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Parasites & Vectors Jan 2021Toxoplasma gondii is a protozoan parasite with a complex life cycle and a cosmopolitan host range. The asexual part of its life cycle can be perpetually sustained in a... (Review)
Review
Toxoplasma gondii is a protozoan parasite with a complex life cycle and a cosmopolitan host range. The asexual part of its life cycle can be perpetually sustained in a variety of intermediate hosts through a combination of carnivory and vertical transmission. However, T. gondii produces gametes only in felids after the predation of infected intermediate hosts. The parasite changes the behavior of its intermediate hosts by reducing their innate fear to cat odors and thereby plausibly increasing the probability that the definitive host will devour the infected host. Here, we provide a short description of such parasitic behavioral manipulation in laboratory rodents infected with T. gondii, along with a bird's eye view of underpinning biological changes in the host. We also summarize critical gaps and opportunities for future research in this exciting research area with broad implications in the transdisciplinary study of host-parasite relationships.
Topics: Animals; Behavior, Animal; Cats; Fear; Host-Parasite Interactions; Humans; Life Cycle Stages; Odorants; Rodentia; Toxoplasma; Toxoplasmosis, Animal
PubMed: 33494777
DOI: 10.1186/s13071-020-04528-x -
Philosophical Transactions of the Royal... Jul 2001A comprehensive literature review identifies 1415 species of infectious organism known to be pathogenic to humans, including 217 viruses and prions, 538 bacteria and...
A comprehensive literature review identifies 1415 species of infectious organism known to be pathogenic to humans, including 217 viruses and prions, 538 bacteria and rickettsia, 307 fungi, 66 protozoa and 287 helminths. Out of these, 868 (61%) are zoonotic, that is, they can be transmitted between humans and animals, and 175 pathogenic species are associated with diseases considered to be 'emerging'. We test the hypothesis that zoonotic pathogens are more likely to be associated with emerging diseases than non-emerging ones. Out of the emerging pathogens, 132 (75%) are zoonotic, and overall, zoonotic pathogens are twice as likely to be associated with emerging diseases than non-zoonotic pathogens. However, the result varies among taxa, with protozoa and viruses particularly likely to emerge, and helminths particularly unlikely to do so, irrespective of their zoonotic status. No association between transmission route and emergence was found. This study represents the first quantitative analysis identifying risk factors for human disease emergence.
Topics: Animals; Classification; Databases, Factual; Disease; Humans; Infections; Risk Factors; Zoonoses
PubMed: 11516376
DOI: 10.1098/rstb.2001.0888 -
Revue Scientifique Et Technique... Aug 2015Babesiosis is the disease caused by infection of the erythrocytes of mammals by Babesia species, which are Apicomplexa protozoa belonging to the suborder Piroplasmidea... (Review)
Review
Babesiosis is the disease caused by infection of the erythrocytes of mammals by Babesia species, which are Apicomplexa protozoa belonging to the suborder Piroplasmidea and the family Babesiidae. They are different from the Theileriidae, which can also infect white blood cells and endothelial cells. Babesiosis is one of the most important tick-borne infectious diseases of domestic and wild mammals and still poses significant diagnostic and therapeutic challenges for veterinary practitioners around the world. It is an increasing problem worldwide because of the expansion of tick habitats and the increased mobility of animals, which promote the spread of parasites into new geographical areas. Babesia species can, exceptionally, infect humans, especially splenectomised or immunocompromised individuals. The majority of human cases involve B. microti, a parasite of rodents, but human infections may also be caused by B. divergens, which infects cattle, or by Babesia related to B. odocoilei, which infect cervids. The majority of new developments, in regard to taxonomy, epidemiology, pathogenesis and control, concern canine babesiosis, whereas piroplasmosis in horses or cattle retains the classical description, therefore the focus of this article will be on infection in dogs.
