Evaluation of Microscopy as a Field Laboratory Test for Diagnosis of Johne's Disease in Farm Animals

Diagnostic potential of microscopy as field laboratory test was compared with IS900 blood PCR for diagnosis and estimation of prevalence of Johne's disease in domestic livestock suffering with clinical disease. Of the 252 animals (39 goats, 133 sheep and 80 cattle) screened, 39.3 and 13.1% were positive by fecal microscopy and blood PCR, respectively. Proportional agreement between microscopy and blood PCR was substantial (72.0%). Of 1262 fecal samples (281 goats, 602 sheep, 309 cattle and 70 buffalo) screened using microscopy, 41.3% were positive for Johne's disease. Prevalence of JD was higher in cattle (61.8%) followed by goats (41.3%), sheep (33.4%) and buffaloes (15.7%). In absence of field based screening test, fecal microscopy can be easily standardized and was promising, cost effective and useful test for large scale screening of domestic ruminants population for Johne's disease.