallesi

Leishmania isolated from the digestive tract of a naturally infected Lutzomyia ovallesi sand fly were cultured in blood agar for rapid growth, cloning, and subsequent identification through schizodeme analysis, dot-blot hybridization, use of monoclonal antibodies with various specificities and absorbed polyclonal antibodies. Twenty-three clones isolated from the primary culture were identified. The results showed that parasites belonging to some clones corresponded to the L. mexicana complex, while others belonged to the L. braziliensis complex. These results clearly establish the coexistence of two Leishmania species in the digestive tract of a single Lu. ovallesi sand fly.

Diagnosis of cutaneous leishmaniasis and species discrimination of parasites by PCR and hybridization

The aim of this study was to assess the efficacy of PCR methodology in establishing the diagnosis of cutaneous leishmaniasis in patients from areas of endemicity in Venezuela. Biopsies from 233 patients with cutaneous ulcers suggestive of leishmaniasis were analyzed by PCR, employing oligonucleotides directed against conserved regions of kinetoplast DNA (kDNA), and the PCR products were then hybridized to nonradioactively labeled, species-specific, cloned kDNA fragments. The ability of PCR to detect Leishmania cells was compared with those of the conventional methodologies: skin testing with killed promastigotes (Montenegro test), examination of Giemsa-stained biopsy smears, and in vitro culture of biopsy tissue. The PCR-hybridization technique detected the presence of Leishmania cells in 98% of patients clinically diagnosed as having leishmaniasis and also positive by the Montenegro skin test. In comparison, leishmania positivity was found in only 42% of cultures and 64% of biopsy smears. By hybridizing the PCR product to new kDNA probes specific for either Leishmania mexicana or Leishmania braziliensis, we found that both species are major causes of cutaneous leishmaniasis in Venezuela, and the species identification was confirmed by restriction enzyme analysis of kDNA from biopsy cultures. This work demonstrates that PCR coupled with hybridization is useful not only for the diagnosis of cutaneous leishmaniasis but also for the taxonomic discrimination essential for both epidemiology and therapy. This technique can be used to diagnose leishmaniasis in a country in which the disease is endemic and can perhaps be adapted for use in a rural clinic.

Molecular karyotype characterization of Leishmania panamensis, Leishmania mexicana, and Leishmania major-like parasites: agents of cutaneous leishmaniasis in Ecuador

Molecular karyotypes of Leishmania isolates from patients with cutaneous leishmaniasis in Ecuador were analyzed by pulsed-field gel electrophoresis (PFGE) and Southern blot hybridization. The DNA karyotypes of L. major-like parasites were similar between two human isolates from a lowland coastal and a highland Andean region, but were apparently different from those of eleven World Health Organization reference strains including L. major. The smallest chromosome of 240 kilobases in L. major-like parasites was found to belong to the 715-class of small linear chromosomal DNAs, which have been shown to appear in some lines of Leishmania. Chromosome banding patterns of L. mexicana isolates exhibited a novel, ordered, chromosomal ladder, and were identical among four human isolates and one canine isolate from a restricted geographic region in the Andes. On the other hand, minor chromosome size polymorphisms were observed among three L. panamensis isolates from different endemic regions near the Pacific Coast. Chromosomal locations of dihydrofolate reductase-thymidylate synthetase and P-glycoprotein genes revealed further differences in chromosomal organizations among these Leishmania species in Ecuador. These results indicate that karyotype analysis by PFGE is useful for epidemiologic studies of leishmaniasis in Ecuador.

Molecular analysis of the cytosolic and glycosomal glyceraldehyde-3-phosphate dehydrogenase in Leishmania mexicana

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity was detected in two cell compartments of Leishmania mexicana promastigotes. These activities could be attributed to two different isoenzymes, one residing in glycosomes, the other in the cytosol. We have cloned and sequenced the genes for both isoenzymes. The glycosomal enzyme is encoded by two tandemly linked genes of identical sequence and contains features frequently found in glycosomal enzymes: the presence of peptide insertions, a small carboxy-terminal extension with a potential glycosomal targeting signal (-SKM) and an excess of positively charged residues (net charge +7). Only one open reading frame was detected for the cytosolic enzyme. The amino acid sequences of the two proteins are only 55% identical. We discuss some evolutionary aspects of the observed organization of the GAPDH genes in the Trypanosomatidae and the role of the two isoenzymes in the metabolism of these organisms. The possibility to develop GAPDH-specific inhibitors that will be effective against the enzyme of various parasitic members of this family is explored.

