JYOTHISREE .CH (MAJOR)SREEDEVI .CSAMATHA .VVINOO .RVEERENDRA .U2024-07-052024-07-052023-04https://krishikosh.egranth.ac.in/handle/1/5810211481The present study was undertaken to determine the prevalence of visceral schistosomosis caused by Schistosoma species in Andhra Pradesh. For this, a total of 467 slaughtered buffaloes mesenteries and livers collected from abattoirs of Krishna district were sampled for a period of one year. On examination, 95 buffaloes were found to be infected with Schistosoma species giving an overall prevalence of 20.34%. The prevalence of schistosomosis was significantly (P<0.001) higher in adults (>2.5yr; 31.95%) than in young (<2.5yr; 13.75%) animals and non-significantly high in females (26.02%) than in males (19.28%). The prevalence was significantly (P<0.001) high during rainy season (28.47%) followed by winter (21.73%) and summer (10.96%) seasons. Month wise prevalence of schistosomosis in the study area revealed highest prevalence of schistosomosis in July (34.21%) and lowest prevalence during May (5.88%). Most of the infections were mild (48.42%) followed by moderate (36.84%) and severe (14.73%) infection. Mild to moderate infections were noticed in young animals and severe infection was noticed in adults. The worms were milky white in colour. Male worms were stout and carried the females in a groove like a gutter i.e, gynaecophoric canal. Based on three to six testicles, a smooth cuticle, a conical projection at the back of the male, and spindle-shaped eggs in the female's uterus the worms were identified as Schistosoma spindale. Grossly infected livers showed petechiae to patchy haemorrhages, necrotic foci, and whitish worms entrenched in portal veins. The serosal surface of the small intestines had white grey nodules and moderate haemorrhages with necrotic foci on the mucosa. The liver sections revealed moderate to severe congestion of blood vessels and mild degenerative changes in hepatocytes along with adult flukes in the central veins and capillaries of sinusoidal spaces. Infected intestines displayed moderate to severe congestion of blood vessels, haemorrhages in mucosa and the cut section of the parasite in the muscularis mucosa. Few sections of liver and intestine were evident with fibrous tissue proliferation surrounding the parasitic ova and development of microgranulomas. Trabecular thickening, and haemosiderin engulfed macrophages were present in mesenteric lymph nodes along with degenerated parasitic ova. The morphologically identified adult fluke were confirmed through amplification of 28S rRNA gene that yielded 330bp product specific for S. spindale. The sequencing and blast analysis of two S. spindale AP isolates revealed 100% homology with Asian populations of S. spindale. Results confirm that schistosomosis is endemic in buffaloes in Andhra PradeshEnglishThesis