Molecular characterization of Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae) from goats in the western part of India by LSU of nuclear ribosomal DNA

A Universal Approach to Molecular Identification of Rumen Fluke Species Across Hosts, Continents, and Sample Types

Rumen fluke are parasitic trematodes that affect domestic and wild ruminants across a wide range of countries and habitats. There are 6 major genera of rumen fluke and over 70 recognized species. Accurate species identification is important to investigate the epidemiology, pathophysiology and economic impact of rumen fluke species but paramphistomes are morphologically plastic, which has resulted in numerous instances of misclassification. Here, we present a universal approach to molecular identification of rumen fluke species, including different life-cycle stages (eggs, juvenile and mature fluke) and sample preservation methods (fresh, ethanol- or formalin-fixed, and paraffin wax-embedded). Among 387 specimens from 173 animals belonging to 10 host species and originating from 14 countries on 5 continents, 10 rumen fluke species were identified based on ITS-2 intergenic spacer sequencing, including members of the genera Calicophoron, Cotylophoron, Fischeroedius, Gastrothylax, Orthocoelium, and Paramphistomum. Pairwise comparison of ITS-2 sequences from this study and GenBank showed >98.5% homology for 80% of intra-species comparisons and <98.5% homology for 97% of inter-species comparisons, suggesting that some sequence data may have been entered into public repositories with incorrect species attribution based on morphological analysis. We propose that ITS-2 sequencing could be used as a universal tool for rumen fluke identification across host and parasite species from diverse technical and geographical origins and form the basis of an international reference database for accurate species identification.

Rumen fluke, Fischoederius elongatus (Trematoda: Gastrothylacidae): Preliminary investigation of suitable conditions for egg hatching

Various temperatures may have different effects on the distribution of paramphistomes that cause amphistomosis in cattle, including Fischoederius elongatus. Therefore, this study aimed to investigate the effects of different temperature treatments on F. elongatus hatching, with specific identification using morphological, histological, and phylogenetic analysis. All specimens were collected from two buffalo (Bubalus bubalis) rumens in a slaughterhouse in Pathum Thani province, Thailand. F. elongatus adults were kept in phosphate buffered saline solution for egg collection. The egg specimens were incubated in tap water under four different temperature conditions: 4 °C, room temperature, 35 °C, and 55 °C. For 31 days, egg specimens of approximately 50 eggs per observation were randomly classified into three stages (undeveloped, developing (or pre-hatching), and hatched). To test the change of temperature, cold water was used for thermal shocking the egg specimens. The results indicated that rates of egg development and hatching were highest at 35 °C and significantly higher than in the other treatments (P < 0.001). In addition, statistical investigation of pre-thermal shock results also suggesting that 35 ºC may be a suitable condition for hatching F. elongatus eggs and could enhance the developing and hatching by longer periods of incubation for more than 26 days. Even changing the temperature could affect development and hatching but initial environment temperature remains an important factor. These data could be used for efficient epidemiological prediction of F. elongatus and applied in livestock management.

First genetic evidence for the presence of the rumen fluke Paramphistomum epiclitum in Pakistan

More than 70 species of the Superfamily Paramphistomoidea, have been identified in ruminants in different parts of the world. Most are pathogenic, causing amphistomosis. Adult flukes within this family have a predilection for the forestomach (rumen) or bile duct of the liver, where they may cause epithelial damage. Identification of adult Paramphistomum, Calicophoron, Gastrothylax and Fischoederius at the species level based on morphology requires specialised expertise, whereas molecular genetic marker analysis is more precise and transferable. In the present study, we performed molecular characterisation of twenty seven adult flukes collected from the forestomachs of buffalo, cattle and goats in the Punjab province of Pakistan. PCR and sequencing of the ITS-2 rDNA region revealed a single haplotype in all cases. Phylogenetic comparison of P. epiclitum ITS2-rDNA sequences with those from other Paramphistomum, Calicophoron, Gastrothylax and Fischoederius species was performed to assess within and between species variation and validate the use of ITS-2 rDNA as a robust species-specific marker for P. epiclitum identification. This work provides a validated species-specific marker of P. epiclitum and the first report of this parasite species from Pakistan. The results of this study also have implications for the diagnosis and control of rumen flukes in the region and the need for accurate species identification to understand parasite distribution and population genetics.

Incidence of amphistome infection in sheep from Mhow, Madhya Pradesh

A total of 445 faecal samples and 128 rumens of sheep collected from Slaughter house, Mhow (Madhya Pradesh) were examined for a period of 1 year from February 2011 to January 2012. Faecal sample examination based, incidence of amphistomes was found to be 23.37% from the study area. The incidence of amphistomes was significantly higher (p < 0.01) during summer (36.75%) than winter (27.74%) and monsoon (3.52%). Age-wise, non-significantly higher infection was observed in ≥1 year-old animals (23.61%) than <1 year-old animals (23.11%). Non-significantly higher rate of infection was recorded in case of females (25.63%) than that of males (19.64%). Out of 128, 49 (38.28%) rumens were found positive for amphistomes. The prevalence of Paramphistomum cervi (27.34%) was found to be significantly (p < 0.01) higher than Gastrothylax crumenifer (10.94%).