Copro-PCR based detection of bovine schistosome infection in India

Schistosomosis and amphistomosis are the two economically important and widely prevalent snail-borne trematode infections in grazing cattle of southern India. Acute infections are symptomatically similar and difficult to detect by routine microscopy for eggs. The present study was directed towards the development of a copro-polymerase chain reaction (copro-PCR) for detection of bovine schistosome species, using custom-designed primers targeting 18S and 28S ribosomal RNA as well as mitochondrial DNA. The study demonstrated the enhanced diagnostic specificity of mitochondrial DNA markers over ribosomal RNA genes as genus-specific probes to detect schistosomes. We developed a sensitive PCR assay using primers designed from mitochondrial DNA sequences targeting the partial rrnl (16S rRNA), tCys (transfer RNA for cysteine) and partial rrnS (12S rRNA) genes of Schistosoma spindale to specifically detect schistosome infection from faecal samples of naturally infected bovines. The salient findings of the work also throw light on to the high similarity of the ribosomal RNA gene sequences of schistosomes with those of Gastrothylax crumenifer and Fischoederius elongatus, the most prevalent pouched amphistomes of the region. Further investigation has to be directed towards unravelling the complete gene sequences of 18S and 28S ribosomal RNA as well as mitochondrial DNA sequences of amphistome isolates from India.