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A 19-year-old Quarter Horse mare was evaluated because of bloody vaginal discharge that was apparent immediately following breeding. On transrectal ultrasonography, it was evident that the uterus was filled with fluid containing echogenic particles; linear hyperechoic structures were also visible. Endoscopy was performed, which revealed a number of bones adhered to the cranial wall and floor of the right uterine horn as well as purulent fluid in both uterine horns. Bacterial endometritis and fetal maceration were diagnosed. The mare was treated with antibiotics, and the fetal bones were manually removed from the uterus. Fetal maceration with intrauterine retention of bones is rare in mares. Use of hysteroscopy supplements ultrasonography in the diagnosis of uncommon conditions of the uterus. Macerated bones may be adhered to the endometrium, thereby requiring manual removal.

Brucella abortus infection has not been documented in llamas. This report describes the abortion of the only pregnant animal in a group of 12. The llama was infected by inoculating 1 x 10(8) viable B. abortus organisms into the conjunctival sac. Forty-three days postinfection, the llama aborted a fetus of approximately 8 months gestational age. Brucella organisms were isolated from the placenta and all fetal specimens examined. These organisms were also isolated from the dam's mammary gland and numerous lymph nodes when the llama was necropsied 42 days later. Microscopically, there was a moderate, multifocal, lymphocytic and histiocytic, subacute placentitis with marked loss of trophoblastic epithelial cells. The superficial chorioallantoic stroma contained abundant necrotic and mineralized debris as well as numerous swollen capillaries protruding multifocally from the denuded surface. Immunohistochemistry revealed that these capillaries, as well as sloughed and intact trophoblasts, were expanded by large numbers of Brucella organisms. Brucellar antigen was also detected in occasional macrophages in the fetal kidney and lung. Ultrastructurally, bacteria labeled by an antibody-based colloidal gold procedure were located within degenerate capillaries, within necrotic leukocytes, and extracellularly in the placental stroma.

Tritrichomonas foetus is a parasite of particular veterinary importance causing bovine tritrichomonosis, a sexually transmitted disease leading to infertility and abortion. The present review summarizes the current knowledge on potential mechanisms of pathogenicity of T. foetus, the immunology of host-parasite interaction in bovine tritrichomonosis, and the experimental model systems of this parasitic disease.

To assess the role of polymorphonuclear neutrophils (PMNs) in Chlamydia psittaci infection in a pregnant mouse model, pregnant and nonpregnant Swiss OF1 mice were depleted of PMNs by treatment with the RB6-8C5 monoclonal antibody before intraperitoneal infection with C. psittaci serotype 1. Nondepleted mice served as infection controls. Depleted mice aborted earlier and had a much higher mortality rate than nondepleted mice. Bacteriological analysis showed that the number of chlamydiae isolated from the spleens of depleted mice at 5 and 7 days postinfection was 100 times greater than that isolated from nondepleted mice. Histopathological analysis of the placentas of depleted mice showed widespread necrosis of the uteroplacental units, with weak immunoreaction to chlamydial antigen, while the placentas of nondepleted mice showed substantial neutrophil infiltration but no large areas of necrosis, with moderate to strong immunoreaction to chlamydial antigen. The livers of depleted mice showed numerous chlamydial inclusions in the hepatocytes, delayed microgranuloma formation, and in the pregnant animals extensive coagulative periportal necrosis. The livers of nondepleted mice displayed multiple small foci of PMNs and mononuclear cells with microgranuloma formation. Among this group of mice, the pregnant animals always had more hepatic damage than nonpregnant animals. Our results suggest that PMNs play an essential role in the response to C. psittaci primary infection, preventing the uncontrolled multiplication of chlamydiae in the liver and spleen.

The abortigenic effects of equine herpesvirus 1 (EHV-1) strain HVS25A, given intranasally, were assessed in pregnant BALB/c, C57BL/6J and Quakenbush mice at day 16 of pregnancy. All EHV-1-infected BALB/c mice showed clinical signs typical of EHV-1-induced disease, together with evidence of abortion. However, although there were fetal and neonatal deaths in some C57BL/6J and Quakenbush litters, the respiratory and systemic effects of EHV-1 infection in the dams were inconsistent. BALB/c dams were then inoculated at day 15 of pregnancy with either EHV-1 or rabbit kidney (RK) cell lysate (controls) and animals were killed at days 1-5 post-inoculation (pi), i.e., before the occurrence of abortions. EHV-1-infected mice showed a significant fall in rectal temperature between days 1 and 2 pi and lost weight during the first 4 days pi, demonstrating a significant mean difference in weight gain from the control group at days 2, 3, 4 and 5 pi. Death in utero was seen in five of 90 fetuses of EHV-1-infected mice, but in no fetuses from RK-inoculated mice. On days 1, 2, 3, 4 and 5 pi, the fetuses from EHV-1-infected dams were significantly smaller than those from RK-inoculated dams. Congestion and necrosis of the middle layer of trophoblast and chorionic necrosis were observed in the placentae from EHV-1-infected dams and assessed by a scoring system. Virus was isolated rarely from the fetuses (1/73), placentae (3/72) and uteri (1/16) of EHV-1-infected dams, and only from those killed on day 1 or 2 pi. This indicates that, as in the horse, abortion caused by EHV-1 infection in mice is not necessarily a consequence of fetal infection but may be due to fetal compromise due to vascular effects on the placenta.

