Infection of embryos following insemination of donor mares with equine arteritis virus infective semen.

The objective was to evaluate the potential risks associated with embryo transfer from mares bred with equine arteritis virus (EAV) infective semen. Twenty-six mares were embryo donors, whereas 18 unvaccinated and EAV antibody seronegative mares were embryo recipients. Of the 26 donor mares, 15 were unvaccinated and seronegative for antibodies to EAV and 11 were vaccinated for the first time with a commercially available modified live virus vaccine against EVA before breeding and subsequent embryo transfer. All donor mares were bred with EAV-infective semen from a stallion persistently infected with the virus. Twenty-four embryos were recovered 7 d post-ovulation; all were subjected in sequential order to five washes in embryo flush medium, two trypsin treatments, and five additional washes in embryo flush medium (prior to transfer). Twelve and seven embryos (Grades 1 or 2) were transferred from the non-vaccinated and vaccinated donors, respectively, and pregnancy was established in 3 of 12 and 2 of 7. Perhaps trypsin reduced embryo viability and pregnancy rate. The uterine flush fluid of 11 mares (9 of 15 and 2 of 11 from non-vaccinated and vaccinated donor groups, respectively) was positive for EAV by VI (confirmed by real-time RT-PCR); the wash fluid from the embryos of nine of these mares was negative following 10 washes and two trypsin treatments. However, the embryo wash fluid from two mares was still positive for EAV after all 10 washes and the two trypsin treatments, and one embryo was positive for EAV. Two of 18 recipient mares had seroconverted to EAV 28 d after embryo transfer. Virus was not detected in any fetal tissues or fluids harvested after pregnancies were terminated (60 d). In conclusion, we inferred that the washing protocol of 10 washes and two trypsin treatments did not eliminate EAV from all embryos; due to limitations in experimental design, this requires confirmation. Furthermore, there may be a risk of EAV transmission associated with in vivo embryo transfer from a donor mare inseminated with EAV infective semen.

Bovine viral diarrhea virus abortion in goats housed with persistently infected cattle.

Twenty-four border disease virus-seronegative, pregnant, mixed breed goats were experimentally comingled with 3 heifers persistently infected with bovine viral diarrhea virus type 2a (BVDV-2a). Twelve of the 24 exposed does aborted. Twenty-nine fetuses and 16 placentas from affected does were submitted to the Oklahoma Animal Disease Diagnostic Laboratory for a necropsy examination. Infection with BVDV was confirmed with a combination of immunohistochemistry, BVDV-2 polymerase chain reaction, and virus isolation in 19 of the 29 fetuses. On gross examination of the 19 fetuses and placentas in which BVDV-2a infection was confirmed, a mild placentitis (3/19), fetal mummification (1/19), and facial deformities (4/19) were noted. Histologically, placentitis (2/19), myocarditis (4/19), thymic depletion (5/19), choroid plexitis (3/19), encephalitis (2/19), and cerebral gliosis (1/19) were noted. Other causes of abortion in goats, including common bacterial and viral infections, were ruled out with histology, virus isolation, polymerase chain reaction, and aerobic bacteriologic cultures. As supported by the findings in this case, BVDV-2a should be included as a differential for abortion in goats. This is the first report of abortion in goats after exposure to persistently infected cattle.

Distribution of bovine viral diarrhea virus antigen in aborted fetal and neonatal goats by immunohistochemistry.

Bovine viral diarrhea virus (BVDV) infection in goats can result in severe reproductive losses, with abortion rates reaching 80%. Infection with BVDV in aborted goat fetuses and stillborn kids can result in placentitis, encephalitis, myocarditis, and thymic depletion. This study investigates the distribution of viral antigen within the organ systems of aborted goat fetuses, stillborn kids, and nonviable kids infected with BVDV at various stages of gestation using immunohistochemistry (IHC). Virus antigen was detected within the placenta (8/13), thymus (4/9), heart (4/11), and brain (4/15) of affected goats. Uncommonly, BVDV antigen was detected within the skin (1/14), liver (1/13), kidney (1/12), lung (1/11), and trachea (1/3). BVDV antigen was not detected within the spleen (0/9), nasal turbinate (0/2), or thyroid (0/3). The results of this study indicate that placenta, heart, thymus, and brain are the most reliable tissues for BVDV antigen detection using IHC in aborted goat fetuses.

Equine viral arteritis: current status and prevention.

