title: Vertical transmission of Rift Valley fever virus without detectable maternal viremia.
abstract: Rift Valley fever virus (RVFV) is a zoonotic bunyavirus that causes abortions in domesticated ruminants. Sheep breeds exotic to endemic areas are reportedly the most susceptible to RVFV infection. Within the scope of a risk assessment program of The Netherlands, we investigated the susceptibility of a native breed of gestating sheep to RVFV infection. Ewes were infected experimentally during the first, second, or third trimester of gestation. Mortality was high among ewes that developed viremia. Four of 11 inoculated ewes, however, did not develop detectable viremia nor clinical signs and did not seroconvert for immunoglobulin G (IgG) or IgM antibodies. Surprisingly, these ewes were found to contain viral RNA in maternal and fetal organs, and the presence of live virus in fetal organs was demonstrated by virus isolation. We demonstrate that RVFV can be transmitted vertically in the absence of detectable maternal viremia.
authors.affiliation: Central Veterinary Institute of Wageningen University Research Centre, Lelystad, The Netherlands.
authors.forename: A F G
authors.initials: AF
authors.lastname: Antonis
authors.forename: J
authors.initials: J
authors.lastname: Kortekaas
authors.forename: J
authors.initials: J
authors.lastname: Kant
authors.forename: R P M
authors.initials: RP
authors.lastname: Vloet
authors.forename: A
authors.initials: A
authors.lastname: Vogel-Brink
authors.forename: N
authors.initials: N
authors.lastname: Stockhofe
authors.forename: R J M
authors.initials: RJ
authors.lastname: Moormann
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D005260:Female; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary*; D009426:Netherlands / Q000453:epidemiology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000401:mortality / Q000662:veterinary* / Q000821:virology; D012367:RNA, Viral / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012295:Rift Valley Fever / Q000401:mortality / Q000635:transmission* / Q000821:virology; D012296:Rift Valley fever virus / Q000302:isolation & purification / Q000502:physiology*; D012756:Sheep; D012757:Sheep Diseases / Q000401:mortality / Q000635:transmission* / Q000821:virology; D014766:Viremia / Q000662:veterinary
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral