Bovine herpesvirus-1: evaluation of genetic diversity of subtypes derived from field strains of varied clinical syndromes and their relationship to vaccine strains.

Bovine herpesvirus-1 (BoHV-1) causes significant disease in cattle. Control programs in North America incorporate vaccination with modified live viral (MLV) or killed (KV) vaccine. BoHV-1 strains are isolated from diseased animals or fetuses after vaccination. There are markers for differentiating MLV from field strains using whole-genome sequencing and analysis identifying single nucleotide polymorphisms (SNPs). Using multiple primer sets and sequencing of products permits association of BoHV-1 isolates with vaccines. To determine association between vaccine virus and strains isolated from clinical cases following vaccination, we analyzed 12 BoHV-1 isolates from animals with various clinical syndromes; 9 corresponded to BoHV-1.1 respiratory group. The remaining three corresponded to BoHV-1.2b, typically found in genital tracts of cattle. Four BoHV-1 isolates were identical to a vaccine strain; three were from post-vaccination abortion episodes with typical herpetic lesions whose dams had received MLV vaccine during pregnancy, and one from a heifer given a related MLV vaccine; Sequences of two respiratory isolates perfectly matched mutations characterizing RLB106 strain, a temperature sensitive mutant used in intranasal and parenteral vaccines. The last three respiratory strains clearly appeared related to a group of MLV vaccines. Previously the MLV vaccines were grouped into four groups based on SNPs patterns. In contrast with above-mentioned isolates that closely matched SNP patterns of their respective MLV vaccine virus, these 3 strains both lacked some and possessed a number of additional mutations compared to a group of MLV vaccine viral genome. Finding BoHV-1.2b in respiratory cases indicates focus should be given BoHV-1.2b as an emerging virus or a virus not recognized nor fully characterized in BRD.

Short communication: Attempts to identify Clostridium botulinum toxin in milk from three experimentally intoxicated Holstein cows.

Three adult lactating Holstein cows were injected in the subcutaneous abdominal vein with 175 ng/kg of body weight of Clostridium botulinum type C toxin (451 cow median toxic doses) to determine if this botulinum toxin crosses the blood-milk barrier. Whole blood (in sodium heparin) and clotted blood serum samples were taken at 0 min, 10 min, and 3, 6, 9, and 12 h postinoculation. Milk samples were taken at 0 min and at 3, 6, 9 and 12 h postinoculation. All samples were tested for the presence of the toxin using the mouse bioassay and immunostick ELISA test. The immunostick ELISA identified the toxin in whole blood and the mouse bioassay identified the toxin in serum at all times examined in all 3 animals. Toxin was not identified by either detection method in milk samples collected from the 3 animals. From these results, it appears that Clostridium botulinum type C toxin does not cross from the blood to the milk in detectable concentrations.

Causes of caprine abortion: diagnostic assessment of 211 cases (1991-1998).

In an 8-year period, 1991-1998, 217 accessions of caprine abortions were submitted to the California Veterinary Diagnostic Laboratory System. Of these 217 submissions, 211 were suitable for examination in this study (6 had insufficient data). Infectious agents as the cause of abortions were found in 37% of the cases: bacterial agents were identified in 30.5%, viral agents in 2%, fungal agents in 0.5%, and protozoal agents in 4% of the cases submitted. The most common causes of abortions were Chlamydia psittaci and Coxiella burnetii infection, which accounted for 23% of all goat abortions. Mineral deficiencies were observed in 4%, fetal anomalies accounted for 3%, and leukoencephalomalacia of the brain (probable oxygen deprivation) accounted for 3% of the submissions. No diagnosis was made in 112 of the 211 submissions (53%). No lesions were noted in 104 of the submissions (49%). The other 8 submissions (4%) had histologic lesions suggestive of a bacterial agent; however, no infectious agents were identified in these cases.

Molecular genetic evidence of a novel morbillivirus in a long-finned pilot whale (Globicephalus melas).

A long-finned pilot whale with morbilliviral disease was stranded in New Jersey. An immunohistochemical stain demonstrated morbilliviral antigen. Reverse transcriptase-polymerase chain reaction for morbillivirus P and N genes was positive. Novel sequences most closely related to, but distinct from, those of dolphin and porpoise morbilliviruses suggest that this virus may represent a third member of the cetacean morbillivirus group.

Evaluation of cross-reacting anti-human antibodies in the euthymic hairless guinea pig model (HGP) suggests that the HGP may be a model for the study of proliferative skin disease.

