[Abortion in cattle caused by Chlamydia psittaci]

Interaction of different Chlamydiae species with bovine spermatozoa

Background

Interaction of spermatozoa and Chlamydiae spp. might contribute to reduced fertility in cattle. To proof this hypothesis, bovine semen was incubated with viable or heat inactivated Chlamydia (C.) abortus or psittaci (Multiplicity of infection = 1) and sperm motility was monitored with a computer-assisted sperm analyzer over 24 h. Additionally, the interaction with the spermatozoa was further investigated by means of light and transmission electron microscopy (TEM).

Results

Only viable Chlamydiae of both species decreased sperm motility and this only after about 9 h. Taking binding rates into account, the loss of sperm motility after about 9 h could likely be a consequence of Chlamydiae attachment to the spermatozoa. About two thirds of the Chlamydiae elementary bodies were bound to the front third of the sperm, the acrosomal region. No inclusions of Chlamydiae in spermatozoa were observed in TEM after 2 h co-incubation.

Conclusions

As initial motility was not affected following co-incubation of viable Chlamydiae and bovine sperm, it seems likely that sperm could serve as a carrier/vehicle for Chlamydiae facilitating cervical passage of Chlamydiae spp. in cattle. Additionally, our results suggest that spermatozoa carrying Chlamydiae may have no initial disadvantage in reaching the oviduct, but are immotile at the time of ovulation what might have an impact on fertilization capacities of the individual sperm. Consequently, high concentrations of the investigated Chlamydiae in the seminal plasma or female genital tract might play a role in reduced fertility in cattle.

Bovine Fetal Placenta During Pregnancy and the Postpartum Period

Bovine abortion is a worldwide problem, but despite extensive histopathologic and molecular investigations, the cause of abortion remains unclear in about 70% of cases. Cellular debris is a commonly observed histopathologic finding in the fetal placenta and is often interpreted as necrosis. In this study, the nature of this cellular debris was characterized, and histologic changes in the normal fetal placenta during pregnancy and after delivery were assessed. In addition, the presence of the most common abortifacient pathogens in Switzerland ( Chlamydiaceae, Coxiella burnetii, Neospora caninum) was tested by polymerase chain reaction. We collected 51 placentomes and 235 cotyledons from 41 and from 50 cows, respectively. In total, cellular debris was present in 48 of 51 (94%) placentomes and in 225 of 235 (96%) cotyledons, inflammation occurred in 1 of 51 (2%) placentomes and in 46 of 235 (20%) cotyledons, vasculitis was seen in 1 of 51 (2%) placentomes and 46 of 235 (20%) cotyledons, and 18 of 51 (35%) placentomes and 181 of 235 (77%) cotyledons had mineralization. The amount of cellular debris correlated with areas of positive signals for cleaved caspase 3 and lamin A. Therefore, this finding was interpreted as an apoptotic process. In total, 10 of 50 cotyledons (20%) were positive for C. burnetii DNA, most likely representing subclinical infections. The results of our study indicate that histologic features in the fetal placenta such as cellular debris, inflammation, vasculitis, and mineralization must be considered physiological processes during pregnancy and after delivery. Therefore, their presence in placentae of aborted fetuses must be interpreted with caution and might not be necessarily linked to an infectious cause of abortion.

Chlamydia-related abortions in Cattle from Graubunden, Switzerland

In 2001, the first case of bovine chlamydial abortion was reported in canton Graubunden, Switzerland. In this region, Chlamydophila (Cp.) abortus is endemic in small ruminants. Hence, we aimed to investigate the incidence of chlamydia-related abortions in cattle from Graubunden. During breeding seasons of 2003-2004, formalin-fixed and paraffin-embedded placenta specimens ( n = 235) from late-term abortions in cattle were analyzed by histopathology, immunohistochemistry with a Chlamydiaceae-specific monoclonal antibody against chlamydial lipopolysaccharide (LPS), and 2 different polymerase chain reaction (PCR) methods (16 S ribosomal ribonucleic acid [rRNA] PCR, intergenic spacer [IGS-S] PCR), followed by PCR product sequencing. In 149 of 235 cases (63.4%), histopathologic lesions such as purulent and/or necrotizing placentitis were observed. Chlamydial antigen was clearly demonstrated in immunohistochemistry in only 1 of 235 cases (0.4%). Cp. abortus or Cp. psittaci was found in 12 of 235 (5.1%) and 10 of 235 cases (4.2%) by 16 S rRNA PCR and IGS-S PCR, respectively. However, we detected, by 16 S rRNA PCR, 43 of 235 cases (18.3%) to be positive for chlamydia-like organisms. In contrast to the situation in small ruminants in the canton Graubunden, bovine abortion from Cp. abortus seems not to play an important role. Nevertheless, zoonotic potential should be taken into account when handling abortion material from cattle. The significance of chlamydia-like isolates other than Waddlia chondrophila remains an open question in abortion and needs further investigation.

Investigation of Chlamydiaceae in semen and cauda epididymidis and seroprevalence of Chlamydophila abortus in breeding bulls

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.

