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Taylor equigenitalis that results in short-term infertility in mares and rare abortion. The United States is considered to be free of CEM, but six outbreaks have occurred in the U.S. in the past 15 years, including a 2008-10 outbreak during which over 1

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SUMMARY

Bovine herpesvirus type 1 (bhv-1) isolates are classified into 3 subtypes by use of restriction endonuclease analysis. Isolates from aborted fetuses have been either subtype 1 or 2a, whereas subtype 2b viruses have not been associated with abortion. We assessed the abortifacient property of isolates representing each of the 3 bhv-1 subtypes by iv inoculation of heifers with the virus 25 to 27 weeks after breeding. Three heifers were given Cooper (subtype 1) isolate, 3 heifers were given FI (subtype 2a) isolate, and 5 heifers were given K22 (subtype 2b) isolate. All heifers developed fever and viremia 2 to 5 days after inoculation. Heifers given Cooper or FI isolate aborted between 17 and 85 days after inoculation. The 5 heifers given K22 isolate delivered full-term calves. Placenta was obtained from 4 of the 5 heifers, and K22 virus was isolated from each placenta. Four calves had bhv-1 neutralizing antibody in precolostral serum, with titer ranging from 1:4 to 1:512.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine the ability of Brucella abortus strain RB51 to induce placentitis and abortion in bison after SC vaccination.

Animals

10 pregnant bison cows, 3 to 10 years old and at 3 to 8 months' gestation.

Procedure

Pregnant bison cows on a Montana ranch were vaccinated SC with 109 colony-forming units of B abortus strain RB51. Two cows, identified prior to the study, were euthanatized and examined 5 weeks after vaccination to obtain optimal histologic samples of placenta. Other cows were euthanatized and examined after abortion. After euthanasia, tissue specimens were collected for histologic and immunohistochemical evaluation. Tissue and fluid specimens for bacteriologic culture were also collected during necropsy.

Results

Of 8 cows, 2 aborted at 68 and 107 days after vaccination. Aborting cows had endometritis. Strain RB51 was isolated from reproductive tissues and supramammary lymph nodes. Fetal lesions were not seen; however, fetal bronchial lymph nodes and amniotic fluid contained strain RB51. Cows examined 5 weeks after vaccination had placentitis and endometritis, with numerous bacteria within trophoblastic epithelial cells that were immunoreactive for strain RB51 antigen. Strain RB51 was isolated from placentomes and numerous lymph nodes. Fetal lesions were not seen 5 weeks after vaccination; however, strain RB51 was isolated from numerous lymph nodes and lung, allantoic fluid, and rectal swab specimens.

Conclusions

The vaccine candidate B abortus RB51 has tropism for the bison placenta, and can cause placentitis, which induces abortion in pregnant bison. The vaccine dose used was similar to that being tested in cattle, but may not be appropriate for pregnant bison. (Am J Vet Res 1996;57:1604–1607)

Free access
in American Journal of Veterinary Research

SUMMARY

The Cooper isolate of bovine herpesvirus 1 (bhv-1) was used to produce a thymidine kinase-negative ( tk ) recombinant by insertion of a β-galactosidase (bgal) expression cassette into the tk coding region. The recombinant virus (tk bgal+) was tested for abortifacient activity in cattle by inoculation of 5 pregnant heifers at 25 to 29 weeks gestation. Five additional heifers were inoculated with the Cooper tk positive ( tk +) virus to serve as controls. After inoculation, both groups of heifers developed similar febrile responses and neutralizing antibody titers. Virus was isolated from blood of all heifers during the first postinoculation (pi) week, and isolation frequencies were similar for both groups. In contrast, whereas virus was isolated from many of the nasal and vaginal swab specimens of heifers inoculated with tk + virus, only rare virus isolations were made from the heifers given tk bgal+ virus. All heifers inoculated with tk + virus aborted between pidays 19 and 35. The finding of characteristic microscopic lesions and viral antigen in fetal tissues indicated that the abortions were caused by bhv-1 infection. Virus was isolated from 3 fetuses, and all isolates were tk +. Two heifers inoculated with tk bgal+ virus aborted at PI days 25 and 39. Fetal tissues had typical bhv-1 microscopic lesions and viral antigen. Virus was isolated from blood of both fetuses, and the isolates were tk bgal+. Results of this study indicate that inactivation of the tk gene reduces, but does not eliminate, the abortifacient activity of bhv-1.

Free access
in American Journal of Veterinary Research

Summary

Pregnant sows, immune against pseudorabies after vaccination, were inoculated at 70 days of gestation either with autologous blood mononuclear cells that had been infected in vitro with pseudorabies virus (prv) or with cell-free prv. The infected cells or cell-free prv were inoculated surgically into the arteria uterina.

Eight sows (A to H) had been vaccinated with an inactivated vaccine. The titer of seroneutralizing antibodies in their serum varied between 12 and 48. Five sows (A to E) were inoculated with autologous mononuclear cells, infected either with a Belgian prv field strain or with the Northern Ireland prv strain NIA3. These 5 sows aborted their fetuses: 2 of them (B and C) 3 days after inoculation, and the other 3 (A, D, and E) 10, 11, and 12 days after inoculation, respectively. Sows F, G, and H were inoculated with a cell-free prv field strain. They farrowed healthy litters after normal gestation. Neutralizing antibodies were absent against prv in the sera of the newborn pigs, which were obtained prior to the uptake of colostrum.