Animal models have an important role in cutaneous research. The guinea pig has proven to be a useful model in a wide spectrum of these cutaneous studies; however, its usefulness is often compromised by the need for depilation. A euthymic hairless guinea pig (HGP) model avoids the problems associated with depilation. Morphologically, as in human skin, these animals have a multi-cell-layer epidermis. Proliferation kinetic studies, as well as documentation of the degree of immunologic cross-reactivity between available antibodies to human cutaneous antigens, could extend the usefulness of this animal model. We performed a battery of anti-human antibodies on formalin fixed tissue, to a variety of antigens present within the skin and on inflammatory cells. These included CD3, UCHL-1, OPD4, L-26, KP-1, Factor XIIIa, S-100 protein, cytokeratin (AE1, AE3 and CK1), CAM 5.2, vimentin, CD 34, Factor VIII, fibronectin, SM actin, collagen IV, laminin, Bcl-2, p53, Ki-67, and PCNA. Cross-reacting antibodies included: CD3, S-100 protein, cytokeratin (AE1, AE3 and CK1), vimentin, Factor VIII, SM actin, collagen IV, p53, Ki-67, and PCNA. Although this battery of antibodies is limited, the markedly increased staining of Ki-67 and PCNA within keratinocytes in the epidermis as compared to normal human skin reflects a high proliferative rate. In addition, positive staining for p53, Ki-67, and PCNA may be useful in studying effects on cell cycle kinetics and apoptosis.

Proliferative lesions of the testis in ad libitum-fed and food-restricted Fischer-344 and FBNF1 rats.

The effect of 40% food restriction on spontaneous proliferative lesions of the testis was evaluated in lifetime and cross-sectional (serial sacrifice) studies of 419 Fischer (F-344) and 304 Fischer x Brown Norway (FBNF1) male rats. Interstitial cell hyperplasia and interstitial cell adenoma (ICA) were the most common proliferative lesions in each genotype; incidence of each was less in the FBNF1. In each genotype, food restriction delayed the onset of both lesions and reduced the incidence of ICA. At 12 months interstitial cell hyperplasia was present in 11 of 12 ad libitum (AL)-fed and 0 of 12 food-restricted (FR) F-344 rats. In FBNF1 rats interstitial cell hyperplasia was observed first at 18 months in AL-fed and at 36 months in FR groups. Interstitial cell adenoma developed in 5 of 12 AL-fed F-344 rats by 18 months and in 2 of 12 FR rats by 24 months; 2 of 12 AL-fed FBNF1 rats had ICA at 30 months, and 1 of 12 FR rats had ICA at 42 months. In these cross-sectional studies approximately half the ICA cases in F-344 rats were bilateral; no FBNF1 rats had bilateral ICA. In lifetime studies the incidence of ICA was reduced from 49% in AL-fed rats to 19% in FR F-344 rats and from 9% in AL to 4% in FR FBNF1 rats. The incidence of mesothelioma was low in both genotypes and was not obviously altered by food restriction. A malignant embryonal neoplasm, an unclassified benign neoplasm, and three seminomas were present in the testes of FBNF1 rats.

Histopathologic features seen in sulfur mustard induced cutaneous lesions in hairless guinea pigs.

Sulfur mustard (SM), a chemical warfare agent first used early in the 20th century, has re-emerged in the past decade as a major threat around the world. At present, there are no effective therapeutic measures for SM exposure. Because the skin as well as other interface epithelial surfaces are the first tissues effected as this agent is absorbed, reactions within the skin are an area of active research into the mechanism of action of this alkylating agent. The euthymic hairless guinea pig has been used as the animal model for the study of SM induced injuries because of morphologic similarity of its skin to human skin, with a multiple layer epidermis, and because this animal has a normal immune system. We reviewed 102 biopsy specimens from 51 animals exposed to three different dose times of saturated SM vapor. Histopathologic evidence exists for increased programmed cell death as well as cellular necrosis, subepidermal blister formation, and delayed re-epithelialization secondary to problems with adhesion. Information obtained from this study adds to the body of information important in the investigation of the mechanisms of action of SM.

Sulfur mustard: its continuing threat as a chemical warfare agent, the cutaneous lesions induced, progress in understanding its mechanism of action, its long-term health effects, and new developments for protection and therapy.

Although sulfur mustard (SM) has been used as a chemical warfare agent since the early twentieth century, it has reemerged in the past decade as a major threat around the world. SM is an agent that is easily produced even in underdeveloped countries and for which there is no effective therapy. This agent is a potential threat not only on the battlefield but also to civilian populations. The skin and other epithelial surfaces are the first targets as this agent is absorbed, and reactions within the skin are the subject of active research into the mechanism of action of this alkylating agent. The depletion of glutathione, generation of reactive oxygen species, and the formation of stable DNA adducts remain theoretic and demonstrated by-products of SM exposure implicated in the disease produced. However, new findings related to the effects of SM on the basement membrane zone; interest in delayed healing of the lesions induced; the inflammatory mediators, enzymes, and cytokines that result; and cellular typing of the inflammatory infiltrate will increase our understanding of the pathophysiology of the lesions caused by SM. In addition, the recent development of a topical skin protectant for SM and for other chemical warfare agents may have broad applications within dermatology.

