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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 -
Advances in Parasitology 2023Data on human gastrointestinal parasites (GIP) infections in the african sub-regions and countries are mainly lacking in terms of prevalence and population... (Review)
Review
Data on human gastrointestinal parasites (GIP) infections in the african sub-regions and countries are mainly lacking in terms of prevalence and population stratification by afflicted age group, symptomatology, multi-parasitism, and diagnostic methods. This study aims to describe the GIP reported in african countries and discuss the extent of the burden in the african context. Only 68.42% (39/57) of african countries reported human cases of GIP with helminths (45%, CI: 40-50%, I: 99.79%) as the predominant parasitic group infecting the african population. On a regional scale, Central Africa had the highest pooled prevalence for GIP (43%, CI: 32-54%, I: 99.74%), while the Central African Republic led all countries with a pooled prevalence of 90% (CI: 89-92%, I: 99.96%). The vulnerable population (patients who are minorities, children, old, poor, underfunded, or have particular medical conditions) was the most affected (50%, CI: 37-62%, I: 99.33%), with the predominance of GIP in the 6 to <20 years age group (48%, CI: 43-54%, I: 99.68%). Reports on multi-parasitism (44%, CI: 40-48%, I: 99.73%) were almost double the reports of single infections (43%, CI: 27-59%, I: 99.77%) with combined molecular and non-molecular techniques demonstrating the best performance for GIP identification. The current review spans more than 40 years of GIP reports from the african continent. Geographical characteristics, environmental factors, habits of its inhabitants, and their health status play a crucial role in GIP modulation and behaviour in its captive hosts. Strategies for regular and enhanced surveillance, policy formation, and high-level community awareness are necessary to identify the true incidence in Africa and the transmission of the pathogens via water and food.
Topics: Child; Animals; Humans; Parasites; Intestinal Diseases, Parasitic; Helminths; Africa; Prevalence; Feces
PubMed: 36707173
DOI: 10.1016/bs.apar.2022.10.001 -
Current Protein & Peptide Science 2024Lectins are proteins widely distributed among plants, animals and microorganisms that have the ability to recognize and interact with specific carbohydrates. They have... (Review)
Review
Lectins are proteins widely distributed among plants, animals and microorganisms that have the ability to recognize and interact with specific carbohydrates. They have varied biological activities, such as the inhibition of the progression of infections caused by fungi, bacteria, viruses and protozoa, which is related to the interaction of these proteins with the carbohydrates present in the cell walls of these microorganisms. Leishmaniasis are a group of endemic infectious diseases caused by protozoa of the genus and tests with promastigotes and amastigotes of demonstrated that lectins have the ability to interact with glycoconjugates present on the cell surface of the parasite, it prevents their development through various mechanisms of action, such as the production of ROS and alteration of membrane integrity, and can also interact with defense cells present in the human body, thus showing that these molecules can be considered alternative pharmacological targets for the treatment of leishmaniasis. The objective of the present work is to carry out a bibliographic review on lectins with leishmanicidal activity, emphasizing the advances and perspectives of research in this theme. Through the analysis of the selected studies, we were able to conclude that lectins have great potential for inhibiting the development of leishmaniasis. However, there are still few studies on this subject.
Topics: Leishmania; Humans; Lectins; Leishmaniasis; Animals; Antiprotozoal Agents; Reactive Oxygen Species
PubMed: 38284715
DOI: 10.2174/0113892037275751231221053730 -
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 -
The Journal of Parasitology Dec 2023Rectal contents of 56 adult bobcats (Lynx rufus) in 2014 and 2017 from remote areas of Mississippi were examined microscopically for parasite stages after the sugar... (Review)
Review
Rectal contents of 56 adult bobcats (Lynx rufus) in 2014 and 2017 from remote areas of Mississippi were examined microscopically for parasite stages after the sugar flotation method. Among the helminths, eggs/larvae found were: Paragonimus sp. in 12, Toxocara cati-like in 16, trichurid-capillarid-like in 3, hookworms in 27, and lungworms in 28. Among the protozoa, oocysts/cysts found were: Cystoisospora felis-like in 2, Cystoisospora rivolta-like in 4, Cryptosporidium sp. in 1, and Giardia sp. in 1. Additionally, numerous Sarcocystis sporocysts were detected in the feces of 12 bobcats; sporocysts were described morphologically. The status of C. felis derived from the bobcat and other wild felids is reviewed and compared with C. felis from the domestic cat. It is the first record of C. rivolta from the bobcat. The presence of eggs of Paragonimus sp. and T. cati in feces of 21.4% and 28.5%, respectively, suggests a role for the bobcat in the dissemination of these zoonotic helminths in the environment in the wild. Taxonomy of coccidia of wild Felidae is discussed and Isospora lyncisLevine and Ivens, 1981 from the Lynx is now regarded as a species inquirenda.
