VirusA virus similar to those found in bats may be the cause of a severe brain infection in children whose immune systems are low, according to research.

The finding, published in Clinical Infectious Diseases, could lead to a greater number of children with the brain infection – known as encephalitis – being diagnosed and treated. 

Encephalitis can be dangerous in children with severely impaired immune systems and, if untreated, children can struggle to survive. Some cases of encephalitis have been found to be caused by common viruses, but in some 63% of cases no cause can be confirmed. As a result, while some cases can be treated with antiviral drugs, the majority can’t be managed efficiently.

Teams at Great Ormond Street Hospital (GOSH), along with colleagues at University College London (UCLH), have now identified a new astrovirus that belongs to a family of viruses known to cause diarrhoea and vomiting and may lead to encephalitis in children who have suppressed immune systems. The virus is unlike any other currently seen in humans and shows more similarities to a virus seen in bats, mink, and sheep.

To identify this, a technique was used that allowed all the genetic material within any given sample to be looked at. This meant that viruses could be picked up that couldn’t be using traditional tests, which only have the capability to detect the common viruses. The team demonstrate that this technique and the subsequent analysis can be carried out in less than a week meaning that diagnoses for children with these viruses could come within a very short timeframe.

As well as discovering this virus in a child at GOSH, teams at UCLH have simultaneously observed it in an adult patient with a supressed immune system. This further strengthens the idea that this virus is likely to play a part in a selection of patients with encephalitis.

Julianne Brown, Clinical Scientist and lead researcher, said: “The discovery means that we now have the potential to help diagnose and treat many more patients that we couldn’t before.

“While our study identifies the virus in a child whose immune system was supressed due to recent stem cell therapy, this finding could be relevant for other children whose immune systems are not functioning at full capacity, for example those undergoing treatment for some cancers.”