Mississippi State University, College of Veterinary Medicine - Rosser Lab
Mississippi State University, College of Veterinary Medicine - Rosser Lab
Dr. Graham Rosser
Jonah A. Nguyen1, Ethan T. Woodyard2, Logan R.S. Robison, Matt J. Griffin2, Thomas G. Rosser1
1Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr, Mississippi State, MS 39762; 2Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr, Mississippi State, MS 39762.
The family Ampullariidae is a family of large freshwater snails, commonly known as “apple snails”. Of particular importance are the species belonging to the genus Pomacea, which are commonly kept as aquarium pets and contain multiple species which are invasive in the United States. Of the genus, only one species, the Florida apple snail Pomacea paludosa, is native to the United States. Pomacea maculata is invasive, particularly in the Southeast US, and is damaging to the Louisiana crawfish industry. Herein, general information on rat lungworm Angiostrongylus cantonensis, recent findings on parasites of Pomacea spp., and future research goals will be shared. While a range of parasites infect Pomacea spp., A. cantonensis is of particular importance due to its ability to cause eosinophilic meningitis in mammals, including humans. Pomacea spp. eaten undercooked or raw could thus be potentially deadly. Recent notable parasite findings of Pomacea spp. herein include trematode cercariae belonging to the family Phaneropsolidae. Some phaneropsolid trematodes are known to be zoonotic, highlighting potential human health significance of this finding. To molecularly characterize this phaneropsolid cercaria, Oxford Nanopore and Illumina next-generation sequencing was employed, resulting in ~7 kb of ribosomal DNA and ~20 kb of mitochondrial DNA. Future research goals include determining prevalence of A. cantonensis in Pomacea spp. across the Southeast using qPCR and further investigation of parasites of Pomacea spp.
1Parker L. Dickinson, 2Ethan T. Woodyard, 1James C. Valentine, 1Jonah A. Nguyen, 1Logan R. Robison, 2Divya Rose, 1Lorelei Ford, 2,3Matt J. Griffin, 1Thomas G. Rosser
1Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39759; 2Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39759; 3Thad Cochran National Warmwater Aquaculture Center, Delta Research and Extension Center, Mississippi State University, Stoneville, MS 38776
The American Alligator American mississippiensis is an important apex predator in freshwater ecosystems in the southeastern United States and serves as the definitive host for adult helminths, many of which utilize freshwater fish as intermediate hosts in their life cycles. The ascarid nematode Dujardinascaris waltoni infects the stomach of alligators. Currently, the life cycle of D. waltoni is unknown but is speculated to involve fish intermediate hosts that are prey of alligators. Adult D. waltoni were collected previously from American alligators from Mississippi and used for morphological and molecular analysis. Based on the involvement of gar in the partially-known life cycle of the alligator tongue trematode Odhneriotrema incommodum, our lab has previously examined spotted gar Lepisosteus oculatus for larval parasites. This led to morphological and molecular confirmation of L. oculatus as an intermediate host in the life cycle of the pentastomid Sebekia mississippiensis. During these sampling events, encysted larval nematodes were recovered from the esophagus and mesentery of 37 fish collected by electrofishing from the Atchafalaya River Basin in Louisiana. Genomic DNA was extracted from whole worms and hologenophores of larvae and adult nematodes for molecular analyses. DNA from single adult nematodes was submitted for Oxford Nanopore and Illumina sequencing to generate a complete mitochondrial genome and the full nuclear ribosomal regions. Additionally, partial mitochondrial cytochrome c oxidase subunit 1 gene sequence data generated by Sanger sequencing (~450 bp) were used to verify conspecificity between larvae from gar and adults from alligators. Intraspecific variability ranged from 97.8 – 100% sequence identity. Novel molecular data from mitochondrial and ribosomal regions for D. waltoni suggest a putative transmission route involving a predator-prey association. Descriptions of any pathological changes in both hosts will be pursued in future studies and investigations into the development of eggs and larvae in other fish hosts. The novel sequence data generated in these studies will facilitate more accurate identification of various life cycle stages of D. waltoni as they are encountered, enabling resolution of many ambiguities in the literature regarding this species and its suggested intermediate and paratenic host range.