A novel cause of chronic viral meningoencephalitis: Cache Valley virus
Outbreaks of emerging and reemerging pathogens have stimulated international discussion about the most efficient means for improving early detection so that public and private resources can be mobilized quickly and efficiently to limit widespread transmission and treat affected patients. There is a growing consensus that an optimal surveillance regimen will (1) incorporate an unbiased approach to pathogen identification and (2) focus surveillance efforts on groups of people at high risk for unusual infections (eg, immunodeficient patients and people with relevant exposures).1 An unbiased approach to pathogen identification is important because traditional candidate‐based diagnostic tests essentially fail to identify novel and unusual pathogens, usually due to perceived rarity or exclusion from clinical consideration based on established geographical distribution. Global surveillance efforts need to be streamlined, because it is both time‐consuming and costly for physicians to order many pathogen‐specific tests for geographically and clinically novel organisms. Finally, in the modern era, when international travel has become so commonplace, the need for improved pathogen detection has become clear.
Here, we report the effective deployment of metagenomic next generation sequencing (mNGS) to diagnose Cache Valley virus (CVV), a mosquito‐borne orthobunyavirus,4 in an Australian patient with a primary immunodeficiency suffering from chronic meningoencephalitis. This case demonstrates the power of mNGS to identify the possible movement of an emerging, mosquito‐borne virus to a new continent. Only previously associated with acute neuroinvasive disease, this report also extends the phenotype of CVV infection in humans.