The distribution of [125I]ricin in mice following aerosol inhalation exposure.

Studies were conducted to examine the uptake and redistribution of [125I]ricin from the lungs of mice following nose-only aerosol inhalation exposure. Radiolabelled contents were measured in lung and various extra-pulmonary tissues 15 min through 30 h following 10 min aerosol exposures. Pharmacokinetic analyses were performed on whole-organ data obtained for lungs, stomach, liver and spleen. Radioactivity within the lungs, maximal at 15 min post-exposure, was eliminated in a biexponential fashion with a long beta half-life (approximately 40 h). Large amounts of radiolabel were also found within the gastrointestinal tract. Radiolabel within the stomach exhibited an absorption phase and two-compartment elimination. Radiolabel content of many other tissues, including known accumulation sites for intravenously administered toxin, was significantly (p < 0.05) increased (relative to 15 min post-exposure) in association with the early elimination of radiolabel from the lungs, but levels in these tissues were very low and did not increase after 4 h post-exposure. The only exception was our sample of trachea, which showed delayed elevations in radiolabel (peak at 24 h); this pattern was attributable to the contained thyroid (not removed at necropsy) and its trapping of free [125I] released upon tissue [125I]ricin degradation. The overall data indicate that ricin administered by aerosol inhalation is delivered to both respiratory and gastrointestinal tracts; however, it is not extensively transported from either tract to other potential target sites. Ricin delivered to the lungs is primarily sequestered within the lungs until degradation. Only small amounts of ricin delivered to the gastrointestinal tract are absorbed into the circulation.

Assessment of the histopathological lesions and chemical analysis of feral cats to the smoke from the Kuwait oil fires.

Twenty-six adult or subadult feral cats were collected from Kuwait approximately 8 months after the ignition of the Kuwait oil wells. These animals were obtained from two sources: 12 animals from Kuwait City, a relatively smoke-free area, and 14 from the city of Ahmadi, an area with heavy smoke. Animals were euthanized and a complete set of tissues consisting of all major organs was taken for histopathology. Samples of lung, liver, kidney, urine, and blood were also taken for toxicology. Histopathological lesions observed in the lung were mild accumulations of anthracotic pigment in the lungs of 17 cats. Hyperplasia of the bronchial and bronchiolar gland in 8 cats, and smooth muscle hyperplasia of bronchioles in 14 cats. Tracheal gland hyperplasia was observed in 7 cats, and minimal squamous metaplasia of the tracheal mucosa in 17 cats, Laryngeal lesions consisted of submucosal gland hyperplasia in 2 cats and squamous metaplasia of the mucosa in 5 cats. Hyperplasia of the nasal submucosal glands was observed in 6 animals. The pharyngeal mucosa as well as other organs and organ systems were normal in all cats. Atomic absorption analysis for 11 metals was performed; vanadium and nickel levels (two metals that were present in the smoke from the oil fires) are not indicative of substantial exposure to the oil fires. Based on the histopathological findings and toxicological analysis, it is felt that inhalation of air contaminated with smoke from the oil fires had little or no long-term effect on the animals examined.

Histopathologic lesions in sea otters exposed to crude oil.

Following the Exxon Valdez oil spill in Prince William Sound, Alaska, sea otters (Enhydra lutris) that appeared to be contaminated with oil, that were in danger of becoming contaminated, or that were behaving abnormally were captured and taken to rehabilitation centers. Exposure to oil was assessed by visual examination when otters arrived at the centers. Degree of oil exposure was graded according to the following criteria: oil covering greater than 60% of the body--heavily contaminated; oil covering 30-60% of the body--moderately contaminated; oil covering less than 30% of the body or light sheen on fur--lightly contaminated. If there was no oil visible, otters were considered uncontaminated. Tissues from 51 oil-contaminated sea otters (14 males, 37 females) and from six uncontaminated sea otters (three males, three females) that died in rehabilitation centers were examined histologically. Among oil-contaminated sea otters, 19/46 had interstitial pulmonary emphysema, 13/40 had gastric erosion and hemorrhage, 11/47 had centrilobular hepatic necrosis, 14/47 had periportal to diffuse hepatic lipidosis, and 10/42 had renal tubular lipidosis. Of the uncontaminated sea otters, 1/6 had gastric erosion and hemorrhage and 1/6 had diffuse hepatic lipidosis. Histologic examinations were performed on tissues from five sea otters (three males, two females) found dead with external oil present 15 to 16 days after the spill. Periportal hepatic lipidosis and renal tubular lipidosis were found in 3/5, and interstitial pulmonary emphysema was found in 1/5. Tissues from six apparently normal sea otters (four males, two females) collected from an area not affected by an oil spill were examined histologically, and none of these lesions were found. We conclude that interstitial pulmonary emphysema, centrilobular hepatic necrosis, and hepatic and renal lipidosis of sea otters were associated with exposure to crude oil. Gastric erosion and hemorrhage may have been associated with stress of captivity and/or oil exposure.