The 23 fetuses that were aborted in sows B and C 3 days after the inoculation were homogeneous in appearance and size. Foci of necrosis were not detected in the liver. Viral antigens were located by immunofluorescence in individual cells in lungs, liver, and spleen of 15 fetuses. Virus was isolated from the liver, lungs, or body fluids of 12 fetuses.

The 39 fetuses that were aborted in sows A, D, and E between 10 and 12 days after inoculation were of 2 types: 17 were mummified and 22 were normal-appearing. Foci of necrosis were found in the liver of all mummified fetuses and 13 of the normal-appearing fetuses. In fetuses with foci of necrosis in the liver, viral antigens were located in groups of cells in the liver, lungs, and spleen. Virus was isolated from 16 normal-appearing fetuses and from 11 mummified fetuses.

Pseudorabies virus was isolated from vaginal excretions of sows A and D until 1 and 2 days after abortion, respectively, and of sows B and C until 4 and 5 days after abortion, respectively. Virus was not isolated from sow E.

It was concluded that prv can reach the uterine and fetal tissues, via infected mononuclear cells, in the presence of circulating antibodies induced on vaccination. This cell-associated spread led to abortion. Cell-free virus did not induce abortion under similar circumstances.

Free access
in American Journal of Veterinary Research

SUMMARY

Neospora caninum-induced abortion is a major production problem in the dairy cattle industry in the United States and worldwide. Abortions attributable to naturally acquired N caninum infection also have been observed in pygmy goats. We studied experimentally induced infections with N caninum in pregnant pygmy does to determine whether abortions attributable to N caninum infection would occur after inoculation. Seven pregnant pygmy does (1 control doe and 6 inoculated with N caninum) were studied. The control doe remained clinically normal throughout the study and delivered 2 healthy kids. Abortion, fetal death, and stillbirths were observed in some pregnant does inoculated with N caninum. Two pregnant pygmy does inoculated with N caninum early in gestation (day 51) had fetuses that died and were aborted, or died and were reabsorbed. Neospora caninum tachyzoites and lesions were observed in the brain, spinal cord, and heart of aborted fetuses; parasites also were isolated from the placenta. Four additional pregnant pygmy does (2 inoculated at mid-gestation [day 85], and 2 at late gestation [day 127]) did not abort after inoculation. However, 1 doe inoculated during midgestation delivered a stillborn fetus that had died about 1 week prior to parturition. This kid was congenitally infected with N caninum. Neospora caninum was isolated from the placentas of all inoculated does examined. Neonatal neosporosis was not observed in live-born kids, nor were stages of N caninum isolated from any live-born kid. Does did not undergo abortion or have congenitally infected kids when they were rebred and evaluated for neosporosis.

Free access
in American Journal of Veterinary Research

to the virus during gestation results in fetal infection > 95% of the time. Potential reproductive sequelae associated with BVDV infection in pregnant cattle include reduced conception rates, embryonic death, abortion, congenital malformations, and

Full access
in American Journal of Veterinary Research

production of higher quality colostrum. One major problem with vaccination of pregnant cows is abortion. 12 Vaccine manufacturers are required to state on labels the potential risks related to fetal loss when vaccines are used in pregnant immune-naïve cows

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in American Journal of Veterinary Research

the case was reported to state officials. Duration to diagnosis was defined as the number of days lapsed between the onset of relevant clinical signs and B canis positive 2ME-RSAT/AGID II or culture. Relevant clinical signs included abortion, gait

Open access
in American Journal of Veterinary Research

Abstract

Objective

To determine the scope of strain variations among Campylobacter spp associated with abortion in sheep.

Design

To examine Campylobacter spp isolated from cases of abortion for biochemical, antigenic, and genetic differences.

Sample Population

15 isolates of Campylobacter spp isolated from cases of abortion during a single lambing season.

Procedure

Isolates were examined, using biochemical tests, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane proteins (OMP), and DNA restriction enzyme analysis (REA).

Results

Eight strain variants were detected among the 15 isolates. 14 of the isolates were C jejuni, 13 of which were biotype I and 1 biotype II, and the remaining isolate was identified as C fetus subsp fetus. Five sodium dodecyl sulfate-polyacrylamide gel electrophoresis OMP patterns had distinctive profiles for C fetus subsp fetus and C jejuni biogroup-II isolates and 3 variants within the C jejuni bio-group-I isolates. Examination of REA patterns of DNA from the 15 isolates digested with Cfo I indicated clear differences correlating with species and biogroups and 4 REA variants among biotype-l isolates.

Conclusions

Marked antigenic and genetic heterogeneity of Campylobacter isolates were associated with ovine abortion within a defined geographic area.

Clinical Relevance

Representatives of differing OMP and REA profile groups should be considered for incorporation in vaccines to optimize protection in this region and possibly other geographic areas.

Free access
in American Journal of Veterinary Research