Bovine venereal campylobacteriosis: an overview.

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.

Epidemiology of Bovine Venereal Campylobacteriosis: Geographic Distribution and Recent Advances in Molecular Diagnostic Techniques

“…BVC, although not frequently diagnosed particularly in endemic tropical countries, is assuming a major importance as a reproductive disease in this species. The genus Campylobacter contains several important pathogens of humans and animals affecting mainly the gastrointestinal and reproductive tracts (Mshelia et al. 2007).…”

“…1981). The prepuce of the bulls is the natural reservoir of infection for naïve cows through natural mating (Mshelia et al. 2007).…”

“…Susceptible heifers and cows are infected mainly after being covered by an infected bull but infections could also occur during artificial insemination (AI) with infected semen or through contaminated insemination equipment (OIE 2005). Following infection in a naïve cow, the organism establishes itself in the mucosa of the reproductive tract causing infertility (Mshelia et al. 2007).…”

Infectious Agents

“…9 The prepuce of bulls is the natural reservoir of infection of naive cows through natural mating. 10 The addition of carrier bulls poses a significant risk to a naive herd, although the disease is most commonly seen in newly introduced cows and heifers in herds where bovine campylobacteriosis is endemic. 11 Cow/fetus Venereal campylobacteriosis causes low reproductive efficiency with severe economic losses.…”

“…13,14 After exposure the bacteria colonize in the mucosa of the anterior vagina and cervix of cows. 10 The infection then spreads to the uterus and oviducts under the influence of progesterone. Fertilization and development of the embryo are not directly affected by C. fetus subsp.…”