Seroprevalence studies of bovine brucellosis using indirectenzyme-linked immunosorbent assay (i-ELISA) at organized and unorganized farms in three different states of India.

Aim: The present study was undertaken to know the seroprevalence of brucellosis in cattle and buffaloes. The work was carried out during the period 2011 through 2013 at Centre for Animal Diseases, Research and Diagnostics, IVRI, Izatnagar, Uttar Pradesh, India. Materials and Methods: A total of 1005 sera samples were collected and tested for bovine brucellosis using ELISA Kit; IDEXX, CHEKIT, Brucellose serum, Brucella abortus Antibody Test Kit Results: A total of 1005 serum samples were collected from Karnataka, Uttar Pradesh and Uttarakhand during the period of 2011 to 2013 and were screened for bovine brucellosis using i-ELISA (indirect enzyme linked immunosorbent assay). The prevalence of bovine brucellosis was compared between organized and unorganized farms in order to find the epidemiology of the disease among the animal population. Sera from 5 organized farms in Karnataka were collected for seroprevalence studies. Out of 417 animals, 191 (45.80%) animals were found positive by i-ELISA. A total of 361 serum samples were collected from 5 unorganized farms or villages, of which 82 (22.71%) were positive. From Uttar Pradesh, bovine serum samples were collected from 3 organized farms. Out of 192 animals, 43 (22.39%) animals were found positive for brucellosis. Similarly, sera collected from a single organized farm from Uttarakhand, showed 3 (8.57%) positivity among 35 animals. On the whole, 319 (31.74%) animals were found positive for brucellosis among the 3 states taken for study, which includes 138 (27.21%) cattle and 181 (36.34%) buffaloes. Conclusion: It has been found that Brucella infections are widely prevalent in organized and unorganized dairy farms in investigated states of India.


Introduction
confirmative test [4].However, it is time consuming, requires biosafety level-3 facilities and skilled persons Bovine brucellosis is a major zoonotic disease to handle samples.The alternative methods involving caused by bacteria which affects both cattle and buffaloes serological tests are easy, safe, and less time and resource equally.More prevalent in adults while young ones do intensive.not show infection till maturity.The bacteria commonly The aim of the present study was to study the associated with the bovine brucellosis are mainly prevalence of brucellosis in cattle and buffaloes of Brucella abortus, less frequently Brucella melitensis Karnataka, Uttar Pradesh and Uttarakhand in order to and rarely by B. suis [1].take an effective control measures against contagious The prevalence of bovine brucellosis in dairy infection which causes heavy economic losses.farms has long been reported and studies have confirmed widespread prevalence in different states of India [2,3].

The control of bovine brucellosis is possible only
Ethical consideration: (n=48) positive out of 251 sera tested for brucellosis with i-ELISA in Anand, Vadodara and Kaira districts Preparation of sera samples and i-ELISA: The i-ELISA [3].Gender wise, 18.70 % (n=43) were found positive test was validated using positive and negative control out of 230 females and 23.81 % (n=5) were found positive sera.After collection of blood from cattle and buffaloes among 21 males by i-ELISA [3].Also, prevalence of the serum was separated, inactivated at 56°C for 30 min 23.79% was found in 374 yaks using AB -ELISA in and stored at -20°C till the test was performed.The seroprevalence studies of north-eastern hilly yak tracts serum samples were subjected to i-ELISA using of Arunachal Pradesh [17].manufacturer's protocol.
The prevalence of brucellosis in unorganized Comparison of the prevalence between organized cows and 4.18% buffaloes) by i-ELISA.Also, a low and unorganized farms in Karnataka showed 45.80% seroprevalence of 1.9% in cattle and 1.8% in buffalo (n=191 out of 417 samples) and 22.71% (n=82 out of were reported on serological survey of 19 states in 361 samples) (Table -1).However, previous reports India [15].The high seroprevalence of brucellosis was indicated 22.18% animals sero-positive by i-ELISA recorded in our study, because the samples were in organized dairy farms with history of abortion in collected at the phase of out break, when the heard India [18].Also, in contrary to our work, a study in showing signs of abortion, retained placenta and Punjab revealed that organized farms had lower infertility in the farms.
prevalence in well managed farms (5.2%) when compared A total of 361 sera samples (201 cattle and 160 to unorganized poorly managed farms (14.81%) [19].buffaloes) were collected from 5 unorganized farms or The lower prevalence of brucellosis can be villages of Karnataka.Of this, total of 82 (22.71%) achieved or it can be eliminated from an organized were positive for brucellosis reactivity.This included farm with regular screening and removal of reactive 27.36% (n=55) cattle and 16.87% (27)  ELISA [20].The i-ELISA was found to be the more seroprevalence overall and 24.30% in cows and sensitive among the tests used for screening brucellosis 26.03% in buffaloes as detected by i-ELISA [5].[3,8] and it detected 96 (14.46 %) sera samples positive However, a prevalence 21.74 % was reported in endemic for brucellosis [21].It is considered as gold standard The study was approved by the by accurate diagnosis of the disease at the appropriate period 2011 through 2013.The laboratory analysis was for the diagnosis of brucellosis is isolation, which is the conducted at Centre for Animal Diseases, Research and Diagnostics (CADRAD), IVRI, Izatnagar (UP).doi:10.5455/vetworld.2013.550-553from IDEXX-CHEKIT, Brucellose serum (Netherland) areas [16].Similar reports were shown with 19.12% to screen bovine brucellosis.
buffaloes (Table-1).animals with highly specific screening test like i-The over all prevalence of 22.71% observed in ELISA.Also, false positive reactions shown by Rose unorganized farms of Karnataka (Table-1) was Bengal Precipitation Test (RBPT) can be avoided in icomparable with previous reports of average 25%

Table - 1
. Prevalence of brucellosis in cattle and buffaloes of three different states of India, assayed using i-ELISA