Novel Cyclovirus Isolated from Patients with Acute Central Nervous System Infections

An international team of medical microbiologists and molecular virologists has isolated a previously unknown virus from Vietnamese patients suffering from acute central nervous system (CNS) infections, and used next-generation sequencing techniques to map its entire genome.

CNS infections can be caused by a range of bacterial, parasitic, fungal, and viral pathogens. However, in more than half the cases clinicians fail to establish the cause of the disease. Investigators at Oxford University (United Kingdom) and the University of Amsterdam (The Netherlands) and colleagues in South East Asia examined a group of Vietnamese patients with severe CNS infections for which a causative agent could not be determined.

The investigators used advanced next-generation sequencing techniques to identify and characterize the full genome of a novel cyclovirus (tentatively named cyclovirus-Vietnam [CyCV-VN]) in cerebrospinal fluid (CSF) specimens from two of the patients. Roche Applied Science (Basel, Switzerland) instruments were used for DNA enrichment by PCR followed by sequencing analysis on a FLX genome sequencer.

CyCV-VN was subsequently detected in 4% of 642 CSF specimens from patients with suspected CNS infections but was not found in any of 122 CSFs from patients with noninfectious neurological disorders. A similar detection rate was found in feces from healthy children, which suggested a food-borne or oral-fecal transmission route. High detection rates in feces from pigs and poultry (average, 58%) suggested the existence of animal reservoirs for such transmission.

The genome sequencing results placed CyCV-VN in the Circoviridae family of viruses, which had previously only been associated with diseases in animals, including birds and pigs.

Contributing author Dr. Rogier van Doorn, professor of clinical microbiology at Oxford University, said, "We do not yet know whether this virus is responsible for causing the serious brain infections we see in these patients, but finding an infectious agent like this in a normally sterile environment like the fluid around the brain is extremely important. We need to understand the potential threat of this virus to human and animal health."

The study was published in the June 18, 2013, issue of the journal mBio.

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