Search results: Found 5

Listing 1 - 5 of 5
Sort by
Drug Development for Parasite-Induced Diarrheal Diseases

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452484 Year: Pages: 177 DOI: 10.3389/978-2-88945-248-4 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology
Added to DOAB on : 2018-02-27 16:16:44
License:

Loading...
Export citation

Choose an application

Abstract

One of the top four contributors to the global burden of disease is diarrheal infections. Intestinal parasites are major causes of morbidity and mortality associated with diarrheal diseases in both the developed and developing world. Amebiasis is responsible for 50 million cases of invasive disease and 70,000 deaths annually in the world. Giardiasis has an estimated worldwide prevalence of 280 million cases annually. In developed countries, Giardia lamblia infects about 2% of adults and 6-8% of children. The prevalence of G. lamblia infection is generally higher in developing countries, ranging from 3% to 90%. Furthermore, giardial infections contribute substantially to the 2.5 million annual deaths from diarrheal disease. In Asia, Africa, and Latin America, about 500,000 new giardiasis cases are reported each year. Cryptosporidium accounts for 20% and 9% of diarrheal episodes in children in developing and developed countries, respectively. Infection with Cryptosporidium can be chronic and especially debilitating in immunosuppressed individuals and malnourished children. A recent study to measure disease burden, based on disability-adjusted life years (DALYs), found that cryptosporidiosis and amebiasis produce about 10.6 million DALYs. This exceeds the DALYs of any helminth infection currently being targeted by the World Health Organization for preventive chemotherapy. Because of its link with poverty, Giardia and Cryptosporidium were included in the WHO Neglected Diseases Initiative in 2004. E. histolytica, G. lamblia, and C. parvum have been listed by the National Institutes of Health (NIH) as category B priority biodefense pathogens due to low infectious dose and potential for dissemination through compromised food and water supplies in the United States. Despite the prevalence of amebiasis, giardiasis, and cryptosporidiosis there are no vaccines or prophylactic drugs. The first-line drugs for invasive amebiasis and giardiasis chemotherapy are nitroimidazoles, with the prototype, metronidazole, being the most common drug used worldwide. Metronidazole has been shown to be both mutagenic in a microbiological system and carcinogenic to rodents, and frequently causes gastrointestinal side effects. In spite of the efficacy of nitroimidazole drugs, treatment failures in giardiasis occur in up to 20% of cases. Clinical resistance of G. lamblia to metronidazole is proven and cross resistance is a concern with all commonly used antigiardial drugs. Nitazoxanide, the only FDA-approved drug for the treatment of cryptosporidiosis, is effective in the treatment of immunocompetent patients and partially effective for immunosuppressed patients. Therefore, it is critical to search for more effective drugs to treat amebiasis, giardiasis, and cryptosporidiosis. This Research Topic for Frontiers in Microbiology will explore the recent progress in drug development for parasitic diarrheal diseases. This includes an understanding of drug resistance mechanisms. We would also welcome submissions on the drug development for other diarrheal parasites. We hope that this research topic will include a comprehensive survey of various attempts by the parasitology research community to create effective drugs for these diseases.

Interaction of Trypanosoma cruzi with Host Cells

Author:
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193370 Year: Pages: 97 DOI: 10.3389/978-2-88919-337-0 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology --- Science (General) --- Microbiology
Added to DOAB on : 2013-09-03 13:00:53
License:

Loading...
Export citation

Choose an application

Abstract

Trypanosoma cruzi is a pathogenic protozoan of the Trypanosomatidade Family, which is the etiological agent of Chagas’ disease. Chagas’ disease stands out for being endemic among countries in Latin America, affecting about 15 million people. Recently, Chagas has become remarkable in European countries as well due to cases of transmission via infected blood transfusion. An important factor that has exacerbated the epidemiological picture in Brazil, Colombia and Venezuela is infection after the oral intake of contaminated foods such as sugar cane, açai and bacaba juices. Trypanosoma cruzi is an intracellular protozoan that exhibits a complex life cycle, involving multiple developmental stages found in both vertebrate and invertebrate hosts. In vertebrate hosts, the trypomastigote form invades a large variety of nucleated cells using multiple mechanisms. The invasion process involves several steps: (a) attraction of the protozoan to interact with the host cell surface; (b) parasite-host cell recognition; (c) adhesion of the parasite to the host cell surface; (d) cell signalling events that culminate in the internalization of the parasite through endocytic processes; (e) biogenesis of a large vacuole where the parasite is initially located, and is also known as parasitophorous vacuole (PV); (f) participation of endocytic pathway components in the internalization process; (g) participation of cytoskeleton components in the internalization process; (h) transformation of the trypomastigote into the amastigote form within the PV; (i) lysis of the membrane of the PV; (j) multiplication of amastigotes within the host cell in direct contact with cell structures and organelles; (k) transformation of amastigotes into trypomastigotes, and (l) rupture of the host cell releasing trypomastigotes into the extracellular space. The kinetics of the interaction process and even the fate of the parasite within the cell vary according to the nature of the host cell and its state of immunological activation.

