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Seroprevalence of brucellosis in bovine herds using parallel diagnostic approach in the semi-arid agro-ecological zone in Pakistan

2020; Elsevier BV; Volume: 101; Linguagem: Inglês

10.1016/j.ijid.2020.09.1393

1878-3511

Abdul Rehman, M. R. Khan, Salman Khalid, M. U. D. Ahmad, Muhammad Ijaz, M. H. Mushtaq,

Brucella: diagnosis, epidemiology, treatment

Background: Brucellosis is a highly contagious zoonotic disease that causes significant economic losses through abortion and infertility in animals as well as humans. The infected animal remains carrier for life which makes the control of this infectious malady more difficult. Therefore, the present study was designed to determine the seroprevalence of bovine brucellosis using parallel diagnostic approach in the semi-arid agro-ecological zone in Pakistan. Methods & Materials: A total of 220 serum samples (Gujranwala = 58, Kamoke = 53, Wazirabad = 55 and Nowshera Virkan = 54) from 46 herds were collected from bovines (buffaloes = 112, cattle = 108) – above 6 months of age – in the semi-arid zone. All the serum samples were subjected to Rose Bengal Test (RBT) and indirect enzyme-linked immunosorbent assay (iELISA) for the presence of antibodies (IgG) against Brucella abortus, Brucella melitensis and Brucella suis. Data was also collected to find out the association of various host-related factors with the occurrence of brucellosis. Results: Parallel interpretation of the two tests showed that the estimated animal and herd-level seroprevalences were 22.7% (50/220) and 58.70% (27/46), respectively, whereas the serial interpretation of the tests estimated significantly (P < 0.001) low prevalence, i.e. 12.27% (27/220) and 39.13% (18/46). The animal-level seroprevalence was highest in Gujranwala Tehsil (31.03%), followed by Nowshera Virkan (27.78%), Wazirabad (16.36%) and Kamoke (14.81%). Analysis of host-related risk factors revealed that the seroprevalence was significantly higher (P = 0.02, OR = 4.91) in female animals (25.4%) as compared to males (6.5%). Also, abortion was strongly associated (P < 0.001, OR = 5.46) with seroprevalence of Brucella on livestock farms. A substantial agreement between RBT and iELISA results (Cohen's kappa = 0.642, 95% CI = 0.510–0.773) was observed. Conclusion: The study suggests that both the tests should be used in parallel combination for import decisions while serial interpretation should be applied for the culling purpose. More importantly, the herd-level prevalence suggests that government should take necessary steps to stop further spread of the disease to the other animals as well as farm workers.