Topics: Animals; Cat Diseases; Cryptosporidiosis; Cryptosporidium; Feces; Isospora; Lynx; Mississippi; Oocysts; Sarcocystidae; Sarcocystis
PubMed: 38151049
DOI: 10.1645/23-95 -
MBio Feb 2023Parasite infections affect human and animal health significantly and contribute to a major burden on the global economy. Parasitic protozoan viruses (PPVs) affect the... (Review)
Review
Parasite infections affect human and animal health significantly and contribute to a major burden on the global economy. Parasitic protozoan viruses (PPVs) affect the protozoan parasites' morphology, phenotypes, pathogenicity, and growth rates. This discovery provides an opportunity to develop a novel preventive and therapeutic strategy for parasitic protozoan diseases (PPDs). Currently, there is greater awareness regarding PPVs; however, knowledge of viruses and their associations with host diseases remains limited. Parasite-host interactions become more complex owing to PPVs; however, few studies have investigated underlying viral regulatory mechanisms in parasites. In this study, we reviewed relevant studies to identify studies that investigated PPV development and life cycles, the triangular association between viruses, parasites, and hosts, and the effects of viruses on protozoan pathogenicity. This study highlights that viruses can alter parasite biology, and viral infection of parasites may exacerbate the adverse effects of virus-containing parasites on hosts or reduce parasite virulence. PPVs should be considered in the prevention of parasitic epidemics and outbreaks, although their effects on the host and the complexity of the triangular association between PPVs, protozoans, and hosts remain unclear. PPVs-based regulation of parasitic protozoa can provide a theoretical basis and direction for PPD prevention and control, although PPVs and PPV regulatory mechanisms remain unclear. In this review, we investigated the differences between PPVs and the unique properties of each virus regarding virus discovery, structures, and life cycles, focused on the Trichomonas vaginalis virus, Giardia lamblia virus, RNA virus, and the Cryptosporidium parvum virus 1. The triangular association between PPVs, parasitic protozoa, and hosts reveals the "double-edged sword" property of PPVs, which maintains a balance between parasitic protozoa and hosts in both positive and negative respects. These studies discuss the complexity of parasitic protozoa and their co-existence with hosts and suggest novel pathways for using PPVs as tools to gain a deeper understanding of protozoal infection and treatment.
Topics: Animals; Humans; Parasites; Cryptosporidiosis; Cryptosporidium; Viruses; Protozoan Infections; RNA Viruses
PubMed: 36633419
DOI: 10.1128/mbio.02642-22 -
Veterinary Research Communications Dec 2023Leishmania is a genus of parasitic protozoa that causes a disease called leishmaniasis. Leishmaniasis is transmitted to humans through the bites of infected female... (Review)
Review
Leishmania is a genus of parasitic protozoa that causes a disease called leishmaniasis. Leishmaniasis is transmitted to humans through the bites of infected female sandflies. There are several different species of Leishmania that can cause various forms of the disease, and the symptoms can range from mild to severe, depending on species of Leishmania involved and the immune response of the host. Leishmania parasites have a variety of reservoirs, including humans, domestic animals, horses, rodents, wild animals, birds, and reptiles. Leishmaniasis is endemic of 90 countries, mainly in South American, East and West Africa, Mediterranean region, Indian subcontinent, and Central Asia. In recent years, cases have been detected in other countries, and it is already an infection present throughout the world. The increase in temperatures due to climate change makes it possible for sandflies to appear in countries with traditionally colder regions, and the easy movement of people and animals today, facilitate the appearance of Leishmania species in new countries. These data mean that leishmaniasis will probably become an emerging zoonosis and a public health problem in the coming years, which we must consider controlling it from a One Health point of view. This review summarizes the prevalence of Leishmania spp. around the world and the current knowledge regarding the animals that could be reservoirs of the parasite.
