Laboratory diagnosis of infectious bovine abortion.
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Abortion, Veterinary↗
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Contribution to the diagnosis of infectious swine abortion.
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Abortion, Veterinary↗
Characteristics of a newly-recognized species of Brucella responsible for infectious canine abortions.
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Abortion, Veterinary↗
Infectious bovine abortion: a practitioner's approach to diagnosis.
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Abortion, Veterinary↗
[The importance of bovine neosporosis for abortion in Switzerland].
The protozoan parasite Neospora caninum is one of the most important infectious abortion causes in cattle worldwide. In a Swiss case-control-study we investigated 113 abortion problem farms and 113 control farms. It was possible to detect N. caninum in 21% of 242 investigated aborted fetuses by PCR upon brain samples. Eighty-four % of mothers aborting N. caninum positive fetuses were serologically positive for this parasite. The seroprevalence for N. caninum of all aborting mothers was 44%. Within a period of 3 to 12 months 4,505 cattle from the participating farms were investigated serologically at two different time points. Strong fluctuations of the specific antibody concentration could be observed, resulting in a conversion to seronegativity in the second blood sample in 39% of formerly seropositive animals. Eighteen months after the end of the study, 42 case- and 42 controlfarms were questioned about their present abortion-status. Analysis of the questionnaire revealed that 80% of the former abortion problem farms observed an improvement of the situation. However, in 43% of those farms no preventive measures had been taken and no significant differences in hygiene, forage and animal turnover could be observed between case- and control-farms. Additionally, no significant differences were detected concerning risk factors such as the presence of farm dogs and the disposal procedure for placental and fetal material.
Abortion, Veterinary↗
Analysis of a model of bovine brucellosis using singular perturbations.
In this paper a model of bovine brucellosis spread is analyzed. This model consider four epidemiological classes: susceptibles, aborting infectious, infectious carriers and immune by vaccination. The per capita death rates of susceptibles, aborting and carriers are interpreted as slaughtering rates and they are time variable in order to maintain the size of the herd constant. A description of the evolution of the disease at the beginning of the epizootiological outbreak is given by means of singular perturbation techniques. We obtain a threshold parameter for the outbreak of the disease and a description of the asymptotic behavior of the model by using a theorem of Markus on asymptotically autonomous systems.
Abortion, Veterinary↗
Diagnostic survey of bovine abortion with special reference to Neospora caninum infection: importance, repeated abortion and concurrent infection in aborted fetuses in Southern Brazil.
The protozoa Neospora caninum is an important cause of bovine abortion world-wide. The objective of this survey was to determine the distribution pattern of infectious abortion in Southern Brazil with special reference to N. caninum infection. A total of 161 bovine aborted fetuses from 149 farms were analysed during a 1.5 year period. The cause of abortion was identified in 51.5% of cases. Overall, 23% (37/161) of the fetuses were considered to be infected with N. caninum. Bacterial infection accounted for 17.4% (28/161) of cases, fungal infection for 3.1% (5/161) of cases and viral aetiology for 1.8% (3/161). Six fetuses had concurrent infection with N. caninum and Leptospira spp. Data from 111 fetuses and the respective aborted cows were analysed to investigate the association between previous abortion and current N. caninum infection. The prevalence of N. caninum-infected fetuses from cows with and without a history of previous abortion was 44% (11/25) and 24.4% (21/86), respectively. Cows aborting a N. caninum-infected fetuses were 2.4 times more likely to have aborted previously than cows aborting for other reasons (95% CI of odds ratio=0.9-6.8, P=0.06).
Abortion, Veterinary↗
Host-specific transcription of baculovirus genes.
We examined the differential replication of Autographa californica multicapsid nuclear polyhedrosis virus (AcMNPV; Family: Baculoviridae) in Spodoptera frugiperda (SF) and Bombyx mori (BM) cell lines. Our previous studies have shown that infection of BM cells is abortive; infectious progeny is not produced, and although virogenic stroma is produced, complete virions or inclusion bodies are not assembled. We designed the present study to determine the extent of infected-cell-specific polypeptides (ICSPs) and viral DNA synthesis in the abortive infection and to see if restriction of virus replication in BM cells is due to a block at the transcriptional level. Pulse-labeling studies showed that a majority of the ICSPs detected in productive SF cells were not synthesized in BM cells. Many of these ICSPs were virion components. Viral DNA replicated in BM cells but more slowly and at a much lower level than in SF cells. Northern blot analysis showed that i) AcMNPV immediate-early gene (IE-1) was transcribed in BM cells at higher levels than in SF cells; ii) a delayed-early gene (dnapol) and a late gene (cap) were transcribed at much lower levels in the abortive infection; and iii) a very late gene (polh) was transcribed at extremely low levels in BM cells. We conclude that virus replication in BM cells is primarily restricted during or prior to the delayed-early stage and occurs at the transcriptional level. It appears that the late and very late effects observed are consequences of the primary block.
