Resistance of colostrum-deprived domestic lambs to infection with deer adenovirus.

Seven colostrum-deprived, 3-4-wk-old Rambouillet-Hampshire lambs were inoculated via the mucous membranes with deer adenovirus (DAdV) and monitored for clinical signs for 21 d post-inoculation at which time animals were euthanized and postmortem examinations were performed. Pre-inoculation and post-inoculation serum samples were tested for antibodies to DAdV, ovine adenovirus 7, bovine adenovirus 7, and goat adenovirus 1. Evidence for DAdV infection was determined by virus isolation, PCR tests, and histopathology with immunohistochemistry tests for DAdV. No clinical signs or lesions consistent with adenoviral hemorrhagic disease (AHD) in deer were seen in the lambs, and the lambs did not seroconvert to DAdV. DAdV was not detected by PCR, virus isolation, or immunohistochemistry in any of the samples tested from the lambs. A positive control deer similarly inoculated with DAdV developed fatal AHD 1 wk post-inoculation. Our colostrum-deprived lambs did not become infected when inoculated with DAdV.

The effect of different dietary levels of DL-methionine and DL-hydroxy analogue on the antioxidant status of young turkeys infected with the haemorrhagic enteritis virus.

BACKGROUND: The results of experiments involving broiler chickens and turkeys indicate that increased dietary methionine (Met) levels may improve the antioxidant protection of tissues in fast-growing birds. This is an important consideration since viral infections induce oxidative stress. The aim of this study was to verify the hypothesis that turkey diets with increased Met content can suppress oxidation processes induced by infection caused by the haemorrhagic enteritis virus (HEV), and that the noted effect is determined by the chemical form of this amino acid: DL-methionine (DLM) or DL-hydroxy analogue of Met (MHA). RESULTS: Dietary Met content above 40% higher than the level recommended by the NRC (1994) intensified lipid peroxidation in the small intestine, leading to an increase in malondialdehyde (MDA) and lipid peroxide (LOOH) levels, but it also stimulated antioxidant mechanisms in the blood and liver of turkeys infected with HEV. In comparison with DLM, MHA contributed to more severe symptoms of oxidative stress, such as elevated MDA levels in the intestines, and a decrease in glutathione peroxidase (GPx) activity and ferric-reducing ability of plasma (FRAP). CONCLUSIONS: In HEV-infected turkeys, diets with increased Met content did not exert a clear antioxidant effect, which was noted in uninfected birds. The prooxidant activity of Met observed in the small intestinal wall was suppressed in the blood and liver of turkeys, most likely due to intensified synthesis of uric acid and glutathione. In comparison with MHA, DLM had a more beneficial influence on the analysed parameters of the redox status in the small intestine, blood and liver of turkeys.

Dietary arginine stimulates humoral and cell-mediated immunity in chickens vaccinated and challenged against hydropericardium syndrome virus.

The effects of dietary supplement of arginine on protective humoral and cell-mediated immune responses of broiler chicks vaccinated and challenged against hydropericardium syndrome virus (HPSV) were investigated and compared with those of 2 reference drugs (cyclophosphamide and cyclosporine). Percentage ratios of lymphoid organs (bursa, spleen, and thymus) to BW, postvaccination and challenge serum antibody responses to HPSV, cutaneous basophil hypersensitivity reaction, peripheral lymphoproliferation, postchallenge detection of HPSV in the tissues of infected birds, and ability of chicks to resist virulent HPSV challenge were the parameters utilized to determine the effects of arginine on protective immune responses of chicks. A total of 600 chicks were used in this study. Arginine-supplemented chicks showed significant (P < 0.05) stimulation of lymphoproliferation and cutaneous basophil hypersensitivity reactions compared with untreated control chicks. Similarly, significantly higher body and lymphoid organ weights were (P < 0.05) recorded in arginine-supplemented chicks compared with untreated control chicks. The highest survival rate was recorded in arginine-supplemented HPS-vaccinated chicks compared with immune-suppressed (cyclophosphamide- and cyclosporine-treated and HPS-vaccinated chicks) and untreated unvaccinated control chicks after virulent HPSV challenges. Postchallenge tissue samples from arginine-supplemented and HPS-vaccinated chicks yielded negligible HPSV detections by virus isolation in cell culture or PCR method, or both, compared with untreated control chicks. Thus, it was concluded that dietary supplementation of arginine had beneficial effects on humoral and cell-mediated immune responses of broiler chicks against HPSV.

