Experimental infection of Peste des Petit Ruminant virus and Mannheimia haemolytica A2 in goats: immunolocalisation of Mannheimia haemolytica antigens

Abstract

Nigerian strain of Peste des Petit Ruminant (PPR) virus and Mannheimia haemolytica (MH) biotype A serotype 2, was used successfully to reproduce a concurrent disease in West African Dwarf goats. The development of the various pathological features were studied at regular intervals following infection. The acute inflammatory reaction which had developed by day 3 after initial infection was characterised by flooding of the alveoli by neutrophils, oedema, hemorrhage and syncytial cells together with a moderate bronchial and bronchiolar epithelial necrosis. This progressed to a milder acute broncho interstitial pneumonia with giant cells. At this stage, the mucosal immunity were well developed especially the aggregate form of NALT and more of nodular forms of BALT. The organisms were demonstrated with strong immunostaining in the necrotic center, necrotic alveolar wall, fibrin, serous exudate, and degenerated leukocyte in the alveoli and respiratory airways. The bacterial antigens were observed as a strong immunostaining in the blood vessels of the nasal septum, sinusoid in the liver and interstium of the kidney, cytoplasm of alveolar macrophages, pneumocytes, bronchial and bronchiolar epithelium, in the monocytes in the blood vessels. These findings confirmed the enhancement of MH tropism especially in the respiratory tract, liver and kidney. It also showed that West african dwarf goats are highly susceptible to the intratracheal combined infection of PPR virus and MH. The fact that the infection induces strong mucosal responses, this phenomenon can be explored in Africa with the use of combined PPR virus and MH intranasal vaccines to curtail the menace of pneumonia associated with the combined infection on field.

Detection of peste des petits ruminants and concurrent secondary diseases in sheep and goats in Ngorongoro district, Tanzania

“…Co-association of SRMV with other viral and bacterial infections in small ruminants has been demonstrated before in other studies in different parts of the world (Kul et al 2015). Viral diseases with co-association with SRMV include sheep and goat pox virus, while coassociations with bacterial pathogens include Pasteurella spp., Mccp, and Mannheimia haemolytica (Malik et al 2011;Emikpe et al 2010;Brown et al 1991;Ugochukwu and Agwu 1991). The co-infections detected in this study may have provided complications during field diagnosis that resulted in the persistence and severity in the affected flock.…”

“…Other respiratory diseases of economic importance affecting small ruminants include contagious caprine pleuropneumonia (CCPP), pasturella, sheeppox, and goatpox (Kul et al 2015;Emikpe et al 2010;Brown et al 1991;Ugochukwu and Agwu 1991). Mycoplasma capricolum subspecies capripneumoniae (Mccp) is the causative agent of CCPP, a highly contagious disease of goats first described in 1873 in Algeria (OIE 2014).…”

Peste des Petits Ruminants Virus Tissue Tropism and Pathogenesis in Sheep and Goats following Experimental Infection

“…As mentioned in previous publications, this difference may be due to: 1) differences in the breed of sheep or goat used in the studies; 2) the overall health of the animals; 3) the virus strain/isolate used and how it was amplified or 4) the absence of other bacterial, viral or helminth pathogens, which may compromise the host immune responses. For example, when PPRV was co-administered with the bacterial pathogen Mannheimia haemolytica , enhanced pneumonia was observed [37]. In addition, in natural field settings livestock are likely to be co-infected with other viruses such as capripoxvirus and/or bluetongue virus [38], that would most likely exacerbate the onset and severity of PPR.…”

The Gut and Lung Morphometry in Experimental and Natural Lineage 1 Variant of Peste des Petits Ruminants Virus Infection in Nigerian Goats

“…Portions of the intestine were collected from a formalin fixed natural and previous experimental PPR and PPR and Mannheimia hemolytica infected goat samples (Emikpe & Akpavie, 2010a;Emikpe et al, 2010). Pieces of the intestinal tissue were cut and fixed in 10% buffered formalin in a labeled bottle.…”