A team led by researchers from the University of Vienna have isolated giant viruses that infect the single-celled organism Naegleria fowleri, one of the deadliest human parasites.
Naegleria fowleri is a species of amoeba that thrives in warm water environments and can cause a rare but almost invariably fatal brain infection called primary amoebic meningoencephalitis (PAM). The research team has now identified these new viruses, named Naegleriaviruses, which belong to the group of giant viruses.
Giant viruses, also known as Nucleocytoviricota, are a relatively recently discovered group of viruses that rival bacteria in size and possess unique genetic and structural features previously thought to be exclusive to cellular life. The discovery of Naegleriaviruses, which were isolated from a wastewater treatment plant near Vienna, represents only the fourth isolate from a group called Klosneuviruses.
These newly discovered Naegleriaviruses are mistakenly taken up by the Naegleria amoebas as a food source, but they then proceed to destroy their hosts within just a few hours. The viruses exhibit a "stargate structure" that facilitates the entry of their DNA into the host cells, and they then form a "virus factory" inside the amoeba, replicating their genetic material and assembling hundreds of new virus particles.
“The newly identified Naegleriaviruses may not be suitable to treat Naegleria infections, given the challenging accessibility of the brain, where infections occur. However, this discovery opens the door to the possibility of preventative treatment of at-risk water bodies, such as during swimming pool water treatment, but this would first require further research. Regardless, the discovery of these viruses will enhance our understanding of both Naegleria biology and the viruses that infect them,” says Matthias Horn, senior author of the study published in Nature Communications.