Diagnosing Parasitic Infections
Firza Alexander Gronthoud in Practical Clinical Microbiology and Infectious Diseases, 2020
Parasites can be classified as protozoa, helminths (worms) and ectoparasites. Protozoa are unicellular organisms and can be broadly divided into intestinal and luminal protozoa such as Giardia lamblia, Cryptosporidium spp. and blood- and tissue-dwelling protozoa such as malaria, Leishmania, Trypanosoma cruzi (Chagas) and Trypanosoma brucei (African sleeping sickness). Helminths are multicellular organisms and are associated with intestinal infections or tissue infections. They can be divided into nematodes (Ascaris spp., Strongyloides stercoralis and hook worm), trematodes or flukes (Schistosoma spp., Fasciola hepatica, Paragonimus westermani) and cestodes (Taenia spp. and Hymenolepis nana). Ectoparasites are also multicellular organisms that infest the skin and feed on it. Examples of ectoparasites are scabies, myiasis, tungiasis, fleas and lice.
Beneficial Use of Viruses
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2015
Parasites have remarkably diverse modes of existence and can be classified by where they live, how they live, what they do to the host, how they are transmitted, and their size. Ectoparasites live on the external surface of their hosts, whereas endoparasites reside in the host’s body. Castrators cause total or near-total disruption of their hosts’ reproductive activities. Body snatchers take over their host, often including its behavior. Trophically-transmitted parasites are passed to their next host after ingestion by an initial host. Obligatory parasites require a suitable host to complete their life cycle; most parasites are obligate parasites. Facultative parasites are typically free-living, but they can adopt a parasitic existence. Opportunistic parasites take advantage of particular circumstances to cause infection in a host that they normally do not infect or in which they normally do not cause disease. Hyperparasites exploit other parasites. Microparasites are small and have rapid generation times as compared to their hosts and as it is difficult to quantify the number of microparasites within a host, their numbers are assessed by mathematical models. Macroparasites are larger parasites, such as worms, ticks, or fleas, and can be counted. A parasitoid is an organism that spends a significant amount of time attached to or within a single host (often sterilizing, killing, or consuming it) and after leaving the host often has a free-living period of existence.
An Introduction to Parasitism
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2023
Parasites have remarkably diverse modes of existence and can be classified by where they live, how they live, what they do to the host, how they are transmitted and their size. Ectoparasites live on the external surface of their hosts, whereas endoparasites reside in the host’s body. Within their hosts, some parasites live intracellularly and some are found in extracellular habitats like the gut or blood. Trophically transmitted parasites are passed to their next host after ingestion by an initial host. Obligatory parasites require a suitable host to complete their life cycle; most parasites are obligate parasites. Facultative parasites are typically free-living, but they can adopt a parasitic existence. Opportunistic parasites take advantage of particular circumstances to cause infection in a host that they normally do not infect or in which they normally do not cause disease. Hyperparasites exploit other parasites. Microparasites are small and have rapid generation times as compared to their hosts and as it is difficult to quantify the number of microparasites within a host, their numbers are assessed by mathematical models. Macroparasites are larger parasites, such as worms, ticks, or fleas and can be counted. A parasitoid is an organism that spends a significant amount of time attached to or within a single host (often sterilizing, killing, or consuming it) and after leaving the host often has a free-living period of existence.
Non‐pharmaceutical treatment options for meibomian gland dysfunction
Published in Clinical and Experimental Optometry, 2020
Lid hygiene is also thought to be important because of the association of Demodex mites with MGD.2018 Long‐term practice of lid hygiene is necessary in individuals with Demodex infestation as it is a chronic condition that requires chronic therapy. Demodex folliculorum and Demodex brevis are thought to be the most common ectoparasites in humans. In the eye, D. folliculorum is found preferentially in the lash follicles and D. brevis in lash sebaceous glands.1981 There is a strong association between ocular demodicosis and ocular surface inflammatory conditions such as blepharitis, chalazia, and keratitis as well as MGD.2019 The pathogenesis of Demodex infestation has remained unclear;2000 however, this is in part because demodicosis has a high age‐dependent prevalence and is present frequently in asymptomatic individuals.2010
Infectious diseases among Ethiopian immigrants in Israel: a descriptive literature review
Published in Pathogens and Global Health, 2021
Yulia Treister-Goltzman, Ali Alhoashle, Roni Peleg
Several cases of skin Leishmaniasis [4] and one case of severe, treatment-resistant visceral Leishmaniasis in an EI HIV patient was reported [70]. The positivity rate for Toxoplasma antibodies’ among EI from Operation Solomon (1991) was 34%. This rate was significant compared to native Israeli Jews (about 23%) and significantly lower than Arabs from the same geographical region (about 56%). The seroconversion rate was high in the age period of fertility (20–39 years) at 1% per year, which indicates a need for toxoplasma screening in pregnant women in this ethnic population [71]. Similarly, there was a very high rate of ectoparasites among EI at about 65% who suffered from head lice, with the highest rate among 6–11-year-old children, about 39% had body lice, about 10% had scabies mite, and about 4% had human flea [72].
The protective effect of chrysin against oxidative stress and organ toxicity in rats exposed to propetamphos
Published in Drug and Chemical Toxicology, 2022
Muhammet Yasin Tekeli, Latife Çakır Bayram, Gökhan Eraslan, Zeynep Soyer Sarıca
Propetamphos is a class II moderately toxic compound (EPA 2000, Gupta and Milatovic 2012). Propetamphos is a vinyl organophosphate insecticide, which is effective against a wide range of home pests, including cockroaches, flies, spiders and mosquitoes. It is also used against ectoparasites such as scabies mites, worm flies, ticks and lice (Dix et al. 1992, Garfitt et al. 2002). Similar to other organophosphate insecticides, propetamphos irreversibly inhibits the activity of acetyl cholinesterase, and thus, causes the accumulation of acetylcholine in neuromuscular junctions, postganglionic nerve endings in smooth muscles, and all autonomic ganglia and cholinergic synapses of the central nervous system (Gupta and Milatovic 2012, Milatovic 2017). Thereby, neurological and neuromuscular effects are observed. Clinical findings of intoxication, which are classified as muscarinic, nicotinic and central effects, are observed (Tang et al. 2006, Milatovic 2017).
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