Recently, there has been increased interest in equine viral arteritis (EVA) among veterinarians and horse owners. Outbreaks of the disease were identified initially in New Mexico, USA in 2006, and in the Normandy region of France in the summer of 2007. Both occurrences were associated with AI of cool-shipped semen. Each was linked to respiratory illness, neonatal death, abortion, development of carrier stallions, and cancellation of equestrian events. In light of the increased interest, this paper will present a brief case history, followed by a review addressing common concerns regarding EVA, current status, and control and prevention strategies, including vaccination, and recommended bio-security measures.

The (alpha2-->8)-linked polysialic acid capsule of group B Neisseria meningitidis modifies multiple steps during interaction with human macrophages.

Group B Neisseria meningitidis causes systemic disease, including meningitis, after initial colonization and subsequent penetration of nasopharyngeal mucosa, a tissue which is richly populated by macrophages. In an initial effort to characterize the interaction of N. meningitidis and mature human macrophages, the influence of the alpha2-->8) -linked polysialic acid capsule on the interaction of N. meningitidis with human monocyte-derived macrophages was investigated with a capsulate case isolate and an isogenic Tn916-derived noncapsulate transformant. The capsulate strain was fourfold less adherent to the macrophage surface after cold incubation, although adherence of both strains was significantly increased after opsonization with nonimmune C5-depleted serum. When opsonized inocula were adjusted so that they adhered to macrophages in equal numbers, the two strains were internalized at equivalent rates and both entered membrane-bound compartments (phagosomes). Colocalization of bacteria with the late endosomal and lysosomal marker lysosome-associated membrane protein revealed that fusion of lysosomes with phagosomes containing the capsulate organism was significantly reduced 10 and 30 min after entry, but by 1 h, no difference between the strains was observed. Once internalized, meningococci were effectively killed, although more rapid killing of the capsulate strain was observed over the first 3 h. These results indicate that the (alpha2-->8)-linked polysialic acid capsule modifies the interaction of meningococci with human macrophages at multiple steps, including adherence to the macrophage surface and phagosome-lysosome fusion. Moreover, the discordance between the kinetics of phagosome- lysosome fusion and bacterial killing suggests that a nonlysosomal mechanism may be responsible for a significant fraction of macrophage killing of N. meningitidis.

Pulmonary embolism. Guide to diagnosis, treatment, and prevention.

While more remains to be learned about the natural history of deep vein thrombosis and pulmonary embolism, better information is now available on which to base decisions about diagnosis and treatment. Several retrospective and prospective studies have placed the value of lung scanning, venography, and pulmonary angiography in better perspective. Newer diagnostic techniques for deep vein thrombosis, such as 125I-labeled fibrinogen scanning and impedance plethysmography, are valuable and should be more widely used. Other diagnostic techniques for pulmonary embolism, such as computed tomography and nuclear magnetic resonance imaging, may be of value but are still untested. More effective therapies are now available. Moderate-dose subcutaneous heparin and lower-dose warfarin for long-term therapy of deep vein thrombosis are attractive alternatives to standard warfarin therapy. Thrombolytic therapy has not replaced standard intravenous heparin therapy, although it should be considered in treatment of a massive pulmonary embolus. Perhaps most important, prevention of deep vein thrombosis in most patients at high risk is possible with minidose heparin therapy or intermittent pneumatic compression. One of these methods of prophylaxis should be used in all high-risk patients as the only current effective way to decrease the mortality of pulmonary embolism.

Bronchoalveolar lavage and transbronchial biopsy for the diagnosis of pulmonary infections in the acquired immunodeficiency syndrome.

The efficacy of bronchoalveolar lavage and transbronchial biopsy in diagnosing lung infection was determined in 276 fiberoptic bronchoscopic examinations done on 171 patients with known or suspected acquired immunodeficiency syndrome. Of 173 pathogens (Pneumocystis carinii, cytomegalovirus, Mycobacterium avium-intracellulare, Cryptococcus neoformans, M. tuberculosis, Coccidioides immitis, and Histoplasma capsulatum) identified during the initial evaluation or in the subsequent month, the initial bronchoscopic examination detected 166 (96%). Bronchoalveolar lavage and transbronchial biopsy had sensitivities of 86% and 87%, respectively. When bronchoscopy included both bronchoalveolar lavage and transbronchial biopsy, the yield for all pathogens was 98% and the sensitivity for P. carinii infections was 100%. Follow-up for at least 3 weeks after examination failed to detect any additional false-negative results. Fiberoptic bronchoscopy is extremely accurate for the detection of pathogens in patients with the acquired immunodeficiency syndrome, especially when bronchoalveolar lavage and transbronchial biopsy are combined. In patients at high risk of complications from transbronchial biopsy, bronchoalveolar lavage is sufficiently accurate to be used alone.