insert dashes where needed.\npoaching and loss of habitat not to mention infections and respiratory viruses…

Brief Explanations:

To insert dashes correctly, we use an em dash (or en dash in some cases, but here an em dash for interruption) after "habitat" and before "not to mention" to set off the parenthetical-like phrase "not to mention infections and respiratory viruses". Also, we can use a dash after "viruses" to connect back to the main clause, but more accurately, the first dash is after "habitat" and the second after "viruses" to properly set off the interjected phrase. So the corrected sentence is: "Poaching and loss of habitat — not to mention infections and respiratory viruses — are pushing African apes dangerously close to the brink of extinction."

Answer:

Poaching and loss of habitat — not to mention infections and respiratory viruses — are pushing African apes dangerously close to the brink of extinction.