Characterization of a novel pestivirus originating from a pronghorn antelope.

A unique pestivirus, isolated from a pronghorn antelope (Antilocopra americana), was characterized. Serum neutralization studies suggested that this virus was antigenically related to pestiviruses. Genomic characteristics, unique to pestiviruses, indicated that this virus belongs to the Pestivirus genus. These characteristics included the organization of the 5' untranslated region (5'-UTR), the presence and length of a viral Npro coding region, conservation of cysteine residues in Npro, conservation of predicted amino acid sequences flanking the cleavage sites between viral polypeptides Npro and C and between C and Erns and conservation of predicted hydrophobicity plots of Npro protein. While this data indicated the virus belongs to the Pestivirus genus, phylogenetic analysis in 5'-UTR, Npro and E2 regions suggested that it is the most divergent of the pestiviruses identified to date. This conclusion was also supported by the amino acid identity in coding regions. The corresponding values were much lower for the comparison of pronghorn pestivirus to other pestivirus genotypes than only between previous recognized genotypes. These results suggest the virus isolated from pronghorn antelope represents a new pestivirus genotype. It also represents the only pestivirus genotype first isolated from New World wildlife.

Infectious keratoconjunctivitis in free-ranging mule deer (Odocoileus hemionus) from Zion National Park, Utah.

An epizootic of infectious keratoconjunctivitis (IK) was studied opportunistically in free-ranging mule deer (Odocoileus hemionus) from Zion National Park, Utah (USA), from November 1992 to March 1994. Moraxella sp. and Chlamydia sp. were isolated from the conjunctiva of two of seven deer. In addition, Thelazia californiensis occurred on the conjunctivas of six of seven deer. Based on field observations, adults appeared to be affected clinically at a higher incidence during both years as opposed to juveniles. Corneal opacity was the most apparent clinical sign from 1992 to 1993. However, in the following year, blepharospasm and epiphora were noted more often. We were also able to document the clinical recovery of three affected deer. In addition, Moraxella sp. was recovered from the eyes of a clinically unaffected deer 1 year after the epizootic occurred.

Effect of indomethacin on the vascular architecture of preovulatory ovine follicles: possible implication in the luteinized unruptured follicle syndrome.

Ovarian follicles sometimes fail to rupture and accumulate large quantities of fluid, yet undergo luteinization and form a steroidogenically competent luteal structure, the luteinized unruptured follicle syndrome. This condition can be mimicked in mammals by administration of indomethacin, an inhibitor of biosynthesis of prostaglandins. Blockade of ovulation by this drug is exerted at the follicular level. Ovulatory failure in sheep given a single intramuscular injection of indomethacin after induction of a surge of of luteinizing hormone was associated with follicular hyperemia as assessed by scanning electron microscopic examination of microcorrosion vascular casts and light microscopic quantification of follicular vascular space. The apical stigma of control (ovulatory) follicles was ischemic. The luteinized unruptured follicle syndrome appears to be the consequence of a chronic follicular inflammatory-like reaction involving inhibition of synthesis of prostaglandins.

Morphological studies of the microcirculatory system of periovulatory ovine follicles.

Thecal vascular tissue and blood cells were studied by light, transmission, and scanning electron microscopy during ovulation in the ewe. Cross-sectional areas of vascular lumens increased after the preovulatory surge in luteinizing hormone, decreased before ovulation, and then increased again as corpora lutea formed. Numbers of blood vessels per unit area of thecal tissue declined just before ovulation, then increased during luteinization. The follicular stigma that develops near the time of ovulation was completely void of blood vessels. These findings were paralleled chronologically by evidence of vasodilation, increased vascular permeability, tissue edema, congestion, ischemia, vascular injury, and angiogenesis. Neutrophils and eosinophils migrated out of the vascular compartment before ovulation. Around the time of ovulation, there were masses of extravasated blood in thecal tissue, and numerous platelets adhered to damaged vascular endothelium. Extravasated monocytes/macrophages were evident after ovulation. Numbers of extravascular lymphocytes remained relatively constant, but the lymphocytes were often marginated along endothelium in ovulatory and postovulatory follicles. Basophilic cells accumulated in association with the development of new capillaries during luteinization. Our observations are consistent with the concept that periovulatory follicular processes include acute inflammation, tissue damage, glandular transformation, and healing.