Echinostome cercariae from Biomphalaria straminea (Mollusca: Planorbidae) in a ricefield from northeastern Argentina

Abstract

The species of larval Echinostomatidae that infect Biomphalaria straminea (Dunker, 1848) in a ricefield in Corrientes province, Argentina, were studied. Examination of 5 510 snails during 2 rice cultivation cycles, from December 2010 to May 2011 and from December 2011 to April 2012, revealed the presence of 3 new species: Echinocercaria sp. XIII, Echinocercaria sp. XIV and Echinocercaria sp. XVI in 36 snails (0.65%). The most common species was Echinocercaria sp. XVI. Prevalence of 3 species during the first rice cultivation cycle was low (< 1%), whereas during the second rice cultivation cycle it was somewhat higher, with prevalence greater than 1% only in Echinocercaria sp. XVI. The species of echinocercariae in B. straminea from the agricultural habitat described in the present study are new additions to the species already reported for the genus Biomphalaria in the region.

Morphological Characteristics and Phylogenetic Trends of Trematode Cercariae in Freshwater Snails from Nakhon Nayok Province, Thailand

“…A relationship was shown among the 6 clades according to the specific type of cercariae; for example, the clade Echinostomatida/Echinostomatidae group was found to be able to develop into the adult stage, which was in accordance with the findings of several previous reports [4,11,32]. The specimens of parapleurolophocercous cercariae in the clade can develop into intestinal trematodes in the family Heterophyidae, particularly H. taichui [8,33–36], megalurous cercariae can develop into avian eye trematode in the family Philopthalmidae [3], and furcocercous cercariae can develop into the family Cyathocotylidae [3].…”

The diverse echinostomes from East Africa: With a focus on species that use Biomphalaria and Bulinus as intermediate hosts

“…The second type of peculiar refractile structure was found in clades 4 and 5. The enclosed structure lying just posterior to the oral sucker contains a cluster of granules (20–24), some of which are fused and this feature is similar to other cercariae descriptions by Fain (1953) , Lie (1963) and Fernandez et al (2014) . A third type of refractile structure is exhibited by clades 13–16, also which have an enclosed structure located just posterior to the oral sucker.…”

“…Acquisition of nad 1 sequences for P. vioscai from the American white ibis ( Eudocimus albus ), which is endemic to the Americas, would help clarify the relationship to our clade 2 specimens. We also note of interest that our cercariae in clade 2 resembled cercariae from two South American species of Biomphalaria : 1) cercariae of B. tenagophila from the Uruguay River that transmitted an echinostome cercaria with 58 spines and 16 excretory diverticuli/side ( Martorelli et al, 2013 ), and 2) cercariae from Biomphalaria straminea from Argentina have been reported with 53–54 collar spines, a spine pocket, diverticuli and tail fins ( Fernandez et al, 2014 ). Samples from Kazinga Channel in Uganda also grouped into this clade and clade 3.…”

Cercariae (Digenea: Strigeidae, Diplostomidae) in Biomphalaria straminea (Planorbidae) from a rice field in Northeastern Argentina

“…Similar results were previously observed in the same rice field (Fernández et al, 2014), and this could be related to diverse factors, such as the presence of greater numbers of definitive hosts in the environment during the second rice cultivation cycle, or fewer snails in the environment during the same period.…”

“…Recently, Fernández et al (2013Fernández et al ( , 2014 described larval trematodes in B. straminea from a rice field in Corrientes province, Argentina, one of the main rice producers of Argentina (ACPA, 2014). In this context, the goal of the present work was to complete the description of the cercariae found in the sampling of molluscs of this environment.…”