A bovine fetus aborted at 187 days of gestation was serologically and immunohistopathologically examined. Serum and cerebrospinal fluid samples had high titers of virus-neutralizing antibody for Aino virus. A severe necrotizing encephalopathy was noted. Aino virus antigen was demonstrated in neuroglial cells within the brain lesion. The destruction of developing neuronal cells appeared to be a significant feature of the pathogenesis of lesions due to Aino virus infection in the central nervous system.

Neospora caninum tachyzoites were identified in areas of the cerebrum with lesions of non-suppurative encephalitis in an aborted bovine fetus in Spain.

Objective: To describe the occurrence of chondrodysplasia in Australian Dexter cattle., Design: A pathological and genetic case report., Procedure: Congenital lethal chondrodysplasia was studied in two female Dexter foetuses aborted mid to late gestation. Clinicopathological findings including histological changes in limb bones, and analysis of pedigree information were evaluated., Results: Characteristic features of congenital lethal chondrodysplasia (Dexter bulldog) include abortion, disproportionate dwarfism, a short vertebral column, marked micromelia, a relatively large head with retruded muzzle, cleft palate and protruding tongue and a large abdominal hernia. Histological changes in limb bones are consistent with failure of endochondral ossification. Dexter chondrodysplasia is considered to be inherited in an incompletely dominant manner with the homozygous form producing the congenital lethal condition. A preliminary minimum estimate of heterozygote frequency is 19% within the registered Australian Dexter herd, based on analysis of the contribution of three obligate heterozygotes whose semen has been widely used by artificial insemination in Australia., Conclusion: Dexter chondrodysplasia is present in Australian cattle and further cases of the homozygous form, congenital lethal chondrodysplasia, are likely to occur., Recommendation: It is requested that spleen and liver tissue from bulldog foetuses and blood from their parents be collected to assist research into Dexter chondrodysplasia.

Neospora caninum was found in fetal tissues of 34 of 688 cases of bovine abortion submitted to the Pennsylvania Animal Diagnostic Laboratory System during the period from May 1994 to November 1996. The aborted fetuses ranged in gestational age from 3 to 8 months. Microscopic lesions consisted primarily of encephalitis and myocarditis. A labeled (strept) avidin-biotin staining procedure using anti-N. caninum polyclonal rabbit serum revealed N. caninum organisms within the fetal brain (27 of 27), heart (10 of 13), placenta (5 of 6), kidney (2 of 2), liver (1 of 4) and skeletal muscle (1 of 1).

Problem: It has been proposed that high rates of resorption/spontaneous abortion may result from interaction in the decidua of gamma-interferon-producing natural killer (NK) cells and tumor necrosis factor (TNF)-alpha-producing macrophages. An increased release of TNF-alpha from placental tissue of resorptions has been reported, but macrophages producing TNF-alpha have so far not been demonstrated at the feto-maternal interface. Therefore, we have sought to identify TNF-alpha-producing cells by in situ hybridization at the feto-maternal interface in two inbred, well-characterized, and stable strains of laboratory rodents with high and low resorption rates., Method of Study: Pregnant DBA/2-mated CBA/J mice with a resorption rate of 20% to 30% (dependent on NK cells and macrophages) and diabetes-resistant Bio-Breeding/Edinburgh (DR-BB/E) rats with low resorption rates (presumed to result from chromosomal abnormalities) were studied. AsialoGM1+ cells were detected by immunohistochemistry, and TNF-alpha mRNA+ cells were detected by in situ hybridization., Results: TNF-alpha mRNA+ cells were detected in DBA/2-mated CBA/J mice at the time of resorption but only at the trophoblast-decidual junction. AsialoGM1+ cells were present in decidua, as assessed by immunohistochemistry, but few if any gave a positive signal for TNF-alpha. In rat resorptions, TNF-alpha mRNA-positive cells were present within the yolk sac and in contact with the trophoblast, but not at the trophoblast-decidual junction. In neither species did a significant accumulation of detectable TNF-alpha mRNA+ cells occur before the usual time of onset of resorption., Conclusions: In the DBA/2-mated CBA/J mouse, the removal of the placenta is associated with removal of a thin rim of adherent decidua similar to the location of the TNF-alpha mRNA+ cells detected in this study. Our data suggest that increased TNF-alpha in tissues associated with failing feto-placental units may arise from infiltration/activation of scavenger cells from decidua that are likely to be macrophages. Local TNF-alpha production in decidua, which occurs as a prelude to resorption in the CBA x DBA/2 model, could not be detected due to the insensitivity of the TNF-alpha probe we used; the release of TNF-alpha from decidual tissue left after the removal of the placenta does not differ between resorbing and healthy implant sites. AsialoGM1+ cells did not seem to be major producers of TNF-alpha. TNF-alpha mRNA+ cells in a low rate of resorption (rat) model were only found on the fetal side of the trophoblast, and they may also represent a macrophage response (to dying embryo tissue) derived from a nondecidual source. The location of TNF-alpha mRNA+ cells may identify distinct and different mechanisms of resorption in rodents.

