Screening for Borna disease virus 1 (BoDV-1) in Austria: Absence of human cases in a retrospective case-finding study.

Overview

• This study investigated whether human infections with Borna disease virus 1 (BoDV-1), a virus known to cause severe brain inflammation, are present but undetected in Austria.
• The researchers analyzed stored clinical samples from patients with neurological symptoms but found no evidence of BoDV-1 infection in Austria to date.

Background

• Borna disease virus 1 (BoDV-1) is a zoonotic virus, meaning it can be transmitted from animals to humans.
• It is capable of causing rare but serious encephalitis (inflammation of the brain) in humans.
• The natural reservoir for BoDV-1 is the bicolored white-toothed shrew (Crocidura leucodon), widely distributed across parts of Europe and Southwest Asia.
• Despite the reservoir’s broad presence, human cases have thus far been reported only in Germany.
• Sentinel infections in animals such as horses indicate the virus circulates in neighboring countries, including Austria, though human cases had not been confirmed.

Objective

• The aim was to determine whether human BoDV-1 infections have occurred in Austria but remained undetected by retrospective screening.
• This was done by analyzing stored biological samples from patients exhibiting neurological symptoms consistent with BoDV-1 infection.

Methods

• Researchers accessed biobank samples from the Center for Virology in Vienna.
• They selected samples based on clinical symptoms that might indicate BoDV-1 infection.
• A total of 859 cerebrospinal fluid (CSF) samples were screened for BoDV-1 RNA presence.
• Additionally, 366 serum samples corresponding to these patients were tested for anti-BoDV-1 IgG antibodies, which indicate past or current infection.
• Techniques used likely included PCR for RNA detection and serological assays for antibody detection.

Results

• No BoDV-1 RNA was detected in any of the CSF samples tested.
• No confirmed anti-BoDV-1 IgG antibodies were found in any of the serum samples.
• This suggests no evidence of BoDV-1 infection in the sampled patients with neurological symptoms in Austria.

Conclusions

• The absence of virus RNA or antibodies indicates that human BoDV-1 infections are very rare or possibly nonexistent in Austria among patients with neurological symptoms.
• The study’s findings are preliminary, given the retrospective nature and sampling strategy.
• Researchers recommend further investigations focusing on samples from patients with a clearer geographical link to known endemic areas, such as specific rural regions in Upper Austria.
• Such studies might better elucidate whether any human infections occur in localized zones within Austria.

Significance

• This research helps clarify the epidemiology of BoDV-1 and its risk to humans in Austria.
• It contributes to public health knowledge by ruling out widespread undetected BoDV-1 infections among neurological patients in the country.
• The study highlights the importance of continued surveillance and targeted screening in regions where animal sentinel infections are observed.