Molecular and epidemiological study for brucellosis in mixed farms

Abstract

Some farms may have mixed animals, (cows, goats, sheep & camel). It has not been well described in the literature as to whether cross infection of different species of Brucella occurs, when these animals are kept together, particularly in the case of camels, sheep and goats in which the main virulent organism is the same (Brucella meliensis). Most of the previous studies undertaken followed serological testing for the investigation of Brucella prevalence and epidemiology to investigate this problem. In the present study serological tests were carried out for screening and bio-epidemiological techniques using PCR for confirmation. The objective is to study the incidence of brucellosis in different types of mixed animal herds containing sheep, goats and camel to evaluate the significance of brucellosis problem and the pattern of the disease transmission and shedding of organisms in milk of carriers and resistant animals. . The farms were categorized in two different types namely, agro pastoralist, and Feed-lot. A total of 854 blood samples were collected during the year 2005. Sera was separated and tested using monospecific antigen. The over all prevalence rate in which this study was conducted (Al Quaseem area) according to RBBT was found to be 5.9%. The incidence rates in different mixed farming systems were as follows: A. The incidence rate in Feed lot farms was 8.4% B. The incidence rate in the Agro pastoralist farms was 4.9 % The incidence in different animals within the two different farming systems was found 4.1%in sheep, 9.7% in goats 5% in cow, 2% in camels The predominant species of brucella using monospecific antigen was found to be B. melitensis with some few cases of B. abortus The study revealed that there was a high incidence rate in the feed lot system particularly in the resident animals (goats) in this system. The brucella organism was isolated from both stomach content of aborted sheep fetus and detected by PCR. The study reveals that PCR technique could be used as well as bacteriological testing for confirmation of brucella infection