In a previous immunohistological study, chlamydiae were detected in 5 out of 139 cases of swine abortion, and a possible implication of C. psittaci serovar 1 was suggested. The present study sought to classify the chlamydiae found in the fetal organs of these abortions. DNA extracted from 15 paraffin-embedded tissue specimens (10 livers and 5 lungs, obtained from 10 fetuses from 9 cases of abortion) was amplified in a nested PCR with Chlamydia omp1 genus-specific primers. Chlamydia DNA was amplified in 9 liver and 2 lung specimens. Eight of the amplification products were cloned, and 5 clones of each amplification were sequenced. Sequence analysis demonstrated in 7 specimens the simultaneous presence of porcine C. trachomatis S45 and C. pecorum 1710S omp1 genotypes. All DNA fragments of 1 amplification were identical to the ruminant C. psittaci B577 omp1 genotype (serovar 1). The results suggest that mixed infections with porcine C. trachomatis and C. pecorum dominate chlamydial infections associated with abortion in swine, but ruminant abortigenic C. psittaci are also found.

Formalin-fixed, paraffin-embedded fetal livers and lungs from 139 cases of swine abortion were investigated retrospectively for chlamydiae by means of immunohistochemistry. Using a genus-specific antibody, chlamydial antigen was found in eight livers obtained from five (3.6%) abortion cases from different herds. All lung sections were negative. Chlamydiae were also labeled in five of the eight positive livers using a monoclonal antibody against immunotype 1 of Chlamydia psittaci; the remaining three livers were negative. No reactivity was seen using an antibody specific for C. trachomatis. Chlamydiae should be considered a cause of abortion in sows in Switzerland. Porcine abortigenic strains identified in this study differed immunologically from intestinal strains (known to be mainly C. trachomatis) but shared similarities with abortigenic chlamydiae of ruminants.

The decidua of allopregnant mice contains a novel population of Thy1 Lyt1 CD4 CD8 asialoGM1- non-B small lymphocytic suppressor cells that release transforming growth factor (TGF) SS2-related suppressor molecules. The "null" phenotype of this cell population is similar to some bone marrow-derived natural suppressor cell (NSC) populations, and the latter may release TGF(beta)s. We now report that the TGF beta2-producing suppressor cells in the uterine decidua of DBA/2-mated CBA/J female mice-linked to prevention of abortions-are inactivated effectively by 1E5/B5.1 but not by 2C1.1 rat monoclonal antibodies to murine pregnancy-associated splenic NSC in the presence of complement. Immunostaining of a subpopulation of cells in decidua with 1E5/B5.1 but not with 2C1.1 was shown by flow cytometry. Release of suppressor factor was also abrogated by 1E5/B5.1 + complement but not by 2C1.1 + complement, and the suppressor factor was specifically neutralized by anti-TGF beta2 and not by anti-TGF beta3. Splenic pregnancy NSC are susceptible to 2C1.1, produce TGF beta1, and express CD3 and alpha beta T-cell receptor (TcR) chains. Release of suppressor factor by the decidual NSC was abrogated by treatment with anti-CD3 (145 2C11) and anti-TcR gamma delta (GL4) monoclonal antibodies + complement, but not by anti-TcR alpha beta (H57) + complement; and cells sorted using anti-TcR gamma delta (GL3) released suppressive activity in vitro. Slightly more suppressive activity was released by implantation-site decidua where there was no epithelium than from epithelialized inter-implantation-site decidua; no significant activity was released from placental tissue, but combining implantation-site tissue with placental tissue led to release of enhanced levels of immunosuppressive activity. There appear to be subtypes of bone marrow-derived TcR+ NSC with different phenotypes and tissue localization patterns in pregnancy. The previously reported dependence of decidual NSC activity on the presence of soluble signals from fetal trophoblast may be explainable by the ability of cells bearing TcR gamma delta to recognize and react to placental trophoblast cell antigen.

Twenty-five aborted equine fetuses infected with equid herpesvirus 1 (EHV-1) were examined cardio-histopathologically. The main changes in the heart consisted of interstitial myocarditis and intramyocardial vascular lesions accompanied by degeneration and necrosis of the cardiac myocytes. Vascular pathology of intramyocardial small arteries and arterioles was characterized by endothelial cell necrosis and fibrinoid changes in the media. Eosinophilic intranuclear inclusion bodies characteristic of herpesvirus infection were detected in the myocardial cells and macrophages within and around the inflammatory lesions and in the endothelial cells and medial smooth muscle cells of the damaged vessels. This observation, taken in conjunction with the fact that EHV-1 antigens were detected immunohistochemically in some myocardial and endothelial cells, provides morphological evidence in support of the viral aetiology of the cardiac lesions.

