Characterization of Leishmania spp. from Kuwait by isoenzyme electrophoresis

Leishmania infecting man and wild animals in Saudi Arabia. 9. The black rat (Rattus rattus) a probable reservoir of visceral leishmaniasis in Gizan province, south-west Saudi Arabia

Twenty-two black rats (Rattus rattus) were captured in houses where parasitologically confirmed cases of human visceral leishmaniasis had been recorded in Al-Arda Emara, Gizan province, south-west Saudi Arabia. Four of the rats were found to be infected with Leishmania; isoenzyme characterization showed that 3 were infected with L. donovani sensu lato zymodeme LON42 and the fourth with L. infantum zymodeme LON49. L. donovani s.l. LON42 has also been isolated from human visceral leishmaniasis patients living in this area, while dogs, but not humans, have been found to be infected with L. infantum LON49 in this part of Saudi Arabia.

DNA fingerprints: a tool for identification and determination of the relationships between species and strains of Leishmania

Using nonradioactive hybridization, the multilocal probes 33.15, F10 and (CAC)5 were shown to recognize multiple minisatellite regions in nuclear DNA of Leishmania, producing on Southern blots complex banding patterns typical of DNA fingerprints. We used the 33.15 probe to study 14 different strains belonging to 6 different species from both the sub-genus Viannia and the Leishmania mexicana complex of the sub-genus Leishmania. Distinct DNA fingerprints were obtained for each strain, permitting their identification. On the other hand, each strain showed little or no clonal variation. The information from the fingerprinting maps could be used for constructing phenograms and cladograms of the species and strains of Leishmania.

Biochemical characterization of Leishmania spp. isolated from man and wild animals in Kenya

Isoelectrofocusing in agarose was used to characterize Leishmania spp. isolated from a kala-azar patient, a lizard, genet cat and elephant shrew. Isoenzyme profiles of 12 enzymes and general protein patterns were examined. Both methods were found to be useful for distinguishing between the isolates. The wild animal Leishmania spp. were shown to be indistinguishable from a reference strain of L. major, but the isolate from man was distinctly different from L. donovani sensu stricto. The unique finding that the lizard isolate was similar to L. major and its significance are discussed in some detail. The use of the isoelectrofocusing technique for separation of enzymes and general proteins for characterization purposes is emphasized.

Characterization of Trypanosoma (Trypanozoon) evansi from dromedary camels in Kuwait by isoenzyme electrophoresis

Blood from 115 camels in Kuwait was examined for blood parasites. Two camels of a local herd (1.7%) were found to be infected with Trypanosoma (Trypanozoon) evansi and three camels (2.6%) with microfilarial nematodes. The Trypanosoma stocks isolated from these two camels were screened for isoenzyme patterns of 10 enzymes using thin-layer starch-gel electrophoresis. The results revealed that these two stocks were identical to camel stocks of T. evansi from certain countries in Africa, as well as to two stocks isolated from dogs in Kuwait. This is the first record of Trypanosoma (Trypanozoon) evansi isolates and microfilariae from camels in Kuwait.

Acid phosphatase isoenzyme mapping in Leishmania

The profiles of acid phosphatase isoenzymes of several well defined species of the genus Leishmania were compared. The profiles were generated after isoelectric focusing of parasite extracts in polyacrylamide and incubation of the gels with an appropriate substrate coupled to an azo dye. Analysis of the zymograms showed that there is species-specificity of the acid phosphatase isoenzyme maps in Leishmania. It was also demonstrated that different strains of the same species present identical pattern of enzyme activity. The method even enabled the differentiation of closely related species which were previously difficult to identify. Some technical aspects of the isoelectric focusing procedure are discussed. The method described here can be used as an aid for species identification of Leishmania.

Epidemiological studies on American leishmaniasis in Ceará State, Brazil. Molecular characterization of the Leishmania isolates

Two methods of molecular characterization, using monoclonal antibodies and enzyme electrophoresis, were employed in the identification of 36 stocks of Leishmania isolated from human and canine cases of American visceral (AVL) and cutaneous (ACL) leishmaniases in the northern part of Ceará State, Brazil. Molecular homogeneous strains of Leishmania donovani (chagasi) isolated from both human and canine hosts were detected in 14 municipalities. Two more parasite species, L. braziliensis braziliensis and L. mexicana amazonensis, were also detected in the state. The implication of these results with respect to both the clinical and epidemiological data are discussed.