18S rRNA sequences of Leishmania enriettii promastigote and amastigote

Dideoxy sequencing with reverse transcriptase and universal primers was used to obtain partial sequences of the 18S rRNAs from the promastigote and amastigote life-cycle stages of L. enriettii. Approximately 1400 nucleotides of sequence from the two stages were compared. Unlike Plasmodium berghei, in which 18S rRNAs from the mosquito stage and the mammalian stage of the life cycle are only 96.5% similar, the amastigote and promastigote rRNAs of L. enriettii are identical. In addition, a comparison of 1425 bases of the L. enriettii promastigote sequence with the published sequence of L. donovani revealed only four differences; the two sequences are 99.8% similar. A likely explanation for this high similarity, considering the 97% similarity between L. donovani and the related genus Crithidia fasciculata, is that the two species are closely related and of comparatively recent origin. The low diversity between the 18S rRNA sequences of Leishmania species is similar to that reported for 13 Tetrahymena species, where similarities ranged from 98.1 to 99.9%, but different from the pattern reported in the genus Naegleria, where divergence was greater.

Characterization and classification of leishmanial parasites from humans, wild mammals, and sand flies in the Amazon region of Brazil

Ninety-four leishmanial isolates from the Brazilian Amazon Region (Amapá, Amazonas, Pará, and Rondônia) were identified and classified using specific monoclonal antibodies and an indirect radioimmunoassay (serodeme analysis); eighty-two were also characterized by enzyme electrophoresis (zymodeme analysis), the results of which were subjected to a numerical phenetic analysis. Six isolates from humans (3), Didelphis marsupialis (1), Lutzomyia olmeca nociva (1), and Lu, reducta (1) showed reactivity patterns and isoenzyme profiles similar to those obtained with the Leishmania amazonensis reference strains, and were identified as this species. Eighty-six stocks were classified as members of the L. braziliensis complex; of these, 61 were L. guyanensis or variants, which presented three serodeme subtypes, but whose isoenzyme profiles were all similar to the reference strain. A total of 15 isolates were distinguished as L. braziliensis or variants and were classified into five serodeme subtypes. The isolate from Psychodopugus davisi appeared, from the numerical analysis, to be a distinct parasite species. Ten isolates showed reactivity patterns and isoenzyme profiles similar to those obtained with the L. naiffi reference strain. A parasite isolated from Ps. claustrei appeared to be different from all reference strains by both techniques, and was classified as probably being a new species. The importance of these results with respect to the taxonomic status of the New World Leishmania, and their implications for both clinical and epidemiologic data are discussed.

Andean leishmaniasis in Ecuador caused by infection with Leishmania mexicana and L. major-like parasites

Between 1986 and 1988, epidemiologic studies were carried out in a small rural community in an Andean region of Ecuador, where cutaneous leishmaniasis is highly endemic. A total of 25 human cases, positive for Leishmania parasites by culture and/or smear, were examined. Fourteen of the cases were in infants less than one year of age, suggesting intradomiciliary transmission of the disease. Clinically, many of these cases were similar to descriptions of "uta," a form of cutaneous leishmaniasis which occurs in Andean regions of Peru and is reported caused by L. peruviana. Of the 11 positive cultures obtained from human cases in the present study, eight were identified by molecular characterization as L. mexicana and three were identified as L. major-like. Two additional isolates of L. mexicana were also made from an infected dog and from a sand fly, Lutzomyia ayacuchensis, living in the region, thus implicating the latter species as possible reservoir and vector, respectively, of L. mexicana in this highland community. The significance and validity of recent isolates of L. major-like parasites from the New World are also discussed.

Isolation of Leishmania mexicana from Neotoma micropus collected in Texas

A female Neotoma micropus infected with Leishmania was collected in Zavala County, Texas, on 15 January 1990. The infection was limited to lesions at the bases of the ears, and the parasite grew readily in Schneider's Drosophila medium supplemented with 20% fetal bovine serum. Isozyme analysis determined the parasite to be Leishmania mexicana.

Human cutaneous leishmaniasis in Ecuador: identification of parasites by enzyme electrophoresis

Twenty-six strains of Leishmania were isolated from cutaneous lesions in humans in 3 different geographical areas of Ecuador. The species were identified by enzyme electrophoresis as Leishmania braziliensis, L. panamensis, L. guyanensis, L. mexicana, and L. amazonensis.

Isoenzyme characterization of 112 Leishmania isolates from French Guiana

112 Leishmania isolates, obtained in French Guiana from human lesions, phlebotomine sandflies and wild mammals, were characterized by isoenzyme electrophoresis. Leishmania braziliensis guyanensis and L. mexicana amazonensis were found parasitizing different natural hosts. L.b. guyanensis was the dominant species (103 isolates) responsible for most of the human lesions (96.7%). Based on variations observed in 2 enzymes, 3 distinct zymodemes were distinguished within the L.b. guyanensis taxon.

