Vaccination of dairy calves with bovine adenovirus type 3

A field study was undertaken to determine the efficacy of vaccinating dairy calves with a killed bovine adenovirus type 3 (BA3) vaccine in a herd where pneumonia associated with BA3 infection had been a severe problem. Calves were first vaccinated when they were less than one week old; a second dose was given 10-14 days later. Efficacy of the vaccine was evaluated following natural exposure to the virus by comparing prevalence of pneumonia in control (n = 21) and vaccinated (n = 21) calves. Seroconversion to BA3 was shown in 9 of 12 control calves that developed pneumonia, 4 of these calves subsequently died as a result of the disease. Four additional control calves had a subclinical infection with the virus. All calves in the vaccinated group developed virus-neutralizing antibodies which averaged 1:20 eight weeks after the second vaccination. The serologic response to vaccination was not inhibited in calves possessing low levels of colostral antibodies. Two vaccinated calves developed pneumonia but they did not succumb to the disease. The prevalence of pneumonia in vaccinated calves was significantly reduced (P less than 0.05) when compared to control calves.     

Isolation of bovine adenovirus type 4 from cattle in Oregon.

Four isolates of bovine adenovirus type 4 were recovered from Oregon cattle. One isolate was recovered from a 1-week-old calf with pneumoenteritis, and 1 isolate from an 8-month-old bull with fever and respiratory disease. Two isolates were recovered as latent viruses in testicular cell cultures. All 4 isolates of the virus were shown to have certain physical, chemical, biologic, and antigenic characteristics similar to previously described strains of bovine adenovirus type 4. Of 246 adult beef and dairy cattle in Oregon, 51% had serum-viral neutralizing antibodies to the type 4 virus at the 1:8 dilution level.     

Bovine adenovirus type 3 pneumonia in dexamethasone-treated calves

The effects of immunosuppression were examined in 1.5-month-old calves that were given dexamethasone (DM) before endobronchial inoculation with bovine adenovirus type 3 (BAV-3). Immunohistopathologically, severe necrotizing bronchiolitis with eosinophilic and basophilic intranuclear inclusion bodies was observed both in DM-treated 1.5-month-old infected calves and in non-DM-treated 7-day-old infected calves. These inclusion bodies were correlated with the detection of BAV-3 antigen and viral particles. The presence of inclusion bodies in the desquamated epithelial cells or of BAV-3 antigen, or both, correlated well with the isolated level of BAV-3 in bronchoalveolar lavage (BAL) fluid. Few immunoglobulin (IgG, IgM, and IgA)-containing B lymphocytes or CD8+ T lymphocytes infiltrated the pneumonic lesion in both the 7-day-old and the DM-treated 1.5-month-old infected calves. Thus, depletion of CD8+ T lymphocytes in calves might influence the clearance of BAV-3 from respiratory tissues.     

Isolation of bovine adenovirus type 1 from a calf with pneumo-enteritis

During the last decade, an increasing number of bovine adenoviruses have been isolated from calves suffering from more, or less, well-defined syndromes. These have consisted of respiratory disorders of varying severity, enteritis, or a combination of both, which in typical cases has been termed “pneumo-enteritis”. These investigations have been reviewed by Darbyshire (1968). Wilcox (1969) isolated adenoviruses from kerato-conjunctivitis (KC) in cattle. Furthermore, strains have been isolated from apparently healthy animals (Darbyshire 1968), and from tissue cultures prepared from various organs from calves such as kidneys (Scho- pov et al. 1968), and testes (Rondhuis 1968, Bartha & Csontos 1969). At the present time 9 serotypes of bovine adenoviruses exist, as determined by neutralization tests, and these have recently been reviewed by Guenov et al. (1970). However, several strains, some from cases of pneumonia (Cole 1970, Lupini et al. 1970) and others from KC (Wilcox 1969) remain to be typed and compared with the known prototypes, thereby enabling possible new serotypes to be identified. So far, serotypes 1 and 2 (Darbyshire et al. 1969), serotype 3 (Darbyshire et al. 1966) and serotypes 4 and 5 (Aldasy et al. 1965) have been shown to cause pneumo-enteritis, and serotype 6 (Rondhuis 1970) a mild respiratory disease in experimentally infected calves. Similarly, KC has been produced experimentally by Wilcox (1970), while the pathogenicity for experimental animals of the other typed and untyped strains remains to be investigated.     

