Artical 1

SEROPREVALENCE OF BRUCELLA MELITENSIS INFECTION IN SHEEP AROUND CHENNAI, TAMIL NADU. Maher Sulima, K.S. Venkataraman*, N. Daniel Joy Chandran** and R. Jayakumar*** Department of Veterinary Epidemiology and Preventive Medicine Madras Veterinary College, Chennai – 600 007. ABSTRACT A total of 231 sheep around Chennai city were screened for Brucella melitensis infection by employing the rose bengal test (RBT), standard tube agglutination test (STAT) and indirect

enzyme linked immunosorbent assay (i-ELISA). The overall prevalence by RBT, STAT and

i-

ELISA was found to be 13.85 %, 9.96% and 20.35%, respectively. RBT was able to detect B.melitensis infection more than the STAT; whereas the i-ELISA was found to be highly sensitive in detecting Brucella melitensis antibodies in sheep. The prevalence of B.melitensis infection was found to be different and varied from one area to another area. Key word: B.melitensis- prevalence- sheep- RBT- STAT- i-ELISA Brucellosis is considered to be the most widespread zoonosis in the world (OIE, 2000). The importance of brucellosis is due to its economic impact on the animal industry, and to the severe hazard it represents to human health, through either direct contact with infected animals or more frequently, the consumption of contaminated milk (Abeer, et al.,2003). Ovine Brucellosis due to B.melitensis is widespread in India and is the major cause of abortion in sheep (Das et al., 1961; Ghosh and Verma, 1985). In Tamil Nadu prevalence of brucellosis in sheep has not been reported so far. Hence, the present study was undertaken to focus the seroprevalence of B.melitensis infection in sheep in Tamil Nadu. * Professor ** Professor and Head, Central University Laboratory, Madhavaram Milk Colony, Chennai-51 *** Professor and Head. Maher Sulima (Email:[email protected]) Tamil Nadu university journal 2007

MATERIALS AND METHODS This study was conducted in different areas around Chennai city viz. Kancheepuram, Virapuram, Tiruvallur, Chengelput, Madurapakkam and Otteri. A total of 231 sheep (Madras red) with the history and clinical symptoms of abortion, still birth, repeat breeding and pyrexia were screened for B.melitensis antibodies using serological tests viz. rose bengal test (RBT), standard tubes agglutination test (STAT) and i-ELISA. Rose Bengal Test (RBT) The RBT antigen was obtained from Indian Veterinary Research Institute, Izatnagar. The Rose Bengal test was performed as described by OIE (2000). Standard Tube Agglutination Test (STAT) Brucella melitensis tube antigen was obtained from the Institute of Veterinary Preventive Medicine, Ranipet. The STAT using B.melitensis tube antigen was performed as per the method described by Alton et al (1988). Serum titres of 80 IU or above were considered to be positive, 40 IU as doubtful and less than 40 IU as negative (Alton et al., 1988). Indirect- Enzyme Linked Immunosorbent Assay (i-ELISA) The i-ELISA was performed as described by Brucella antibody test kit (VMRD, Inc., USA). Samples producing a sample / positive control (SP) Ratio of < 25 were negative. Samples with SP ratios of ≥ 25 were positive. RESULTS AND DISCUSSION In the present study, the overall prevalence of B.melitensis infection in sheep tested by RBT, STAT and i-ELISA was 13.85%, 9.96% and 20.35%, respectively (Table-1). Aera prevalence by RBT, STAT and i-ELISA in Kancheepuram was 8.33%, 12.50% and 16.66% respectively, in

Viraupram was 19.05%, 9.52% and 33.33% respectively, in Tiruvallur was 26.66%, 16.66% and 33.33% respectively, in Chengelput was 13.88%, 11.11% and 16.66% respectively, in Madurapakam was 4.84%, 1.61% and 6.45% respectively, in Otteri was 22.72%, 18.18% and 45.45% respectively (Table 2).

The prevalence of B.melitensis infection in sheep by i-ELISA was 4.96% in Karnataka and 4.7% in Uttar Pradesh (Desai et al., 1995; Singh et al., 2000). Kumar et al. (1997) in their studies on ovine brucellosis also reported a prevalence of 50% in Punjab, 33% in Rajasthan and 11% in Northern State of Delhi. Also, the prevalence of brucellosis in sheep in various states of India was found to be different and varied from one place to another (Renukaradhya et al., 2002; Gupta et al., 2003). When compared with these studies the detection of B.melitensis infection in sheep by i-ELISA was moderately higher (20.35%) around Chennai. Further, in the present study also the prevalence varied from one area to another vastly and these findings concurred with earlier studies.

On the whole i-ELISA was able to detect more seropositivity to B.melitensis infection in sheep (20.35%) as also reported by Renukaradhya et al., (2002). Table 1 Overall prevalence of Brucella melitensis infection by RBT, STAT and i-ELISA in sheep

Test RBT STAT i-ELISA

No. tested 231 231 231

No. Positive 32 23 47

% positive 13.85 9.96 20.35

Table 2 Area-wise prevalence of B. melitensis infection by RBT, STAT, i-ELISA in sheep No. of samples tested Kancheepuram 24 Area

RBT Positive

Prevalence STAT % positive

Prevalence i-ELISA Prevalence% % positive

2

8.33

3

12.50

4

16.66

Viraupram

21

4

19.05

2

9.52

7

33.33

Triuvallur

30

8

26.66

5

16.66

10

33.33

Chengelput

72

10

13.88

8

11.11

12

16.66

Madurapakam

62

3

4.84

1

1.61

4

6.45

Otteri

22

5

22.72

4

18.18

10

45.45

Total

231

32

13.85

23

9.96

47

20.35

ACKNOWLEDGEMENT The authors thank the Dean, Madras Veterinary College, Chennai-7 for providing necessary facilities during the study period. REFERENCES Abeer,H.A., Shawkat, Q.L and Yasser Al-Tarazi (2003). Epidemiology of ovine brucellosis in Awassi sheep in northern Jordan. Preventive Veterinary Medicine. 60: 297-306. Alton,G.G., Jones, L.M., Angus, R.D.,

and Verges, J.M. (1988). Techniques for the brucellosis

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Gupta, V.K., Rana, N and Vihan, V.S. (2003). Enzyme liked immunosorbent assay (ELISA) for detection of Brucella melitensis antibodies in goats. Indian Journal of Animal Sciences., 73: 259-261. Kumar, P., Singh, D.K and Barbuddhe, S.B. (1997). Serological evidence of brucellosis in sheep and goats. Indian Journal of Animal Sciences, 67(3): 180-182. OIE (2000). Manual of Standards for Diagnostic Tests and Vaccines. Caprine and ovine brucellosis. OIE., Paris, pp. 475-489. Renukaradhya, G.J., Isloor, S.,

and Rajasekhar, M. (2002). Epidemiology, zoonotic aspects,

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