Vol. 6, Issue 7 (2017)

Author(s):
Lingala Raju Kumar, Manchukonda Udaya Kumar and GS Sreenivasa Murthy

Abstract:
The present study deals with the diagnostic evaluation of PCR assay targeted to a repetitive element (IpSdS) in the genome of Setaria digitata in bovines suspected for microfilariosis. The PCR assay has yielded 125bp and 332 bp products. Similar banding pattern observed with both adult Setaria digitata worm, In-vitro isolated microfilariae. The standardized PCR assay found sensitive in detecting as little as 31.25pg of DNA microfilariae which is equivalent to 1/8^th of single microfilaria. The standardized PCR assay gave positive signals with 49 out of 326 bovine blood samples tested, indicating an overall prevalence of 15.03% of bovine microfilariosis. Comparatively a higher percentage of infection was recorded in buffaloes (17.54% (30/171) than in cattle (12.25% (19/155). A proportionate increase of 2.22%, 8.64%, 17.92% and 23.4%, of bovine microfilariosis was recorded in the age groups starting from <3 years (1/45), 3-6 years (7/81), 6-9 years (19/106), and above 9 years (22/94), respectively. Similarly, highest prevalence of bovine microfilariosis was recorded in lactating 32/146 (21.91%%) animals followed by non lactating 14/110 (12.72%) and heifers 3/42 (7.14%). The PCR assay was found to be superior than Modified Knots technique and Giemsa staining which detected 49, 20 and 13 positive cases of bovine microfilariosis out of 326 samples screened, showing 15.03%, 6.14% and 3.98% of positivity, respectively