Coronavirus and Pasteurella Infections in Bovine Shipping Fever Pneumonia and Evans' Criteria for Causation

Abstract

Respiratory tract infections with viruses andPasteurella spp. were determined sequentially among 26 cattle that died during two severe epizootics of shipping fever pneumonia. Nasal swab and serum samples were collected prior to onset of the epizootics, during disease progression, and after death, when necropsies were performed and lung samples were collected. Eighteen normal control cattle also were sampled at the beginning of the epizootics as well as at weekly intervals for 4 weeks. Respiratory bovine coronaviruses (RBCV) were isolated from nasal secretions of 21 and 25 cattle before and after transport. Two and 17 cattle nasally shed Pasteurella spp. before and after transport, respectively. RBCV were isolated at titers of 1 × 103to 1.2 × 107 PFU per g of lung tissue from 18 cattle that died within 7 days of the epizootics, but not from the lungs of the remaining cattle that died on days 9 to 36. Twenty-five of the 26 lung samples were positive for Pasteurella spp., and their CFU ranged between 4.0 × 105 and 2.3 × 109 per g. Acute and subacute exudative, necrotizing lobar pneumonia characterized the lung lesions of these cattle with a majority of pneumonic lung lobes exhibiting fibronecrotic and exudative changes typical of pneumonic pasteurellosis, but other lung lobules had histological changes consisting of bronchiolitis and alveolitis typical of virus-induced changes. These cattle were immunologically naive to both infectious agents at the onset of the epizootics, but those that died after day 7 had rising antibody titers against RBCV andPasteurella haemolytica. In contrast, the 18 clinically normal and RBCV isolation-negative cattle had high hemagglutinin inhibition antibody titers to RBCV from the beginning, while their antibody responses to P. haemolytica antigens were delayed. Evans' criteria for causation were applied to our findings because of the multifactorial nature of shipping fever pneumonia. This analysis identified RBCV as the primary inciting cause in these two epizootics. These viruses were previously not recognized as a causative agent in this complex respiratory tract disease of cattle.

Canine Respiratory Coronavirus: An Emerging Pathogen in the Canine Infectious Respiratory Disease Complex

“…Coronaviruses are a cause of respiratory disease in many species, including human beings, poultry, and cattle [15][16][17][18][19][20]. The presence of CRCoV in dogs was first described in a large study of dogs with CIRD [9].…”

A new approach for diagnosis of bovine coronavirus using a reverse transcription recombinase polymerase amplification assay

“…Bovine coronavirus (BCoV) is an important pathogen of livestock causing enteric disease in newly born calves (neonatal calf diarrhea), and adult cattle (winter dysentery) (Clark, 1993). The virus is also implicated in respiratory tract infections of growing calves and shipping fever pneumonia in feedlot cattle (Saif, 2010;Storz et al, 2000). Some BCoV virus strains may also be responsible for simultaneous enteric and respiratory tract infections (Decaro et al, 2008a).…”

The role of phagocytic cells in enhanced susceptibility of broilers to colibacillosis after Infectious Bronchitis Virus infection

“…In mice, influenza virus www.elsevier.com/locate/vetimm increases susceptibility to Streptococcus pneumoniae infection (Seki et al, 2004;Speshock et al, 2007) and measles virus predisposes for a range of bacterial infections such as Listeria monocytogenes (Slifka et al, 2003). In cattle, susceptibility for pneumonic pasteurellosis is greatly enhanced by a variety of respiratory viruses including bovine respiratory syncytial virus (Liu et al, 1999), bovine herpes virus-1 (Leite et al, 2002) and bovine coronavirus (Storz et al, 2000). In man, pneumonia has been a leading cause of death during influenza pandemics, supporting the widely held view that influenza virus predisposes for streptococcal infections (McCullers, 2006).…”