Bacterial pathogens in the non-clinical environment

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889195589 Year: Pages: 100 DOI: 10.3389/978-2-88919-558-9 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General)
Added to DOAB on : 2016-01-19 14:05:46
License:

Loading...
Export citation

Choose an application

Abstract

The transmission route used by many bacterial pathogens of clinical importance includes a step outside the host; thereafter refer to as the non-clinical environment (NCE). Obvious examples include foodborne and waterborne pathogens and also pathogens that are transmitted by hands or aerosols. In the NCE, pathogens have to cope with the presence of toxic compounds, sub-optimal temperature, starvation, presence of competitors and predators. Adaptation of bacterial pathogens to such stresses affects their interaction with the host. This Research Topic presents important concept to understand the life of bacterial pathogens in the NCE and provides the reader with an overview of the strategies used by bacterial pathogens to survive and replicate outside the host.

Parasite Infections: From Experimental Models to Natural Systems

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454853 Year: Pages: 294 DOI: 10.3389/978-2-88945-485-3 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Internal medicine
Added to DOAB on : 2019-01-23 14:53:42
License:

Loading...
Export citation

Choose an application

Abstract

Eukaryotic parasites (including parasitic protozoans, worms and arthropods) are more complex and heterogeneous organisms than pathogenic bacteria and viruses. This notion implies different evolutionary strategies of host exploitation. Typically, parasites establish long-term infections and induce relatively little mortality, as they often limit pathological changes by modulating host cells and downregulating adverse immune responses. Their pattern of distribution tends to be endemic rather than epidemic. Despite these seemingly benign traits, parasites usually cause substantial chronic morbidity, thus constituting an enormous socioeconomic burden in humans, particularly in resource poor countries, and in livestock worldwide. Parasite-induced fitness costs are an evolutionary force that can shape populations and contribute to species diversity. Therefore, a thorough understanding of parasites and parasitic diseases requires detailed knowledge of the respective biochemical, molecular and immunological aspects as well as of population genetics, epidemiology and ecology. This Research Topic (RT) bridges disciplines to connect molecular, immunological and wildlife aspects of parasitic infections. The RT puts emphases on four groups of parasites: Plasmodium, Toxoplasma, Giardia and intestinal helminths. Co-infections are also covered by the RT as they represent the most common form of parasite infections in wildlife and domestic animal populations. Within the four types of parasites the following topics are addressed: (1) Experimental models: hypothesis testing, translation and limits. (2) Critical appraisal of experimental models. (3) Natural systems: Technological advances for investigations in natural parasite-host systems and studies in natural systems. (4) The urgent need for better models and methods in natural parasite systems. Hence, the RT covers and illustrate by the means of four main parasitic infections the parasite-host system at the molecular, cellular and organismic level.

G-quadruplex and Microorganisms

Author:
ISBN: 9783039212439 / 9783039212446 Year: Pages: 208 DOI: 10.3390/books978-3-03921-244-6 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Internal medicine
Added to DOAB on : 2019-12-09 11:49:15
License:

Loading...
Export citation

Choose an application

Abstract

G-quadruplexes (G4s) are nucleic acids secondary structures that form in DNA or RNA guanine (G)-rich strands. In recent years, the presence of G4s in microorganisms has attracted increasing interest. In prokaryotes, G4 sequences have been reported in several human pathogens. Bacterial enzymes able to process G4s have been identified. In viruses, G4s have been suggested to be involved in key steps of the viral life cycle: They have been associated with the human immunodeficiency virus (HIV), herpes simplex virus 1 (HSV-1), human papilloma virus, swine pseudorabies virus, and other viruses’ genomes. New evidence shows the presence of G4s in parasitic protozoa, such as the causative agent of malaria. G4 binding proteins and mRNA G4s have been implicated in the regulation of microorganisms’ genome replication and translation. G4 ligands have been developed and tested both as tools to study the complexity of G4-mediated mechanisms in the viral life cycle and as therapeutic agents. Moreover, new techniques to study G4 folding and their interactions with proteins have been developed. This Special Issue will focus on G4s present in microorganisms, addressing all the above aspects.

Listing 1 - 5 of 5
Sort by
Narrow your search