Recipient Organization
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES,IA 50011
Performing Department
Veterinary Medicine
Non Technical Summary
The overall goal of this proposal is to test the hypothesis that Schmallenberg virus is currently an unrecognized cause of pregnancy loss and congenital abnormalities in cattle, sheep and goats in the United States.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
Schmallenberg virus (SBV), a recently discovered member of the genus Orthobunyavirus (family Bunyaviridae), has been associated with pregnancy loss and congenital defects in cattle, sheep and goats in Germany, the Netherlands, Belgium, France and England. Although SBV has not been reported outside of Europe, it is highly likely that this will change in the very near future since arthropod-borne viruses have spread across the globe at an alarming rate in recent years due to the dramatic increase in globalization and the movement of humans, animals and arthropod vectors. This raises the sobering possibilities that SBV will soon be introduced into the United States or that SBV has already been introduced and is currently an unrecognized cause of disease in livestock in this country. It is therefore very important that studies are performed to monitor for potential SBV activity into the United States. Producers need to know if SBV is circulating in the United States to decide if new control measures should be implemented and pharmaceutical companies require this information to determine whether the U.S. is a potential market for future SBV vaccines. Thus, the overall goal of this proposal is to test the hypothesis that SBV is currently an unrecognized cause of pregnancy loss and congenital abnormalities in cattle, sheep and goats in the United States.
Project Methods
Specific Aim 1. Acquire tissue samples from arthrogrypotic cattle, sheep and goats. Aborted fetuses, stillbirths and dead newborns that exhibited arthrogryposis will be submitted to the Iowa State University Veterinary Diagnostic Laboratory (ISU VDL). Serum from the corresponding dam or cow will also be submitted. To acquire diagnostic samples for these studies, a request will be sent via email to all members of the American Association of Bovine Practitioners and the American Association of Small Ruminant Practitioners. Additionally, a request for diagnostic samples will be posted in the Iowa Veterinary Medical Association Update and ISU VDL website. Specific Aim 2. Isolate and genetically characterize orthobunyaviruses from bovine, ovine and caprice tissues. Tissues acquired in specific aim 1 will be tested for the presence of SBV and other orthobunyaviruses by virus isolation in African Green Monkey kidney (Vero) cells. Virus isolates will be identified by RT-PCR and nucleotide sequencing using SBV-specific and orthobunyavirus-specific primers. Tissues will be also tested for other recognized causes of ruminant abortions using protocols routinely performed in the ISU VDL. For small ruminants, this will include Campylobacter, Chlamydophila, Toxoplasma, Coxiella, border disease virus and Salmonella. For bovine abortions, additional testing for bovine viral diarrhea virus will also be conducted. Specific Aim 3. Serologically assay sera and thoracic fluid for evidence of SBV infection. Sera from dams and cows that produced aborted fetuses, stillbirths or arthrogrypotic newborns will be tested for antibodies to SBV and other 9 orthobunyaviruses by plaque reduction neutralization test (PRNT). Thoracic fluid from stillbirths and aborted fetuses will also be tested by PRNT. The PRNT is the gold-standard serological technique for arthropod-borne virus (arbovirus) diagnosis. Specific Aim 4. Isolate and genetically characterize orthobunyaviruses from midges collected in Iowa. Midges are assumed to be the arthropod vector of SBV and thus, midge-based surveillance for SBV and other orthobunyaviruses will be performed. Midges from Iowa will be collected, identified and sorted into pools of up to 100 according to species, study site and date of collection. Midges will be homogenized and tested for SBV and other orthobunyaviruses by virus isolation in Vero cells and by RT-PCR and nucleotide sequencing.