Shuni virus as cause of neurologic disease in horses

Abstract

To determine which agents cause neurologic disease in horses, we conducted reverse transcription PCR on isolates from of a horse with encephalitis and 111 other horses with acute disease. Shuni virus was found in 7 horses, 5 of which had neurologic signs. Testing for lesser known viruses should be considered for horses with unexplained illness.

Figure 1

Electron micrographs of Vero cells infected with virus from horse SAE 18/09. A, B) Negative stain showing fringed particles (bunyavirus size) with bleb formation. C, D) Resin section showing spherical and pleomorphic bunyavirus particles in the range of 80–100 nm. Scale bars = 250 nm.

Figure 2

Maximum-likelihood tree constructed under the HKY codon position substitution model using PhyML (http://code.google.com/p/phyml/) of a 330-bp fragment of small segment RNA of Shuni virus (SHUV) identified in horses in South Africa, with representative sequences of selected other orthobunyaviruses. Scale bar = 0.07 nt substitutions. Estimates were based on bootstrap resampling conducted with 100 replicates. Only values >70 are shown. All SHUV amplicons were sequenced, and the data were deposited in GenBank, accession nos. SAE 18/09–HQ610137, SAE 72/09–HQ610138, SAE 27/10–HQ 610139, SAE 38/10–HQ 610140, SAE 39/10–HQ 610141, SAE 48/10–HQ 610142, and SAE 109/10–HQ 610143. Reference strains and GenBank accession numbers are indicated.