Evidence for Parachlamydia in bovine abortion

Bovine abortion of unknown infectious aetiology still remains a major economic problem. In this study, we focused on a new possible abortigenic agent called Parachlamydia acanthamoebae. Retrospective samples (n=235) taken from late-term abortions in cattle were investigated by real-time diagnostic PCR for Chlamydiaceae and Parachlamydia spp., respectively. Histological sections of cases positive by real-time PCR for any Chlamydia-related agent were further examined by immunohistochemistry using specific antibodies. Chlamydophila abortus was detected only in three cases (1.3%) by real-time PCR and ArrayTube Microarray playing a less important role in bovine abortion compared to the situation in small ruminants in Switzerland. By real-time PCR as many as 43 of 235 (18.3%) cases turned out to be positive for Parachlamydia. The presence of Parachlamydia within placental lesions was confirmed in 35 cases (81.4%) by immunohistochemistry. The main histopathological feature in parachlamydial abortion was purulent to necrotizing placentitis (25/43). Parachlamydia should be considered as a new abortigenic agent in Swiss cattle. Since Parachlamydia may be involved in lower respiratory tract infections in humans, bovine abortion material should be handled with care given the possible zoonotic risk.

Aetiology of bovine abortion in Switzerland from 1986 to 1995--a retrospective study with emphasis on detection of Neospora caninum and Toxoplasma gondii by PCR

In a retrospective study, covering the period from 1986 to 1995, tissues of aborted fetuses were re-examined. A total of 347 cases were tested immunohistochemically, among them samples of 223 brains were examined for Neospora caninum, Toxoplasma gondii and Bovine Virus Diarrhoea Virus (BVDV), and 249 placentae for Chlamydiaceae. Two real-time PCR assays, one for N. caninum, and one for T. gondii, were developed. These potential abortion-inducing agents were detected - and confirmed by PCR, except for BVDV - in 16.1% (N. caninum), 0% (T. gondii), 9.9% (BVDV) and 0.8% (Chlamydiales) of the cases examined. Immunohistochemistry proved to be inadequate for the detection of the protozoal epitopes, whereas it was confirmed as a very useful tool for the detection of BVDV. In abortion material, PCR is considered to be more suitable for the detection of protozoa and Chlamydophila abortus, an adequate sampling presupposed.

The prevalence of chlamydiae of bulls from six bull studs in Germany

Although there are indications for venereal transmission of chlamydiae in cattle, epidemiological data on the presence of these bacteria in bulls and bull semen in particular is still incomplete. We investigated semen (n=120), preputial washing samples (n=121) and faeces (n=122) of bulls from six bull studs located within five Federal States of Germany for the presence of chlamydiae using omp1-PCR and partial omp1 sequencing. Blood serum was examined for chlamydial antibodies using an indirect ELISA (n=122). Chlamydiae were found in 11 (9.2%), 13 (10.7%) and 22 (18.0%) of the semen, preputial washing and faecal samples, respectively. Among individual chlamydial species identified, Chlamydophila (Cp.) psittaci predominated in semen and preputial washing samples, and Cp. pecorum in faeces. Cp. abortus was the third frequently observed species. Chlamydial antibodies were detected in a total of 62 (50.8%) bulls. Bull studs differed in regard to the number of bulls found chlamydia-positive in faeces and serologically positive. No correlation was observed between serological data and PCR of semen, preputial washing samples or faeces. Standard ejaculate parameters did not differ between bulls that were chlamydia-positive and -negative in semen. In conclusion, detection of chlamydiae in semen of bulls suggests a potential for venereal transmission. Chlamydiae appear to be widespread within the bull population in Germany. Serological testing failed to identify bulls shedding chlamydiae in their semen.

Seroprevalences for ovine enzootic abortion in Switzerland

Our aim was to assess the seroprevalence of Chlamydophila (Cd) abortus (Chlamydia psittaci serotype 1), denoted ovine enzootic abortion (OEA), in the Swiss sheep population. A competitive enzyme-linked immunosorbent assay (cELISA) was adapted for the investigation of pooled serum samples (pool approach) and receiver-operator characteristic (ROC) analysis was applied to define the cut-off of the pool approach. At a cut-off value of 30% inhibition, the flock-level pooled sensitivity and specificity were 92.9% and 97.6% when compared to classifying the flock based on individual-animal samples. Subsequently, sera from 775 randomly selected flocks out of 11 cantons of Switzerland were investigated using the pool approach. The cantons included in the study represented 72% of the Swiss sheep flocks and 76% of Swiss sheep population. Antibodies against Cd. abortus were found in almost 19% (144) of the 775 examined sheep flocks. Test prevalences were adjusted for the imperfect test characteristics using the Rogan-Gladen estimator and Bayesian inference. Seroprevalence was highest (43%) in the canton Graubunden. In the remaining 10 cantons the seroprevalence ranged from 2 to 29%. The cELISA in combination with testing pooled sera and statistical methods for true prevalence estimation provided a good survey tool at lower costs and time when compared to other approaches.