Karlsson et al. Acta Veterinaria Scandinavica 2010, 52:2 http://www.actavetscand.com/content/52/1/2 R E S E A R C H Open Access Investigation of Chlamydiaceae in semen and cauda epididymidis and seroprevalence of Chlamydophila abortus in breeding bulls Ann-Charlotte Karlsson1,2*, Stefan Alenius1, Camilla Björkman1, Ylva Persson3, Stina Englund4 Abstract Background: Reproductive disorders associated with chlamydial infection have been reported worldwide in cattle and there are indications of potential venereal transmission. Methods: Semen samples from 21 dairy bulls and cauda epididymidis tissue samples from 43 beef bulls were analysed for chlamydial agent by real-time polymerase chain reaction (PCR) including an internal amplification control (mimic). Additionally, presence of antibodies against Chlamydophila (Cp.) abortus among the bulls was investigated with the commercial Pourquier® ELISA Cp. abortus serum verification kit. Results: No chlamydial agent was detected by PCR in either the semen samples or in the tissue samples. Additionally, no antibodies against Cp. abortus were detected. Conclusions: The results suggest that Cp. abortus is very rare, or absent in Swedish bulls and thus the risk for venereal transmission of chlamydial infection through their semen is low. However, because Chlamydophila spp. infection rates seem to differ throughout the world, it is essential to clarify the relative importance of transmission of the infection through semen on cattle fertility. Background Bovine chlamydiosis has been associated with several disease manifestations [1]. Reproductive disorders such as sporadic abortions and reduced fertility, linked with chlamydial infection have been reported from Germany [2,3], Great Britain [4], Italy [5], Japan [6], Switzerland [7], Taiwan [8] and the USA [9]. In Sweden, the inci- dence of abortion in cows is low. However, reproductive disorders and infertility are major causes of culling but are often difficult to be diagnosed. Chlamydial infection in bulls may be the cause to some of these problems [10]. Experimental studies have shown that the bacteria can be excreted in semen of inoculated bulls and rams [11] and isolation of the agent from semen of naturally infected bulls and rams has been reported [12-14]. The vaginal mucosa in sheep and uterine mucosa in cattle are susceptible to infection [15,16] and transmission of * Correspondence: ann-charlotte.karlsson@vetinst.no 1Division of Ruminant Medicine and Veterinary Epidemiology, Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences (SLU), Box 7054, SE-750 07, Uppsala, Sweden chlamydial agent by experimentally infected semen to heifers and sheep has been demonstrated [17,18]. The two species Chlamydophila (Cp.) abortus and Cp. pecorum are known to infect cattle and are suggested to be ubiquitous [9,19]. Moreover, Cp. psittaci infections in cattle have been reported [20,21]. All three species have been identified in bull semen [22,23]. Cp. abortus is the cause of Ovine Enzootic Abortion (OEA), the major infectious cause of abortion and lamb loss with great economic losses in many sheep-producing countries [24]. Cp. pecorum has foremost been associated with polyarthritis, encephalitis and inapparent intestinal infection, and the impact by Cp. psittaci in ruminants is yet to be investigated. Each year about 80 top-ranked performance-tested yearling beef bulls are sold all over Sweden, mainly to pedigree breeders, after six months of testing at the only performance testing station in the country. These per- formance-tested bulls represent the best-documented beef bulls with the highest impact on the breeding pro- gramme in Sweden and are therefore important poten- tial transmitters of Chlamydophila spp. by venereal © 2010 Karlsson et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.