Use #1– Identifying the exact source of HIV-1 and HIV-2.
Use #2– Determining the ecological/zoonotic/epidemiological implications of Simian Foamy Virus infection in chimpanzees!
Simian Foamy Virus (SFV) is another complex retrovirus, like HIV-1, but on a different branch of the retroviral family tree. So it still has the same basic proteins (gag, pol, and env– Im getting to env), just different bells and whistles.
It also performs its own unique twists on the retroviral life-cycle, like going through the process of reverse transcription as the baby viruses bud off! Yeah not in the new host cell right after infection– right before the immature virus buds off! Weird!
We also know that foamy retroviruses are really, really old. When you line up SFV phylogenetic trees with primate mitochondrial phylogenetic trees, they overlap, implying that SFV has been co-evolving with primates for at least 30-40 million years!
Because these foamy viruses dont appear to be pathogenic in chimpanzees and because of their odd reverse transcription, foamy viruses are currently a popular candidate for gene therapy vectors in humans. BUT just because they dont cause problems in primates, it doesnt mean foamy viruses wont cause problems in humans (ie, HIV).
Hahns group already had extensive poop experience through their HIV work, and theyre rightly concerned about another zoonotic epidemic from SFV, and they would like to anticipate difficulties in gene therapy before these vectors hit patients. So why not try to characterize SFVs behavior in primates by looking for SFV in poop too? I mean, the extra poop is just sitting in the freezer. Might as well use it for something. hehehehehe! Seriously, after reading this paper, it really feels like they thought ‘Um, so, we have some extra poo… wanna see if theres any SFV in it?’ lol! Not that theres anything wrong with that– If youve got some cool samples, suck all the data you can from them!
Its just that this paper is going to be rather anticlimactic (hey, not all science can be sexy– sometimes is just science hehe!)
The chimpanzee colonies they collected poo from had ~44%-100% prevalence of SFV. Every colony was infected to some degree. This wasnt too surprising, as even zookeepers for primates can test positive for SFV, so we knew it was really easy to catch.
They found SFV antibodies in their poo. IgG is the antibody you probably think of when I say ‘antibody’, but IgA is actually secreted in your tears, mucus, poo, etc. So if youve been infected with influenza, you will secrete anti-influenza IgA. If the chimpanzees have been infected with SFV, they would have anti-SFV in their poo. Its just the way our immune system works, so SFV antibodies in poo wasnt unexpected either.
What was unexpected was SFV viral RNA in chimpanzee poo. Remember how I said reverse transcription takes place at viral budding? If viruses are being shed in poo, it should be DNA, not RNA! If there is RNA in poo, that must mean that there are productively infected cells being shed in poo! But the primary site of productive infection is lungs and other oral tissues! Who is the infected cell hiding in poo? Hmmm….
… Well, I wish I had some fun punch-line for this paper, but like I said, it kinda feels like they just had some extra poo leftover from their HIV study and wanted to see what else they could fish out.
They found some SFV.
Honestly, I just wanted an excuse to talk about HIVs crazy uncle, Simian Foamy Virus. Like Mystery Rays noted, one rarely gets a ‘newsy’ reason to write about foamy viruses, so Im grabbing on to this opportunity, however anticlimactic is may be! (thanks to Wilkins for the Mystery Rays reference! Gud blag!)