Eighty bovine fetuses with confirmed neosporosis were used to score lesion severity and presence of parasites in brain, heart, and liver. A comparison was made between epizootic and sporadic abortion cases. The possible influence of fetal age was also investigated. Histologic lesions of multifocal encephalitis, myocarditis, and periportal hepatitis with or without focal hepatocellular necrosis were almost always observed. Neospora caninum tachyzoites were identified immunohistochemically in 85% of the brains, 14% of the hearts, and 26% of the livers. Tissue cysts were observed in 21% of the brains. Significant differences between epizootic and sporadic abortion cases were found only in the liver. Hepatic lesions were more prominent and N. caninum tachyzoites were observed more frequently and in higher numbers in epizootic cases. Examination by immunohistochemistry of the liver in addition to the brain can be highly contributive diagnostically, particularly in epizootic cases. There were no significant age-related differences except for a higher presence of tachyzoites in the hearts of younger fetuses (3-4 months gestational age).

Between January and April 1995, the brains and hearts of 281 aborted lambs derived from 209 submissions to veterinary investigation centres in England and Wales were examined histologically. One-hundred-and-seventy-nine samples of fetal pleural fluid from these lambs and 141 from lambs not examined histologically were examined for antibodies to Neospora by an indirect fluorescent antibody test. Non-suppurative myocarditis and encephalitis were present in nine lambs. Immunocytochemistry using antisera against Neospora caninum and Sarcocystis species resulted in no labelling but anti-sera to Toxoplasma gondii revealed labelled organisms in four lambs. No significant antibody titres against Neospora were detected in any of the samples of fetal pleural fluid. These results suggest that Neospora infection is not associated with significant numbers of abortions in sheep in England and Wales.

The effect of Toxoplasma gondii inoculation on pregnancy and on endocrine foetal-placental function in pregnant goats was studied. Five susceptible goats were inoculated subcutaneously with T. gondii bradyzoites at 71 +/- 2 days of gestation. Another five goats were used as controls. Plasma was analysed for progesterone, oestrone sulphate and 15-ketodihydro-PGF2 alpha. The condition of the foetuses was monitored by real-time ultrasonography. All inoculated goats aborted or delivered stillborn or weak kids 54-73 days after inoculation. None of the goats showed signs of general disease. In cases of foetal death, the ultrasound examination revealed that death occurred between day 1 and 12 before abortion or birth. The appearance of the foetuses varied from fresh to mummified, depending on the number of days between foetal death and expulsion. All five goats became serologically positive to T. gondii after inoculation. None of the goats used as controls aborted, but one goat delivered one mummified and one weak kid for unknown reasons. In inoculated animals an increase in 15-ketodihydro-PGF2 alpha levels in plasma and a subsequent tendency to a decrease in oestrone sulphate levels were observed from about day 40 after inoculation and until abortion or birth. High levels of 15-ketodihydro-PGF2 alpha were seen after foetal death. High levels of 15-ketodihydro-PGF2 alpha were not always followed by a drop in progesterone levels. The mean level of progesterone was slightly decreased after inoculation and onwards. The pattern of progesterone levels around abortion in the inoculated goats was very similar to the pattern around parturition in the control goats. However, 15-ketodihydro-PGF2 alpha levels were higher both before and after abortion in inoculated goats than in control goats. The level of oestrone sulphate did not increase in the inoculated group before abortion in contrast to the level in goats which delivered healthy kids. The patterns of changes in levels of 15-ketodihydro-PGF2 alpha and oestrone sulphate in inoculated animals indicate that the endocrine foetal-placental function was disturbed in most of the inoculated goats, probably due to the injury caused by the establishment and development of T. gondii infection in the placenta and foetus.

Four Welsh Mountain pony mares at 3 months of gestation and one mare at 5 months were inoculated intranasally with equid herpesvirus-1 (EHV-1: Ab4 isolate) at doses of 10(5) to 10(6.6) TCID50. All five mares became infected, but no cases of paresis or abortion occurred. On days 8, 9, 11, 12 (3-month-pregnant mares) and 13 (5-month-pregnant mare) after infection, a detailed examination of the pregnant uterus was made. Small numbers of vascular lesions with EHV-1 antigen expression in endothelial cells were present in the uteri of the early gestational mares; thrombi were rare and foci of thromboischaemic damage were not seen. Six pony mares previously inoculated with EHV-1 Ab4 at 9 months of gestation had a significantly greater degree of vascular abnormality than that found in the four mares infected at 3 months of gestation, but the degree of EHV-1 antigen expression and thrombosis in the uterus was similar to that found in the single mare infected when 5 months pregnant.