Animals↗
Investigations into virus carriership in human semen and mouse testicular cells.
Virological investigations were performed to approach the mechanism of male infertility and recurrent abortions. Infectious adenovirus or herpes simplex virus was found in nearly 40% of semen samples obtained from sterile men. The viruses were detected in latent form in 60% of the cells. The same viruses as in the father's cells were found in the aborted material. In vitro inoculation of cell cultures with material of semen origin made the presence of other latent viruses probable. The affinity of adeno- and herpesviruses to urogenital organs was supported by animal experiments in which a new method of in vivo intratesticular inoculation was applied. The close interaction between urogenital cells and viruses was also supported by in vitro infection of human semen with adeno- or herpesviruses. The viruses absorbed to cells, penetrated the latter and their components replicated inside. It is suggested that local chronic viral infection may play part in male infertility and some cases of the recurrent abortions through damaging of cells. In patients treated with Zovirax, virus carriership ceased and the normal function of sperms started again.
Adenoviruses, Human↗
Chlamydia psittaci infection in sheep: a paradigm for human reproductive tract infection.
Chlamydiae are important reproductive tract pathogens in a wide variety of animals. In humans, chronic or repeated infection of the female genital tract with Chlamydia trachomatis has been identified as a significant factor in the development of occlusive infertility or increased risk of ectopic pregnancy. The spectrum of reproductive disease recognized in sheep to be caused by Chlamydia psittaci has been primarily restricted to pregnant animals because the organism was clearly identified as a major cause of infectious abortion. However, following pregnancy failure, a chronic chlamydial infection can become established in the reproductive tracts of experimentally infected ewes. Persistent infection of the ewe's reproductive tract may eventually result in pathology, similar to that observed in women infected with C. trachomatis, thus decreasing the breeding life of affected ewes. Furthermore, ewes that experienced C. psittaci induced abortion provide a unique opportunity to study the host: parasite dynamic as it relates to persistent infection. This natural model of persistent infection may, in some ways, be superior to more contrived models in which the chlamydial isolate is not a normal reproductive pathogen of the study animal. Thus, the study of persistent chlamydial infection in sheep may be used for the benefit of both human and veterinary medicine.
Abortion, Veterinary↗
Relationships between maternal and fetal liver copper, iron, manganese, and zinc concentrations and fetal development in California Holstein dairy cows.
Associations between maternal trace element deficiencies and abortion have been made for many mammalian species. Objectives of this study were to estimate and correlate maternal and fetal hepatic Cu, Fe, Mn, and Zn concentrations through gestation. Additionally, aborted fetuses, stratified by cause of abortion (infectious or noninfectious), were compared to size-matched nonaborted fetuses to examine for magnitude and direction of change in hepatic trace element status. Dam and fetal liver were removed at slaughter from 103 Holstein dairy cows judged grossly normal by ante- and postmortem examination. Liver samples were collected from fetuses submitted by veterinarians for routine diagnosis of abortion (n = 80). Hepatic Cu, Fe, Mn, and Zn concentrations were determined by flame spectrophotometry. Comparisons of groups, estimations of correlations, and derived prediction equations were made by least-squares methods. Maternal liver Cu, Fe, Mn, and Zn concentrations did not vary during gestation. Compared with the dam, fetal liver Fe and Zn concentrations were higher (P < 0.05), fetal Cu concentrations were similar (P > 0.05), and fetal liver Mn concentrations were lower (P < 0.05). As fetal size increased, fetal liver Cu and Zn concentrations increased (P < 0.05), fetal liver Fe concentration decreased (P < 0.05), and fetal liver Mn did not change (P > 0.05). Aborted fetuses had lower liver Cu, Mn, and Zn concentrations than did nonaborted fetuses (P < 0.05). Liver Fe concentration was lower in aborted fetuses than in nonaborted fetuses in the second trimester only (P < 0.05). Consistently lower liver Cu, Fe, Mn, and Zn concentrations in aborted fetuses suggest a nonspecific change in trace element status, which implies an effect of abortion, not a cause of abortion.
