Spatial and temporal variability of myxozoan parasite, Myxobolus inornatus, prevalence in young of the year smallmouth bass in the Susquehanna River Basin, Pennsylvania

Abstract

A myxozoan parasite, Myxobolus inornatus, is one disease agent identified in young of the year (YOY) smallmouth bass in the Susquehanna River Basin, Pennsylvania. We investigated spatial and temporal variability in M. Inornatus prevalence across the Susquehanna River Basin and at several out-of-basin sites. We examined potential land use drivers of M. Inornatus prevalence including agricultural and developed land use. In 1,267 YOY smallmouth bass collected from 32 sites during 2013-2016, M. Inornatus was documented in 43.6% of samples. Among-site variability in parasite prevalence was greater than among-year variability. The effect of agricultural land use on M. Inornatus prevalence had a high probability of being positively correlated at multiple spatial scales (probability of positive effect > 0.80). The effect of developed land use on M. Inornatus prevalence had a relatively high probability of being negatively correlated at multiple spatial scales (probability of negative effect > 0.70). Our results suggest that land use practices could be related to M. Inornatus infection of smallmouth bass. Further study will be necessary to determine whether disease dynamics are a consequence of effects on the host, alterations of instream habitat mediating invertebrate host dynamics and/or survival and dispersal of the parasite infective stage.

Pathological and immunological analyses of Thelohanellus kitauei (Myxozoa:Myxosporea) infection in the scattered mirror carp, Cyprinus carpio

“…Myxozoans (phylum Myxozoa Grasse) have long been regarded as a class of protozoa, but more recent evidence suggests that they are highly differentiated metazoan parasites that infect invertebrates and aquatic animals as the main hosts 26–28 . Metazoans predominantly infect fish 26 , with limited activity on platyhelminth, reptiles, and amphibians 29,30 .…”

Fisheries Volume 45 Number 11 November 2020

“…Several of the parasites that have been identifi ed have complex life cycles (e.g., myxozoans, trematodes, and cestodes; Figure 1 ) that can be infl uenced by host and environmental interactions. For example, the prevalence of a myxozoan parasite, M. inornatus , is likely to be infl uenced positively by agriculture land use, indicating that land use practices in the watershed could be contributing to infection rates (Schall et al 2018 ). One possible explanation is that nutrient and sediment inputs from agricultural activities may be altering instream habitat and subsequently increasing the availability of suitable habitat conditions for invertebrate host populations (e.g., aquatic oligochaetes; Kaeser and Sharpe 2006 ).…”

Application of Molecular Pathology Techniques to Understand Mechanisms of Disease in Smallmouth Bass

“…In studies analyzing land use and fish health metrics, spatial scale has been determined to be influential. Previous work has found associations between land use at the local scale and physiological processes in fish (Jeffrey et al 2015), parasite abundance (Schall et al 2018) and parasite diversity (Blanar et al 2016 (Schall et al 2018).…”

“…Many stream ecology studies focus on land use at the local scale; however, due to the high interconnectivity of riverine systems, large scale analyses should also be considered (Allan 2004). In a previous study on YOY SMB, agNHD positively predicted M. inornatus infections and infection rates were suggested to be influenced by increased nutrification and the myxozoan intermediate host (Schall et al 2018). The results of the current study showed agriculture and development at multiple spatial scales can be used to model coinfections and liver helminth prevalence in YOY SMB.…”

“…Predictor variables and modeling efforts were focused on explaining spatial variability in prevalence of liver helminths and coinfections related to site locations rather than temporal variability given the limited temporal scope of the study (n=4 years). Site related characteristics were summarized similar to methods in Schall et al (2018), which used developed and agricultural land use at two spatial scales to investigate spatial variability in a myxozoan parasite in YOY smallmouth bass. Land use data were obtained from the National Land Cover Dataset…”