Five pregnant mares, at between 6 and 8 months gestation, were experimentally infected with the Bucyrus strain of equine arteritis virus (EAV). Of the five mares, four aborted and one died. The pathogenesis of the abortions was studied, using histopathologic techniques, tissue immunofluorescence and virus isolation. Common microscopic lesions in the maternal reproductive organs indicated myometritis with a degeneration of the myocytes and an infiltration of the mononuclear cells. Epithelial cells of the endometrial gland showed sporadic degeneration. Lesions in the fetal tissue included an atrophy of the lymphoid follicles in the spleen and lymph nodes with degenerated lymphocytes. The placentae were oedematous and degenerated fibroblasts were observed in the subvillous layers. Immunofluorescence detected EAV antigen in the myometrium and the endometrial gland in the dams, in the subvillous layer of the placentae, and in the aborted fetuses. EAV was recovered from the maternal uteri, placentae and fetuses. The placentae yielded the greatest amounts of the virus. Transplacental infection of the fetus was clearly demonstrated in the EAV infection.

Microscopic lesions in four cases of abortion caused by porcine reproductive and respiratory syndrome virus (PRRSV) were characterized by arteritis, myocarditis, and encephalitis. Fetal PRRSV infection was confirmed by virus isolation or immunohistochemistry and serology. Although fetal microscopic lesions in PRRSV abortions are rarely reported, diagnosticians should consider PRRSV when these lesions occur.

Nine aborted fetuses and one newborn calf, diagnosed as Chlamydia psittaci (C. psittaci) infection, were pathologically examined. The characteristic lesions in the liver were focal necrosis in 9 aborted fetuses and granulomatous necrotic foci in the newborn calf. Moderate numbers of intranuclear inclusion bodies were found in necrotic foci of the liver, spleen, thymus, lymph nodes, adrenal gland, kidney, lung and forestomach. Immunohistologically, a small number of C. psittaci antigens was demonstrated in necrotic foci of the liver and correlated with distribution of elementary bodies. Moderate numbers of infectious bovine rhinotracheitis (IBR) virus antigens were also detected in degenerating and necrotizing parenchymal cells in various organs and correlated with distribution of intranuclear inclusion bodies. Thus, these aborted bovine fetuses and newborn calf were interpreted as being dually infected with C. psittaci and IBR virus during pregnancy.

Fetal infectivity of Ehrlichia risticii was investigated in 19 ponies that were E risticii negative on the basis of results of an indirect fluorescent antibody (IFA) test. Thirteen pregnant ponies were infected by IV administration of E risticii between 90 and 180 days of gestation. Six pregnant ponies served as noninfected controls. Each infected pony had clinical signs of equine monocytic ehrlichiosis, was confirmed to be ehrlichemic, and developed an IFA titer to E risticii. Two infected ponies became recumbent, were unresponsive to supportive care, and were euthanatized. After recovery from clinical illness, the remaining ponies were observed throughout gestation for reproductive abnormalities. On abortion, each fetus was necropsied and tissue specimens from the liver, bone marrow, spleen, colon, and mesenteric lymph nodes were inoculated into canine monocyte cell cultures. Six infected ponies aborted at a mean 217 days of gestation, which was between postinoculation days 65 and 111. Five fetuses were recovered for evaluation, and E risticii was isolated from 4 of them. All 5 fetuses recovered had similar histologic finding, including enterocolitis, periportal hepatitis, and lymphoid hyperplasia with necrosis of the mesenteric lymph nodes and spleen. All 5 fetuses tested negative for IgG to E risticii, although 3 had low IgM titer to E risticii. The remaining 5 infected ponies had normal parturition. Presuckle IFA titer to E risticii was measured in 4 of the term foals, and results for 3 were positive. Two foals from infected ponies were monitored for 6 months and daily gain in body weight was comparable to that of a control foal. None of the control ponies became ill or seroconverted during the clinical illness phase, and none aborted throughout gestation Two control ponies seroconverted to E risticii 6 weeks before parturition. Results of this study indicate that E ristcii is a primary abortifacient under experimental conditions.

Selected brains and fetal viscera from 190 aborted or stillborn bovine fetuses submitted to Veterinary Investigation Centres in England and Wales between August 1992 and January 1993 were examined histologically. Non-suppurative inflammation of the brain and/or myocardium and placental cotyledons was identified by light microscopy in 20 (10.5 per cent). An immunocytochemical examination of fixed tissue sections using antisera against Neospora caninum, Toxoplasma gondii and Sarcocystis species revealed positive immunolabelling for N caninum in the brains of eight (4.2 per cent), but no labelling with anti-T gondii or anti-Sarcocystis species antisera was evident. These results suggest that N caninum may be an important cause of reproductive failure in cattle in England and Wales.