Study of Leishmania mexicana electrokaryotype by clamped homogeneous electric field electrophoresis

In spite of the wide use of electrokaryotypes for Leishmania identification, the number, ploidy and associated functions of the chromosomal bands still remain controversial topics. In the present work, we studied these problems in the pathogenic organism Leishmania mexicana using the clamped homogeneous electric field electrophoresis (CHEF) technique, which allows the separation of uniform chromosomal bands in one run. We arrived at the following general conclusions: (i) a comparative densitometric study using haploid Saccharomyces cerevisiae cells as standard reveals that although L. mexicana is an aneuploid organism, its larger bands are diploid; (ii) a total of 18 chromosomal bands ranging from 3.2 to 0.245 Mbp were resolved. These molecules summed to 1.34 X 10(8) bp, a value within the range of the Leishmania genome; (iii) in hybridisation experiments using different housekeeping gene probes, the majority hybridised with chromosomal band 17 or 18 of L. mexicana, with additional locations for some genes; (iv) the presence of the ubiquitous leishmanial (CA/GT)n sequence in the DNA probes could lead to erroneous gene localisation.

Identification and distribution of New World Leishmania species characterized by serodeme analysis using monoclonal antibodies

Five hundred thirty stocks of Leishmania isolated from human and domestic and wild reservoir hosts, representing a wide geographic distribution of endemic foci of American cutaneous (ACL) and visceral leishmaniases (AVL) were characterized and identified at species and/or subspecies levels based on their reactivity to a cross-panel of specific monoclonal antibodies using a radioimmune binding assay. This study confirms and extends our preliminary results on the high specificity of some of these monoclonals for the L. braziliensis, L. mexicana, and L. donovani complexes. This study also demonstrates the relative stability of these molecular markers and the general usefulness of the method for parasite identification. Two hundred ninety-two of 420 isolates of ACL were classified as members of the L. braziliensis complex. Two hundred twenty-seven were L. b. braziliensis; these showed the widest geographical distribution (Brazil: Amazonas, Bahia, Ceara, Espirito Santo, Goias, Minas Gerais, Para, Paraiba, Rio de Janeiro, and Sao Paulo; Honduras: Santa Barbara and Yoko; Peru: Ancash, Piura, and Ucayali; and Venezuela: Cojedes, Distrito Federal, Lara, Portuguesa, Vale Hondo, Yaracuy, and Zulia). Forty-one stocks were identified as L. b. guyanensis (from North Brazil: Amazonas, Amapa, Para, and Rondonia). Twenty-one stocks were identified as L. b. panamensis (from Costa Rica: Alajuela, Guanacasten, Limon, Puntarenas, and San Jose; and Honduras: El Paraiso, and Olancho). Out of 128 isolates classified as members of the L. mexicana complex, 74 were differentiated as L. m. amazonensis (from Bolivia; Brazil: Amazonas, Bahia, Ceara, Goias, Maranhao, Mato Grosso do Norte, and Para; Peru: Pasco Forest and Van Humboldt; and Venezuela: Carabobo, Guarico, and Merida). Forty-four stocks were identified as L. m. venezuelensis (from Venezuela: Lara). Six stocks were L. m. mexicana (from Belize; and Mexico: Campeche [corrected] and Quintana Roo, Yucatan). One hundred ten isolates from AVL were identified as L. donovani chagasi (from Brazil: Bahia, Ceara, Maranhao, Minas Gerais, Mato Grosso do Sul, Piaui, Rio de Janeiro, and Sergipe; and Honduras: Valle). The implications of these results with respect to both the clinical and epidemiological data (including the detection of seven unusual characterized stocks) are discussed.

The ribosomal gene spacer as a tool for the taxonomy of Leishmania

A recombinant DNA ribosomal gene spacer of Leishmania braziliensis Y was used as probe to test different Leishmania species. Based on the similarity of their restriction patterns, three groups were distinguished with respect to international Leishmania references: first a group with a similar restriction pattern to L. braziliensis Y and the reference organism L. mexicana garnhami JAP78; a second group with restriction patterns similar to the reference organism L. mexicana mexicana M379; and finally a group where all the restriction patterns were related to the reference organism L. braziliensis braziliensis M2903. These results support the existence of L. garnhami as an independent Leishmania species; they confirm previous studies on L. mexicana and L. braziliensis and open the way for the more exact diagnosis of New World Leishmaniasis.