Isolation of an adenovirus and an adeno-associated virus from goat kids with enteritis.

A dairy goat operation in Minnesota experienced a sudden, markedly increased mortality among its neonatal goats. Approximately 60 of 130 kids (46%) died. The animals had diarrhea and dyspnea of 1-2 days duration before death. Necropsy of 4 goat kids revealed marked, acute, catarrhal enteritis and fibrinous pleuropneumonia. Mannheimia haemolytica was isolated from the lungs. Basophilic inclusion bodies filling the entire nucleus were present in enterocytes of the ileum of 3 goats. Adenoviral particles were detected in the feces by electron microscopy and adenovirus was subsequently isolated from the intestinal content together with a parvo-like virus (dependovirus). Morphology, physicochemical characteristics, and neutralization tests indicated that the adenovirus resembled ovine adenovirus-2 (OAdV-2). However, the PstI restriction endonuclease pattern produced by the goat adenovirus was distinct from that of OAdV-2. This is the first report of enteritis in goats with an adenovirus antigenically related to OAdV-2 and with a parvo-like dependovirus.     

Isolation and identification of a bovine adenovirus type 3 with an adenovirus-associated virus.

A bovine adenovirus with agglutinating activity was isolated from feedlot calves and classified as serotype 3. The agglutinating activity was shown to be the property of an adenovirus-associated virus (AAV). The AAV was isolated from the bovine adenovirus by isopycnic centrifugation in CsCl; the AAV had a density of 1.4 g/cm2. This AAV is serologically related to bovine AAV-TR-15, but is distinct from bovine parvovirus-1 and primate AAV types 1 to 4, using counterimmunoelectrophoresis and hemagglutination-inhibition.     

Isolation of bovine coronavirus from feces and nasal swabs of calves with diarrhea.

Fecal and nasal samples were collected from 180 calves with diarrhea and 36 clinically normal co-habitants, and tested for virus using HRT-18 cell cultures derived from human rectal adenocarcinoma. A cytopathic virus was isolated from 5 fecal and 56 nasal samples obtained from diarrheic calves. All calves in which the virus was isolated from diarrheic feces were positive for virus isolation from nasal swabs. The virus was also isolated from the nasal swabs of 10 clinically normal calves that were co-habitants with diarrheic calves. Because they were morphologically similar to coronavirus, agglutinated mouse erythrocytes and serologically identical with the Nebraska calf diarrhea coronavirus, new isolates were identified as bovine coronavirus. The demonstration of viral antigens in nasal epithelial cells by a direct immunofluorescence was in close agreement with the virus isolation in HRT-18 cell cultures. This is the first report on the isolation of bovine coronavirus from newborn calves with diarrhea in Japan. The evidence that the virus was frequently isolated from nasal swabs is of great interest for understanding the pathogenesis of bovine coronavirus infection.     

Effects of 4-ipomeanol on bovine parainfluenza type 3 virus-induced pneumonia in calves.

Previous research has demonstrated that 4-ipomeanol toxicosis can enhance the severity of para-influenza virus-induced pneumonia in mice. The objectives of this study were to determine whether calves are susceptible to 4-ipomeanol-induced enhancement of parainfluenza type 3 viral pneumonia and to determine whether 4-ipomeanol alters pulmonary replication of parainfluenza virus. Male Holstein calves were injected with either 4-ipomeanol (3 mg/kg) or vehicle (polyethylene glycol) 3 days prior to intratracheal inoculation with either parainfluenza virus or sham inoculum of culture medium. Calves in the four treatment groups (ipomeanol-parainfluenza, ipomeanol-medium, vehicle-parainfluenza, and vehicle-medium) were necropsied at 5 days after inoculation with parainfluenza virus or medium. The lungs were studied by correlated methods of light and electron microscopy, digitizing morphometry and pulmonary lavage to quantitate the severity of pneumonia. Pulmonary viral titers were determined, and viral antigen was identified in the lung by immunoperoxidase technique. The calves in the ipomeanol-virus treatment group had over a 9-fold higher (P less than 0.05) volume density of virus-induced interstitial pneumonia than did the calves in the other three treatment groups. This 4-ipomeanol-enhanced viral pneumonia was associated with significantly greater (P less than 0.05) numbers of pulmonary macrophages and neutrophils in the lavage fluid and higher (P less than 0.05) pulmonary titers of pulmonary infectious parainfluenza virus. Four-ipomeanol-enhanced viral pneumonia was characterized in part by extensive hyperplasia of type II alveolar epithelial cells and by dense aggregates of macrophages and neutrophils in alveolar spaces and interalveolar septa. The results indicate that 4-ipomeanol exacerbates interstitial pneumonia in calves induced by bovine parainfluenza type 3 virus.     