Chronic emesis caused by a nematode-induced gastric nodule in a cat.

A spirurid nematode-induced gastric nodule was believed to be responsible for chronic gastric irritation and vomiting in a domestic short-hair cat. Clinical improvement was noticed following surgical removal of the parasitic nodule in the wall of the pylorus. Morphologic characteristics of the parasite were most consistent with Spirocerca lupi. Infection with Spirocerca lupi is most commonly reported in Canids, often resulting in chronic granulomatous disease of the distal portion of the esophagus. In some animals, the lesions transform into fibrosarcomas and osteogenic sarcomas.

Nose-only versus whole-body aerosol exposure for induction of upper respiratory infections of laboratory mice.

The effectiveness of two aerosol delivery systems, nose-only and whole-body, were compared using Swiss-Webster mice and two pathogens, Klebsiella pneumoniae and Venezuelan equine encephalitis (VEE) virus. With K. pneumoniae the median lethal dose (LD50) and the mean time to death correlated with the inhaled dose. An LD50 value of 335 colony forming units (cfu) for nose-only exposure was significantly less than the LD50 value of 3741 cfu obtained for whole-body exposure. The LD50 values obtained with VEE virus for nose-only exposure [8 plaque forming units (pfu)] and whole-body exposure (11 pfu) were similar to each other. Following a 10-min nose-only exposure, concentrations of K. pneumoniae approximating 10(4)/g were present after 24 hr in the upper respiratory tract (URT) and lungs. The numbers of bacteria reached a peak at 72 hr, when resolution of the infection began. Detectable levels of bacteria in the blood and tissues were delayed in mice given whole-body exposure, plus there was a decreased concentration of bacteria per gram of tissue. Major pathological lesions induced by K. pneumoniae were mild suppurative rhinitis and minimal suppurative bronchopneumonia. Viremia was greatest at 96 hr following aerosol exposure to VEE. Virus concentrations in the URT, lungs, cerebrum, spleen and mesenteric lymph nodes reached maximum titers earlier for mice exposed by nose-only than for mice exposed to whole-body aerosols.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemoimmunotherapy of B 16 melanoma and P388 leukemia with cyclophosphamide and pyrimidinones.

Since increasing evidence indicates that combination modality of cancer treatment is preferable, and a series of 5-halo-6- phenylpyrimidinones has been found to induce interferon production and to stimulate a variety of immune responses, several were tested alone or in combination with cyclophosphamide (CY) against B 16 melanoma and P388 leukemia. Thus far, 2-amino-5-bromo-6-(3-fluorophenyl)-4(3H)pyrimidinone ( ABMFPP ) and its sister compound 2-amino-5-bromo-6-(2-fluorophenyl)-4(3H)pyrimidinone ( ABOFPP ) were found to be superior to other pyrimidinones including 2-amino-5-bromo-6-(6-phenyl)-4-pyrimidinone which is currently under clinical investigation. Neither ABMFPP nor ABOFPP alone had any significant activity against P388 leukemia. However, a marked synergistic effect was observed when a single i.p. injection of CY at 24 hr after tumor inoculation (10(6) cells/mouse) was followed by multiple i.p. injections of either ABMFPP or ABOFPP . For instance, the increase of life span was about 180% when animals received both CY (150 mg/kg) and ABMFPP (125 mg/kg/injection) as compared to 100% increased life span when animals received CY alone, and 0% increased life span when animals received ABMFPP alone. Also, 80% of the animals were long-term survivors (greater than 30 days) when animals received the combination therapy as compared to 20% survivors when animals received CY alone. The synergistic effect exhibited by ABMFPP or ABOFPP correlated positively to the initial reduction of tumor burden by CY. The optimal gap between CY and pyrimidinone administration was one day. The best therapeutic response was observed when pyrimidinone was given every 4 days for a total of 7 injections; however, other schedules and dosing frequencies also gave significant responses. The synergistic effect was also observed with B 16 melanoma when animals received the combination therapy. The significance of these findings, in terms of theoretical consideration as well as drug development, is discussed.