Molecular karyotype of species and subspecies of Leishmania

The DNA karyotypes of three species and several subspecies of New World Leishmania were found to be distinct. The karyotypes were more similar among closely related isolates than among more distantly related groups. Two classes of chromosomal DNA differences were detected among stocks; +/- 50 kb size differences among DNAs, some of which were shown to contain homologous sequences, and DNAs having no obvious corresponding chromosomal DNA in other isolates. A total of 14-24 chromosomal DNA bands were resolved, depending on the isolate, but densitometric analyses suggest that these isolates contain 26-33 distinct DNA molecules. These molecules total about 2.5 X 10(7) bp, a substantial fraction of the genomic DNA. The chromosomal DNA locations of gene sequences homologous to alpha- and beta-tubulin, ribosomal RNA, thymidylate synthetase-dihydrofolate reductase, and the H-region sequence were determined. The homologous sequences were located on chromosomal DNAs of similar, but not identical sizes among different stocks. We also found species- and some subspecies-specific beta-tubulin chromosomal loci. We conclude that the DNA karyotype is useful for stock identification, taxonomy, and gene localization in Leishmania. Its potential for identifying the species and subspecies in natural infections appears less useful unless applied in conjunction with specific hybridization probes.

Isolation of Leishmania mexicana amazonensis from the bone marrow in a case of American visceral leishmaniasis

The first documented human case of visceral leishmaniasis caused by L. mexicana amazonensis is reported. Leishmania were isolated from bone marrow aspirate material from a typical visceral leishmaniasis patient. Further characterization by isoenzyme electrophoresis and by a panel of species- and subspecies-specific monoclonal antibodies established its classification as L. m. amazonensis.

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.

Subcellular and taxonomic specificity of monoclonal antibodies to New World Leishmania

Murine monoclonal antibodies to flagellar, surface membrane and cytoplasmic antigens of New World Leishmania were assessed for their taxonomic specificity in enzyme-linked immunosorbent assays with three genera of the family Trypanosomatidae and three species and seven subspecies of the genus Leishmania. Antibodies exhibiting exclusive reactivity with either the flagellum, flagellar pocket, kinetoplast, or nucleus lacked specificity at all phylogenetic levels and, in fact, recognized epitopes common to cultured mammalian cells. Monoclonals to intracellular antigens were capable of distinguishing Leishmania from Trypanosoma and Endotrypanum. Antibodies reactive at the surface membrane could separate six isolates of L. braziliensis from three isolates of L. mexicana but the differences in antigen expression were frequently quantitative rather than qualitative. Antigenic variability within species and/or subspecies often exceeded that which was observed between species and/or subspecies. At least one monoclonal antibody was specific for a surface antigen peculiar to a subpopulation of promastigotes of an L. braziliensis panamensis isolate.

Flagellate infections of Brazilian sand flies (Diptera: Psychodidae): isolation in vitro and biochemical identification of Endotrypanum and Leishmania

Flagellate infections were found in 1,063 of 18,895 sand flies collected in the states of Amazonas, Pará, Rondonia and Acre, Brazil. Infection rates were 13.4% (species group Shannoni); 7.5% (subgenus Nyssomyia); 6.7% (subgenus Lutzomyia series Cruciata); 0.5% (genus Psychodopygus) and 3.1% for other sand flies (various subgenera). Leishmania braziliensis guyanensis and L. mexicana amazonensis were isolated, respectively, from the known vectors, Lutzomyia umbratilis and L. flaviscutellata. Single stocks of L. braziliensis-like and L. mexicana-like organisms were isolated, respectively, from L. whitmani and L. yuilli. Thirty-eight flagellate stocks, isolated by direct culture from sand flies were characterized in detail by morphology in culture, behavior in hamsters and mice and by enzyme profiles. Sixteen stocks from Lutzomyia sp. (Shannoni group) were identified as Endotrypanum schaudinni; 8 stocks from Lutzomyia sp. (Shannoni group) were identified as Endotrypanum sp.; 7 stocks from Psychodopygus ayrozai and P. paraensis were identified as Leishmania sp. previously isolated from the armadillo, Dasypus novemcinctus; 2 stocks of Trypanosoma rangeli were isolated from recently fed Lutzomyia sp. (Shannoni group) sand flies; the remaining 5 stocks from L. umbratilis and L. yuilli could not be identified. Observations suggested that Shannoni group sand flies were the natural vectors of Endotrypanum. Leishmania sp. infections in the man-biting flies P. ayrozai and P. paraensis were restricted to the midgut and associated with recent bloodmeals. Unidentified flagellates in L. umbratilis and L. yuilli were distributed throughout the digestive tract with no trace of bloodmeals.