Laboratory diagnosis of a new outbreak of acute African swine fever in smallholder pig farms in Jos, Nigeria.

African swine fever (ASF) is a highly contagious fatal infectious disease of pigs and wild suids. The disease has a worldwide occurrence and significant impact on pig production. Two adult intensively raised large white boars from two farms in Jos with a history of sudden death were diagnosed of ASF between July and August 2019. Post-mortem examination of carcasses grossly showed splenomegaly, haemorrhagic lymphadenitis and hepatomegaly with severe congestion. The kidneys were enlarged and had generalized petechiae and blood clot in the pelvis. The heart was moderately enlarged. Microscopic examination of the spleen and lymph nodes revealed severe lymphocytic depletion, haemorrhage and severe haemosiderosis. The liver was severely congested with focal coagulative necrosis of the hepatocytes. The kidneys were severely congested and showed renal tubular necrosis with few tubular protein casts. Tissue samples were confirmed to be positive for African swine fever virus (ASFV) by polymerase chain reaction (PCR) assay, and phylogenetic analysis revealed that the isolate belonged to genotype I.

Histological and immunohistochemical assessments of pneumonia in sheep slaughtered at Ibadan, Nigeria and Kumasi, Ghana.

There is a decline in sheep production and contribution to the economy. This study described the histological pattern, immunohistochemically demonstrate bacterial and viral agents of pneumonia in sheep slaughtered in metropolitan abattoirs in Nigeria and Ghana. A total of 805 (600 in Ghana and 205 in Nigeria) sheep lungs were examined for pneumonic lesions. Sections were fixed in 10% formalin for histological and immunohistochemical analysis. Pneumonia of 8.7% was in Ghana and 13.3% in Nigeria. The histological findings included bronchopneumonia (16/70), broncho-interstitial pneumonia (9/70), interstitial pneumonia (9/70) and proliferative pneumonia (7/70). Ten (14.3%) cases were positive for PPRV, PI3V, and RSV antigens while five (7.2%) were positive for multiple viral antigens; including two (PI3V and PPRV), two (RSV and PPRV), and one (PI3V and RSV). RSV was in interstitial pneumonia, PPRV and PI3V were in interstitial and broncho-interstitial pneumonia. PPRV and PI3V antigens 3 (4.4%) were in proliferative alveolitis. Mannheimia haemolytica (2) and Pasteurella multocida (2) infection were in combination with PPRV, RSV, and PI3V. Three sheep lungs (4.4%) were negative for viruses and bacteria. This study revealed ovine pneumonia is still a problem in West Africa, and multivalent vaccine incorporating some of these agents will be useful for the control.

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

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.