“Chlorovirus ATCV-1 is part of the human oropharyngeal virome and is associated with changes in cognitive functions in humans and mice ”
A metagenomics study of the throat virome of a bunch of people in Baltimore revealed that a full 40% of them were persistently infected with a clade of chloroviruses, very large ~300 kilobase DNA viruses (possibly very distantly related to poxviruses but it’s difficult to tell) which have previously only been known to infect freshwater algae. Upon looking at correlations, they found an extremely significant correlation between infection and a mild degradation in memory and attention tasks. Infecting mice with the virus both caused a decline in memory function as measured by maze-running tasks and, since unlike a human you can crack open a mouse and extract RNA from pieces of its brain, very clear changes in the gene expression of the hippocampus. Not a clue about the mechanism.
This virus had already been noted to be odd a few years ago—a paper from 2011 (http://www.sciencedirect.com/science/article/pii/S1360138511002275) noted that they contained carbon catabolism genes and carbohydrate-processing enzymes that seem to come from animals despite the fact that they were only known to infect algae.
Interestingly, human-and-algae-infecting viruses appear to have been empirically identified in the vaginal secretions of people whose secretions killed algae by scientists in Ukraine several years ago, and this has largely gone unnoticed (possibly justifiably) since it was published (www.bioorganica.org.ua/UBAdenovo/pubs_9_2_11/Stepanova.pdf) in a small journal with poor English translation.
I didn’t much like it. This thing reeks of data dredging in every step; I don’t see why they controlled for birth place where you’d think that current residence would be much more relevant (Baltimore has rich and poor areas like most big cities; and if nothing else, it’d give you an idea of infection vectors if carriers cluster around the harbor or specific places); I find it odd that their WAIS subtest shows zero (0.0) decrease in the infected group while their weirdo IQ test I’ve never heard of shows a fall; and I’m not sure how convincing I find their mice models* - to what extent does it really mimick human infections with no apparent symptoms? It wouldn’t surprise me if, every time you gave mice a big injection of infectious organisms, their scores fell simply because you made them sick with something, so I’m not sure whether the mice experiment part is testing the right causal hypothesis (it might be testing ‘raging infections decrease cognitive performance’, not ‘this algae, and not other infectious agents, decreases cognitive performance’).
I would not be surprised if this never replicates.
* kudos to them for trying to experimentally test it, though
Good points all—I was hoping you’d show up. It’s odd enough though that I would be quite interested in any attempts at replication. Course, that might be coming from my interest in the evolutionary history and ecological role of a virus that can apparently infect organisms as different as blue-green algae and mammals.
I keep on wondering to what degree our discovery and exploration of the all the microflora and microfauna that lives insides us will overturn “standard” medical theories of how humans work. It’s already generally accepted that the diet’s effect on nutrition is noticeably mediated by the gut biota, though the details are still very very fuzzy, and that’s only a crude start...
I figured this would be broadly of interest to this site:
http://www.pnas.org/content/111/45/16106.abstract
“Chlorovirus ATCV-1 is part of the human oropharyngeal virome and is associated with changes in cognitive functions in humans and mice ”
A metagenomics study of the throat virome of a bunch of people in Baltimore revealed that a full 40% of them were persistently infected with a clade of chloroviruses, very large ~300 kilobase DNA viruses (possibly very distantly related to poxviruses but it’s difficult to tell) which have previously only been known to infect freshwater algae. Upon looking at correlations, they found an extremely significant correlation between infection and a mild degradation in memory and attention tasks. Infecting mice with the virus both caused a decline in memory function as measured by maze-running tasks and, since unlike a human you can crack open a mouse and extract RNA from pieces of its brain, very clear changes in the gene expression of the hippocampus. Not a clue about the mechanism.
This virus had already been noted to be odd a few years ago—a paper from 2011 (http://www.sciencedirect.com/science/article/pii/S1360138511002275) noted that they contained carbon catabolism genes and carbohydrate-processing enzymes that seem to come from animals despite the fact that they were only known to infect algae.
Interestingly, human-and-algae-infecting viruses appear to have been empirically identified in the vaginal secretions of people whose secretions killed algae by scientists in Ukraine several years ago, and this has largely gone unnoticed (possibly justifiably) since it was published (www.bioorganica.org.ua/UBAdenovo/pubs_9_2_11/Stepanova.pdf) in a small journal with poor English translation.
Fulltext: https://pdf.yt/d/dr3uP9XOtT1BPimU / https://dl.dropboxusercontent.com/u/5317066/2014-yolken.pdf / http://libgen.org/scimag7/10.1073/pnas.1418895111.pdf
I didn’t much like it. This thing reeks of data dredging in every step; I don’t see why they controlled for birth place where you’d think that current residence would be much more relevant (Baltimore has rich and poor areas like most big cities; and if nothing else, it’d give you an idea of infection vectors if carriers cluster around the harbor or specific places); I find it odd that their WAIS subtest shows zero (0.0) decrease in the infected group while their weirdo IQ test I’ve never heard of shows a fall; and I’m not sure how convincing I find their mice models* - to what extent does it really mimick human infections with no apparent symptoms? It wouldn’t surprise me if, every time you gave mice a big injection of infectious organisms, their scores fell simply because you made them sick with something, so I’m not sure whether the mice experiment part is testing the right causal hypothesis (it might be testing ‘raging infections decrease cognitive performance’, not ‘this algae, and not other infectious agents, decreases cognitive performance’).
I would not be surprised if this never replicates.
* kudos to them for trying to experimentally test it, though
Good points all—I was hoping you’d show up. It’s odd enough though that I would be quite interested in any attempts at replication. Course, that might be coming from my interest in the evolutionary history and ecological role of a virus that can apparently infect organisms as different as blue-green algae and mammals.
I keep on wondering to what degree our discovery and exploration of the all the microflora and microfauna that lives insides us will overturn “standard” medical theories of how humans work. It’s already generally accepted that the diet’s effect on nutrition is noticeably mediated by the gut biota, though the details are still very very fuzzy, and that’s only a crude start...