Bovine venereal campylobacteriosis: an overview.

Abstract

Abstract Campylobacter fetus is a well-recognized pathogen of animals and humans. The organism has been divided into two subspecies, C. fetus subsp. venerealis and C. fetus subsp. fetus , that are highly related phenotypically and genotypically. Due to this relatedness, it has become imperative to differentiate these two subspecies in order to avoid misdiagnosis and highlight clonal origins geographically. The principal phenotypic differentiating test at the moment is the growth of C. fetus subsp. fetus in the presence of 1% glycine, but glycine-tolerant variants of C. fetus subsp. venerealis have also been described. Molecular tools such as polymerase chain reaction (PCR), amplified fragment length polymorphism (AFLP), numerical analysis of pulsed-field gel electrophoresis (PFGE)-DNA profiles and gene sequence analysis amongst others have been used to differentiate C. fetus subspecies; and they seem to hold promise for the future. C. fetus subsp. fetus colonize the intestines of cattle and sheep and is associated with sporadic abortions and enteritis, while, C. fetus subsp. venerealis is highly adapted to the genital tracts of cattle and is the causative agent of bovine venereal campylobacteriosis (BVC). This disease has a worldwide distribution and is of major economic concern to cattle industries in various parts of the world. The prevalence of the disease is highest in the developing countries where natural breeding in cattle is widely practiced. BVC is associated with lowered fertility, embryo mortality and abortion; other clinical features of the disease include many services per conception, poor pregnancy rates, long calving intervals, stillbirths and birth of weak calves that may eventually die. Vaccines have been shown to be useful in the protection of cattle against the menace of BVC, but commercial vaccines are only available in some parts of the world where advanced agricultural practices have limited its occurrence. The continued presence of this disease in the developing world poses a threat to sustainable cattle production efforts in these countries. Previous reviews highlighted the epidemiology, pathogenesis and diagnosis of the disease; in this review the clinical features of BVC, advances in diagnosis, treatment and prevention, as well as the geographic distribution of the disease have been reviewed. To achieve faster results worldwide, the need for collaborative research on BVC between investigators in developing countries and their counterparts in the developed countries has been recommended.