​Molecular Detection and Phylogenetic Analysis of the Genotype of Larval Cestode Cysticercus cellulosae of Pigs and Taenia solium of Man
Authors: Biswakarma B. , Deka D.K. , Islam S. , Sarmah P.C. , Bhattacharjee K. , Das S.K. , Upadhyaya T.N. , Tamuly S. , Kakoty P. , Laha R. 
Published: June 2022

Background: Porcine cysticercosis, caused by Cysticercus cellulosae a larval stage of adult Taenia solium, is a zoonotic parasitic disease where pigs harbour intermediate stage and human being acts as a definite host. The people of north eastern region of India are mostly non-vegetarian and consumption of pork is very much preferred by the people of this region. Hence,it is essential to detect C. cellulosae infections in pork. But traditional method of detection of C. cellulosae by post mortem examination of pork has disadvantages like need of expert and may be over lookedin case of light infections. Molecular diagnosis have been reported to be highly specific and sensitive for its diagnosis. Keeping in view of the above, the present study on molecular detection of larval cestode C. cellulosae of pigs was undertaken. A study on phylogenetic relation of C. cellulosae of pigs or human Taenae solium of this region was done to know its relation with other parts of the world, as not yet done so far. Methods: A total of 654 pig carcasses in 17 market places of three prime districts of state Arunachal Pradesh, India were examined to detect Cysticercus cellulosae of pigs. The cysticerci samples were obtained manually from the infected muscles and organs of the infected pigs that were preserved in phosphate buffer saline until DNA extraction. Stool samples of human patients who attended out-patient department (OPD) of Community Health Centers, Nursing homes and District etc. of study area of Aunachal Pradesh, India were collected randomly and examined by salt flotation technique for the presence of T. solium eggs. The segments of tapeworm voided by patientswere then identified for species identification and T. solium segments were collected in normal saline solutions (NSS) after clearing the debris and faecal materials. Genomic DNA extraction from 3-4 numbers of cysticerci and T. solium segments collected from affected human being were extractedusing a spin column kit (D Neasy tissue kit: QUIGEN).The technique polymerase chain reaction (PCR) with published primers were used for molecular detection of C. cellulosae and to get molecular (PCR) products of T. solium for further study. The mitochondrial gene cytochrome b oxidase subunit was amplified by PCR. The PCR products were purified, sequenced and phylogenetic tree was constructed using the neighbor-joining method. Result: The present study recorded a PCR amplification of cytochrome b oxidase genes with a definite product size of 1068 bp from DNA extracted from C. cellulosae and T. solium. The product size obtained from C. cellulosae will be helpful for meat inspection by molecular detection of C. cellulosae infections in pork. The present finding signifies that the same genomic isolate of both the larval cestode and adult parasite of T. solium is prevailing in the study areas. The neighbors-joining phylogenic tree shows close similarity of the present isolates with that prevailing in other South East Asian countries and thus it can be assumed from the present finding that the same genotypic isolate of T. solium parasite is prevalent in the whole of South East Asian region.