CDC develops test for Cache Valley virus, other uncommon mosquito-borne diseases
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Key takeaways:
- Few cases of Cache Valley virus have ever been reported in the U.S.
- A new test from the CDC, which uncovered previously unreported cases, will make testing for Cache Valley virus faster and easier.
A test created to detect Cache Valley virus and other similar and uncommon viruses yielded fast and accurate results, which could make testing for these viruses easier in the future.
“We know very little about Cache Valley virus and the disease it causes in people,” Amanda Calvert, MSc, PhD, research microbiologist with CDC’s Division of Vector-Borne Diseases, told Healio. “The current diagnostic assay to test for Cache Valley virus takes days to run and requires a specialized lab. The current test cannot distinguish a recent infection from a past infection. To make diagnostic testing more widely available, we developed new tools and an assay that can detect a recent infection of Cache Valley virus in people.”
In an effort to expand human serological diagnostic capacity for Cache Valley virus, which is spread by infected mosquitoes, researchers developed an IgM-antibody capture enzyme-linked immunosorbent assay for detection of anti-Cache Valley virus human IgM in diagnostic specimens. The team also developed an HEK-293 cell line expressing a human-murine chimeric to improve the lack of human positive sera used as controls in the assay.
According to the study, which was presented at the American Society of Tropical Medicine & Hygiene meeting, they then used previously collected specimens from 27 patients from Mexico and nine from the U.S. with acute febrile illness with no apparent cause to test the assay.
Overall, the test revealed that 16 patients — 10 from Mexico and six from the U.S. — had evidence of exposure to Cache Valley virus, with samples testing positive for a past Cache Valley virus infection or another closely related virus. Calvert added that U.S. samples from patients with a previously confirmed diagnosis of Cache Valley virus were retested with the new test, which showed positive test results for seven of the nine samples.
“Once validated, the new test will help make testing for Cache Valley virus faster and easier.
Although very few cases of Cache Valley virus disease have been reported in the U.S., the virus can make people very sick,” Calvert said.
She added that Cache Valley virus can cause birth defects in sheep and other animals, and although experts are unsure if the virus could do the same thing in people, a better understanding of how the virus affects people is important.
“This new test could help better identify cases to provide a more complete picture of how many people are getting infected and how the virus affects humans,” Calvert said.
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Calvert AE, et al. Abstract 5255. Presented at: American Society of Tropical Medicine & Hygiene; Oct. 18-22, 2023; Chicago.
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