A retrospective study of bovine abortions associated with Bacillus licheniformis is described. The material consisted of 2445 bovine abortions submitted for diagnostics from 1986 through 1993. Initially, B. licheniformis had been isolated from 81 cases. Sections of these cases were re-examined microscopically and immunohistochemically by a PAP technique using a primary antibody against B. licheniformis. Of these abortions, 47 were most likely associated with B. licheniformis as tissue lesions with immunostained bacteria were present in these. In the remaining cases the diagnosis may not have been established due to the lack of sufficient materials, or the isolation of the bacterium was considered to be a result of contamination. In four cases concomitant infections with B. licheniformis and bovine virus diarrhoea virus were present. Abortions caused by B. licheniformis were predominantly seen during the winter months and in late pregnancy. The most common lesions were necrotizing placentitis followed by fetal multifocal suppurative bronchopneumonia. Immunohistochemically, B. licheniformis was demonstrated in association with tissue lesions and intracellularly in trophoblasts. The pattern of bacterial isolations, especially from the placenta, lungs, and abomasal contents, combined with the histological findings points to B. licheniformis abortions as being of haematogenous origin with subsequent transplacental spread to the fetus.

An immunohistochemical technique using a monoclonal antibody was evaluated as a diagnostic tool to specifically label Tritrichomonas foetus in formalin-fixed, paraffin-embedded sections of placenta and fetal lung from bovine abortions. Trichomonads were demonstrated in tissues from each of 12 abortions due to T. foetus and none of 15 abortions due to other or unidentified causes. Moderate to marked background staining occurred only in severely autolyzed tissues from T. foetus-infected fetuses. The antibody faintly labeled 1 of 3 other species of trichomonads (Trichomonas gallinae) but did not label other protozoa, bacteria, or fungi tested.

Problem: Immunodeficient SCID mice on the CB-17 have been used to test the role of "rejection" in a xenogeneic blastocyst transfer model of recurrent miscarriage, but interpretation of the data requires knowing syngeneic within-species matings have a high success rate and do not require immunotrophic factors expected only in immunocompetent non-T-cell deficient mice., Method: Resorption rates were studied in a SCID CB-17 barrier facility that provided the mice used to test the role of immunology in the resorption model., Results: Spontaneous resorption in syngeneically mated immunodeficient SCID mice on the CB-17 background occurred at an unexpectedly high rate and could not be prevented by treatment with anti-asialo GM1 antibody or GM-CSF, both of which are effective in ameliorating abortion in DBA/2J-mated CBA/J mice. Immunocompetent CB-17 +/+ mice showed an even higher rate of loss. The latter was also not affected by treatment with antiasialo GM1 antibody or by GM-CSF and was not prevented by tetracycline (which is effective in the DBA/2-CBA/J system) or progesterone treatment. Mating experiments showed a scid/+ x scid@+ cross gave the highest rate of loss, and it appeared that the presence of +/(+)-type embryos in the uterus could be augmenting abortion with selective discrimination against scid/scid embryos. High abortion rates were associated both with appearance of a coagulase-negative Staphylococcus sp. in feces and with loss of one component of the SPF flora. Decidual tissue from mated CB-17 +/+ mice showed premature release of TNF-alpha in absence of TGF-beta 2-related suppressor activity, and vascular lesions (fibrinoid necrosis), varying in extent, were associated with both scid/scid x scid/scid and +/+ x +/+ pregnancies. TNF-alpha also appeared prematurely in pregnant scid/scid mice, but the levels were lower (and areas of necrosis smaller than in +/+ x +/+ pregnancies). Outcrossing onto a C57B1/6 background dramatically reduced the abortion rate, indicating an important genetic effect on susceptibility with heterogeneity protecting against abortion., Conclusions: SCID mice on the CB-17 background do not have a high rate of successful syngeneic pregnancies, and a TNF-alpha induced vasculopathy may be responsible. Abortion was not caused by immunodeficiency leading to loss of immunotrophism because immunocompetent non-SCID CB-17 mice had a higher rate of loss. Factors augmenting the abortion rate included the presence of embryos of the +/+ genotype in the uterus and treatment with anti-asialo GM1 antibody. Abortion rates were not reduced by treatments effective in the DBA/2-mated CBA/J mouse model but were reduced by re-establishing a new colony with defined flora (a temporary effect) and by outcrossing mice with a different (C57B1/6) background. Together, the data suggest an infectious trigger (identity uncertain) of the vasculopathy and an important genetic influence on susceptibility with heterozygosity and a SCID mouse mutation providing against abortion a degree of protection.

The first case of porcine reproductive and respiratory syndrome (PRRS) in Denmark was diagnosed in March 1992 by the detection of specific antibodies against PRRS virus in serum samples originating from sows in a herd located on the island of Als. Subsequently, PRRS virus was isolated from a 200-sow farrow-to-finish herd with clinical signs consistent with PRRS. The virus was isolated by inoculation of pleural fluid from a stillborn piglet onto porcine pulmonary alveolar macrophages. The isolate was identified as PRRS virus by staining with a specific antiserum. By electron microscopy, the virus particle was found to be spherical and enveloped, measuring 45-55 nm in diameter and containing a 30-35 nm nucleocapsid. Only minor antigenic differences were found between the Danish and a Dutch isolate. Following intranasal inoculation of 3 pregnant gilts with the Danish isolate transplacental infection was demonstrated by the re-isolation of PRRS virus from approximately 45% of the piglets from the experimentally infected gilts. However, the experimental infection produced no significant reproductive disorders or other clinical signs. At autopsy, histopathological examination revealed slight interstitial pneumonia in a few piglets.

