Management Factors Associated with Operation-Level Prevalence of Antibodies to Cache Valley Virus and Other Bunyamwera Serogroup Viruses in Sheep in the United States.

A cross-sectional study was performed to identify operation-level risk factors associated with prevalence of antibody to Bunyamwera (BUN) serogroup viruses in sheep in the United States. Sera were obtained from 5150 sheep in 270 operations located in 22 states (three in the west, nine central states, and 10 in the east) and tested at a dilution of 1:20 by a plaque reduction neutralization test (PRNT) using Cache Valley virus (CVV). Antibodies that neutralized CVV were identified in 1455 (28%) sheep.

Substitution of the premembrane and envelope protein genes of Modoc virus with the homologous sequences of West Nile virus generates a chimeric virus that replicates in vertebrate but not mosquito cells.

Background: Most known flaviviruses, including West Nile virus (WNV), are maintained in natural transmission cycles between hematophagous arthropods and vertebrate hosts. Other flaviviruses such as Modoc virus (MODV) and Culex flavivirus (CxFV) have host ranges restricted to vertebrates and insects, respectively. The genetic elements that modulate the differential host ranges and transmission cycles of these viruses have not been identified.

Orthobunyaviruses, a common cause of infection of livestock in the Yucatan peninsula of Mexico.

To determine the seroprevalence of selected orthobunyaviruses in livestock in the Yucatan Peninsula of Mexico, a serologic investigation was performed using serum samples from 256 domestic animals (182 horses, 31 sheep, 1 dog, 37 chickens, and 5 turkeys). All serum samples were examined by plaque reduction neutralization test using Cache Valley virus (CVV), Cholul virus (CHLV), South River virus (SOURV), Kairi virus, Maguari virus, and Wyeomyia virus. Of the 182 horses, 60 (33.

Orthobunyavirus antibodies in humans, Yucatan Peninsula, Mexico.

We performed a serologic investigation to determine whether orthobunyaviruses commonly infect humans in the Yucatan Peninsula of Mexico. Orthobunyavirus-specific antibodies were detected by plaque reduction neutralization test in 146 (18%) of 823 persons tested. Further studies are needed to determine health risks for humans from this potentially deadly group of viruses.

Sequence and phylogenetic data indicate that an orthobunyavirus recently detected in the Yucatan Peninsula of Mexico is a novel reassortant of Potosi and Cache Valley viruses.

We determined the complete nucleotide sequences of the small (S) and medium (M) RNA segments of an orthobunyavirus isolated from mosquitoes in the Yucatan Peninsula of Mexico. A 528-nt region of the large (L) RNA segment was also sequenced. The S RNA segment has greatest nucleotide identity to the homologous region of Cache Valley virus (CVV; 98%) followed by Potosi virus (POTV; 89%) and Northway virus (86%).

Evidence of efficient transovarial transmission of Culex flavivirus by Culex pipiens (Diptera: Culicidae).

This study determined the transovarial transmission (TOT) potential and tissue tropisms of Culex flavivirus (CxFV), an insect-specific flavivirus, in Culex pipiens (L.). Several hundred mosquito egg rafts were collected in the field, transferred to the insectaries, reared to the fourth larval instar, and identified using morphological characteristics.

Isolation and sequence analysis of Culex flavivirus from Culex interrogator and Culex quinquefasciatus in the Yucatan Peninsula of Mexico.

Previously, we reported a high prevalence of Culex flavivirus (CxFV) in Culex quinquefasciatus (Say) in the Yucatan Peninsula of Mexico. To determine whether other Culex spp. mosquitoes in this region are susceptible to natural CxFV infection, Cx.

Immunohistochemical staining of IFN-gamma positive cells in porcine reproductive and respiratory syndrome virus-infected lungs.

Paraffin-embedded lungs were obtained from a previous porcine reproductive and respiratory syndrome virus (PRRSV)-challenged experiment involving three groups: an uninfected control group, a low virulence (LV, Resp PRRSV/Repro)-infected group, and a high virulence (HV, VR-2385)-infected group. Tissues were collected at 3, 7, 10, 14 or 28 days post-inoculation (DPI) (n=5). Lungs were examined to detect IFN-gamma positive cells by immunohistochemical staining using polyclonal antibodies to IFN-gamma.