Cutaneous leishmaniasis caused by Leishmania major in Baringo District, Kenya

Leishmania major was isolated from lesions of a patient suffering from cutaneous leishmaniasis in Baringo District of Kenya. Isoenzyme mobilities of this strain were compared with those of L. major, L. donovani, L. aethiopica and L. tropica reference strains and also L. major from a sand fly, Phlebotomus duboscqi, and a rodent, Arvicanthis niloticus, trapped in the same region. The patient's isolate had similar banding patterns to the L. major reference strain and also the rodent and the sand fly strains with the 9 enzymes examined. This is the first report in Kenya of an indigenous case with naturally acquired zoonotic cutaneous leishmaniasis.

Isoenzyme characterization of trypanosomes of the subgenus Herpetosoma

Isoenzyme analysis was used to characterize 6 species of trypanosomes of the subgenus Herpetosoma using 13 different enzyme systems. The species studied were Trypanosoma lewisi, T. musculi, T. grosi, T. microti, T. evotomys and T. nabiasi which cannot be distinguished on morphological grounds. Extracts for thin-layer starch-gel electrophoresis were prepared from cultures of insect forms in either Schneider's Drosophila or Grace's insect tissue culture media with foetal calf serum or a nutrient agar medium. Extracts of T. lewisi and T. musculi bloodstream forms were also run for comparison. All parasites gave distinct patterns which enabled them to be differentiated on one or more enzyme systems. Two types of computer analysis were used to group the parasites; using these techniques the murine parasites T. lewisi, T. musculi and T. grosi fell into one broad group, and T. microti and T. evotomys of microtine rodents formed another. These findings are in accord with earlier observations on the behavioural characteristics of these parasites in their mammalian host and their vector (fleas). The clear differences observed provide the basis for the application of other biochemical and immunological techniques for differentiation within this subgenus of trypanosomes.

Study of T cell subsets in patients with cutaneous leishmaniasis

The proportion of T lymphocyte populations was assessed using monoclonal antibodies (OKT3, OKT4, OKT8) and spontaneous E-rosette tests with SRBC (for total and active TE cells) in 36 patients with cutaneous leishmaniasis subdivided according to the clinical variety. The T cell profile was normal in patients with simple cutaneous leishmaniasis of early ulcerative type whereas active TE cells and OKT4 positive cells were reduced in some cases of late ulcerative type. A significant reduction of active TE cells and of OKT4 positive cells (helper/inducer phenotype) and increase of OKT8 positive cells (suppressor/cytotoxic phenotype) was observed in peripheral blood of all patients with persistent active lesions and leishmaniasis recidivans. In patients with highly ulcerated persistent lesions a low proportion of active TE cells was also demonstrated in cellular extracts from dermal tissue. The results support the data obtained in experimental leishmaniasis that lack of helper/inducer cells and generation of suppressor T cells may be responsible for the development of chronic leishmaniasis.

Leishmania in the Old World: 2. Heterogeneity among L. tropica zymodemes

Isoenzyme profiles of 27 stocks of Leishmania tropica from widely separated geographical areas were compared with those of reference strains of L. tropica and L. major using starch-gel electrophoresis of 13 enzymes (GPI, GD, ES, PGM, PEPD, NH, ASAT, ALAT, PK, MPI, 6PGD, SOD, MDH). 18 zymodemes were seen. L. tropica showed considerable intraspecific variation which did not correlate with its epidemiological uniformity. Isolates from cases of cutaneous and visceral leishmaniasis and leishmaniasis recidivans were identified as L. tropica. Only one isoenzyme band was held in common with the enzyme profile of the L. major reference strain thus supporting the status of L. tropica as a separate species.

Leishmania in the Old World: 5. Numerical analysis of isoenzyme data

Numerical analysis of 59 zymodemes of Old World Leishmania, based on the enzyme profiles of 280 stocks, revealed several distinct clusters. Some of these clusters corresponded with traditional taxonomic groupings: L. major, L. tropica, L. aethiopica and L. donovani sensu lato, but hitherto unrecognized groups were also indicated. The analysis provided an overview of the interrelationships between the Leishmania zymodemes.