Evaluation of the pathogenic potential of cervid adenovirus in calves.

Four 3-month-old Jersey calves and three 3-month-old Holstein calves were inoculated with cervid adenovirus and monitored for clinical signs until necropsied between 10 and 42 days postinoculation. The neonatal Jersey calves had received colostrum, and the Holstein calves were colostrum deprived. Preinoculation and postinoculation serum samples were tested for antibodies to the cervid adenovirus, bovine adenovirus type 6, bovine adenovirus type 7, and goat adenovirus type 1. Virus isolation was performed on kidney, nasal secretion, and/or lung homogenates in fetal white-tailed deer lung cells. Negatively stained preparations of feces from Jersey calves were examined weekly using an electron microscope, and weekly blood samples were collected for complete blood counts. Full necropsies were performed on all calves. A complete selection of tissues was evaluated for microscopic changes, and immunohistochemistry was performed on all tissues using a polyclonal antibody to deer adenovirus. No clinical signs were observed in the calves during the study period. Following inoculation, colostrum-deprived calves developed low antibody titers to deer adenovirus, while the Jersey calves that received colostrum did not. Calves that received colostrum had high antibody titers to bovine adenovirus type 7 and goat adenovirus type 1. No consistent gross or microscopic lesions were seen. Adenovirus was not observed in negatively stained preparations of feces. Immunohistochemistry results did not demonstrate virus in all tissues examined microscopically, and virus was not isolated from lungs, nasal secretions, and kidneys.

Pathogenesis of infection induced by an adenovirus isolated from a goat.

OBJECTIVE: To determine the pathogenic potential of an adenovirus isolated from a goat. ANIMALS: 14 colostrum-deprived, isolation-reared goat kids approximately 3 weeks old. PROCEDURE: Kids were inoculated with either cell culture fluid containing adenovirus (n = 10) or uninfected cell culture fluid (n = 4): 2 ml transtracheally and 1 ml/nostril. Clinical signs of disease and rectal temperature were recorded daily; nasal secretion and fecal specimens were collected daily. Control kids were necropsied, 2/d, on postinoculation days (PID) 5 and 10. Virus-inoculated kids were necropsied on PID 3, 5, 7, 10, and 28. After necropsy, lung, liver, kidney, and brain specimens were aseptically collected for virus isolation attempts. Tracheal fluid was collected on sterile cotton swabs. Turbinate, trachea, lung, mediastinal lymph node, liver, kidney, duodenum, jejunum, ileum, mesenteric lymph node, colon, and brain specimens were collected for histologic evaluation. RESULTS: Kids developed mild-to-moderate clinical respiratory tract infection. Virus was recovered consistently from nasal secretion and sporadically from fecal specimens. Grossly, there were multiple areas of atelectasis and hyperemia, principally in the cranioventral portion of the lungs. Microscopically, there was detachment and sloughing of foci of epithelial cells of the terminal bronchioles and alveoli. In kids necropsied late in the disease, these changes were accompanied by hyperplasia of type-II epithelial cells. Viral inclusions were not an obvious feature, but a few cells contained probable inclusions. CONCLUSIONS AND CLINICAL RELEVANCE: The caprine adenovirus reported here is capable of inducing respiratory tract disease and lesions in the lungs of young kids.

Nitrogen metabolism of calves inoculated with bovine adenovirus-3 or with infectious bovine rhinotracheitis virus.

Beef calves were inoculated with bovine adenovirus-3 or infectious bovine rhinotracheitis virus. After inoculation, plasma fibrinogen increased, serum phosphorus decreased, and nitrogen and phosphorus digestibility decreased compared with preinoculation values. Urinary N excretion increased when calves developed rectal temperatures greater than 39.7 C. Results indicated that clinical infection of calves with infectious bovine rhinotracheitis virus increases urinary N excretion and reduces N and phosphorus balance, and that clinical and subclinical infections with either virus reduce dietary N digestibility.

[Adenovirus infections of cattle]. / Vurkhu adenovirusnite infektsii po govedata.

