Skeletal and neurological malformations in pigs congenitally infected with Menangle virus

Abstract

To describe the pathological findings in stillborn piglets and fetuses delivered by sows naturally infected with Menangle virus, a recently recognised Paramyxovirus. Observations of the gross and microscopic pathology of natural disease. Postmortem examinations were performed on 49 stillborn piglets, 35 mummified or semi-mummified full-term fetuses and 6 aborted fetuses from 20 litters at a 2600-sow intensive piggery in New South Wales during an outbreak of reproductive disease from June to September 1997. Body weights, crown-rump lengths and gross pathological changes were recorded. Tissues, including brain and spinal cord, were processed for histopathological examination. Litters with reduced numbers of live born piglets had mummified fetuses and stillborn piglets. Affected stillborn and aborted piglets frequently had arthrogryposis, craniofacial and spinal deformities, pulmonary hypoplasia and degeneration of the brain and spinal cord. Intranuclear and intracytoplasmic inclusion bodies were observed in neurones and other cells in the brain and spinal cord in association with extensive degeneration, necrosis, infiltration of macrophages and gliosis. In utero infection of piglets with Menangle virus is associated with severe skeletal and neurological malformations.