RESUMO
The objective of the present study is to characterize the dipteran larvae species infesting the sheep being maintained at SRRC, Mannavanur, by means of COI gene based PCR. During the last week of May 2021, post mortem examination of the skull of an Avikalin male sheep (20 months old) revealed the presence of larvae in its nasal sinuses. The larvae were washed in PBS (pH 7.2) and preserved in 70% alcohol. Total genomic DNA was isolated from the larvae using an initial step of grinding with liquid Nitrogen in a sterile mortar and pestle. Using the isolated genomic DNA from the larvae as a template, Cytochrome c oxidase subunit I (COI) gene based PCR was employed using the primers designed based on the COI gene of reference isolate of Oestrus ovis available in the GenBank. Full length COI gene (1534 bp) gene of Oestrus ovis in sheep from South India was targeted in the PCR experiment. The pTZ57R/T vector was used for the cloning of the PCR amplified fragment and the confirmed recombinant plasmid was subjected to sequencing experiments. In addition to morphological examination, based on COI gene based PCR, eventual sequencing experiments and BLAST analysis, it was confirmed that the larvae in the nasal sinuses of sheep from South India were Oestrus ovis. The South Indian isolate of Oestrus ovis is sharing 100% sequence identity both at nucleotide and amino acid levels with that of O. ovis from Spain. The North Indian isolate of O. ovis (from Jammu) exhibited 92% and 99% identity at respective nucleotide and amino acid levels with South Indian isolate. With other members of the subfamily Oestrinae, the share of per cent nucleotide and amino acid identities of South Indian O. ovis ranged from 85-86% to 95-96%, respectively. O. ovis from South India was grouped with the other members of Oestrinae from different geographical areas of the globe in the analysis of phylogenetic tree based on COI amino acid sequences. Based on the research findings, it is concluded that Oestrus ovis is the dipteran species infesting the sheep at Mannavanur, Tamil Nadu, India. To our knowledge, this is the first report on full length nucleotide sequences of COI gene of O. ovis in sheep from Indian subcontinent. Supplementary Information: The online version contains supplementary material available at 10.1007/s12639-024-01666-2.
RESUMO
PURPOSE: Tape worm infection is common among sheep at SRRC, Mannavanur, Palani hills, Tamil Nadu, India. The aim of the present study is to find out the cestode species infecting the sheep being maintained at SRRC, Mannavanur, by means of molecular method. METHODS: During the second week of June 2021, the hogget flock of sheep (comprising both Bharat Merino and Avikalin sheep breeds) was drenched on empty stomach with commercial preparation of anthelmintic drug containing Niclosamide plus Albendazole, as per the standard dose specified by the manufacturer (Niclozole™: each 5 ml contains 500 mg of Niclosamide and 150 mg of Albendazole: dose for sheep-10 ml/15 kg body weight). The tapeworms expelled in dung by the drug-treated sheep were collected, washed in PBS (pH 7.2), and fixed in between two glass slides using 10% formalin. Furthermore, cytochrome c oxidase subunit I (Cox-I) gene-based PCR was carried out. Only partial sequence (1593 bp) of Cox-I gene of Moniezia expansa from Sheep at SRRC, Mannavanur, Tamil Nadu, India was obtained by PCR. The PCR amplified fragment was cloned into pGEM-T vector and the recombinant plasmid was sequenced. The obtained nucleotide sequences of Cox-I gene of the M. expansa from Indian sheep were analysed with that of 27 more cestode species from different mammalian species (available in GenBank) using bioinformatics tools. RESULTS: The species of the tapeworm was identified as Moniezia species by the Department of Veterinary Parasitology, VC& RI, Orathanadu, TANUVAS by the standard Acidic alum carmine staining method. Due to the ambiguity in the conventional method, Cox-I gene-based PCR and subsequent gene sequencing protocols were used for the identification of the species of cestode infecting sheep at SRRC, Mannavanur, and it was confirmed as M. expansa upon BLAST analysis. Moniezia expansa from SRRC, Mannavanur is having 100% sequence identity at nucleotide level with that of M. expansa from Sengal/Ethiopia. M. benedeni shared 87-88% nucleotide identity with Indian M. expansa. With taenids, the share of percent nucleotide identity of Indian M. expansa ranged from 79 to 81%. M. expansa from Indian sheep was clustering with other anaplocephalids from various mammalian species in the analysis of phylogenetic tree based on Cox-I nucleotide sequences. CONCLUSION: From the present study, it is concluded that M. expansa is the anoplocephalid cestode infecting the sheep at Mannavanur, Tamil Nadu, India. To our knowledge, this is the first report on partial nucleotide sequences of Cox-I gene of M. expansa from Sheep of Indian peninsula. An investigation on the involvement of oribatid mites as the vector in the transmission of M. expansa among sheep at SRRC, Mannavanur needs to be carried out.
