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The Parasite's Way of Life
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
G. lamblia is by no means unique in this regard. Stage-specific gene expression has been demonstrated for a wide range of protozoa. The apicomplexan Cryptosporidium parvum, for instance, is an epicellular parasite of the intestinal epithelium. Its life cycle consists of both an extracellular, invasive stage (the sporozoite) and intracellular stages (the merozoite or the gamont-see the Rogues’ gallery for details of the life cycle). This later stage is often referred to as epicellular rather than intracellular, as the parasite remains surrounded by host membrane material, which forms the parasitophorous vacuole. There are 3,774 known protein-encoding genes in its genome. Transcriptomic analysis has shown that 173 of these genes are upregulated during the sporozoite stage, with 1,259 upregulated during intracellular stages. In Leishmania major approximately 9% of whole-genome expression is altered as the parasite moves from sand fly vector to mammalian host.
History and Onset of the Epidemic
Published in Yamuna Deepani Siriwardana, Leishmaniasis in Sri Lanka, 2023
Diagnosis was confirmed by both microscopy and in vitro cultivation of the lesion material in both cases. Both were suspected to be imported cases which were supported by clinical evidence that was compatible with self-healing Leishmania major infections occurring in Nigeria and dry, chronic lesions of L. tropica occurring in urban Iraq.
Skin infections
Published in Rashmi Sarkar, Anupam Das, Sumit Sethi, Concise Dermatology, 2021
Shankila Mittal, Rashmi Sarkar
Cutaneous forms are found around the Mediterranean littoral and North Africa and in South America. The ‘Mediterranean’ type is caused by Leishmania major and L. tropica. After an incubation period of about 2 months, a boil-like lesion appears, usually on an exposed site (‘Baghdad boil’). Later, this breaks down to produce a sloughy ulcer (‘oriental sore’: Figure 3.19), which persists for some months before healing spontaneously, with scarring and the development of immunity.
Evaluation of the antileishmanial effect of polyclonal antibodies and cationic antimicrobial peptides
Published in Pathogens and Global Health, 2023
Mahsa Esmaeilifallah, Hossein Khanahmad, Zahra Ghayour, Sedighe Saberi, Reza Kalantari, Seyed Hossein Hejazi
The (MRHO/IR/75/ER) strain of Leishmania major is maintained in the Department of Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran, through cryopreserved vials in a nitrogen tank. After removing the vials containing frozen promastigotes, the parasites were transferred to a 37°C water bath for defrosting. The contents of the vials were then washed three times using sterile PBS and centrifugation. After washing and resuspension, a drop of it was observed under a light microscope to ensure that the parasites were alive; they were transferred to Novy–MacNeal–Nicolle medium and incubated at 24 ± 1°C. After three passages, they were run into RPMI 1640 medium (GlutaMAX Supplement, Gibco™, US), pH = 7.2, containing 10% (v/v) FBS (Tet system, Gibco™, UK), 100 IU/mL of penicillin, and 100 μg/mL of streptomycin. Sub-culturing was done every 3–4 days in complete fresh media to mass-produce promastigotes until further experimentation [16].
Use of genetically modified lactic acid bacteria and bifidobacteria as live delivery vectors for human and animal health
Published in Gut Microbes, 2022
Romina Levit, Naima G. Cortes-Perez, Alejandra de Moreno de Leblanc, Jade Loiseau, Anne Aucouturier, Philippe Langella, Jean Guy LeBlanc, Luis G. Bermúdez-Humarán
Leishmaniasis is a disease caused by more than 30 species of the Leishmania parasite and is transmitted by the female sandfly vector to humans.122 Different alternatives have been evaluated with the aim of developing a live oral vaccine for this human parasite. A strain of L. lactis co- expressing the protective Leishmania homologue of activated C kinase (LACK) and mouse IL-12 induced an antigen-specific mucosal immune response in protected mice.123 Another study used a GM strain of L. lactis to express the protein PpSP15 an immunogenic component of saliva from the sand fly Phlebotomus papatasi. The strain was evaluated to immunize mice and it was described the induction of a strong immune response with a long-term protection against Leishmania major.41
Vaccines against leishmaniasis: using controlled human infection models to accelerate development
Published in Expert Review of Vaccines, 2021
Vivak Parkash, Paul M. Kaye, Alison M Layton, Charles J Lacey
A long-standing practice for many centuries in Leishmania-endemic countries, particularly in the Middle East, was ‘leishmanization.’ This involves inoculation of parasites transferred from a person with an active cutaneous lesion, to an anatomical site where lesion development and scarring would be less stigmatizing such as the buttocks. The observation was made that healing of the lesion protected the recipient from further Leishmania infections throughout their lifetime [58]. Leishmanization proliferated in the mid to later part of the 20th century, notably involving service personnel involved in conflicts in hyperendemic areas of the Middle East. Approximately 2 million people underwent leishmanization in this setting, which included a number of refugees, and a significant reduction in new cases was observed [59]. After the cessation of the Iran–Iraq conflict, leishmanization was largely abandoned. Adverse effects included exacerbated localized reactions in comparison to the usual disease course of the inoculated species Leishmania major [60], and hypersensitivity [59]. Reliability and viability of the inoculated parasite also varied widely, although currently leishmanization still occurs sporadically in Uzbekistan [61].