Cross-transmission of brucellosis can occur between cattle, swine, sheep and goats and other species, including dogs, horses, feral swine, bison, reindeer, caribou and camels. In some instances, the infection is dead-end, e.g. dogs eating placentas from infected animals following abortion, while in other situations, such as feral swine, onward transmission to cattle or domestic swine occurs readily. Therefore, in any brucellosis surveillance programme where there is epidemiological or bacteriological evidence that wildlife or feral species are a source of new or re-infections in cattle, swine, sheep and goats, these species should be routinely monitored, either by a defined capture programme or using routine hunting activities to obtain tissues and blood for examination.
Camel husbandry is vital for numerous pastoralist groups in Asia and Africa. Infection in camels is caused by different biotypes of B. abortus and B. melitensis. Currently, many gaps exists in knowledge of the epidemiology of the disease in camels. Many countries with long standing traditions of camel keeping and usage do not have clear-cut policies regarding the control of camel brucellosis. Seroprevalence of brucellosis in camels is low in beasts kept under extensive pastoralist husbandry, whilst it is rather high in more camels maintained under intensive conditions. An important aspect of the epidemiology of brucellosis in camels is the role of the intercalving interval in the transmission of infection between camels within a herd. Nomadic camels usually have a lengthy intercalving interval, estimated to be between 2 and 3 years. Since most brucellosis contamination occurs following an abortion or delivery by an infected female, then the long intercalving interval might contribute to a lower incidence of brucellosis in nomadic or extensively raised camels. The use of Strain 19 and Rev.1 vaccines have been recommended for use in controlling camel brucellosis. In countries where camels are kept extensively and where seroprevalence of the disease is low, whole-herd vaccination is recommended, preceded by blood testing using the Rose Bengal test. Seropositive animals could be identified by branding or earmarking and retested. In high prevalence countries with intensive management system of camel production, test and slaughter followed by vaccination is recommended. In such countries, the economy is generally strong to support such control measures. Public education and sensitization is essential to the success of control programmes in both management systems of camels.
