Volume 25, Number 6—June 2019
Research Letter
Highly Pathogenic Swine Getah Virus in Blue Foxes, Eastern China, 2017
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Ning Shi, Li-Xia Li, Rong-Guang Lu, Xi-Jun Yan, and Hao Liu
Abstract
We isolated Getah virus from infected foxes in Shandong Province, eastern China. We sequenced the complete Getah virus genome, and phylogenetic analysis revealed a close relationship with a highly pathogenic swine epidemic strain in China. Epidemiologic investigation showed that pigs might play a pivotal role in disease transmission to foxes.
Getah virus (GETV; genus Alphavirus, family Togaviridae) is a mosquitoborne RNA virus that causes death in young piglets, miscarriage in pregnant sows, and mild illness in horses (1–3). Serologic surveys show that the infection might occur in cattle, ducks, and chickens (4); some evidence suggests that GETV can infect humans and cause mild fever (5,6).
Figure. Dissected brain and lung of a dead fox, collected in 2017 in Shandong Province, eastern China, and histopathologic examination of samples using hematoxylin and eosin staining. A) Brain, showing congestion in...
In September 2017, twenty-five 5-month-old blue foxes at a farm in Shandong Province in eastern China showed symptoms of sudden fever, anorexia, and depression; 6 of the 25 animals had onset of neurologic symptoms and died on the third day of illness. We collected blood samples from 45 healthy and 25 ill foxes. We subjected the tissue samples from dead animals, including the brains, lungs, spleens, kidneys, livers, intestines, hearts, and stomachs, to hematoxylin and eosin staining. Microscopic examination confirmed the presence of typical lesions in cerebral cortices with mild neuronal degeneration and inflammatory cell infiltration in vessels, as well as severe hemorrhagic pneumonia, congestion, and hemorrhage with a large number of erythrocytes in the alveolar space (Figure) (1). No obvious lesions were found in other organs.
We used supernatants of homogenized brain and lung tissues from each dead fox to inoculate Vero cells, as described previously (7). We observed a cytopathogenic effect within 72 hours. We observed numerous spherical, enveloped viral particles, ≈70 nm in diameter, after negative staining in a transmission electron microscope. To identify potential viral pathogens, we performed reverse transcription PCR (RT-PCR) to detect a panel of viruses, including canine distemper virus, canine parvovirus, canine coronavirus, and canine adenovirus. However, we detected none of these classical endemic viruses.
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