Prevalence of paratuberculosis in water buffaloes on public livestock farms of Punjab, Pakistan.

The present study had the goal to assess the prevalence of paratuberculosis in 4 public livestock farms of the Punjab (Pakistan). It included 627 total animals of more than 2-year-old tested by Avian Tuberculin, i.e., Purified Protein Derivative. The results of the PPD test were confirmed by indirect ELISA and by Ziehl-Neelsen (ZN) test. An overall prevalence of 1.3% was recorded. The values were between 0.0% and 3.03%. The results of odds ratio suggested that there are 2.18 time's higher chances of disease when body weight of buffaloes is less than 500 kg; 1.65 times in  dry  than  lactating  animals;  2.58  times  when  small  ruminants  are  present;  and  1.19  times when cattle are absent. The total positive buffaloes observed by Avian PPD were 12, although only 10 were then confirmed by ELISA, and 8 by ZN faecal microscopy. The relative sensitivity and  specificity  of  Avian  PPD  by  considering  ELISA  as  standard  test  were  80.0%  and  89.47%, respectively.  Similarly,  the  relative  sensitivity  and  specificity  of  the  ZN  faecal  test  were  70.0% and 97.37%, respectively. The relative sensitivity and specificity of Avian PPD by considering ZN faecal test as standard were 100% and 90%, respectively. Among haematological parameters, platelets significantly decreased and MCH increased in paratuberculosis positive animals. It can be concluded that ELISA may be used as a screening test in future studies for paratuberculosis, tuberculin testing can be used when the ELISA is not affordable to assess the disease situation at the farm; while ZN microscopy, being it a non-invasive test, is a better option than skin testing.