title: Virus-induced congenital malformations in cattle.
abstract: Diagnosing the cause of bovine congenital malformations (BCMs) is challenging for bovine veterinary practitioners and laboratory diagnosticians as many known as well as a large number of not-yet reported syndromes exist. Foetal infection with certain viruses, including bovine virus diarrhea virus (BVDV), Schmallenberg virus (SBV), blue tongue virus (BTV), Akabane virus (AKAV), or Aino virus (AV), is associated with a range of congenital malformations. It is tempting for veterinary practitioners to diagnose such infections based only on the morphology of the defective offspring. However, diagnosing a virus as a cause of BCMs usually requires laboratory examination and even in such cases, interpretation of findings may be challenging due to lack of experience regarding genetic defects causing similar lesions, even in cases where virus or congenital antibodies are present. Intrauterine infection of the foetus during the susceptible periods of development, i.e. around gestation days 60-180, by BVDV, SBV, BTV, AKAV and AV may cause malformations in the central nervous system, especially in the brain. Brain lesions typically consist of hydranencephaly, porencephaly, hydrocephalus and cerebellar hypoplasia, which in case of SBV, AKAV and AV infections may be associated by malformation of the axial and appendicular skeleton, e.g. arthrogryposis multiplex congenita. Doming of the calvarium is present in some, but not all, cases. None of these lesions are pathognomonic so diagnosing a viral cause based on gross lesions is uncertain. Several genetic defects share morphology with virus induced congenital malformations, so expert advice should be sought when BCMs are encountered.
authors.affiliation: Section for Veterinary Reproduction and Obstetrics, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlaegevej 68, 1870, Frederiksberg C, Denmark. jager@sund.ku.dk.
authors.forename: Jørgen S
authors.initials: JS
authors.lastname: Agerholm
authors.affiliation: Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany. Marion.Hewicker-Trautwein@tiho-hannover.de.
authors.forename: Marion
authors.initials: M
authors.lastname: Hewicker-Trautwein
authors.affiliation: Department of Pathology, GD Animal Health, Arnsbergstraat 7, P.O. Box 9, 7400 AA, Deventer, The Netherlands. k.peperkamp@gddiergezondheid.nl.
authors.forename: Klaas
authors.initials: K
authors.lastname: Peperkamp
authors.affiliation: Faculty of Veterinary Science, University of Sydney, Camden, NSW, 2570, Australia. peter.windsor@sydney.edu.au.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Windsor
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000151:congenital* / Q000175:diagnosis* / Q000473:pathology / Q000821:virology