Leishmania in the Old World: 1. The geographical and hostal distribution of L. major zymodemes

135 stocks of Leishmania major from man, reservoir hosts and sandflies were characterized using thin-layer starch-gel electrophoresis of 13 enzymes: MDH, 6PGD, GD, SOD, ASAT, ALAT, PK, PGM, ES, NH, PEPD, MPI, GPI. Homogeneity in this species was demonstrated by identical electrophoretic mobilities in nine enzymes. Polymorphism in four enzymes: 6PGD, GPI, PEPD, ES, gave six zymodemes among the collection. Stocks from sandflies and several species of burrowing rodents were indistinguishable from those from man in the same areas. Stocks of Leishmania from North-West India were identified as L. major. In some foci the distribution of zymodemes has some correlation with the presence of particular rodent reservoir hosts. The enzymic homogeneity of L. major throughout its geographical and host range appears to be correlated with the close association between L. major and sandflies of the subgenus Phlebotomus. The status of L. major as a distinct species is supported.

Leishmania in the Old World: 3. The distribution of L. aethiopica zymodemes

Isoenzyme profiles of 28 stocks of Leishmania aethiopica were compared with those of reference strains of L. aethiopica, L. tropica and L. major using starch-gel electrophoresis of 13 enzymes (GPI, GD, ES, PGM, PEPD, NH, ASAT, ALAT, PK, MPI, 6PGD, SOD, MDH). 13 zymodemes were seen. L. aethiopica showed some infraspecific variation. Stocks from Phlebotomus longipes and Procavia habessinica were indistinguishable from those from man. Stocks from cases of diffuse cutaneous and cutaneous leishmaniasis were indistinguishable. Only one enzyme pattern was held in common with the L. tropica reference strain enzyme profile, and none with the L. major reference strain. The status of L. aethiopica as a separate species is supported.

Leishmania infecting man and wild animals in Saudi Arabia. 1. General survey

Using up to 13 enzymes, biochemical characterization of 75 isolates of Leishmania made from man, wild animals and sandflies from a wide variety of localities in the Kingdom of Saudi Arabia has revealed the presence of L. major (two similar zymodemes), L. tropica (two zymodemes) and a parasite of the L. donovani-L. infantum complex. Zymodeme LON-4 of L. major has been found in 52 of 53 isolates so far characterized from man, from one specimen of Phlebotomus papatasi, from 15 Psammomys obesus, from one Meriones libycus and from one dog. One isolate from man has been identified as a new variant of L. major. This variant, zymodeme LON-65, varies from zymodeme LON-4 in a single enzyme. While this is the only example of zymodeme LON-65 identified so far, zymodeme LON-4 has also been obtained from Kuwait and Iraq. These are the first reports of L. major in Meriones libycus from Saudi Arabia and the first proven isolate from the dog in any country. L. tropica was identified from only two foci, whereas L. major appears to be widely distributed in the Kingdom. Two infants with kala-azar were found to be infected with a parasite apparently identical to zymodeme LON-42 of L. donovani (sensu lato) which also occurs in the highlands of Ethiopia.

Sexual processes in the kinetoplastida

The commonly held view that the kinetoplastida, and in particular trypanosomes, are asexual is largely derived from the principle that an organism is asexual until proved sexual. If the basis for this view is examined in detail, it largely arises from the lack of morphologically distinguishable gametes, the difficulties encountered in visualizing chromosomes and a few experiments, using drug-resistant stocks, in which no recombination between stocks could be demonstrated. While it is clear that these organisms are able to reproduce asexually, the existence of a sexual cycle was, until recently, an entirely open question. The early work strongly suggests that any sexual process (in the species examined extensively at the morphological level) does not involve classical well-differentiated gametes and so must involve fusion of morphologically very similar cells. These findings taken together with the inability to visualize chromosomes and thereby identify meiosis, mean that classical methods are unable to detect any sexual process even if it did occur. This review examines the evidence provided by the experimental approaches which have been applied recently to the question of kinetoplastid sexuality. These approaches include isoenzyme studies and the analysis of possible genetic exchange by the use of selective markers (e.g. drug resistance). The results which these techniques have produced make it clear that the kinetoplastid protozoans cannot be regarded as a totally asexual group of organisms.

The epidemiology of cutaneous leishmaniasis in Kuwait

Studies in Kuwait have suggested that sandflies feed on man and domestic animals, but not on rodents in different habitats. Of 1129 feral and wild rodents, none showed evidence of leishmanial infection nor did their incidental lesions resemble those produced by inoculating a human strain. Five out of 30 patients with lesions of cutaneous leishmaniasis claimed they had never been outside the country, but the validity of these claims is questioned. Cutaneous leishmaniasis in Kuwait is essentially an imported disease, with no substantial evidence that it is yet endemic.

