AsianScientist (Jun. 24, 2013) – Researchers in Vietnam have identified a new virus in patients with severe brain infections.
Brain infections may be fatal and surviving patients, usually children and young adults, are often left severely disabled. Infectious agents responsible for brain infections could be bacterial, fungal, parasitic, or viral in nature. Yet despite comprehensive diagnostics, doctors are still unable to pinpoint the cause of infection in more than half of all cases, making interventions difficult.
The team, comprising of researchers from the Oxford University Clinical Research Unit, the Wellcome Trust South East Asia Major Overseas Program, and the Academic Medical Center at the University of Amsterdam, first isolated the virus from the fluid around the brain of patients with brain infections.
Using next-generation sequencing techniques, the team identified the new virus, tentatively named CyCV-VN, in 28 out of 644 patients with severe brain infections but not in patients with non-infectious brain disorders. This newly sequenced virus species belongs to the Circoviridae family, which previously had been only associated with diseases in animals such as birds and pigs.
Dr. Rogier van Doorn, Head of Emerging Infections at the Wellcome Trust Vietnam Research Program and Oxford University Clinical Research Unit Hospital for Tropical Diseases in Vietnam, explained:
“We don’t 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.”
Interestingly, although researchers were not able to detect CyCV-VN in patient blood samples, it was detected in 8 out of 188 fecal samples from healthy children. Also, the virus was found in more than half of the fecal samples from local poultry and pigs in the geographic area of the patient from whom the virus was initially isolated, which may suggest an animal source of infection.
Dr. Le Van Tan of the Wellcome Trust Major Overseas Program added that while the discovery of the virus in the fluid around the brain is “remarkable,” it does not necessarily mean that it is causing disease.
“The evidence so far seems to suggest that CyCV-VN may have crossed into humans from animals, another example of a potential zoonotic infection. However, detecting the virus in human samples is not in itself sufficient evidence to prove that the virus is causing disease, particularly since the virus could also be detected in patients with other known viral or bacterial causes of brain infection,” he said.
Currently, the team is attempting to culture the virus in the laboratory, thereby developing a serum assay to test for antibody responses in patient samples, which could ascertain if an immune response has been mounted against CyCV-VN. By extension, this assay also allows the study of CyCV-VN exposure in the asymptomatic patient population.
In addition to understanding its geographical distributions and scope of disease, research efforts have extended across Southeast Asia and to the Netherlands to determine if CyCV-VN can be detected in patients outside Vietnam.
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Source: Wellcome Trust; Photo: Wellcome Images.
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