Topics: Animals; Babesia; Babesiosis; Europe; Humans
PubMed: 26601462
DOI: 10.20506/rst.34.2.2385 -
Frontiers in Cellular and Infection... 2022Parasitic infections caused by protozoans that infect the mucosal surfaces are widely neglected worldwide. Collectively, spp. and infect more than a billion people in... (Review)
Review
Parasitic infections caused by protozoans that infect the mucosal surfaces are widely neglected worldwide. Collectively, spp. and infect more than a billion people in the world, being a public health problem mainly in developing countries. However, the exact incidence and prevalence data depend on the population examined. These parasites ultimately cause pathologies that culminate in liver abscesses, malabsorption syndrome, vaginitis, and urethritis, respectively. Despite this, the antimicrobial agents currently used to treat these diseases are limited and often associated with adverse side effects and refractory cases due to the development of resistant parasites. The paucity of drug treatments, absence of vaccines and increasing problems of drug resistance are major concerns for their control and eradication. Herein, potential candidates are reviewed with the overall aim of determining the knowledge gaps and suggest future perspectives for research. This review focuses on this public health problem and focuses on the progress of drug repositioning as a potential strategy for the treatment of mucosal parasites.
Topics: Animals; Cryptosporidiosis; Cryptosporidium; Entamoeba histolytica; Feces; Female; Giardia lamblia; Humans; Mucous Membrane; Parasites
PubMed: 35548465
DOI: 10.3389/fcimb.2022.860442 -
Nature Reviews. Microbiology Oct 2019Antimicrobial treatment failure threatens our ability to control infections. In addition to antimicrobial resistance, treatment failures are increasingly understood to... (Review)
Review
Antimicrobial treatment failure threatens our ability to control infections. In addition to antimicrobial resistance, treatment failures are increasingly understood to derive from cells that survive drug treatment without selection of genetically heritable mutations. Parasitic protozoa, such as Plasmodium species that cause malaria, Toxoplasma gondii and kinetoplastid protozoa, including Trypanosoma cruzi and Leishmania spp., cause millions of deaths globally. These organisms can evolve drug resistance and they also exhibit phenotypic diversity, including the formation of quiescent or dormant forms that contribute to the establishment of long-term infections that are refractory to drug treatment, which we refer to as 'persister-like cells'. In this Review, we discuss protozoan persister-like cells that have been linked to persistent infections and discuss their impact on therapeutic outcomes following drug treatment.
Topics: Antiprotozoal Agents; Biological Variation, Population; Chagas Disease; Drug Tolerance; Humans; Leishmania; Leishmaniasis; Malaria; Plasmodium; Toxoplasma; Toxoplasmosis; Treatment Failure; Trypanosoma cruzi
PubMed: 31444481
DOI: 10.1038/s41579-019-0238-x -
Developmental and Comparative Immunology Nov 2016Fish intestinal parasites cause direct mortalities and also morbidity, poor growth, higher susceptibility to opportunistic pathogens and lower resistance to stress. This... (Review)
Review
Fish intestinal parasites cause direct mortalities and also morbidity, poor growth, higher susceptibility to opportunistic pathogens and lower resistance to stress. This review is focused on microscopic parasites (Protozoa and Metazoa) that invade the gastrointestinal tract of fish. Intracellular parasites (mainly Microsporidia and Apicomplexa) evoke almost no host immune reaction while they are concealed in the cytoplasmic and nuclear compartments, and can even use fish cells (macrophages) as Trojan horses to spread in the host. Inflammatory reaction only appears when the parasite bursts infected cells. Immunity against extracellular parasites is depicted for the myxozoans Ceratonova shasta and Enteromyxum spp. The cellular and humoral innate responses and the production of antibodies are crucial for resolving some of these myxozoonoses, but an excessive inflammatory reaction (concerted by cytokines) can become a fatal pathophysiological consequence. The local immune response plays a key role, with numerous genes more strongly regulated in the intestine than at lymphohaematopoietic organs.