Results are given of studies on the adenoviral infections in cattle in the region of Southeast Bulgaria. Serologic methods were used to elucidate some moments of the enzootic process and the part played by bovine adenoviruses in the etiology of the respiratory diseases of calves. Demonstrated was the participation of adenovirus strains of group II. It was established that the technologic moments influence the course of the adenoviral enzootics. A successful attempt was made to uncode the type picture and the circulation of types 1, 2, 3, and 8 adenoviruses within the cattle herds. The method of direct immunofluorescence was successfully employed in the diagnostics of adenoviral diseases in calves when alive. Demonstrated was also the presence of specific skin supersensitivity in cattle infected with adenoviruses. Data are given on the specificity of the reaction, the quality and standardization of the allergen, the age-associated dynamics of the process, etc.

[Age-related dynamics of adenovirus antibodies in calves]. / Vuzrastova dinamika na protivolela u teleta sreshtu adenovirusi.

Experiments were carried out on calves from 3 cattle-breeding farms, failing to fight respiratory disorders, aged 10-120 days, in order to prove the participation of cattle adenoviruses in the etiology of the illness. Age susceptibility, as well as the dynamics of passive and active antibodies in young calves against adenoviruses were studied with regard to technology of their breeding. It was proved that the persistence of antiadenoviral antibodies of colostral origin was determined within the limits of 4-8 weeks, whereas the infection of the young and growing calves with adenoviruses took place most frequently within the limits of 2-16 weeks after their birth and this process is greatly influenced by the regime of breeding. An earlier grouping of calves (8-10 days after their birth) advances age susceptibility, and conversely. The regrouping of calves from unsuccessful farms at the age of 20 days led to a later manifestation of adenoviral disease in the group. In the blood serum of calves from one farm were proved virus neutralizing antibodies, corresponding simultaneously to cattle adenoviruses serotypes 3 and 8, as well as precipitating ones against group specific antigens from I and II adenoviral subgroups. It was proved that 40-50% of the growing calves suffer from adenoviral infection.

Probable role of viruses in calfhood diseases.

Bovine enteroviruses, bovine viral diarrhea virus, rotavirus (formerly called reovirus-like agent), coronavirus-like agent, bovine adenovirus, and bovine parainfluenza-3 virus have been isolated from calves suffering from neonatal disease. The experimental disease produced by these viruses is not necessarily severe or fatal, but under farm and ranch conditions, each probably serves as an added to mortality from neonatal disease. After initial losses following the introduction of a virus into a herd, the subsequent losses will be limited because the cow will produce antibodies to protect the fetus during gestation. Antibodies will also be concentrated in colostrum to protect the calf at birth. However, colostrum must be fed immediately after birth, before the calf becomes infected.

Lesions and pathogenesis of disease in young calves experimentally induced by a bovine adenovirus type 5 isolated from a calf with weak calf syndrome.

Lesions induced in each of 9 young colostrum-deprived calves closely resembled lesions seen in naturally occurring "weak calf syndrome" of eastern Idaho and southwestern Montana. The disease was experimentally induced by intravenous injection of bovine adenovirus type 5 that had been isolated from a calf with weak calf syndrome...

A bovine adenovirus type 3: isolation, characterization, and experimental infection in calves.

A virus was isolated from a group of feedlot cattle with acute respiratory disease that was characterized by physicochemical methods as an adenovirus and identified serologically as a bovine adenovirus type 3. Intratracheal inoculation of three 4 month old colostrum deprived calves resulted in pyrexia, hyperpnea, dyspnea, anorexia and in one animal a mild diarrhea.

Hypogammaglobulinemia predisposing to infection in foals.

Measurement of serum immunoglobulins in 46 foals less than 2 weeks old revealed 9 foals with hypogammaglobulinemia. The hypogammaglobulinemia was attributed to failure in transfer of immunoglobulins from dam to foal via colostrum. Three of the affected foals did not nurse at all, or only slightly, and 2 of these died of infections within a few days after birth, whereas the 3rd foal did not grow as well as normal foals. Six of the affected foals nursed in an apparently normal manner, and 5 of these had nonfatal respiratory infections between 2 and 5 weeks of age. Analysis of serum samples from surviving foals demonstrated that immunoglobulins were eventually produced. One other foal examined had hypogammaglobulinemia at 57 days of age, an age when the foal should have produced large amounts of immunoglobulin independent of passive transfer. This foal had simultaneous infections and hypogammaglobulinemia, but eventually produced normal amounts of immunoglobulin. Cellmediated immunity was normal at 3 months of age. This condition was designated transient hypogammaglobulinemia and was thought to be due to a temporary inability to make immunoglobulins.