Every species on Earth, like about 1.8 million of them, harbours viruses. Good ‘ol Homo Sap, all 7 billion of them, are also doing their part in providing accommodation and breeding grounds for the viruses, which are then sent off down the sewers to see the world. So the horse has bolted. These unknown viruses are already present, in humans, unless someone's being unusually creative down there in the sewers.
What’s apparently happening is a range of choices:
1. That the viruses, which are more or less by definition highly mutable, are producing multiple generations of mutants around the clock which are by this point unrecognizable, therefore the unknown genetic signatures.
2. This study has simply found a range of viruses nobody knew existed because nobody was looking at sewage. Rather strange environmental pathology, given that stool samples and urine samples are common medical diagnostic tools, and normal tracing of diseases uses environmental vectoring.
3. There are families of unknown viruses living in the sewers themselves, breeding on effluent- related organisms. This would be a normal ecological result for viral populations. It would also explain previous unobserved genetic signatures, because the sewers are a unique environment.
4. Many of the viruses come from plants. Humans eat plants, and that’s a potential nuclear blast for agriculture, if these viruses are coming from food stocks. It means that there’s a lot about plant viruses in the food chain that isn’t being investigated. Many viruses are quite harmless to their hosts and their related food chains, but at least a few always pose risks.
... Bacteria are also present in sewage, so it was not surprising that the viruses that prey on bacteria dominated the known genetic signatures. Finally, a large number of the known viruses found in raw sewage came from plants, probably owing to the fact that humans eat plants, and plant viruses outnumber other types of viruses in human stool.
This study was also the first attempt to look at all the viruses in the population. Other studies have focused on bacteria, or certain types of viruses. The researchers also developed new computational tools to analyze this data. This approach, called metagenomics, had been done before, but not with raw sewage
This is an extremely important method of study for another, more pressing reason- The sewers lead to the rivers and oceans. The exact nature of any future threat to the riverine and marine ecology is likely to show up in these outfalls. Marine viral populations went up by astronomical numbers in the period from the 1960s to 2000. To give some idea, the original viral counts were single digit figures. By 2000, they were six digits. Large new populations of viruses are likely to be everybody’s business before too long. There are now approximately 10 million viruses per millilitre of surface sea water
. Any guesses what happens if that number goes up?
It’s a bit late to start a global campaign of anal recidivism and urinary rectitude. Suggestion: Grab a shovel and a good library, and scamper off to places that need more organic materials. Either that or go swimming in a spacesuit.