Sample collection
During the period of ASFV outbreaks in northern Vietnam, infected pigs showed clinical signs of high fever (41 – 42°C), diarrhea, vomiting, anorexia and reflexes, depression, dyspnea, haemorrhages in the skin, neurological signs, coma and death. Typical gross findings at the post-mortem examination were haemorrhagic lesions in multiple organs, including diffuse haemorrhage in superficial inguinal (Fig 1a), mandibular, pulmonary, gastrohepatic, renal and mesenteric (Fig 1b) lymph nodes, in addition to hyperemic splenomegaly with friable consistency and dark discoloration (Fig 1c), petechial haemorrhage in the renal cortex, diffuse haemorrhage in the renal pelvis (Fig 1d), haemorrhage in pericardium and myocardium (Fig 1e, f), swollen liver and oedema of the gall bladder wall, hemorrhagic cerebral meninges with oedema and interstitial oedema of the lungs. A blood sample was collected for real-time polymerase chain reaction (qPCR) work, and tissue samples from various organs were fixed in 10% neutral buffered formalin and routinely processed for histopathological examination. Background information for each pig was tabulated in Table 1.
Ethics statement: The diseased pigs were collected at moribund stage and humanely euthanized by veterinarians. There was no unnecessary pain inflicted on the animals because all sampling procedures were conducted during necropsy.