Seroprevalence and molecular investigation of brucellosis in camels of selected districts of Punjab, Pakistan

Abstract

Camels still play an important role in providing food security in several developing countries, especially in the arid zones. As brucellosis has zoonotic importance, thereby diseased camels can infect humans chiefly via milk. In spite of its vital importance, limited studies are available of brucellosis in camels in Pakistan. Keeping in view the fact, this study was designed and executed. For this purpose, serum samples (n=761) from various herds of camel with history of abortion from different locations of Punjab province, Pakistan were collected. Initial screening was done using Rose Bengal plate test (RBPT). To avoid improper judgment of the diagnosis of brucellosis caused by serological tests, positive samples were subjected to competitive enzyme-linked immunosorbent assay (cELISA). Detection of Brucella genome was carried out through conventional PCR in RBPT and cELISA positive test samples. Overall, 3.41% (n=26, 95% CI 2.24-4.97) of the camels were seropositive with RBPT. Prevalence of brucellosis significantly varied in the animals with different geographical source, sex, age, lactation number and health status. In molecular analysis, out of 18 samples confirmed through cELISA, only two samples were positive for Brucella genome through PCR. The sequences were aligned with reported sequences in NCBI GenBank and revealed 100% sequence homology with the bcsp-31 gene of Brucella reported from other parts of the world. The study highlights the epidemiologic, economic and public health impact of camel brucellosis as a basis for designing further diagnostic improvements and effective control strategies.