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Weinersmith KL, Nadler LE, Bengston E, Turner AV, Birda A, Cobian K, Dusto JA, Helland-Riise SH, Terhall JM, Øverli Ø, Hechinger RF. EXPERIMENTAL INFECTIONS WITH EUHAPLORCHIS CALIFORNIENSIS AND A SMALL CYATHOCOTYLID INCREASE CONSPICUOUS BEHAVIORS IN CALIFORNIA KILLIFISH (FUNDULUS PARVIPINNIS). J Parasitol 2023; 109:362-376. [PMID: 37527277 PMCID: PMC10658870 DOI: 10.1645/23-35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023] Open
Abstract
Some parasites manipulate their host's phenotype to enhance predation rates by the next host in the parasite's life cycle. Our understanding of this parasite-increased trophic transmission is often stymied by study-design challenges. A recurring difficulty has been obtaining uninfected hosts with a coevolutionary history with the parasites, and conducting experimental infections that mimic natural processes. In 1996, Lafferty and Morris provided what has become a classic example of parasite-increased trophic transmission; they reported a positive association between the intensity of a brain-infecting trematode (Euhaplorchis californiensis) in naturally infected California killifish (Fundulus parvipinnis) and the frequency of conspicuous behaviors, which was thought to explain the documented 10-30× increase in predation by the final host birds. Here, we address the primary gap in that study by using experimental infections to assess the causality of E. californiensis infection for increased conspicuous behaviors in F. parvipinnis. We hatched and reared uninfected F. parvipinnis from a population co-occurring with E. californiensis, and infected them 1-2 times/week over half their life span with E. californiensis and a small cyathocotylid trematode (SMCY) that targets the host's muscle tissue. At 3 time points throughout the hosts' lives, we quantified several conspicuous behaviors: contorting, darting, scratching, surfacing, and vertical positioning relative to the water's surface. Euhaplorchis californiensis and SMCY infection caused 1.8- and 2.5-fold overall increases in conspicuous behaviors, respectively. Each parasite was also associated with increases in specific conspicuous behaviors, particularly 1.9- and 1.4-fold more darting. These experimental findings help solidify E. californiensis-F. parvipinnis as a classic example of behavioral manipulation. Yet our findings for E. californiensis infection-induced behavioral change were less consistent and strong than those previously documented. We discuss potential explanations for this discrepancy, particularly the idea that behavioral manipulation may be most apparent when fish are actively attacked by predators. Our findings concerning the other studied trematode species, SMCY, highlight that trophically transmitted parasites infecting various host tissues are known to be associated with conspicuous behaviors, reinforcing calls for research examining how communities of trophically transmitted parasites influence host behavior.
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Affiliation(s)
- Kelly L. Weinersmith
- Department of BioSciences, Rice University, Houston, Texas 77005
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
| | - Lauren E. Nadler
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
- Present address: School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton SO14 3ZH, U.K
| | - Erik Bengston
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
| | - Andrew V. Turner
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
| | - Abhinav Birda
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
| | - Karina Cobian
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
| | - Jennifer A. Dusto
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
| | - Siri H. Helland-Riise
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo 1407, Norway
| | - Jasmine M. Terhall
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
| | - Øyvind Øverli
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo 1407, Norway
| | - Ryan F. Hechinger
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037
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Bosi G, Maynard BJ, Pironi F, Sayyaf Dezfuli B. Parasites and the neuroendocrine control of fish intestinal function: an ancient struggle between pathogens and host. Parasitology 2022; 149:1842-1861. [PMID: 36076315 PMCID: PMC11010486 DOI: 10.1017/s0031182022001160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/03/2022] [Accepted: 08/11/2022] [Indexed: 12/29/2022]
Abstract
Most individual fish in wild and farmed populations can be infected with parasites. Fish intestines can harbour protozoans, myxozoans and helminths, which include several species of digeneans, cestodes, nematodes and acanthocephalans. Enteric parasites often induce inflammation of the intestine; the pathogen provokes changes in the host physiology, which will be genetically selected for if they benefit the parasite. The host response to intestinal parasites involves neural, endocrine and immune systems and interaction among these systems is coordinated by hormones, chemokines, cytokines and neurotransmitters including peptides. Intestinal fish parasites have effects on the components of the enteric nervous and endocrine systems; mechanical/chemical changes impair the activity of these systems, including gut motility and digestion. Investigations on the role of the neuroendocrine system in response to fish intestinal parasites are very few. This paper provides immunohistochemical and ultrastructural data on effects of parasites on the enteric nervous system and the enteric endocrine system in several fish–parasite systems. Emphasis is on the occurrence of 21 molecules including cholecystokinin-8, neuropeptide Y, enkephalins, galanin, vasoactive intestinal peptide and serotonin in infected tissues.