Topics: Humans; Female; Animals; Horses; Leishmaniasis; Zoonoses; Leishmania; Psychodidae; Rodentia; Horse Diseases
PubMed: 37438495
DOI: 10.1007/s11259-023-10171-5 -
Virchows Archiv : An International... Feb 2022Organic (such as parasites or vegetable remnants) and inorganic substances may be encountered during routine pathology diagnostic work up of endoscopic gastrointestinal... (Review)
Review
Organic (such as parasites or vegetable remnants) and inorganic substances may be encountered during routine pathology diagnostic work up of endoscopic gastrointestinal biopsy samples and major resections, causing possible diagnostic conundrums for the young and not so young pathologists. The main aim of this review is the description of the most frequent oddities one can encounter as foreign bodies, in gastrointestinal pathology, on the basis of the current literature and personal experience. The types of encountered substances are divided into four principal categories: parasites (helminths such as Enterobius vermicularis, Strongyloides, Schistosoma, and Anisakis, and protozoa such as Entamoeba, Giardia and some intestinal coccidia); drugs and pharmaceutical fillers (found as deposits and as bystanders, innocent or not); seeds (possibly confused with worms) and plant remnants; pollutants (secondary to post-resection or post-biopsy contamination of the sample). An ample library of images is provided in order to consent easy referencing for diagnostic routine.
Topics: Animals; Enterobius; Giardia; Giardiasis; Humans; Intestinal Diseases, Parasitic
PubMed: 34599376
DOI: 10.1007/s00428-021-03188-1 -
Expert Opinion on Therapeutic Targets Sep 2020Introduction Cryptosporidium species are protozoan parasites that are important causes of diarrheal disease including waterborne outbreaks, childhood diarrhea in... (Review)
Review
Introduction Cryptosporidium species are protozoan parasites that are important causes of diarrheal disease including waterborne outbreaks, childhood diarrhea in resource-poor countries, and diarrhea in compromised hosts worldwide. Recent studies highlight the importance of cryptosporidiosis in childhood diarrhea, malnutrition, and death in resource-poor countries. Despite this, only a single drug, nitazoxanide, has demonstrated efficacy in human cryptosporidiosis and its efficacy is limited in malnourished children and patients with HIV. Areas covered In this review, we highlight work on potential targets for chemotherapy and review progress on drug development. A number of new targets have been identified for chemotherapy and progress has been made at developing drugs for these targets. Targets include parasite kinases, nucleic acid synthesis and processing, proteases, and lipid metabolism. Other groups have performed high-throughput screening to identify potential drugs. Several compounds have advanced to large animal studies. Expert opinion Development of drugs for cryptosporidiosis has been plagued by a lack of success. Barriers have included poor correlations between in vitro activity and clinical success as well as frequent unanticipated adverse effects. Without a clear pathway forward, it is wise to maintain a diverse development pipeline. Drug developers should also realize that success will likely require a sustained, methodical effort.
Topics: Animals; Antiprotozoal Agents; Child; Child Nutrition Disorders; Cryptosporidiosis; Diarrhea; Drug Development; HIV Infections; High-Throughput Screening Assays; Humans; Molecular Targeted Therapy
PubMed: 32552166
DOI: 10.1080/14728222.2020.1785432 -
PLoS Neglected Tropical Diseases Aug 2021Protozoan parasites are responsible for severe disease and suffering in humans worldwide. Apart from disease transmission via insect vectors and contaminated soil, food,... (Review)
Review
Protozoan parasites are responsible for severe disease and suffering in humans worldwide. Apart from disease transmission via insect vectors and contaminated soil, food, or water, transmission may occur congenitally or by way of blood transfusion and organ transplantation. Several recent outbreaks associated with fresh produce and potable water emphasize the need for vigilance and monitoring of protozoan parasites that cause severe disease in humans globally. Apart from the tropical parasite Plasmodium spp., other protozoa causing debilitating and fatal diseases such as Trypanosoma spp. and Naegleria fowleri need to be studied in more detail. Climate change and socioeconomic issues such as migration continue to be major drivers for the spread of these neglected tropical diseases beyond endemic zones. Due to the complex life cycles of protozoa involving multiple hosts, vectors, and stringent growth conditions, studying these parasites has been challenging. While in vivo models may provide insights into host-parasite interaction, the ethical aspects of laboratory animal use and the challenge of ready availability of parasite life stages underline the need for in vitro models as valid alternatives for culturing and maintaining protozoan parasites. To our knowledge, this review is the first of its kind to highlight available in vitro models for protozoa causing highly infectious diseases. In recent years, several research efforts using new technologies such as 3D organoid and spheroid systems for protozoan parasites have been introduced that provide valuable tools to advance complex culturing models and offer new opportunities toward the advancement of parasite in vitro studies. In vitro models aid scientists and healthcare providers in gaining insights into parasite infection biology, ultimately enabling the use of novel strategies for preventing and treating these diseases.
Topics: Animals; Host-Parasite Interactions; Humans; Life Cycle Stages; Parasitic Diseases; Parasitology; Plasmodium; Trypanosoma
PubMed: 34437538
DOI: 10.1371/journal.pntd.0009668