Placentomes were extracted from the uteri of 22 aborted cows and examined to detect the cause of abortion; fetuses or fetal abomasal contents from 15 of the cows were also examined. Firm diagnoses of Pasteurella haemolytica, Actinomyces pyogenes, Listeria monocytogenes, Bacillus licheniformis, Aspergillus fumigatus or Mortierella wolfii abortion were made in 11 cases. The histopathological lesions showed some correlation with the identity of the bacterium isolated; the lesions of mycotic abortion were distinct and characterised by a coagulative necrosis. The removal of a placentome was not followed by any observable deleterious effects.

A syndrome of neonatal foals characterized by hyperplasia of the thyroid gland and concurrent musculoskeletal deformities (TH-MSD) has been described in western Canada and may be increasing in incidence. In an attempt to improve recognition and understanding of this syndrome, 2946 records of equine abortuses, stillborns, and dead neonatal foals were examined to determine the laboratory involved, the year and month of submission, the breed and sex of the fetus or foal, the type of perinatal loss, the length of gestation, and whether or not the submission had evidence of a lesion of the thyroid gland, the musculoskeletal system, or other abnormal clinical or postmortem findings. One hundred and fifty-four (5.2%) records indicated the presence of an abnormal thyroid gland. Of these, 79 (2.7%) had additional lesions consistent with the TH-MSD syndrome described in the 1980s, while 75 (2.5%) were without these additional lesions. Comparisons among these two groups and a third group of fetuses and foals without lesions of the thyroids glands are described. The results confirm that the TH-MSD syndrome is a specific and unique disease with no breed or sex predilection. It is argued that there may be an "exposure-related" cause, and based on a review of similar disease syndromes of the horse, it is suggested that an examination of the feed is indicated in outbreaks of the TH-MSD syndrome.

Pathologic and microbiologic examinations were performed on 1,211 aborted equine fetuses, stillborn foals, and placentas from premature foals in central Kentucky during the 1988 and 1989 foaling seasons to determine the causes of reproductive loss in the mare. Placentitis (19.4%) and dystocia-perinatal asphyxia (19.5%) were the 2 most important causes of equine reproductive loss. The other causes (in decreasing order) were contracted foal syndrome and other congenital anomalies (8.5%), twinning (6.1%), improper separation of placenta (4.7%), torsion of umbilical cord (4.5%), placental edema (4.3%), equine herpesvirus abortion (3.3%), bacteremia (3.2%), fetal diarrhea (2.7%), other placental disorders (total of 6.0%), and miscellaneous causes (1.6%). A definitive diagnosis was not established in 16.9% of the cases submitted. Streptococcus zooepidemicus, Escherichia coli, Leptospira spp., and a nocardioform actinomycete were organisms most frequently associated with bacterial placentitis, and Aspergillus spp. was the fungus most often noted in mycotic placentitis. No viral placentitis was noticed in this series. Dystocia-perinatal asphyxia was mostly associated with large foals, maiden mares, unattended deliveries, and malpresentations. The results of this study indicate that in central Kentucky, the noninfectious causes of equine reproductive loss outnumber the infectious causes by an approximate ratio of 2:1, placental disorders are slightly more prevalent than nonplacental disorders, Leptospira spp. and a nocardioform actinomycete are 2 new important abortifacient bacteria in the mare, the occurrence of contracted foal syndrome is unusually frequent, the incidence of twin abortion has sharply declined, and torsion of the umbilical cord is an important cause of abortion in the mare.

Of 1,799 accessions of ovine abortions and stillbirths by the South Dakota Animal Disease Research and Diagnostic Laboratory during a 10-year period, 1,784 were suitable for examination. Etiologic diagnoses were made in 786 (44%). Infectious agents were found responsible in 702 accessions (39%), and noninfectious causes were involved in 84 (5%). No diagnosis was made in 998 accessions (56%), 61 of which were mummified fetuses. Lesions, most of which indicated the presence of an infectious agent, were found in 274 cases (15%) in which no agent could be identified. Together, Toxoplasma gondii, Campylobacter sp., and Chlamydia psittaci caused approximately 25% of all abortions and stillbirths examined.

In the winter of 1990/91 a new, economically devastating disease occurred in european pig breeding herds, characterized by late-term abortion, stillbirth and a high morbidity and mortality of suckling piglets. Because of the clinical picture the disease was named porcine epidemic and respiratory syndrome (PEARS). In this study investigations were carried out in tissues of uterus and placentae of late gestational sows (107 to 112 days of gestation) in three different groups of animals: group I = control animals (n = 2) group II = naturally infected sows (n = 12) from farms, where PEARS recently had been introduced; group III = sows (n = 2), experimentally inoculated with placental homogenates from animals of group II. Both in naturally infected as well as in experimentally infected sows a multifocal, lymphohistiocytic vasculitis and perivascular cell infiltration was observed in the endometrium and maternal part of the placenta, but not in the fetal one. In the fetomaternal unit there were multifocal microseparations of the epithelial layers present. Transmission electron microscopically spherical or oval virus-like particles of 45 to 75 mm in diameter were frequently found on the surface of endothelial cells of blood vessels in the maternal placenta, in a few cases in the intercellular channel system between uterine epithelial cells or on endothelial cells of capillaries in the fetal placenta. Serological results indicate, that an infection with Lelystad virus had occurred in naturally and experimentally infected sows and that transplacental infection was present.