Characterization of populations of promastigotes of Leishmania donovani

Promastigotes of Leishmania donovani cultured for either 3 or 10 days in vitro and inoculated intracardially into golden hamsters with an equal number of organisms from either population showed a 7-fold difference in infectivity when compared at both 10 and 16 days post-infection. Reproducible histochemical staining for the promastigote enzymes glucose-6-phosphate dehydrogenase (G6PDH) and peptidase after polyacrylamide gel electrophoresis showed two isoelectric variants of G6PDH (Bands 1 and 2) that displayed a 45% decrease (Band 1) and a 60% increase (Band 2) in total activity when 3- and 10-day-old promastigotes were compared. Peptidase activity, present in a single band, increased 7-fold in 10-day-old promastigotes. A decrease in the lectin-induced agglutination of promastigotes by castor bean agglutinin (RCA60), specific for D-galactose and N-acetyl-D-galactosamine, was seen when 3- and 10-day-old promastigotes are compared. Antisera raised against sonicated 10-day-old promastigotes showed a unique precipitin band between the antiserum and sonicated 10-day-old promastigotes not found between the antiserum and sonicated 3-day-old promastigotes.

Protist biogeography

Autecology (cellular organelles and secretions, encystment and dispersal abilities), environmental conditions (physiological tolerances and interaction with other organisms), and evolutionary history contribute to protist biogeography, which manifests ecological and historical aspects. Ecological biogeography is seen in the influence of geochemistry on the distribution of fresh-water phytoflagellates and algae, and of moisture and vegetation type on soil-litter protists. A temporal feature is often present because many protists encyst and respond only to certain ranges of temperature and organic content. Historical biogeography has occurred by radiative host evolution on symbiotic protozoa (e.g., termite flagellates and rumen ciliates), and by the isolating effects of water currents, temperature, and density gradients on oceanic protists (coccoliths, dinoflagellates, foraminifera, radiolaria, and tintinnines). These two aspects combine in protists living on animal surfaces. Humans affect protist biogeography by increasing parasite ranges through human migrations and by water pollution. They can diminish these situations by disease control and exploiting appropriate ciliates in sewage disposal. Many free-living protozoa appear to be cosmopolitan, but mating types and isoenzyme studies suggest that speciation with its geographic connotations may be more widespread than presently appreciated.

The electrophoretic mobilities and activities of eleven enzymes of bloodstream and culture forms of Trypanosoma brucei compared

Eleven soluble enzymes in the supernatant of bloodstream Trypanosoma brucei were compared for electrophoretic mobility and activity with those of T. brucei cultures grown in 3 different media. All bands of each enzyme found in the bloodstream form were also present in the cultured material, but extra bands of malate dehydrogenase (MDH) (EC 1.1.1.37), aspartate aminotransferase (ASAT) (EC 2.6.1.1), and in 2 to 6 cultures of isocitrate dehydrogenase (ICD) (EC 1.1.1.42) were present in culture forms but not in bloodstream forms. An interfering enzyme, peculiar to cultured T. brucei, which reacted with 2-oxoglutarate and possibly a trace amount of ammonium ions, ran with the fast-moving ASAT bands. Threonine dehydrogenase activity, high in cultured trypanosomes irrespective of the medium used but low in bloodstream trypanosomes, was markedly lower in Trypanosoma evansi and a much passaged T. brucei 8/18. Glucosephosphate isomerase activity on the other hand was high in bloodstream and low in cultured trypanosomes. Glutamate dehydrogenase activity was too low to record reliably in bloodstream trypanosomes, but could be clearly detected in cultured forms. As the differences point to some changes in gene expression between the two forms, culture material is likely to replace trypanosomes from living animals for electrophoretic characterization only when considerable comparative work has been done.

Morphologic and biochemical characterization of Crithidia brasiliensis sp. n

A trypanosomatid with a choanomastigote stage and, therefore, belonging to the genus Crithidia, was isolated in culture from the alimentary tract of the hemipteran genus Zelus. The trypanosomatid was able to grow at 37 C, a characteristic reported to date from only 2 other members of Crithidia, C hutneri and C. luciliae thermophila. Subsequently, the flagellate was cloned for biochemical studies which involved cleaving of kDNA by restriction endonucleases and analyses of the isoenzyme and histone patterns. In all the attributes revealed by the foregoing methods, the organism from Zelus differed from the latter 2 congeneric species. On these and morphologic grounds, this organism appears to belong in a new species for which the name Crithidia brasiliensis sp. n. is proposed.

