Experimental respiratory infection of goats with caprine herpesvirus andPasteurella haemolytica

Abstract

Groups of six male goats were inoculated intratracheally and intranasally with either caprine herpesvirus followed 6 days later by Pasteurella haemolytica, canine herpesvirus alone or P. haemolytica alone. Pneumonic lesions were observed in five of the six goats inoculated with caprine herpesvirus followed by P. haemolytica and in three of the six goats inoculated with P. haemolytica alone, but were not observed in goats inoculated with caprine herpesvirus alone or in non-infected controls. Pasteurella haemolytica was isolated from seven of eight lungs with pneumonia, but only from one of sixteen lungs without pneumonia. The lesions ranged from fatal acute exudative necrotising pneumonia to predominantly proliferative pneumonia. Half of the caprine herpesvirus-inoculated goats developed a clinical catarrhal rhinitis five days post-inoculation and the only virus-specific histopathological lesion was a mild tracheitis. Canine herpesvirus was recovered from the nasal swabs of all caprine herpesvirus- inoculated goats developed a clinical catarrhal rhinitis five days post-inoculation and the only virus-specific histopathological lesion was a mild tracheitis. Canine herpesvirus was recovered from the nasal swabs of all canine herpesvirus-inoculated goats and from the lungs of three goats inoculated with caprine herpesvirus alone. The experimental inoculations demonstrated that P. haemolytica alone can produce pneumonia in goats. In addition, the study showed that caprine herpesvirus readily proliferates in the upper respiratory tract and lungs of goats but the role of caprine herpesvirus in the aetiology of pneumonia remains uncertain.

The role of concurrent haemonchosis in the development of pneumonic pasteurellosis in goats

“…However, this appeared to have stressed the goats enough to induce sufficient immunosuppression to allow the development of the experimentally induced pneumonic pasteurellosis. Similar observations have been made with viral infections in the respiratory tract or infection by Ehrlichia phagocytophilia (Davies et al, 1982;Gilmour et al, 1982;Buddle et al, 1990) but not previously with a gastrointestinal helminth infection.…”

“…It is commonly caused by Pasteurella haemolytica, which has been recognized as part of the normal flora of the nasopharynx and oropharynx of various animals (Dungworth, 1985). Environmental stressors and respiratory diseases have been shown to play a major predisposing role in the pathogenesis of this disease (Buddle et al, 1990;Zamri-Saad et aL, 1991). The stress is thought to cause immunodepression leading to the proliferation and establishment of P. haemolytica in the respiratory tract (Baskerville, 1981).…”

A caprine pneumonia outbreak associated with caprine herpesvirus andPasteurella haemolyticarespiratory infections

“…Detection and identification of P. haemolytica in nasal secretions, and mycoplasma and viruses in nasal secretions and lung samples, were carried out using methods described by Buddie et al (3). Pasteurella haemolytica was isolated from the lungs by swabbing a freshly cut surface, streaking the swab on a blood agar plate and incubating for 24 h at 37°C.…”

“…Pasteurella haemolytica was isolated from the lungs by swabbing a freshly cut surface, streaking the swab on a blood agar plate and incubating for 24 h at 37°C. Serum antibodies against CHV, parainfluenza type 3 virus and respiratory syncytial virus were measured as described elsewhere (3). Cross virus neutralisation tests with a caprine herpesvirus (genital strain) and infectious bovine rhinotracheitis (IBR) virus, were carried out on caprine kidney cells grown in microtitre plates, using 100 cell culture infective doses (CCIDso) of virus per well and doubling dilutions of serum.…”

The Effect ofPasteurella haemolyticaA2 Infection on Phagocytosis Efficiency of Caprine Broncho‐Alveolar Macrophages

“…Pneumonic pasteurellosis is a common disease of sheep and goats throughout the world. It is a debilitating, often fatal disease caused by Pasteurella haemolytica A2 following a primary viral infection (Sharp et al, 1978; Buddle et al, 1990), concurrent diseases (Zamri‐Saad et al, 1994) or stressful environmental conditions (Zamri‐Saad et al, 1991). These predisposing factors cause immunosuppression in the host (Chiang et al, 1990) leading to the proliferation of P. haemolytica A2 in the respiratory tract, colonization and establishment of infection in the lung (Gonzalez and Maheswaran, 1993).…”