Prevalence and microscopic studies of Sarcocystis infection in naturally infected water buffaloes (Bubalus bubalis) of Andhra Pradesh.

Sarcocystis species are the obligate tissue protozoan parasites of livestock causing clinical and subclinical disease resulting in downgrading of the meat and their products thereby leading to economic losses. The present study reveals the prevalence and distribution of sarcocystosis in water buffaloes (Bubalus bubalis) slaughtered at local abattoirs in A.P for a period of 1 year from June 2014 to May 2015. A total of 137 buffalo carcasses were screened grossly and microscopically organ wise viz., esophagus, tongue, heart, diaphragm and intercostal muscles. Out of 137 screened, 91 were infected with an overall prevalence of 66.42 %. Age wise analysis of 89 young male calves aged about 18-36 months old revealed 65.16 % (58/89) and 48 old she buffaloes (5-8 years) showed 68.75 % (33/48). The organ wise prevalence was highest in esophagus (51.82 %) followed by tongue (47.44 %), heart (29.92 %), diaphragmatic muscles (28.46 %) and intercostal muscles (18.24 %), respectively. Morphometric studies revealed the presence of two Sarcocystis species, i.e., S.levinei and S.fusiformis infection with a prevalence of 43.79 and 22.62 %, respectively, along with mixed infection rate of 43.06 %. Microscopic studies of S.levinei showed sarcocyst length/width/cyst wall thickness ranged between 0.31-0.69/0.09-0.12 mm/<1 µm, respectively, and bradyzoites with an average of 6.25 µm length/2.5 µm width. Similarly, S.fusiformis cyst ranged between 2 and 8.5 mm/1-3 mm/2-5 µm and bradyzoites with an average of 10 µm length/2.5 µm width. The histopathological studies revealed congestion and degenerative changes of myocytes along with infiltration of mononuclear cells.