Animals↗
A case of intrauterine fetal death associated with maternal Campylobacter coli bacteraemia.
Campylobacter species are known to cause infectious abortion in domestic animals. In humans, Campylobacter are an important cause of enteritis, an occasional cause of systemic infection and have had a rare association with abortion and perinatal infection. A case history of spontaneous abortion, at 26 weeks' duration, associated with maternal bacteraemia, due to Campylobacter coli is presented. Transmission, pathogenesis, treatment, and the need for further investigation are discussed.
Adult↗
Factors associated with Neospora caninum serostatus in cattle of 20 specialised Costa Rican dairy herds.
Twenty-five specialised Costa Rican dairy farms (located in the Poás area) were used to determine neosporosis seroprevalence and the association of seropositivity with environmental and management factors. The farms involved were selected intentionally and all of them use VAMPP 5.1 (Veterinary Automated Management and Production Control Programme) as management-information system. Holstein-Friesian, Jersey and crosses between them were the most-frequent breeds in these herds. The number of females per farm varied from 41 to 296. Our cross-sectional study had two phases. In the first phase, we determined the presence or absence of seropositivity at herd level. For the second phase, all females in 20 seropositive farms were bled. Serum samples were tested for antibodies to Neospora caninum using an indirect enzyme-linked immunosorbent assay (ELISA). A questionnaire with factors mentioned in the literature was administered to the farmers. Logistic regression (LR with herd as random effect) was used to assess the relationships of the serostatus at the individual level with characteristics of the cows and environmental factors. In the first phase all herds had >20% seropositive females; therefore, all herds were eligible for the second phase. In the second phase, the overall prevalence was 39.7% (1191/3002), and within-herd prevalences were between 25.0 and 70.5%. Age 3-6 years, parity < or =2 of the dam of the cow, Jersey breed and lack of purposive sampling to diagnose abortive infectious disease were associated with positive serostatus; other management and environmental factors did not show significant associations. The lack of association between management and environmental factors with serostatus might be because all farms were exposed to a considerable number of potential factors. That all herds of this study were seropositive for neosporosis and the within-herd prevalence was considerable raises questions about how far the infection is spread in other dairy areas of Costa Rica.
Abortion, Veterinary↗
[Diagnosis of septic abortion in dairy cows].
During a two year period, March 1977 to April 1979, a total of 92 bovine abortions were studied. The cause of abortion was determined in 34.8% of the cases examined. Opportunistic bacteria, the most commonly diagnosed cause of abortion, accounted for 31.2% of the cases. Leptospirosis was associated with 28.1% of the abortions, infectious bovine rhinotracheitis and fungi in respectively 15.7%, bovine viral diarrhea in 6.2%. A congenital abnormality accounted for one case (3.1%). In 23 cases (25%), there was no definitive diagnosis, in spite of evidence of experience with pathogen or suggestive findings of pathology, but insufficient evidence to warrant diagnosis. No findings were recorded in 35.8% of the (possibly noninfectious) cases and in only four cases (4.4%), specimens were unsatisfactory for examination.
Abortion, Septic↗
Neospora caninum immunoblotting improves serodiagnosis of bovine neosporosis.