Leishmaniasis in Tuscany (Italy): (II) Leishmania form wild Bodentia and Carnivora in a human and canine leishmaniasis focus

From April 1977 to February 1978, wild mammals were trapped in a focus of low leishmanial endemicity (Baccinello) in the Province of Grosseto (Tuscany, Italy). Spleen homogenates of the trapped animals were injected i.p. into hamsters, from which spleen biopsies were taken after 60 days and impression smears carefully observed for the presence of Leishmania. Positive spleens were subinoculated into hamsters. 404 animals of 12 species were trapped: 31 insectivores, 317 rodents and 56 carnivores. Black rats (Rattus rattus) and field mice (Apodemus sylvaticus) were the rodent species most frequently trapped--160 and 139 respectively--of which 143 and 134 respectively were tested in hamsters for Leishmania. 35 foxes (Vulpes vulpes) were caught, of which 16 were tested for Leishmania. Four hamsters were found infested with Leishmania. Three of them had been injected with spleen homogenates from R. rattus and one from V. vulpes although liver and spleen impression smears of all trapped animals were negative for Leishmania on direct microscopical examination. The significance of Leishmania infection in wild animals in the leishmanial focus of Baccinello 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.

Leishmania spp. in Iraq. Electrophoretic isoenzyme patterns. II. Cutaneous leishmaniasis

Leishmania organisms isolated from the sores of patients in Iraq suffering from cutaneous leishmaniasis were compared between themselves and with Leishmania major, L. tropica and L. donovani, all of which had been identified on clinical and geographical grounds. The comparisons were made by examination of the electrophoretic mobilities of seven soluble enzymes: malic enzyme E.C.1.1.1.40; glucose phosphate isomerase E.C.5.3.1.9; glucose-6-phosphate dehydrogenase E.C.1.1.1.49; phosphoglucomutase E.C.2.7.5.1; malate dehydrogenase E.C.1.1.1.37; aspartate aminotransferase E.C.2.6.1.1 and alanine aminotransferase E.C.2.6.1.2. following thin-layer starch-gel electrophoresis. The Iraqi isolations of Leishmania spp. from cutaneous lesions fell clearly into two groups, one of which gave isoenzyme patterns identical to those of a marker stock of L. major isolated in the USSR, and the other which gave patterns identical to those given by L. tropica also from the USSR. Previously it had been thought that L. tropica alone was responsible for cutaneous leishmaniasis in Iraq. The L. tropica and L. major isoenzyme patterns clearly differentiated these organisms from L. donovani.

Leishmania spp. in Iraq. Electrophoretic isoenzyme patterns. I. Visceral leishmaniasis

Leishmania donovani organisms isolated from 10 children coming from different districts in Iraq, were compared between themselves, with Leishmania donovani isolated in Iran and the Sudan, and with a Leishmania sp. isolated from the viscera of a rat caught in Baghdad. The comparison was made by examination of the electrophoretic mobilities of seven soluble enzymes: malic enzyme E.C.1.1.1.40; glucose phosphate isomerase E.C.5.3.1.9; glucose-6-phosphate dehydrogenase E.C.1.1.1.49; phosphoglucomutase E.C.2.7.5.1.; malate dehydrogenase E.C.1.1.1.37; aspartate aminotransferase E.C.2.6.1.1 and alanine aminotransferase E.C.2.6.1.2 following thin-layer starch-gel electrophoresis. The Iraqi isolations of L. donovani fell clearly into three groups. Group A contained the organisms from seven children, six from the Wasit district and one from the outskirts of Baghdad; Group B, the organism from one child from the Hilla district (100 km south of Baghdad) with severe visceral leishmaniasis which relapsed following chemotherapy; Group C, the organisms from two children from Suaira in the Wasit district. The Iranian and Sudanese isolations gave patterns different from each other and from those from Iran. The Leishmania sp. isolated from the viscera of the rat gave a pattern identical to that of L. tropica.

The primary isolation of Leishmania donovani from Iraq on different culture media

Leishmania donovani was isolated by culturing bone marrow aspirates from kala-azar patients, on three types of culture media. The isolation was successful in 88% of the cases. The effects of pH, D-glucose, L-proline and antibiotic concentration in the isolation were investigated. The semi-solid medium used (pH 7.4) with L-proline, was better than the modified NNN media for the primary isolation.

Identification of economically important parasites

The taxonomy of a parasite can be an important guide to its pathogenic characteristics. A wide range of anatomical, biochemical and behavioural tests is now being developed to define different strains and subspecies of the main tropical parasites.