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An Introduction to Parasitism
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
More complex examples are known in which a host insect such as the pea aphid Acyrthosiphon pisum can harbor a nested set of parasites. Within the aphid is a larva of the parasitoid wasp, Aphidius smithi. This larva can in turn be infected by the larva of another parasitoid wasp, Alloxysta victrix (Figure 1.9). This hyperparasite can be colonized by larvae of a “hyper-hyperparasite,” Asaphes californicus, yet another parasitoid wasp. Given that A. californicus likely harbors a bacterium in its gut that might itself support a bacteriophage infection, a single aphid might conceivably support five nested levels of parasitism. Note the use of the term “parasitoid.” A parasitoid is an organism that spends a significant amount of its life on or within a single host, often sterilizing it, often killing it and sometimes fully consuming it in the process. It then leaves the host and often has a free-living period of existence. As discussed later, parasitoids have many of the properties we associate with parasites but are often more detrimental to their hosts.
Population and Community: Count Variables
Published in Song S. Qian, Mark R. DuFour, Ibrahim Alameddine, Bayesian Applications in Environmental and Ecological Studies with R and Stan, 2023
Song S. Qian, Mark R. DuFour, Ibrahim Alameddine
We explore the multinomial response variable model through three examples. The first example is developed based on a study of insect oviposition behavior in evolutionary ecology. The data for this example includes observed number of eggs laid by a species of wasp. This species of wasp is an insect parasitoid, which lays eggs in or on the eggs, larvae, pupae, or adults of other insects. The number of eggs they laid in each host is known as the clutch size. Some parasitoids are used for biological control of insect pests in orchards and other agricultural settings. On the one hand, the number of eggs laid in a host can affect the survival and fitness of the offspring. The ecological hypothesis is that the clutch size is evolved to produce the maximum number of offspring from each host that are fit to further propagate the population. Too many eggs will lead to competition among offspring for the limited resource (reducing the fitness of offspring), too few eggs constitutes a waste of the resource. On the other hand, the number of eggs a parasitoid lays in a single host can be affected by other factors. It takes time and effort for a parasitoid to find a host and then locate suitable spots on the host to lay eggs. Laying too few eggs would cost the parasitoid time and energy. Hilborn and Mangel [1997] used data from an observational study of a number of wasps to learn whether the clutch size is also a function of numbers of eggs each insect carried (egg complements).
Lipid-Based Nanocarriers for the Treatment of Infected Skin Lesions
Published in Andreia Ascenso, Sandra Simões, Helena Ribeiro, Carrier-Mediated Dermal Delivery, 2017
Sandra Simöes, Manuela Carvalheiro, Maria Manuela Gaspar
A parasite is an organism that grows, feeds, and is sheltered from or at the expense of its host. Some parasites do not affect the host while others make the host sick resulting in a parasitic infection [20].
Assessment of genotoxic and pathologic potentials of fipronil insecticide in Labeo rohita (Hamilton, 1822)
Published in Toxin Reviews, 2021
Abdul Ghaffar, Riaz Hussain, Ghulam Abbas, Rahela Khan, Kashfa Akram, Hina Latif, Saman Ali, Sidra Baig, Xiaoxia Du, Ahrar Khan
Pesticides are extensively used in agriculture to control pests and in veterinary practice to remove the parasitic infestation. In the Indo-Pak region, farmers use pesticides on their food crops usually without following the guidelines of the company/manufacturer. This irrational and frequent use of such dangerous kind of chemicals causes the contamination/pollution of the environment and the adjoining water sources, causing damage to both the human health and the environment (Zaluski et al. 2015, Qureshi et al. 2016). In the present study, different behavioral abnormalities in treated fish, such as loss of coordination, increased opercular movement, swimming area, and mucus secretion, body imbalance, and tremors of fins, were all the very noticeable signs of fipronil toxicity. Previously, no reports were available about the behavioral and nervous effects of fipronil on the freshwater fish Labeo rohita. However, similar behavioral and nervous abnormalities due to fipronil pollution were reported in Nile tilapia (Oreochromis niloticus) (El-Murr et al. 2015). Moreover, it was also reported that fipronil causes blockage of GABA-regulated chloride channels and ultimately induces the behavioral and nervous changes in exposed species (Nwani et al. 2013, El-Murr et al. 2015). The nervous signs in fish caused by fipronil usually appear as a result of the targeting of γ-aminobutyric acid receptors (Pandey et al. 2011).
Diagnostic and management strategies of ocular cysticercosis: current perspectives
Published in Expert Review of Ophthalmology, 2020
Cystercosis is a cestode infection that is an important problem in tropical medicine [1–3]. This is a form of Taenia species infection. The human cysticercosis is an accidental dead ended infection caused by pork tapeworm (Taenia solium). The disease is caused by larval cysts of the tapeworm. The two main ways that the patients can acquire this infection are ingestion of tapeworm eggs through a fecal-oral transmission or autoinfection. Basically, human is a definitive host for adult parasite and pig plays role as an intermediate hosts harboring parasitic larva. Accidentally, human might act as an intermediate host and result in cysticercosis. The heteroinfection due to intake of contaminated food or water with the parasitic eggs, external autoinfection by ingestion ova of the existing parasite or internal autoinfection by retrograde peristalsis that pushes proglottids bearing eggs from intestine directly to stomach are the three ways that a human might become an intermediate host and further develops cysticercosis. The disease is strongly related to poor hygiene and common in areas with poor background sanitation.
Nanoparticles for antiparasitic drug delivery
Published in Drug Delivery, 2019
Yuzhu Sun, Dongmei Chen, Yuanhu Pan, Wei Qu, Haihong Hao, Xu Wang, Zhenli Liu, Shuyu Xie
Chemical antiparasitic drugs are mainly used for controlling parasitic diseases. They are critical in animal husbandry development and animal health safety, but most antiparasitic drugs have low bioavailability due to their insolubility and their short half-life. Therefore, the treatment of parasitic diseases needs frequent dosage for a long-time because of the long-life cycles of parasites. The repeated treatment might cause animal stress, big labor intensity of farmer and drug resistance (Vercruysse et al., 2007). For example, praziquantel is hardly soluble in aqueous solution and its bioavailability is poor regarding its natural metabolism in the liver and rapid elimination from the body. The repeated high doses for a long time are required in the treatment of cestode infection and thus might result in dizziness, tiredness, nausea, and hangover sense.