|HUDSON, PINTO - Federal University Of Minas Gerais|
|GRIFFIN, MATT - Mississippi State University|
|WARE, CYNTHIA - Mississippi State University|
|DE MELO, ALAN - Federal University Of Minas Gerais|
Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/3/2015
Publication Date: 1/1/2016
Citation: Hudson, P.A., Griffin, M.J., Quiniou, S., Ware, C., De Melo, A.L. 2016. Biomphalaria straminea (Mollusca: Planorbidae) as an intermediate host of Drepanocephalus spp. (Trematoda: Echinostomatidae) in Brazil: a morphological and molecular study. Parasitology Research. 115:(1)51-62.
Interpretive Summary: Drepanocephalus spp. are parasites of piscivorous birds, primarily cormorants (Phlachorocorax spp.) and fish. Adult Drepanocephalus spp. have been recovered from birds in Brazil, but their second intermediate host has remained elusive. This study identified Biomphalaria straminea in Brazil as a second intermediate host for at least two species of Drepanocephalus, one of which (Drepanocephalus spathans) parasitizes the snail Planorbella trivolvis in catfish production ponds in the southeastern United States. This work increases the known host range of Drepanocephalus spathans.
Technical Abstract: Species of trematodes belonging to the genus Drepanocephalus are intestinal parasites of piscivorous birds, primarily cormorants (Phalachrocorax spp.), and are widely reported in the Americas. During a 4-year malacological study conducted on an urban lake in Brazil, 27-collar-spined echinostome cercariae were found in 1,665/15,459 (10.7%) specimens of Biomphalaria straminea collected. The cercariae were identified as Drepanocephalus spp. by sequencing 18S rDNA, 28S rDNA, ITS1/5.8S rDNA/ITS2 region, cytochrome oxidase subunit 1 (CO1) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) markers. In experimental life cycle studies, metacercariae developed in laboratory-reared guppies (Poecilia reticulata), however attempts to infect birds and rodents were unsuccessful. Two closely related morphotypes of cercariae were characterized. One species, identified by molecular markers as a genetic variant of Drepanocephalus spathans (99.6–99.8% homology at SSU; 100% at LSU; 100% at ITS; 97.7–98.1% at CO1; 95.5% at ND1), differs slightly from the North American isolate of the species recently obtained from birds and snails. A second species, putatively identified as Drepanocephalus sp., has smaller cercariae and demonstrates significant differences at the CO1 (9.2–9.6%) and ND1 (14.8%) markers compared to D. spathans. Aspects related to the morphological taxonomic identification of 27-collar spined echinostome metacercariae are briefly discussed. This is the first report of the involvement of molluscs of the genus Biomphalaria in the transmission of Drepanocephalus in South America.