Jeyabal, L(MAJOR)Venu, RRavi Kumar, PSatish Kumar, Varanasi V2018-08-032018-08-032018-04http://krishikosh.egranth.ac.in/handle/1/5810063278THESESABSTRACT: “Parasitological and molecular screening of feral rats from Krishna District, Andhra Pradesh for endoparasites” was undertaken to study their prevalence. A total of 55 live rats (Rattus rattus and R. norvegicus) were trapped from April 2017 to December 2017 using rat traps and were examined for the presence of endoparasitic infections based on conventional and molecular diagnostic methods. Blood samples collected through cardiac puncture were initially screened for blood protozoan parasites by wet blood film, Giemsa staining technique and acridine orange fluorescent staining technique. Further, the genomic DNA was screened for few blood protozoans viz., Trypanosoma lewisi, T. evansi, Babesia sp., Babesia microti, Hemogregarindae and A. phagocytophilum, a gram-negative bacteria. All the visceral organs were examined for helminthic infections and the organs infected with helminths were subjected to histopathological examination. Out of fifty-five feral rats, 19 were found to be infected with different parasites with an overall prevalence rate of 34.55%, among which, 7.27% rats were found heavily infected with Trypanosoma lewisi and none was found positive for T. evansi, Babesia spp., Hemogregarindae and A. phagocytophilum. Further, the visceral organs (intestine, liver) screened for various helminth parasites were positive for Hymenolepis diminuta (7.27%), Taenia taeniaeformis (3.64%), Ascaris spp. (1.82%) and a mixed infection of Heterakis spumosa and C. hepatica was found in 10.91% of feral rats (four rats with only C. hepatica and 2 had both). Few faecal samples revealed eggs of Strongyloides spp. (1.82%) and Trichuris spp. (1.82%) eggs. T. lewisi was confirmed with conventional morphometry (29.34 μm) and PCR for ITS1 region of genomic rDNA with the product size of 220 bp. Further, the gel eluted T. lewisi ITS1 gene was cloned in RBC TA Cloning Vector Kit and transformation was carried out in E. coli. The plasmid DNA was purified and molecular sequence analysis revealed 92% identity with T. lewisi and phylogenetic analysis revealed a close relationship with two Brazilian isolates of T. lewisi viz., Trycc 35 ITS-1 and Af ITS-1. The purpose of cloning T. lewisi ITS1 gene was to develop a recombinant protein based diagnostic assay.ennullThesis