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Affiliation(s)
- Giampaolo Bosi
- Department of Veterinary Medicine and Animal Science, University of Milan, St. dell'Università 6, 26900 Lodi, Italy
| | - Barbara J. Maynard
- The Institute for Learning and Teaching, Colorado State University, Fort Collins, CO 80523, USA
| | - Flavio Pironi
- Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
| | - Bahram Sayyaf Dezfuli
- Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
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Blecharz-Klin K, Świerczyńska M, Piechal A, Wawer A, Joniec-Maciejak I, Pyrzanowska J, Wojnar E, Zawistowska-Deniziak A, Sulima-Celińska A, Młocicki D, Mirowska-Guzel D. Infection with intestinal helminth (Hymenolepis diminuta) impacts exploratory behavior and cognitive processes in rats by changing the central level of neurotransmitters. PLoS Pathog 2022; 18:e1010330. [PMID: 35286352 PMCID: PMC8947016 DOI: 10.1371/journal.ppat.1010330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 03/24/2022] [Accepted: 02/02/2022] [Indexed: 12/12/2022] Open
Abstract
Parasites may significantly affect the functioning of the host organism including immune response and gut-brain-axis ultimately leading to alteration of the host behavior. The impact of intestinal worms on the host central nervous system (CNS) remains unexplored. The aim of this study was to evaluate the effect of intestinal infection by the tapeworm Hymenolepis diminuta on behavior and functions of the CNS in rats. The 3 months old animals were infected, and the effects on anxiety, exploration, sensorimotor skills and learning processes were assessed at 18 months in Open Field (OF), Novel Object Recognition (NOR) and the Water Maze (WM) tests. After completing the behavioral studies, both infected and non-infected rats were sacrificed, and the collected tissues were subjected to biochemical analysis. The levels of neurotransmitters, their metabolites and amino acids in selected structures of the CNS were determined by HPLC. In addition, the gene expression profile of the pro- and anti-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-10) was evaluated by Real-Time PCR to determine the immune response within the CNS to the tapeworm infection. The parasites caused significant changes in exploratory behavior, most notably, a reduction of velocity and total distance moved in the OF test; the infected rats exhibited decreased frequency in the central zone, which may indicate a higher level of anxiety. Additionally, parasite infestation improved spatial memory, assessed in the WM test, and recognition of new objects. These changes are related to the identified reduction in noradrenaline level in the CNS structures and less pronounced changes in striatal serotonergic neurotransmission. H. diminuta infestation was also found to cause a significant reduction of hippocampal expression of IL-6. Our results provide new data for further research on brain function during parasitic infections especially in relation to helminths and diseases in which noradrenergic system may play an important role. Recent advances in the research on parasitic manipulation and/or control of the nervous system of their host resulted in the development of neuro-parasitology, a new and emerging branch of science. There have been advances in this area in relation to parasite-insect interactions or parasites directly invading central nervous system (CNS). However, the neuro-parasitology of parasitic infections in vertebrate hosts remains unexplored. In our study the effect of intestinal infection by the tapeworm on the behavior, neurotransmission and functions of the CNS in rats was evaluated. This infection positively influenced spatial memory and new object recognition. At the same time, the infected animals developed a greater level of anxiety and move more slowly. Behavioral changes were related to the reduction in noradrenaline level in the CNS structures, and less pronounced changes in striatal serotonergic neurotransmission. The results provide important data for the further progress in neuro-parasitology and our understanding of parasite-host interactions. In our opinion in the near future may turn out that the role of the intestinal host macrobiome in the CNS functioning may be just as significant as that of the microbiome. Presented neuro-immunological data provide a new perspectives for further studies on the CNS under intestinal parasite infection. The data of behavioral changes induced by active parasitic infection may be valid for explanations of the host-parasite relationship at the evolutionary level and their molecular adjustment.
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Affiliation(s)
- Kamilla Blecharz-Klin
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Warsaw, Poland
| | - Magdalena Świerczyńska
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Warsaw, Poland
| | - Agnieszka Piechal
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Warsaw, Poland
| | - Adriana Wawer
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Warsaw, Poland
| | - Ilona Joniec-Maciejak
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Warsaw, Poland
| | - Justyna Pyrzanowska
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Warsaw, Poland
| | - Ewa Wojnar
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Warsaw, Poland
| | | | - Anna Sulima-Celińska
- Department of General Biology and Parasitology, Medical University of Warsaw, Warsaw, Poland
| | - Daniel Młocicki
- W. Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland
- Department of General Biology and Parasitology, Medical University of Warsaw, Warsaw, Poland
- * E-mail: (DM); (DM-G)
| | - Dagmara Mirowska-Guzel
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Warsaw, Poland
- * E-mail: (DM); (DM-G)
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