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The Challenge of Parasite Control
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
First, D. medinensis has an Achilles’ heel in its life cycle; Guinea worms are the only helminth parasite that is almost entirely dependent on the consumption of contaminated drinking water to achieve transmission to its definitive host. Furthermore, its transmission is highly focal. In an ironic twist, Guinea worm, a parasite with obligatory aquatic stages, does best under drought conditions. In arid Africa, where the parasite now makes its last stand, few or no new cases are seen during relatively wet years. But during a drought, as rivers and many water bodies dry up, both humans and copepods increasingly depend on the few isolated water sources that remain. All the elements necessary for increased transmission—humans (including those previously infected), intermediate hosts and water—converge. Copepods thrive in the warm water, and humans may have no other options when it comes to finding water for drinking, cooking and bathing. Consequently, control and eradication of Guinea worm can focus on preventing consumption of contaminated water. The strategies to do this in the case of D. medinensis are numerous, simple and often very cheap. A simple piece of muslin can be used to filter copepods out of drinking water and small handheld filters can be used to ensure that any water consumed is copepod-free. Treating water with Temephos, a chemical that kills copepods that is relatively safe for vertebrates, also can interrupt transmission.
Bacteria
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Cholera remains a major problem in Third World countries and in any area where water supplies are contaminated with domestic sewage. Incidence of the disease increased about 20-fold between 1938 and 1988. The disease is caused by Vibrio cholerae, a curved Gram-negative rod that adheres to the mucosa within four to six hours. The cholera toxin of especially virulent strains (V. cholerae 01 or 0139) is an A-B subunit toxin (see E. coli toxins, above) that stimulates adenylate cyclase production which increases intracellular levels of cAMP. in turn, cAMP initiates secretion of both water and ions from the gut epithelial cells. It is the loss of water and salt that causes the shock characteristic of the disease. Ten to fifteen percent of those infected may die. Treatment is to restore water and electrolyte balance. The patient is made to consume sufficient balanced salt solution to replace the lost water and salt. Endemic infections occur in areas with poor sewage and water treatment facilities. Transmission occurs by contamination of food and water by the diarrheal feces. Between the epidemics the organisms probably survive as harmless parasites of copepods and other animals living in rivers, ponds and estuaries. It is probable that the organism came originally from rivers in northern India.
Diseases and Parasites of Pufferfish and Their Management
Published in Ramasamy Santhanam, Biology and Ecology of Toxic Pufferfish, 2017
Infection locus: Anterior and posterior sectors of the gill arch Species of parasite: Parabrachiella sp. (Copepoda, Lernaeopodidae)
Toxicity and biomarkers of micro-plastic in aquatic environment: a review
Published in Biomarkers, 2021
Kamrul Hassan Suman, Md Niamul Haque, Md Jamal Uddin, Most Shirina Begum, Mahmudul Hasan Sikder
The hydrophobic properties of MPs may lead to the aggregations and incorporation of MPs into marine structures such as marine snow. Hydrophobicity with larger surface area promote accumulation of organic pollutants such as polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenylethers (PBDEs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethane (DDT) (Cole et al. 2011, Napper et al. 2015, Andrady 2017) that adsorb onto MPs at concentrations that are several orders of magnitude higher than in the surrounding water, which is increasing the exposure of aquatic organisms (Anderson et al. 2016). Association of MPs with swimming legs, feeding apparatus, appendages, antennae, even inside the digestive system of copepods have been observed (Cole et al. 2013, Vroom et al. 2017). PS fragments (<30 µm) were aggregated about 30-90% of the total gut either in the front or hind guts of copepod, Calanus finmarchicus (Vroom et al. 2017).
Metabarcoding and metabolomics offer complementarity in deciphering marine eukaryotic biofouling community shifts
Published in Biofouling, 2018
Jean-François Briand, Xavier Pochon, Susanna A. Wood, Christine Bressy, Cédric Garnier, Karine Réhel, Félix Urvois, Gérald Culioli, Anastasija Zaiko
Both sessile and motile eukaryotes were identified. This implies that sequenced communities could also include organisms associated with algae, such as the copepod Harpacticus sp., which constituted the most abundant taxa based on sequence reads number. In some cases, the high-level taxonomic assignment didn’t allow us to draw any conclusions on specific biological traits. For example, one of the most abundant OTUs (OTU 115) could only be attributed to Maxillopoda that includes both motile copepods and sessile barnacles. Among the unicellular and highly diverse Ciliophora group, sessile (mainly Zoothamnium spp. and Vorticellidae from the order Sessilida), vagile (Hypotrichia) but also planktonic (Chloreotrichia) taxa were identified in this study. The diversity of vagile taxa has previously been reported to be linked to the increasing complexity of the habitat associated with the development of algae or sessile organisms (Antoniadou et al. 2011). A possible associative relationship can be inferred from the Dinophyceae observed in the Lorient samples. They are known as epibionts of Ulvophyceae, and are rarely reported among photosynthetic microorganisms on artificial substrata (e.g. Railkin, 2004). The present study revealed that dinoflagellates most commonly co-occurred with green algae, as shown by both visual inspections and metabarcoding data. The high diversity of Ciliates recorded at Lorient could also follow the development of algae, which increased the complexity of the habitat.
Comparative study of dissolved and nanoparticulate Ag effects on the life cycle of an estuarine meiobenthic copepod, Amphiascus tenuiremis
Published in Nanotoxicology, 2018
Mithun Sikder, Emily Eudy, G. Thomas Chandler, Mohammed Baalousha
The meiobenthos, a group of short-lived micro-invertebrates, has gained attention as a useful collection of species for chronic bioassay of environmentally realistic sediment and waterborne contaminants over life cycle (Lotufo 1997; Dahl, Gorokhova, and Breitholtz 2006; Breitholtz and Wollenberger 2003). Meiobenthic copepods such as Amphiascus tenuiremis serve as a predominant food source for juvenile fishes, shrimps, and crabs (Coull 1990; Gee 1989) and are often the most sensitive meiobenthic taxon to pollution (Coull and Chandler 1992). Since, A. tenuiremis is at the base of the food web in estuarine ecosystems, changes in its population quantity or quality may result in population changes of other dependent fauna.