"Included among the heteroxeneous trypanosomatids are species responsible for a broad spectrum of human and animal diseases, such as Trypanosoma cruzi and Leishmania sp., which are responsible for respectively Chagas disease , visceral and tegumentary leishmaniasis (Stuart et al., 2008). Although insect trypanosomatids are considered non-pathogenic to humans, several reports have shown that they can infect people , particularly those infected with human immunodeficiency virus (HIV), and the lesions may mimic diffuse cutaneous and visceral leishmaniasis (Chicharro and Alvar, 2003; Ghosh et al., 2012; Jiménez et al., 1996; Morio et al., 2008; Singh et al., 2013). "
[Show abstract][Hide abstract] ABSTRACT: We investigated whether ELISA using crude antigens from insect and plant trypanosomatids, which are non-pathogenic and easily cultivated in large scale, has the same positivity data as Leishmania (Leishmania) chagasi, the etiological agent of human visceral leishmaniasis (VL) or canine leishmaniasis (CanL), or as T. cruzi, the etiological agent of Chagas disease (CD). The antigens from Crithidia fasciculata, Crithidia luciliae, and Leptomonas seymouri showed 100% cross-reactivity with VL and CanL samples, with no statistically titers differences from L. (L.) chagasi, however, 34% (17/50) of VL samples revealed higher titers using the insect trypanosomatids than the homologous antigen. On the other hand, antigens from Strigomonas culicis, Angomonas deanei, and Phytomonas serpens showed low cross-reactivity with VL and CanL samples. The sera from patients with American tegumentary leishmaniasis showed low levels of cross-reactivity with all trypanosomatids investigated, even with L. (L) chagasi, without titers dissimilarity among them. These parasites were also worthless as antigen source for detection of CD cases, which required homologous antigens to reach 100% positivity. This study showed, by ELISA, that crude extract of Crithidia and Leptomonas have epitopes similar to L. (L.) chagasi, which supports the idea of using them as antigens source for the serodiagnosis of visceral leishmaniasis.
"In addition, due to increasing international travel and population migration Leishmania parasites are imported into other regions of the world, including areas non-endemic for the disease (Harms et al. 2003; Schönian et al. 2003; Johnston et al. 2009). Furthermore, the fact that lower trypanosomatids related to the monoxenous parasites of insects of the genera Leptomonas or Herpetomonas, have been identified as causative agents of VL in southern Europe (Jimenez et al. 1996), South America (Pacheco et al. 1998) and in the Indian subcontinent (Bhattarai et al. 2009) points to the need for species identification even in areas where, so far, only one species had been thought to cause the disease. The advantage of molecular approaches based on PCR or other amplification techniques is that they combine high sensitivity for direct detection of the infecting parasites in various human, animal and sand fly tissues, with species specificity. "
[Show abstract][Hide abstract] ABSTRACT: Molecular approaches are being used increasingly for epidemiological studies of visceral and cutaneous leishmaniases. Several molecular markers resolving genetic differences between Leishmania parasites at species and strain levels have been developed to address key epidemiological and population genetic questions. The current gold standard, multilocus enzyme typing (MLEE), needs cultured parasites and lacks discriminatory power. PCR assays identifying species directly with clinical samples have proven useful in numerous field studies. Multilocus sequence typing (MLST) is potentially the most powerful phylogenetic approach and will, most probably, replace MLEE in the future. Multilocus microsatellite typing (MLMT) is able to discriminate below the zymodeme level and seems to be the best candidate for becoming the gold standard for distinction of strains. Population genetic studies by MLMT revealed geographical and hierarchic population structure in L. tropica, L. major and the L. donovani complex. The existence of hybrids and gene flow between Leishmania populations suggests that sexual recombination is more frequent than previously thought. However, typing and analytical tools need to be further improved. Accessible databases should be created and sustained for integrating data obtained by different researchers. This would allow for global analyses and help to avoid biases in analyses due to small sample sizes.
"Additionally, trypanosomatids not normally infectious to humans (e.g. Herpetomonads and Leptomonads) are also emerging as pathogens in immunosuppressed patients, mainly in HIVinfected individuals, who develop a clinical pattern very similar to visceral and/or cutaneous leishmaniasis-like syndromes (McGhee & Cosgrove, 1980 ; Dedet et al. 1995 ; Jiménez et al. 1996 ; Pacheco et al. 1998 ; Boisseau-Garsaud et al. 2000 ; Dedet & Pratlong, 2000 ; Miller, 2000). These opportunistic trypanosomatids are morphologically indistinguishable from pathogenic ones, impairing their identification . "
[Show abstract][Hide abstract] ABSTRACT: The expression of proteolytic activities in the Trypanosomatidae family was explored as a potential marker to discriminate between the morphologically indistinguishable flagellates isolated from insects and plants. We have comparatively analysed the proteolytic profiles of 19 monoxenous trypanosomatids (Herpetomonas anglusteri, H. samuelpessoai, H. mariadeanei, H. roitmani, H. muscarum ingenoplastis, H. muscarum muscarum, H. megaseliae, H. dendoderi, Herpetomoas sp., Crithidia oncopelti, C. deanei, C. acanthocephali, C. harmosa, C. fasciculata, C. guilhermei, C. luciliae, Blastocrithidia culicis, Leptomonas samueli and Lept. seymouri) and 4 heteroxenous flagellates (Phytomonas serpens, P. mcgheei, Trypanosoma cruzi and Leishmania amazonensis) by in situ detection of enzyme activities on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE ) containing co-polymerized gelatine as substrate, in association with specific proteinase inhibitors. All 23 trypanosomatids expressed at least 1 acidic proteolytic enzyme. In addition, a characteristic and specific pattern of cell-associated metallo and/or cysteine proteinases was observed, except for the similar profiles detected in 2 Herpetomonas (H. anglusteri and H. samuelpessoai) and 3 Crithidia (C. fasciculata, C. guilhermei and C. luciliae) species. However, these flagellates released distinct secretory proteinase profiles into the extracellular medium. These findings strongly suggest that the association of cellular and secretory proteinase pattern could represent a useful marker to help trypanosomatid identification.
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