Experimental infection of calves with an adenovirus isolated from sheep and related to bovine Adenovirus type 2 I. Clinical and virological studies.

Colostrum deprived calves were experimentally infected with an adenovirus isolated from sheep and related to bovine adenovirus type 2. The calves showed respiratory symptoms and mild diarrhoea from the third day after infection. Laboratory tests revealed the development of leucopenia, lymphopenia, a drop of the pH of the urine and the appearance of pathological changes in the urine. The animals shed the virus in their nasal discharge, faeces and urine. Comparing the clinical and virological findings with the previous experimental infection of lambs it is concluded, that this type of adenovirus is similarly pathogenic for the two ruminant species.     

Serological studies of parainfluenza type 3 virus, bovine adenovirus type 3 and bovine respiratory syncytial virus infection in beef calves

Six serum samples were taken at monthly intervals from birth to weaning from each of 41 newborn calves in the autumn and spring calf crops of a beef cow--calf herd. The serum hemagglutination-inhibition (HI) antibody titres to parainfluenza type 3 virus (PIV-3), virus-neutralization (VN) antibody titres to bovine adenovirus type 3 (BAV-3) and bovine respiratory syncytial virus (BRSV) were determined using microtitration techniques. There was serological evidence of a significantly higher incidence of infection with BAV-3 in the fall calves than in the spring calves. Serological responses to BAV-3 were not detected in calves with VN titres of greater than 1/256. Serological evidence of subclinical infection with PIV-3 occurred mainly in late February or early March during a period of marked environmental temperature fluctuations. Serological evidence of a high incidence of infection with BRSV was obtained for both the fall and spring calf crops. Serum antibody appeared to be unable to prevent infection with BRSV. An association between infection with BRSV and clinical pneumonia was found in 3 out of 9 calves. BAV-3 infection was related to pneumonia in only 1 instance; however, there was simultaneous evidence of BRSV infection in this calf. PIV-3 infection was found to be related to pneumonia in only 1 instance. There was serological evidence of infection with BAV-3 in association with the occurrence of diarrhea in 3 calves.     

Viral enteritis of calves.

Calf diarrhoea is an important cause of economic loss. The aetiology of the disease is considered with particular reference to the role of viruses. Although many microbial organisms have been associated with the disease, there is doubt concerning their true role as causative agents. Two viruses, neonatal calf diarrhoea reovirus-life agent and calf coronavirus, have been discovered recently which appear to play an important role in many cases of diarrhoea and the evidence for considering them to be primary causes of the disease is discussed.     

Experimental inoculation of heifers with bovine adenovirus type 3.

Nine 2-year-old heifers having BAd3-neutralizing antibody titers between 1:120 and 1:1080 were individually exposed intranasally to an aerosol of 10(8) pfu of wild type (wt) bovine adenovirus type 3 (BAd3). Four animals were kept as non-inoculated controls. The heifers were examined daily for rectal temperature, weight gain/loss, nasal and ocular discharges, and other clinical signs for 10 d post-inoculation. None of the animals showed any sign of clinical disease. Virus excretion was observed in one animal only on Day 3 post-inoculation. All BAd3-inoculated heifers demonstrated a significant (P < 0.005, paired t-test) rise in BAd3-specific serum IgG, IgG1, or IgG2 ELISA titers and virus-neutralizing antibody titers compared to the titers before inoculation. All virus-inoculated animals demonstrated increased levels of BAd3-specific IgA ELISA titers in nasal secretions. These results suggest that in the presence of circulating BAd3-neutralizing antibodies, intranasal inoculation of cattle with wt BAd3 would result in inapparent infection.