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An Overview of Parasite Diversity
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Members of the kingdom Animalia (animals, or metazoans) are unique among the world’s organisms for the development in most of integrated nervous and muscular systems that give them unprecedented mobility and responsiveness to environmental circumstances. Animals are multicellular heterotrophs that usually acquire their energy from ingestion of organic compounds (phagotrophy), although several parasitic groups acquire nutrients by absorption across their body walls. Many of the world’s most familiar and medically significant parasites are found among animals. Parasitism has arisen independently on several occasions with estimates ranging from 60 to over 223 occasions, in both major and minor lineages, but especially in the Arthropoda, the largest phylum by far in the animal kingdom. Some lineages of animals are exclusively parasitic, some have a mixture of free-living and parasitic species, and some as best we know are without parasitic representatives (Figure 2.18).
Epidemiology, Disease Transmission, Prevention, and Control
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
In common medical usage not all pathogenic organisms are called parasites. Generally bacteria, viruses, fungi, rickettsia, and chlamydia are not referred to as parasites. The organisms commonly called parasites by people in the medical profession are protozoa and metazoa. To the biologist, however, all of the pathogenic organisms are considered parasites. The protozoa are unicellular organisms that produce, among other diseases, malaria, amoebiasis, giardiasis, leishmaniasis, and trypanosomiasis. The metazoa are multicellular parasites that produce diseases such as trichinosis, schistosomiasis, and ascariasis. The metazoa usually infect their hosts after a stage of free-living development in either soil or water.
Animal Source Foods
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Food products of animal origin occupy the second place after plant foods within the human diet domain. Animals including humans are classified under the Kingdom Animalia, also called Metazoa (1–4). Over a million to 1.5 million species of animal have been described until now on this planet (1, 3).
Effects of anti-aging interventions on intestinal microbiota
Published in Gut Microbes, 2021
Yanjiao Du, Yue Gao, Bo Zeng, Xiaolan Fan, Deying Yang, Mingyao Yang
The intestine is a critical target organ for improving the health of aged animals and humans.8 The intestinal tract harbors an extremely complex and diverse community of microorganisms known as the gut microbiota. The gut microbiota influences the long-term homeostasis of metazoans by maintaining epithelial integrity in the intestinal tract, supporting digestion, training the intestinal immune system, and preventing the growth of pathogenic bacteria.9 Abnormal shifts in the gut microbiota are associated with age-related chronic diseases. The gut microbiome is becoming a key factor in the aging process.10 Therefore, we speculate that the gut microbiota could be a new anti-aging target. In this review, we will focus on nongenetic interventions, discuss the changes in and beneficial effects of the gut microbiota under various anti-aging approaches and explore the interactions between anti-aging interventions and the gut microbiota (Figure 1).
CRISPR/Cas: from adaptive immune system in prokaryotes to therapeutic weapon against immune-related diseases
Published in International Reviews of Immunology, 2020
Juan Esteban Garcia-Robledo, María Claudia Barrera, Gabriel J. Tobón
All organisms are part of the three main branches of the tree of life, bacteria, archaea (prokaryotes), and eukaryotes, that split from a common Last Universal Common Ancestor (LUCA) [2, 15]. Multicellular eukaryotes comprising most of kingdom Animalia emerged approximately 600 million years ago during the metazoan age [16]. These metazoan organisms branched rapidly along different lineages, and about 500 million years ago multiple lineages emerged [16]. Even simple life forms such as prokaryotes and single-celled eukaryotes possess heritable innate immune mechanisms [17]. Alternatively, adaptive immune systems able to provide protection based on previous exposure to foreign invaders was thought to first appear with the rise of jawed vertebrates (a metazoan lineage) [16, 18]. The adaptive immune system is based on cellular and humoral components (T cells and B lymphocytes, respectively) expressing antigen-recognizing receptors. These receptors are formed by genetic recombination during cell fate determination and maturation, allowing for the creation of multiple cell clones expressing receptors specific for different epitopes of microorganisms [18, 19].
Highlights of human ectopic fascioliasis: a systematic review
Published in Infectious Diseases, 2019
Ali Taghipour, Leila Zaki, Ali Rostami, Masoud Foroutan, Fatemeh Ghaffarifar, Atefeh Fathi, Amir Abdoli
A total of five EFs were reported from skin and subcutaneous tissues. Cutaneous and sub-cutaneous ectopic migration was reported from three and two patients, respectively [7,10,34–36]. All the cases were reported from Asian countries (between 1987 and 1995). The demographic characteristics of all patients are shown in the Supplementary Table 1. Three out of five cases had a history of consuming raw vegetables. The risk factors in two other cases have not been reported (Supplementary Table 1). In most of the patients, fever, gastrointestinal disorders, cutaneous nodules in the chest and epigastric regions were main reported symptoms. Since the gastrointestinal pain was mostly in the right upper quadrant and localized to one part of the liver, they were suspected of gallbladder disease or liver abscess or hydatid cyst. Diagnosis of the ectopic migration was made according to the clinical symptoms. The majority of EF cases were diagnosed using histopathological examination of the nodules. Skin nodules revealed granulomatous reactions, Charcot–Leyden crystals, and also a section of a metazoan parasite. The final diagnosis was an immature Fasciola spp. Indeed, two out of five patients had healed following common anti-parasitic therapy, but the situation in three other cases has not been reported in the literature (Supplementary Table 1).