An overview is given of the results of diagnostic investigations into the cause of death of 463 goats performed by the Animal Health Service of West and Middle Netherlands during the period 1 January 1986 to 31 December 1991. The results are discussed and analysed with regard to the age of the animals, the anamnesis, and the abnormalities found at post-mortem examination and with regard to the results of further parasitological, bacteriological, and virological investigations. Enterotoxaemia caused by (epsilon-toxin-positive) Clostridium perfringens was present in 9% of the animals and fibrinous pneumonia with pasteurella in 15% of the animals. Animals with Aujeszky's disease did not show the 'itching' symptom. There were few parasitic infections.

Twelve Welsh Mountain pony mares in late gestation were infected intranasally with EHV-1 (AB4 isolate) at dose rates from 10(3) to 10(7.3) TCID50. This resulted in 3 cases of paresis, at Days 9, 10 and 12 after inoculation, and 5 abortions, at Days 6, 9, 18, 19 and 20. Euthanasia was performed between Days 6 and 21, with collection of uterine specimens for histopathology, virus isolation and immunoperoxidase staining from the pregnant horn, non-pregnant horn and body. EHV-1 replication in endometrial vessels was detected as early as Day 6 and was maximal at Days 9-11, when widespread thromboischaemic damage was present. By Days 15-19 in mares remaining pregnant, EHV-1 antigen expression in the endometrium was sparse, despite residual lesions but little associated thrombosis. Endometrial vascular pathology varied considerably in degree and extent, and no consistent predilection sites for replication within the uterus were apparent.

Brucellosis was studied opportunistically in bison (Bison bison) in the free-ranging Jackson herd of approximately 120 in Teton County, Wyoming (USA) in March 1989. Recent abortion was diagnosed in a 2-yr-old cow and Brucella abortus biovar 1 was isolated from vaginal discharge, uterine contents, uterus, and supramammary lymph nodes. Endometritis was characterized by lymphoplasmacytic infiltrates in the lamina propria and neutrophils in uterine glands and within necrotic debris and exudate in the uterine lumen. A 5-yr-old bull had diffuse lymphoplasmacytic infiltrates in epididymis and accessory sex glands; B. abortus was isolated from seminal vesicle and ampulla. Twenty-seven (77%) of 35 bison tested from 1989 to 1990 were serologically positive or suspect on tests for Brucella antibodies. We report the occurrence of abortion due to brucellosis in free-ranging bison in the Jackson herd, suggest that bison in this herd are capable of transmitting brucellosis to other susceptible hosts, and report the first confirmation of brucellosis in this herd.

In a 10-year survey started in 1980, specimens from 8,995 bovine abortions and stillbirths were submitted to the South Dakota Animal Disease Research and Diagnostic Laboratory. Of these, 8,962 were suitable for some type of examination. Viruses were associated with 948 (10.58%). Bovine herpesvirus-1 (IBR) was detected in 485 (5.41%), and bovine viral diarrhea virus (BVDV) was detected in 407 (4.54%). In 1 year of the survey, BVDV was detected in 8/32 fetuses that had lesions of passive congestion. Bovine herpesvirus-4 was isolated from 47 specimens (0.52%), parvovirus and enterovirus were each isolated from 2, and adenovirus, parainfluenza virus, and pseudorabies virus were each isolated from 1. Malignant lymphoid neoplasia was present in 2 fetuses, and their abortion was assumed to have been caused by the bovine leukosis virus.

Three Jersey cows were inoculated SC and IM with 26 million Neospora caninum tachyzoites at 129 (cow 1), 126 (cow 2), and 81 (cow 3) days after mating. Cows remained clinically normal for at least 1 month after inoculation of N caninum. Cow 1 was euthanatized 32 days after inoculation because of gangrenous mastitis. Cow 1 had a live fetus with no gross lesions; however, microscopic lesions were seen in the fetus and consisted of severe nonsuppurative necrotizing encephalitis of the cerebral white matter. Neospora caninum was identified in lesions by staining with anti-N caninum serum in an immunohistochemical test, by bioassays in mice, and by inoculation of bovine monocyte cultures with fetal tissue homogenate. Neither N caninum nor lesions were associated with infection with the protozoon identified in tissues of cow 1. Cows 2 and 3 aborted small autolysed fetuses 101 and 74 days, respectively, after inoculation with N caninum; the fetuses and attached placenta were unsuitable for laboratory investigations. Cows 2 and 3 remained clinically normal 4 months after abortion. Results of this study indicated that N caninum can be transmitted transplacentally in cattle.