Neospora caninum ranges among the major causes of infectious abortion in cattle worldwide. The present study was designed to improve the serodiagnostic tools by complementing a conventional ELISA with a highly sensitive and species-specific N. caninum immunoblot. To evaluate this test combination, sera from several groups of cows were tested. The first group, consisting of experimentally infected calves, showed that immunoblot antibody reactivities were detectable 1 to 3 days earlier than those found in ELISA. The first immunodominant bands that appeared were a 29-kDa (NcSAG1) and a 36-kDa (NcSRS2) antigen. Other groups, based upon naturally infected cattle, were used to compare the diagnostic sensitivity of ELISA and immunoblotting. Overall, N. caninum immunoblotting exhibited a higher sensitivity (98%) than ELISA (87%). Conversely, immunoblotting also confirm in two other cases, true transient negativation in some animals. In general, banding patterns and band staining intensity correlated to the semiquantitative ELISA findings. On the other hand, the banding pattern could not be used to discriminate between sera from animals with a recent abortion and those of cows with latent N. caninum infection. We also addressed putative cross-reactions due to infection with Toxoplasma gondii. Sera from animals with a serologically proven T. gondii infection were either clearly negative by Neospora immunoblotting or they yielded a specific immunoblot antibody profile indicating a double infection with N. caninum. Sera from animals with positive findings in both Toxoplasma and Neospora ELISA thus provided dichotomic results in the immunoblot by allowing to confirm or to rule out the specificity of the antibody reaction in Neospora ELISA. Altogether, our findings demonstrate that N. caninum immunoblotting is a very sensitive and specific complementary tool to improve the serology for N. caninum infections in cattle.
Abortion, Veterinary↗
Foetal loss in dairy goats: an epidemiological study in 515 individual goats.
Effects of various factors pertaining to the individual goat on the reproductive performance were studied during one season in 515 pregnant dairy goats from seven herds. A significant difference in the risk of foetal loss was found between the herds. Advanced age, difficulty in conceiving, low social status, pregnancy with > or = 3 foetuses and previous foetal loss were significantly associated with current loss. No association was found between foetal loss and the current goat index, milk production last year, daily milk production at the time of dry-off and the presence or absence of horns or dehorning of the goat. The risk of foetal loss was not related to mating with specific bucks. No indication of relationship between goats with foetal loss was found by pedigree analysis including the sire, dam and dam's sire. However, the incidence of foetal loss was significantly higher in daughters of does that had suffered reproductive loss than in daughters of does without such a loss. This suggests a maternal or genetic influence on the occurrence of foetal loss. Culling of goats suffering non-infectious abortion and of their surviving progeny therefore seems reasonable.
Animal Husbandry↗
Identification of Neospora antigens recognized by CD4+ T cells and immune sera from experimentally infected cattle.
Neospora caninum is recognized as a major cause of infectious abortion in cattle. Very little is known about immunity to Neospora. Cell mediated responses have previously been shown to be important in the development of protective immunity to the closely related parasite Toxoplasma gondii, and may therefore be an important component in the immune response to Neospora. In this paper we report that a group of low molecular weight NCI strain tachyzoite antigens (< or = 30 kDa) separated by SDS PAGE and bound to nitrocellulose membrane stimulated proliferation in vitro of CD4+ T cells from calves experimentally infected with N. caninum. Proliferation was accompanied by production of high concentrations of IFN-gamma. Several of these antigens were also recognized by antibody produced in these animals. As the most effective vaccines require the stimulation of both humoral and cell mediated immune responses, these antigens may be important in the development of a vaccine against neosporosis.
Animals↗
Cellular immune responses in cattle experimentally infected with Neospora caninum.
Neospora caninum has recently been identified as an important cause of infectious abortion in cattle. The parasite is closely related to Toxoplasma gondii, but the two species are antigenically distinct. To examine cell proliferative responses and the induction of IFN-gamma in experimentally infected cattle, four 2-4 months old calves were subcutaneously inoculated with N. caninum tachyzoites. Peripheral blood mononuclear cells were collected regularly and stimulated in vitro with a crude lysate of N. caninum or T. gondii tachyzoites. Significant proliferative responses to N. caninum antigen were recorded in all calves from days 4-6 postinoculation. This response was accompanied by production of high levels of IFN-gamma. Although the calves remained seronegative to T. gondii, while seroconverting to N. caninum, stimulation with T. gondii lysate resulted in cell proliferation of a similar magnitude as that obtained using the N. caninum lysate. However, the T. gondii lysate appeared less effective than the N. caninum lysate to stimulate IFN-gamma production. Cells taken from uninfected control animals did not show any significant proliferation to either N. caninum or T. gondii antigen and no IFN-gamma was produced. These results suggest that the two parasites may possess cross-reacting T-cell epitopes, but that the T cells specific for N. caninum may have a different functional capacity. This highlights the need to investigate the antigen specificity and cytokine profile of T cells from infected animals to help understand their role in immunity to N. caninum.
Animals↗