Topics: Animals; Apicomplexa; Fishes; Gastrointestinal Tract; Immune Evasion; Immunity, Innate; Inflammation; Microsporidia; Microsporidiosis; Myxozoa; Parasitic Diseases, Animal; Protozoan Infections
PubMed: 26828391
DOI: 10.1016/j.dci.2016.01.014 -
Clinical Microbiology and Infection :... Jan 2018
Topics: Aged; Diarrhea; Feces; Humans; Isospora; Isosporiasis; Male; Paraproteinemias
PubMed: 28712665
DOI: 10.1016/j.cmi.2017.07.009 -
Annals of Parasitology 2018Amoebas from the genus Acanthamoeba are cosmopolitan organisms, which can exist as free-living organisms and as parasites within host tissue. Acanthamoeba infection... (Review)
Review
Amoebas from the genus Acanthamoeba are cosmopolitan organisms, which can exist as free-living organisms and as parasites within host tissue. Acanthamoeba infection present a serious risk to human health and are characterized by high mortality, especially in immunocompromised individuals. These protozoa are the etiological factors of granulomatous amoebic encephalitis (GAE) and Acanthamoeba keratitis (AK). They can also live in the lungs, adrenals glands, nose, throat, and bones of the host. Furthermore, the amoebas can be vectors of pathogenic bacteria. Acanthamoeba infection caused is a serious clinical problem mainly due to limited progress in diagnostics and treatment of this infection, which is associated with insufficient knowledge of pathogenesis, pathophysiology and the host immune response against Acanthamoeba antigens. This review study presents the biology of Acanthamoeba sp. as well as pathogenicity, diagnostics, and treatment of amoebas infections. It also presents data, including experimental results, concerning pathogenic properties and the host’s immunology response against Acanthamoeba sp.
Topics: Acanthamoeba; Amebiasis; Humans; Immunocompromised Host
PubMed: 30720249
DOI: 10.17420/ap6404.164 -
Trends in Parasitology Aug 2020Reptiles are reservoirs of a wide range of pathogens, including many protozoa, helminths, pentastomids, and arthropod parasitic species, some of which may be of public... (Review)
Review
Reptiles are reservoirs of a wide range of pathogens, including many protozoa, helminths, pentastomids, and arthropod parasitic species, some of which may be of public health concern. In this review we discuss the zoonotic risks associated with human-reptile interactions. Increased urbanization and introduction of exotic species of reptile may act as drivers for the transmission of zoonotic parasites through the environment. In addition, being a part of human diet, reptiles can be a source of life-threatening parasitoses, such as pentastomiasis or sparganosis. Finally, reptiles kept as pets may represent a risk to owners given the possibility of parasites transmitted by direct contact or fecal contamination. Awareness of reptile-borne zoonotic parasitoses is important to advocate control, prevention, and surveillance of these neglected diseases.
Topics: Animals; Food Parasitology; Humans; Parasites; Parasitic Diseases; Pets; Reptiles; Zoonoses
PubMed: 32448703
DOI: 10.1016/j.pt.2020.04.014 -
Viruses Apr 2017Free-living amoebae (FLA) are parasites within both humans and animals causing a wide range of symptoms and act as hosts of, and vehicles for phylogenetically diverse... (Review)
Review
Free-living amoebae (FLA) are parasites within both humans and animals causing a wide range of symptoms and act as hosts of, and vehicles for phylogenetically diverse microorganisms, called endocytobionts. The interaction of the FLA with sympatric microorganisms leads to an exceptional diversity within FLA. Some of these bacteria, viruses, and even eukaryotes, can live and replicate intracellularly within the FLA. This relationship provides protection to the microorganisms from external interventions and a dispersal mechanism across various habitats. Among those intracellularly-replicating or -residing organisms there are obligate and facultative pathogenic microorganisms affecting the health of humans or animals and are therefore of interest to Public Health Authorities. Mimiviruses, Pandoraviruses, and Pithoviruses are examples for interesting viral endocytobionts within FLA. Future research is expected to reveal further endocytobionts within free-living amoebae and other protozoa through co-cultivation studies, genomic, transcriptomic, and proteomic analyses.
Topics: Amoeba; Animals; Disease Transmission, Infectious; Disease Vectors; Humans
PubMed: 28368313
DOI: 10.3390/v9040065